JP2014128047A - Storage battery converter, power supply system, and method for controlling power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable stable power supply with high conversion efficiency in a configuration for supplying DC power via a line.SOLUTION: A storage battery converter 101 comprises: a voltage conversion unit 13 capable of performing a discharge operation to convert a DC voltage from a storage battery 106 and supply the converted power to a line 151, and a charge operation to convert a DC voltage from the line 151 and supply the converted power to the storage battery 106; and a control unit 12 for controlling the charge operation and the discharge operation of the voltage conversion unit 13. The control unit 12 causes a charge operation to start when the voltage of the line 151 rises to become equal to or higher than a charge start threshold, causes the charge operation to stop when the voltage of the line 151 declines to become equal to or lower than the charge stop threshold, causes a discharge operation to start when the voltage of the line 151 declines to become equal to or lower than a discharge start threshold, and causes the discharge operation to stop when the voltage of the line 151 rises to become equal to or higher than the discharge stop threshold. The charge stop threshold and the discharge stop threshold are values between the charge start threshold and the discharge start threshold.

Description

  TECHNICAL FIELD The present invention relates to a storage battery conversion device, a power supply system, and a power supply control method, and in particular, a storage battery conversion device that controls DC power supply via a line by controlling charge / discharge of the storage battery, a power supply system, and power. The present invention relates to a supply control method.

  In general homes and offices, power supplied to various electrical devices is usually AC power from the power system.

  On the other hand, for example, for the utilization of natural energy and coping with power system power outages, power generators such as solar cells and storage batteries are installed, and the DC power from these power generators and storage batteries is converted into AC power. A DC power distribution system that has been converted into a power supply and supplied to various electrical devices has been developed.

  For example, JP 2012-161189 A (Patent Document 1) discloses the following technique. That is, in a power system including a solar cell and a power conditioner that converts the DC power of the solar cell into AC power and outputs it to a load, charge / discharge control of the power of the solar cell is performed on the storage battery. More specifically, a bidirectional DC / DC converter is interposed between the DC bus line in the power conditioner and the storage battery, the line voltage in the DC bus line is monitored, and the line voltage is within a certain range. Thus, the bidirectional DC / DC converter is PWM-controlled to control charging of the storage battery and discharging of the charging voltage of the storage battery to the DC bus line.

JP2012-161189A

  However, in the technique described in Patent Document 1, since the DC / DC converter finely changes the current value in order to maintain the line voltage in the DC bus line at a constant value, current oscillation occurs. When this current oscillation occurs, there is a problem that the current flowing through the DC bus line exceeds the upper limit, the device stops operating for protection, and the power supply stops.

  Further, since the state where the output current of the DC / DC converter is small is continued, the circuit is operated in a state where the on-resistance of the semiconductor switch element in the DC / DC converter is large, and the conversion efficiency is lowered.

  This invention was made in order to solve the above-mentioned subject, and the object is in the composition which supplies direct-current power via a track, and conversion for storage batteries which can perform stable and high conversion efficiency power supply An apparatus, a power supply system, and a power supply control method are provided.

  (1) A storage battery conversion device according to an aspect of the present invention includes a discharging operation for converting a DC voltage from a storage battery and supplying the converted voltage to the line, and a charging operation for converting the DC voltage from the line and supplying the same to the storage battery. And a control unit for controlling the charging operation and the discharging operation of the voltage conversion unit, and the control unit increases the voltage of the line to a charge start threshold value or more. Then, the charging operation is started, the charging operation is stopped when the voltage of the line drops below the charging stop threshold, and the discharging operation is started when the voltage of the line drops below the discharging start threshold, When the voltage of the line rises and exceeds a discharge stop threshold, the discharge operation is stopped, and the charge stop threshold and the discharge stop threshold are values between the charge start threshold and the discharge start threshold. There, the control unit, the current flowing from the voltage converter to the battery is controlled to a constant value in the charging operation, and is controlled to a constant value the current flowing from the battery to the voltage converter in the discharge operation.

  With such a configuration, it is possible to provide a period during which the charging operation and discharging operation of the storage battery are stopped. Therefore, it is possible to suppress oscillation of the line current and stabilize the voltage level of the line. Moreover, even if the voltage of the storage battery changes depending on the remaining amount of stored electricity, the charge / discharge current of the storage battery can be controlled to a constant value, so that stable operation can be realized. Further, by setting the values of the discharge current and the charging current to a certain extent, for example, the circuit can be operated in a state in which the on-resistance of the semiconductor switching element in the storage battery conversion device is small, thereby increasing the efficiency of the storage battery conversion device. be able to. Therefore, in a configuration in which DC power is supplied via a line, stable and high conversion efficiency power supply can be performed.

  (2) Preferably, the said storage battery converter is further provided with the measurement part which measures the voltage of the said storage battery when the said charge operation and the said discharge operation have stopped.

  As described above, the configuration in which the charging operation and the discharging operation are stopped by setting each threshold voltage is ensured, and the voltage of the storage battery is measured in the stopping period, so that the electromotive force of the storage battery can be accurately and easily measured. it can. For example, it is possible to accurately grasp the remaining amount of the storage battery by measuring the electromotive force of the storage battery.

  (3) More preferably, the said control part calculates the electrical storage residual amount of the said storage battery based on the said voltage measured by the said measurement part.

  With such a configuration, it is possible to determine the accurate remaining power of the current storage battery from the electromotive force of the storage battery measured during the stop period. For example, an error in current value integration for calculating the charge rate of the storage battery is corrected. can do.

  (4) More preferably, the control unit does not start the charging operation or the discharging operation regardless of the voltage of the line when the calculated remaining power storage amount satisfies a predetermined condition.

  With such a configuration, it is possible to perform a charging operation and a discharging operation in consideration of the remaining storage amount of the storage battery calculated using the measurement result in the stop period. Therefore, in the configuration for supplying DC power via the line, Overcharge and overdischarge can be prevented.

  (5) Preferably, the control unit controls a current flowing from the voltage conversion unit to the storage battery in the charging operation to a predetermined value, and a current flowing from the storage battery to the voltage conversion unit in the discharging operation is a predetermined value. To control.

  In this way, with the configuration in which the storage battery is discharged and charged with a constant current, current value integration can be accurately performed from the discharge time or charge time and the constant current value. In addition, by setting the constant current value to be large to some extent, for example, when the storage battery conversion device includes a transistor and an IGBT (Insulated Gate Bipolar Transistor) is used as the transistor, the circuit can be operated with a low on-resistance of the IGBT. Since it can be operated, the efficiency of the storage battery conversion device can be increased. Moreover, since the ratio of the stop time to the discharge time or the charge time is increased by setting the constant current value to a certain extent, the iron loss of the reactor and / or the transformer included in the storage battery converter is reduced, and the efficiency Can be increased.

  (6) More preferably, the storage battery conversion device further includes a measurement unit that measures a current flowing between the storage battery and the voltage conversion unit, the voltage conversion unit includes a switch element, and the control unit includes: In the charging operation, the switch element is controlled so that the current measured by the measuring unit becomes a predetermined value, and in the discharging operation, the current measured by the measuring unit becomes a predetermined value. The switch element is controlled.

  With such a configuration, it is possible to perform constant-current discharging and constant-current charging of the storage battery by a simple and appropriate method for controlling switching of the switch element in the voltage conversion unit.

  (7) Preferably, the charge stop threshold and the discharge stop threshold are median values of the charge start threshold and the discharge start threshold.

  With such a configuration, it is possible to suppress the occurrence of a difference in the length of the stop time of the discharge operation and the charge operation when the voltage rises and drops on the line. The remaining amount can be calculated stably. Further, since the threshold value for stopping charging and the threshold value for stopping discharging can be made common, it is possible to simplify the control of the charging operation and the discharging operation based on the voltage of the line.

  (8) A power supply system according to an aspect of the present invention includes a converter for a power generator that converts a DC voltage from a power generator and supplies the converted voltage to a line, and a DC voltage from a storage battery that is supplied to the line. A storage battery conversion device capable of performing a discharging operation and a charging operation for converting a DC voltage from the line and supplying the storage battery to the storage battery, wherein the storage battery conversion device includes the line When the voltage rises above the charging start threshold, the charging operation is started, and when the line voltage falls below the charging stop threshold, the charging operation is stopped, and the line voltage drops to start discharging. The discharge operation is started when the threshold value is lower than the threshold value, and the discharge operation is stopped when the voltage of the line rises and becomes equal to or higher than the discharge stop threshold value. Is a value between the charge start threshold and the discharge start threshold.

  With such a configuration, it is possible to provide a period during which the charging operation and discharging operation of the storage battery are stopped. Therefore, it is possible to suppress oscillation of the line current and stabilize the voltage level of the line. Further, by setting the values of the discharge current and the charging current to a certain extent, for example, the circuit can be operated in a state in which the on-resistance of the semiconductor switching element in the storage battery conversion device is small, thereby increasing the efficiency of the storage battery conversion device. be able to. Therefore, in a configuration in which DC power is supplied via a line, stable and high conversion efficiency power supply can be performed.

  (9) Preferably, when the voltage of the power line rises and becomes equal to or higher than a first limit threshold value that is larger than the charging start threshold value, the power generator conversion device does not exceed the predetermined upper limit value. The output suppression control is performed.

  With such a configuration, in a configuration in which DC power is supplied via a line, it is possible to prevent the voltage on the line from becoming excessive and to supply more stable power.

  (10) Preferably, the power supply system further includes an AC power supply conversion device that converts an AC voltage from an AC power supply into a DC voltage and supplies the converted voltage to the line, and the AC power supply conversion device includes the line. When the voltage increases to a second limit threshold value greater than the charge start threshold value, output suppression control is performed so that the line voltage does not exceed a predetermined upper limit value.

  With such a configuration, in a configuration in which DC power is supplied via a line, it is possible to prevent the voltage on the line from becoming excessive and to supply more stable power.

  (11) Preferably, the power supply system further includes a load conversion device that converts a DC voltage from the line and supplies the converted voltage to a load, the load conversion device including a voltage conversion unit, and the storage battery. The output voltage of the voltage converter is controlled in a cycle shorter than the cycle of starting and stopping the charging operation or the discharging operation of the converter.

  With such a configuration, even if the DC voltage of the line fluctuates, a constant DC voltage or AC voltage can be supplied to the load.

  (12) A power supply control method according to an aspect of the present invention includes a discharge operation for converting a DC voltage from a storage battery and supplying the same to a line, and a charging operation for converting the DC voltage from the line and supplying the same to the storage battery. Power storage control method for a storage battery conversion device capable of performing the above-described step, wherein the charging operation is started when the voltage of the line rises above a charging start threshold, and the voltage of the line decreases. A step of stopping the charging operation when the charge stop threshold is not exceeded, a step of starting the discharge operation when the voltage of the line is lowered to be not more than a discharge start threshold, and the voltage of the line is increased to be not less than the discharge stop threshold. The charge stop threshold and the discharge stop threshold are the difference between the charge start threshold and the discharge start threshold. We are of value.

  With such a configuration, a period during which the charging operation and discharging operation of the storage battery are stopped can be provided, so that the line current can be suppressed from changing in a short time and the line voltage level can be stabilized. Therefore, in a configuration in which DC power is supplied via a line, stable and high conversion efficiency power supply can be performed.

  ADVANTAGE OF THE INVENTION According to this invention, in the structure which supplies direct-current power via a track | line, the stable and high conversion efficiency electric power supply can be performed.

It is a figure which shows the structure of the electric power supply system which concerns on embodiment of this invention. It is a figure which shows the structure of the conversion apparatus for storage batteries which concerns on embodiment of this invention. It is a figure which shows an example of the correspondence of the charging rate and battery voltage of the storage battery which concern on embodiment of this invention. It is a figure which shows the structure of the converter for power generators which concerns on embodiment of this invention. It is a figure which shows an example of charging / discharging operation | movement of the converter for storage batteries which concerns on embodiment of this invention. It is a figure which shows an example of the threshold voltage for charging / discharging operation | movement in the converter for storage batteries which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the electric power supply operation | movement by the storage battery converter which concerns on embodiment of this invention. It is a figure which shows an example of the electric power supply operation | movement by the converter for storage batteries which concerns on embodiment of this invention. It is a figure which shows the simulation result at the time of the power shortage of the power supply system which concerns on embodiment of this invention. It is a figure which shows the simulation result at the time of the power shortage of the power supply system which concerns on embodiment of this invention. It is a figure which shows the simulation result in the time of the electric power surplus of the electric power supply system which concerns on embodiment of this invention. It is a figure which shows the simulation result in the time of the electric power surplus of the electric power supply system which concerns on embodiment of this invention. It is a figure which shows the simulation result at the time of the electric power balance of the electric power supply system which concerns on embodiment of this invention. It is a figure which shows the other simulation result of the electric power supply system which concerns on embodiment of this invention. It is a figure which shows an example of the relationship between the control period of the load converter in the electric power supply system which concerns on embodiment of this invention, and the on / off period of the storage battery converter.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Configuration and basic operation]
FIG. 1 is a diagram showing a configuration of a power supply system according to an embodiment of the present invention.

  Referring to FIG. 1, a power supply system 201 includes a storage battery conversion device 101, a power generation device 102, a power generation device conversion device 103, an AC power supply 104, an AC power supply conversion device 105, a storage battery 106, A load conversion device 107.

  The power supply system 201 is a distributed power supply system such as a solar power supply system, for example, and supplies power to the load device 108 via the line 151. The power supply system 201 may perform system linkage, that is, the power supply destination from the line 151 may be on the AC power supply 104 side.

  In the power supply system 201, for example, DC power generated by the power generation device 102 is boosted by the power generation device conversion device 103 and charged in the storage battery 106, or converted into AC power by the load conversion device 107. It is supplied to the load device 108. Charge / discharge of the storage battery 106 is controlled by the storage battery conversion device 101.

  More specifically, the storage battery conversion device 101, the power generation device conversion device 103, the AC power supply conversion device 105, and the load conversion device 107 are electrically connected to the line 151.

  The power generation device 102 is a power generation device using natural energy, such as a solar power generator or a wind power generator, and outputs the generated DC power to the power generation device conversion device 103. The output power of the power generator 102 is, for example, 2.4 kW.

  The power generator conversion device 103 is, for example, a DC / DC converter, and converts the DC power received from the power generator 102 into DC power having a different voltage value and outputs the DC power to the line 151. The power generator conversion device 103 maximizes the output power of the power generator 102 by performing MPPT (maximum power point tracking) control, for example.

  The storage battery 106 is, for example, a lead battery, a Li ion battery, a redox flow battery, a NAS battery, a NI-Cd battery, a Ni-MH battery, an electric double layer capacitor, or a Li ion capacitor. More specifically, the storage battery 106 is, for example, a 4-series lead storage battery having an electromotive force of 12 V, a capacity of 105 Ah, and an output power of 5 kWh. Alternatively, the storage battery 106 is, for example, a two-series Li ion battery having an electromotive force of 30 V, a capacity of 40 Ah, and an output power of 2.4 kWh. In the simulation described later, the above lead storage battery is used as the storage battery 106.

  The storage battery conversion device 101 is, for example, a bidirectional DC / DC converter. In the discharging operation, the DC power from the storage battery 106 is converted into DC power having a different voltage value and output to the line 151. In the charging operation, the line 151 Is converted into DC power having a different voltage value and output to the storage battery 106.

  AC power converter 105 is, for example, an AC / DC converter including a power factor correction circuit, and converts 100 V AC power received from AC power supply 104 in a commercial power system or the like into DC power and outputs the DC power to line 151. For example, AC power conversion device 105 performs constant current control for controlling the current supplied to line 151 to a constant value.

  Load converter 107 is, for example, a DC / AC converter, and converts DC power from line 151 into AC power of, for example, 100 V and outputs it to load device 108. Load device 108 is, for example, a home appliance. The load conversion device 107 can be a DC / DC converter according to the type of the load device.

  The combined capacity of the line 151 by the storage battery conversion device 101, the power generation device conversion device 103, the AC power supply conversion device 105, and the load conversion device 107 is 9 mF. The combined capacity and the power consumption of the load device 108 determine the slopes of the voltage rise and voltage drop of the line 151 when the storage battery 106 is charged and discharged.

  FIG. 2 is a diagram showing a configuration of the storage battery conversion device according to the embodiment of the present invention.

  Referring to FIG. 2, the storage battery conversion device 101 includes a measurement unit 11, a control unit 12, a voltage conversion unit 13, voltage measurement devices 36 and 37, and a current measurement device 38. The control unit 12 includes a PI calculation unit 20, a charge / discharge determination unit 21, and a battery remaining amount calculation unit 22. The voltage conversion unit 13 includes a PWM (Pulse Width Modulation) circuit 23 and a step-up / down chopper circuit 24. The step-up / step-down chopper circuit 24 includes capacitors 31 and 35, a coil 32, and transistors 33 and 34. Note that the step-up / step-down chopper circuit 24 may be configured to include other types of switch elements instead of transistors.

  The voltage conversion unit 13 can perform a discharging operation that converts the DC voltage from the storage battery 106 and supplies the converted voltage to the line 151, and a charging operation that converts the DC voltage from the line 151 and supplies the same to the storage battery 106. The control unit 12 controls the charging operation and the discharging operation of the voltage conversion unit 13.

  More specifically, the voltage measuring device 37 measures the voltage Vdc of the line 151 and outputs the measured value to the measuring unit 11. The voltage measuring device 36 measures a battery voltage Vb, for example, a voltage between terminals of the storage battery 106, and outputs a measured value to the measuring unit 11. The current measuring device 38 measures a current flowing between the storage battery 106 and the voltage conversion unit 13, specifically, a battery current Ibdc input or output to the storage battery 106, and outputs a measured value to the measurement unit 11.

  Measurement unit 11 outputs measured values of voltage Vdc, battery voltage Vb, and battery current Ibdc to PI operation unit 20, and outputs measured values of voltage Vdc to charge / discharge determination unit 21. Measurement unit 11 measures the charging time and discharging time of storage battery 106, and outputs the charging time and discharging time, and measured values of battery voltage Vb and battery current Ibdc to battery remaining amount calculating unit 22.

  Based on voltage Vdc received from measurement unit 11, charge / discharge determination unit 21 determines whether charging and discharging operations of storage battery 106 are started and stopped, and outputs the determination result to PI calculation unit 20.

  The battery remaining amount calculation unit 22 calculates the remaining amount of charge of the storage battery 106, for example, the charging rate, based on the measured values of the charging time and discharging time of the storage battery 106 received from the measuring unit 11 and the battery voltage Vb and the battery current Ibdc. Then, the battery remaining amount calculation unit 22 determines whether to start and stop the charging operation and discharging operation of the storage battery 106 based on the calculated charging rate, and outputs the determination result to the PI calculation unit 20.

  FIG. 3 is a diagram showing an example of a correspondence relationship between the charging rate of the storage battery and the battery voltage according to the embodiment of the present invention.

  Referring to FIG. 3, storage battery 106 is, for example, a liquid lead storage battery for general starting use or cycling, and the battery voltage when the charging rate is 100%, that is, the electromotive force is 12.72 V, and the charging rate is lowered. As the electromotive force becomes smaller, the electromotive force when the charging rate is 25% becomes 11.82V.

  For example, the storage battery conversion device 101 stores information indicating the correspondence relationship of FIG. Based on the measured values of the charging time and discharging time of the storage battery 106 and the battery voltage Vb and the battery current Ibdc received from the measurement unit 11, the battery remaining amount calculation unit 22 generates the electromotive force of the storage battery 106, ie, the terminal voltage of the storage battery 106. To calculate a voltage value excluding the voltage component due to the current flowing through the internal resistance of the storage battery 106. And the battery remaining charge calculation part 22 calculates | requires the charging rate of the storage battery 106 from the electromotive force of the storage battery 106 with reference to the correspondence shown in FIG.

  Referring again to FIG. 2, PI calculation unit 20 determines the determination result received from charge / discharge determination unit 21, the determination result received from battery remaining amount calculation unit 22, and voltage Vdc and battery voltage Vb received from measurement unit 11. The PI (proportional integration) operation is performed based on the measured value of the battery current Ibdc, and the switching duty ratios of the transistors 33 and 34 in the buck-boost chopper circuit 24 are obtained.

  The PWM circuit 23 generates PWM control signals for the transistors 33 and 34 in the step-up / step-down chopper circuit 24 according to the duty ratio received from the PI calculation unit 20, and outputs them to the transistors 33 and 34.

  Transistors 33 and 34 are, for example, IGBTs (Insulated Gate Bipolar Transistors) having a backflow prevention diode, and switch based on a PWM control signal received from PWM circuit 23. Thereby, for example, in the discharging operation of the storage battery 106, the battery voltage Vb of the storage battery 106 is boosted and supplied to the line 151, and in the charging operation of the storage battery 106, the voltage Vdc of the line 151 is stepped down and supplied to the storage battery 106. .

  For example, the voltage conversion unit 13 performs constant current charging as the charging operation of the storage battery 106 and performs constant current discharging as the discharging operation of the storage battery 106. That is, the control unit 12 controls the current flowing from the voltage conversion unit 13 to the storage battery 106 in the charging operation to a constant value, and controls the current flowing from the storage battery 106 to the voltage conversion unit 13 in the discharging operation to a constant value. This constant value is, for example, a value preset by the user, that is, a predetermined value.

  More specifically, the control unit 12 controls the transistors 33 and 34 so that the current Ibdc measured by the measurement unit 11 becomes a predetermined value in the charging operation of the storage battery 106, and the measurement is performed in the discharging operation of the storage battery 106. The transistors 33 and 34 are controlled so that the current Ibdc measured by the unit 11 becomes a predetermined value.

  For example, in the charging operation of the storage battery 106, the control unit 12 always turns off the transistor 33 and switches the transistor 34 between the on state and the off state so that the input current Ibdc of the storage battery 106 becomes a predetermined value. In addition, in the discharging operation of the storage battery 106, the control unit 12 always turns off the transistor 34 and switches the transistor 33 between the on state and the off state so that the output current Ibdc of the storage battery 106 becomes a predetermined value.

  FIG. 4 is a diagram showing a configuration of the power generator conversion device according to the embodiment of the present invention.

  Referring to FIG. 4, power generation device conversion device 103 includes measurement unit 41, PI calculation unit 42, voltage conversion unit 43, voltage measurement devices 66 and 67, and current measurement device 68. Voltage conversion unit 43 includes a PWM circuit 51 and a boost chopper circuit 52. Boost chopper circuit 52 includes capacitors 61 and 65, coil 62, transistor 63, and diode 64.

  More specifically, the voltage measuring device 67 measures the voltage Vdc of the line 151 and outputs the measured value to the measuring unit 41. The voltage measuring device 66 measures a power generation voltage Vg that is, for example, a voltage between terminals of the power generation apparatus 102, and outputs a measured value to the measurement unit 41. The current measuring device 68 measures the generated current Ig output from the power generation apparatus 102 and outputs the measured value to the measuring unit 41.

  Measuring unit 41 outputs measured values of voltage Vdc, generated voltage Vg, and generated current Ig to PI calculating unit 42.

  PI calculation unit 42 performs a PI (proportional integration) calculation based on the measured values of voltage Vdc, generated voltage Vg, and generated current Ig received from measurement unit 41, and sets the switching duty ratio of transistor 63 in boost chopper circuit 52. Ask.

  PWM circuit 51 generates a PWM control signal in accordance with the duty ratio received from PI calculation unit 42 and outputs the PWM control signal to transistor 63 in boost chopper circuit 52.

  Transistor 63 is, for example, an IGBT, and switches based on the PWM control signal received from PWM circuit 51. Thereby, for example, the power generation voltage Vg of the power generation apparatus 102 is boosted and supplied to the line 151.

  FIG. 5 is a diagram illustrating an example of a charge / discharge operation of the storage battery conversion device according to the embodiment of the present invention.

  With reference to FIG. 5, here, a case where the lower limit value of the voltage Vdc of the line 151 is set to 160V and the upper limit value is set to 190V will be described. Further, it is assumed that the power consumption of the load device 108 is constant.

  When the power generation amount of the power generation device 102 increases and the voltage Vdc of the line 151 increases to reach 190 V, the storage battery conversion device 101 starts charging the storage battery 106 (timing t1). As a result, surplus power generated by the power generation apparatus 102 is supplied to the storage battery 106, and the voltage Vdc of the line 151 decreases. At this time, the current in the storage battery 106 is −30 A, that is, a charging current of 30 A flows from the line 151 to the storage battery 106.

  Thereafter, for example, when the charge amount of the storage battery 106 is large, when the voltage Vdc of the line 151 decreases and reaches 175 V, the storage battery conversion device 101 stops charging the storage battery 106 (timing t2). The integral value of the charging current is calculated by the product of 30A and the time from timing t1 to timing t2.

  After that, when the voltage Vdc of the line 151 increases again to reach 190 V, the storage battery conversion device 101 starts charging the storage battery 106 again (timing t3).

  Further, the storage battery conversion device 101 starts discharging the storage battery 106 when the power generation amount of the power generation device 102 decreases and the voltage Vdc of the line 151 decreases to 160 V (timing t11). Thereby, the shortage of the generated power of the power generation apparatus 102 is supplied to the line 151, and the voltage Vdc of the line 151 increases. At this time, the current in the storage battery 106 is 30 A, that is, a discharge current of 30 A flows from the storage battery 106 to the line 151.

  Thereafter, for example, when the discharge amount of the storage battery 106 is large, when the voltage Vdc of the line 151 increases and reaches 175 V, the storage battery conversion device 101 stops discharging the storage battery 106 (timing t12). The integrated value of the discharge current is calculated by the product of 30A and the time from timing t11 to timing t12.

  Thereafter, when the voltage Vdc of the line 151 decreases again and reaches 160 V, the storage battery conversion device 101 starts discharging the storage battery 106 again (timing t13).

  Moreover, when the voltage of the line 151 rises to 195 V or more, which is greater than 190V, the power generator conversion device 103 performs output suppression control so that the voltage of the line 151 does not exceed a predetermined upper limit value, for example, 195V. More specifically, when the power generation amount of the power generation device 102 increases, the voltage Vdc of the line 151 increases to reach 190 V, and charging of the storage battery 106 is started (timing t21), the power generation amount of the power generation device 102 is very high. Is larger, the voltage Vdc of the line 151 further rises to reach 195V. Then, the power generator conversion device 103 stops the MPPT control of the power generator 102 and performs control so that the voltage Vdc of the line 151 does not exceed 195 V. Specifically, the current received from the power generator 102 is limited ( Timing t22). Then, when the power generation amount of the power generation device 102 decreases and the output voltage decreases from 195 V, the power generation device conversion device 103 resumes MPPT control.

  Further, AC power conversion device 105 performs output suppression control so that voltage of line 151 does not exceed a predetermined upper limit value, for example, 193 V, when the voltage of line 151 rises to 193 V or more, which is greater than 190V. More specifically, when the power generation amount of the power generation device 102 increases, the voltage Vdc of the line 151 increases to reach 190 V, and charging of the storage battery 106 is started (timing t31), the power generation amount of the power generation device 102 is very high. Is larger, the voltage Vdc of the line 151 further rises to reach 193V. Then, AC power conversion device 105 stops constant current control, and controls voltage Vdc of line 151 not to exceed 193 V. Specifically, current received from AC power supply 104 is limited (timing t32). . Then, AC power conversion device 105 resumes constant current control when the power generation amount of power generation device 102 decreases and the output voltage decreases from 193V.

  In this way, by making the limit threshold that is the voltage at which the AC power converter 105 starts the output suppression control smaller than the limit threshold that is the voltage at which the power converter 103 starts the output suppression control, The use of natural energy using the device 102 can be prioritized.

  In addition, the storage battery conversion device 101, the power generation device conversion device 103, the AC power supply conversion device 105, and the load conversion device 107 increase the voltage of the line 151 abnormally when the voltage of the line 151 increases to 200V. Stops operation.

  In the operation as described above, the charging current and discharging current of the storage battery 106 are constant at 30A.

  In the power supply system 201, the charging current and the discharging current can be set to a constant large current, and when the IGBT is used as the transistor in the storage battery conversion device 101, the circuit is operated with a low on-resistance of the IGBT. Therefore, the efficiency of the storage battery conversion device 101 can be increased.

  The voltage Vdc of the line 151 is not limited to a positive voltage and may be a negative voltage. In the case of a negative voltage, the “rising” of the voltage means, for example, that the magnitude of the voltage changes in the direction from −180 V to −190 V, and the “decreasing” of the voltage, for example, in the direction from −190 V to −180 V. This means that the magnitude of the voltage changes.

  FIG. 6 is a diagram illustrating an example of a threshold voltage for charge / discharge operation in the storage battery converter according to the embodiment of the present invention.

  Referring to FIG. 6, charge start voltage Vdchi is 190V, charge / discharge stop voltage Vdc0 is 175V, and discharge start voltage Vdclo is 160V.

  Note that the charge stop voltage and the discharge stop voltage may be different voltages. That is, the charge stop voltage and the discharge stop voltage may be a voltage between the charge start voltage Vdchi and the discharge start voltage Vdclo.

  In the example illustrated in FIG. 6, the charge stop voltage and the discharge stop voltage are median values of the charge start voltage Vdchi and the discharge start voltage Vdclo.

  The control unit 12 in the storage battery conversion device 101 starts the charging operation when the voltage Vdc of the line 151 rises and becomes equal to or higher than the charge start threshold, that is, equal to or higher than the charge start voltage Vdchi, and the voltage Vdc of the line 151 decreases and the charge stop threshold. Thereafter, when the charge / discharge stop voltage Vdc0 or less is reached, the charging operation is stopped.

  In addition, the control unit 12 starts the discharge operation when the voltage Vdc of the line 151 decreases and becomes equal to or lower than the discharge start threshold, that is, equal to or lower than the discharge start voltage Vdclo, and the voltage Vdc of the line 151 increases and exceeds the discharge stop threshold. When the stop voltage becomes equal to or higher than Vdc0, the discharge operation is stopped.

  FIG. 7 is a flowchart showing a procedure of power supply operation by the storage battery converter according to the embodiment of the present invention. In the stop mode shown in FIG. 7, the storage battery conversion device 101 stops the charging and discharging operations of the storage battery 106. In the charging mode, the storage battery conversion device 101 performs the charging operation of the storage battery 106. Conversion device 101 performs a discharging operation of storage battery 106.

  For example, in the storage battery conversion device 101, the measurement unit 11 measures the voltage Vb of the storage battery 106 in the stop mode, that is, when the charging operation and the discharging operation are stopped.

  Further, for example, the control unit 12 calculates the remaining amount of power stored in the storage battery 106 based on the voltage Vb of the storage battery 106 measured by the measurement unit 11 in the stop mode. And the control part 12 does not start charge operation or discharge operation, regardless of the voltage Vdc of the line 151, when the calculated remaining power storage amount satisfies a predetermined condition.

  Specifically, referring to FIG. 7, in the stop mode (step S1), control unit 12 determines voltage Vdc of line 151 (step S2), and when voltage Vdc is greater than charging start voltage Vdchi. Therefore (YES in step S2), when the remaining amount of the storage battery 106, for example, the charging rate is equal to or less than a predetermined value (YES in step S3), a transition is made to the charging mode (step S4).

  Next, in the charging mode (step S4), the control unit 12 determines the voltage Vdc of the line 151 (step S5), and continues the charging mode until the voltage Vdc reaches the charge / discharge stop voltage Vdc0 (in step S5). NO), when voltage Vdc reaches charge / discharge stop voltage Vdc0 (YES in step S5), transition to stop mode is made (step S1).

  In the stop mode (step S1), the control unit 12 determines the voltage Vdc of the line 151 (step S2), and the voltage Vdc is equal to or lower than the charge start voltage Vdchi and lower than the discharge start voltage Vdclo ( If NO in step S2 and YES in step S6), when the remaining amount of storage battery 106, for example, the charging rate is equal to or greater than a predetermined value (YES in step S7), the mode changes to the discharge mode (step S8).

  Next, in the discharge mode (step S8), the control unit 12 determines the voltage Vdc of the line 151 (step S9), and continues the discharge mode until the voltage Vdc reaches the charge / discharge stop voltage Vdc0 (in step S9). NO), when voltage Vdc reaches charge / discharge stop voltage Vdc0 (YES in step S9), transition to stop mode is made (step S1).

  On the other hand, even when voltage Vdc is higher than charging start voltage Vdchi (YES in step S2), control unit 12 charges when the remaining amount of storage battery 106, for example, the charging rate is higher than a predetermined value (NO in step S3). The stop mode is continued without changing to the mode (step S1).

  Further, even when the voltage Vdc is less than the discharge start voltage Vdclo (YES in step S6), the control unit 12 determines that the remaining amount of the storage battery 106, for example, the charging rate is less than a predetermined value (NO in step S7). The stop mode is continued without transitioning to the discharge mode (step S1).

  FIG. 8 is a diagram illustrating an example of a power supply operation performed by the storage battery conversion device according to the embodiment of the present invention.

  Referring to FIG. 8, control unit 12 selects the stop mode when voltage Vdc of line 151 is at charge / discharge stop voltage Vdc0, for example, 175V.

  At this time, since the power generation amount of the power generation apparatus 102 is larger than the power consumption amount of the load apparatus 108, the voltage Vdc increases.

  When the voltage Vdc increases from the state where the voltage Vdc is lower than the charging start voltage Vdchi to the state where the voltage Vdc is higher than the charging start voltage Vdchi due to the increase in the voltage Vdc, the control unit 12 transitions to the charging mode.

  After the transition to the charging mode, when the power generation amount of the power generation device 102 is smaller than the sum of the power consumption amount of the load device 108 and the charge amount of the storage battery 106, the voltage Vdc decreases.

  When the voltage Vdc falls from the state where the voltage Vdc is higher than the charge / discharge stop voltage Vdc0 to the state where the voltage Vdc is lower than the charge / discharge stop voltage Vdc0 due to the drop in the voltage Vdc, the control unit 12 transitions to the stop mode.

  After the transition to the stop mode, when the power generation amount of the power generation device 102 is larger than the power consumption amount of the load device 108, the voltage Vdc rises again.

  When the voltage Vdc increases from the state where the voltage Vdc is lower than the charging start voltage Vdchi to the state where the voltage Vdc is higher than the charging start voltage Vdchi due to the increase in the voltage Vdc, the control unit 12 transitions again to the charging mode.

  Further, after the transition to the stop mode due to the decrease in the voltage Vdc, when the power generation amount of the power generation device 102 is smaller than the power consumption amount of the load device 108, the voltage Vdc decreases.

  When the voltage Vdc drops from the state in which the voltage Vdc is higher than the discharge start voltage Vdclo to the state in which the voltage Vdc is lower than the discharge start voltage Vdclo due to the drop in the voltage Vdc, the control unit 12 transitions to the discharge mode.

  After the transition to the discharge mode, when the sum of the power generation amount of the power generation device 102 and the discharge amount of the storage battery 106 is larger than the power consumption amount of the load device 108, the voltage Vdc rises again.

  When the voltage Vdc increases from the state where the voltage Vdc is lower than the charge / discharge stop voltage Vdc0 to the state where the voltage Vdc is higher than the charge / discharge stop voltage Vdc0 due to the increase in the voltage Vdc, the control unit 12 transitions to the stop mode.

  After the transition to the stop mode, when the power generation amount of the power generation device 102 is smaller than the power consumption amount of the load device 108, the voltage Vdc drops again.

  Then, when the voltage Vdc drops from the state in which the voltage Vdc is higher than the discharge start voltage Vdclo to the state in which the voltage Vdc is lower than the discharge start voltage Vdclo due to the drop in the voltage Vdc, the control unit 12 transitions again to the discharge mode.

  FIG. 9 is a diagram showing a simulation result when the power supply system according to the embodiment of the present invention has insufficient power.

  In FIG. 9, CH1 is a battery current, that is, a current flowing through the storage battery 106, CH2 is a terminal voltage Vb of the storage battery 106, CH3 is a DC bus voltage, that is, a voltage Vdc of the line 151, and CH4 is an inverter voltage, that is, a load conversion. This is the output voltage of the device 107. In this simulation, the charging current of the storage battery 106 was set to 20A, and the discharging current was set to 37.5A.

  The scale of CH1 is 20 A / div, the scale of CH2 is 2 V / div, the scale of CH3 is 10 V / div, and the scale of CH4 is 200 V / div. The scale of the horizontal axis indicating time is 20 ms / div.

  FIG. 9 shows a case where the output power of the power generation apparatus 102 is zero and the power consumption of the load apparatus 108 that is, for example, an AC electronic load is 500 W, that is, the amount of power generation is insufficient by 500 W.

  Referring to FIG. 9, when DC bus voltage CH3 decreases and reaches 160V, discharging operation of storage battery 106 is started, and discharge current CH1 of storage battery 106 increases, thereby increasing DC bus voltage CH3. At this time, the terminal voltage CH2 of the storage battery 106 slightly decreases.

  When the DC bus voltage CH3 rises and reaches 175 V, the discharge operation of the storage battery 106 is stopped, the discharge current CH1 of the storage battery 106 becomes zero, and the DC bus voltage CH3 falls again.

  That is, it can be seen that the DC bus voltage CH3 is stable within a predetermined range, the inverter voltage CH4 is stable, and power is stably supplied to the load device 108.

  FIG. 10 is a diagram showing a simulation result when the power supply system according to the embodiment of the present invention has insufficient power. The way of viewing the figure is the same as in FIG.

  FIG. 10 shows a case where the output power of the power generation apparatus 102 is 500 W, for example, when the power consumption of the load apparatus 108 that is an AC electronic load is 1000 W, that is, the amount of power generation is insufficient by 500 W.

  In this case, the operation is the same as in FIG. That is, it can be seen that the DC bus voltage CH3 is stable within a predetermined range, the inverter voltage CH4 is stable, and power is stably supplied to the load device 108.

  FIG. 11 is a diagram illustrating a simulation result when the power supply system according to the embodiment of the present invention has a surplus power. The way of viewing the figure is the same as in FIG.

  FIG. 11 shows a case where the output power of the power generation apparatus 102 is 500 W and the power consumption of the load apparatus 108 that is, for example, an AC electronic load is zero, that is, the amount of power generation exceeds 500 W.

  When the DC bus voltage CH3 rises and reaches 190V, the charging operation of the storage battery 106 is started, the charging current CH1 of the storage battery 106 rises, and thereby the DC bus voltage CH3 falls. At this time, the terminal voltage CH2 of the storage battery 106 slightly increases.

  When the DC bus voltage CH3 decreases and reaches 175 V, the charging operation of the storage battery 106 is stopped, the charging current CH1 of the storage battery 106 becomes zero, and the DC bus voltage CH3 increases again.

  That is, it can be seen that the DC bus voltage CH3 is stable within a predetermined range, the inverter voltage CH4 is stable, and power is stably supplied to the load device 108.

  FIG. 12 is a diagram showing a simulation result when the power supply system according to the embodiment of the present invention has a surplus power. The way of viewing the figure is the same as in FIG.

  FIG. 12 shows a case where the output power of the power generation apparatus 102 is 1000 W, for example, when the power consumption of the load apparatus 108 that is an AC electronic load is 500 W, that is, the amount of power generation surpasses 500 W.

  In this case, the operation is the same as in FIG. That is, it can be seen that the DC bus voltage CH3 is stable within a predetermined range, the inverter voltage CH4 is stable, and power is stably supplied to the load device 108.

  FIG. 13 is a diagram showing a simulation result at the time of power balance of the power supply system according to the embodiment of the present invention. Except for the fact that the scale of the horizontal axis indicating time is 1 s / div, the way of viewing the figure is the same as in FIG.

  In FIG. 13, the output power of the power generation apparatus 102 is 500 W, for example, the power consumption of the load apparatus 108 that is an AC electronic load is 450 W, and the power loss of the path from the power generation apparatus 102 to the load apparatus 108 is 50 W. That is, it shows a case where the power generation amount and the power consumption amount are balanced.

  Referring to FIG. 13, even in such a power balance, DC bus voltage CH3 is stable within a predetermined range, inverter voltage CH4 is stable, and power is stably supplied to load device 108. I understand.

  FIG. 14 is a diagram showing another simulation result of the power supply system according to the embodiment of the present invention.

  In FIG. 14, the graph G1 indicates the voltage Vdc of the line 151, the graph G2 indicates the input power of the power generator conversion device 103, the graph G3 indicates the output power of the load conversion device 107, and the graph G4 indicates the storage battery 106. The output power is shown. Each graph is a plot of average values for one second.

  Referring to FIG. 14, the weather is cloudy at 13:51, the output power of power generation device 102 is small, and the storage battery 106 is being discharged.

  Next, after 13:51, when the weather changes from cloudy to clear and the output power of the power generation apparatus 102 increases (graph G2), the discharge operation of the storage battery 106 stops and the output power of the storage battery 106 decreases. (Graph G4).

  Next, at 13:53 before, the charging operation of the storage battery 106 is started by the increase in the output power of the power generation apparatus 102 (graph G4).

  Next, when the weather becomes temporarily cloudy after 13:57, the output power of the power generation apparatus 102 is switched from the charging operation of the storage battery 106 to the discharging operation due to the decrease in the output power of the power generation apparatus 102, and the output power of the storage battery 106 is temporarily reduced. (Graph G4). The same operation is performed at 13:59, after 14:00, and before 14: 1. Specifically, between 13:57 and 14: 1, the output power of the power generator 102 fluctuates four times, and the first time the output power of the power generator 102 drops to 0 W in 10 seconds, The state in which the output power of the power generation apparatus 102 has increased to 1000 W in 10 seconds, the second time the output power of the power generation apparatus 102 has decreased to 0 W in 5 seconds, and has increased to 1000 W in 5 seconds. In the fourth state, the output power of the power generation apparatus 102 drops to 0 W in 1 second and rises to 1000 W in 1 second.

  Next, when the weather changes from clear to cloudy at 14:02 and the output power of the power generation device 102 decreases (graph G2), the charging operation of the storage battery 106 stops, and the output power of the storage battery 106 decreases. Then, the charging operation of the storage battery 106 is started (graph G4).

  It can be seen that the DC bus voltage, that is, the voltage Vdc of the line 151 is stable in the range of 160 V to 190 V against the above-described weather fluctuation (graph G1). Moreover, the input / output of the power of the line 151 by switching between the charging operation and the discharging operation of the storage battery 106 can be appropriately performed with respect to the fluctuation of the output power of the power generation apparatus 102 between 13:57 and 14: 1. (Graph G4).

  FIG. 15 is a diagram illustrating an example of the relationship between the control cycle of the load conversion device and the on / off cycle of the storage battery conversion device in the power supply system according to the embodiment of the present invention.

  Referring to FIG. 15, load conversion device 107 includes a voltage conversion unit for performing power conversion as described above. The load conversion device 107 is configured to start and stop the charging operation or discharging operation of the storage battery conversion device 101, specifically, the voltage conversion unit at a cycle shorter than the on / off cycle of the charging operation or discharging operation. The operation content of can be changed. For example, the load conversion device 107 controls the output voltage of the voltage conversion unit at a cycle shorter than the cycle of starting and stopping the charging operation or discharging operation of the storage battery conversion device 101.

  More specifically, when the power generation device 102 performs solar power generation of 1300 W, for example, the on / off cycle of the charging operation or discharging operation of the storage battery conversion device 101 is about 50 ms (milliseconds), that is, the frequency is 20 Hz.

  The cycle of the load conversion device 107, for example, the cycle of the PWM control signal needs to be sufficiently shorter than the on / off cycle of the charging operation or discharge operation of the storage battery conversion device 101, for example, 66.7 us (microseconds). ) That is, the frequency is 15 kHz.

  By the way, in the technique described in Patent Document 1, since the DC / DC converter changes the current value finely in order to maintain the line voltage in the DC bus line at a constant value, current oscillation occurs. When this current oscillation occurs, there is a problem that the current flowing through the DC bus line exceeds the upper limit, the device stops operating for protection, and the power supply stops. Further, since the state where the output current of the DC / DC converter is small is continued, the circuit is operated in a state where the on-resistance of the semiconductor switch element in the DC / DC converter is large, and the conversion efficiency is lowered.

  On the other hand, in the storage battery converter according to the embodiment of the present invention, the control unit 12 starts the charging operation when the voltage Vdc of the line 151 rises and becomes equal to or higher than the charging start threshold, and the voltage Vdc of the line 151 is started. When the value falls below the charging stop threshold, the charging operation is stopped. Further, the control unit 12 starts the discharge operation when the voltage Vdc of the line 151 decreases and becomes equal to or lower than the discharge start threshold value, and stops the discharge operation when the voltage Vdc of the line 151 increases and becomes equal to or higher than the discharge stop threshold value. The charge stop threshold and the discharge stop threshold are values between the charge start threshold and the discharge start threshold. Then, the control unit 12 controls the current flowing from the voltage conversion unit 13 to the storage battery 106 in the charging operation to a constant value, and controls the current flowing from the storage battery 106 to the voltage conversion unit 13 in the discharging operation to a constant value.

  That is, in the storage battery conversion device according to the embodiment of the present invention, the charging current and the discharging current are made constant, and the switching period and the switching stop period are repeated.

  With such a configuration, a period during which the charging operation and discharging operation of the storage battery 106 are stopped can be provided, so that the current in the line 151 can be suppressed from oscillating and the voltage level of the line 151 can be stabilized. Further, even if the voltage of the storage battery 106 changes depending on the remaining amount of stored electricity, the charging / discharging current of the storage battery 106 can be controlled to a constant value, so that stable operation can be realized. In addition, by setting the values of the discharge current and the charging current to a certain extent, for example, the circuit can be operated in a state where the on-resistance of the transistors 33 and 34 in the storage battery conversion device 101 is small. Efficiency can be increased.

  Therefore, in the storage battery conversion device according to the embodiment of the present invention, it is possible to perform stable and high conversion efficiency power supply in a configuration in which DC power is supplied via a line.

  In addition, as a method for calculating the charging rate of the battery, as described above, there is a method of calculating the charging rate based on the integrated value of the charging current or discharging current of the battery. In this method, the error in calculating the charging rate increases as the operating time of the system increases. For this reason, in a system using a storage battery such as a lithium ion battery, it is difficult to manage the remaining battery level during operation.

  Further, when the storage battery deteriorates, the electromotive force decreases with respect to the charging rate. Therefore, it is necessary to grasp the change in the electromotive force and appropriately reflect it in the determination of the charging rate. Here, in the lead battery and the lithium ion battery, when current flows, the output voltage apparently increases due to internal resistance. For this reason, it is difficult to accurately grasp the electromotive force that serves as an index for determining the charging rate.

  On the other hand, in the storage battery conversion device according to the embodiment of the present invention, the measurement unit 11 measures the voltage Vb of the storage battery 106 when the charging operation and the discharging operation are stopped.

  As described above, the configuration in which the charging operation and the discharging operation are stopped by setting each threshold voltage is ensured, and the voltage of the storage battery is measured in the stopping period, so that the electromotive force of the storage battery can be accurately and easily measured. it can. For example, the remaining amount of the storage battery 106 can be accurately grasped. This makes it possible to accurately measure the electromotive force of the storage battery 106 while using a small and inexpensive lead battery or lithium ion battery as a storage battery without using a large battery such as a redox flow battery that can easily measure the electromotive force. And it can be measured easily.

  Moreover, in the storage battery conversion device according to the embodiment of the present invention, the control unit 12 calculates the remaining power storage amount of the storage battery 106 based on the voltage Vb of the storage battery 106 measured by the measurement unit 11.

  With such a configuration, it is possible to obtain an accurate remaining power amount of the current storage battery 106 from the electromotive force of the storage battery 106 measured during the stop period. For example, current value integration for calculating the charging rate of the storage battery 106 The error can be corrected.

  In the storage battery conversion device according to the embodiment of the present invention, the control unit 12 performs the charging operation or the discharging operation regardless of the voltage Vdc of the line 151 when the calculated remaining power storage amount satisfies the predetermined condition. Do not start.

  With such a configuration, the charging operation and the discharging operation can be performed in consideration of the remaining amount of power stored in the storage battery 106 calculated using the measurement result in the stop period. Therefore, in the configuration in which DC power is supplied through the line Overcharge and overdischarge can be prevented.

  Moreover, in the storage battery converter according to the embodiment of the present invention, the control unit 12 controls the current flowing from the voltage conversion unit 13 to the storage battery 106 in the charging operation to a predetermined value, and converts the voltage from the storage battery 106 in the discharging operation. The current flowing to the unit 13 is controlled to a predetermined value.

  As described above, the configuration in which the storage battery 106 is discharged and charged with a constant current makes it possible to accurately perform the current value integration from the discharge time or charge time and the constant current value.

  In addition, by setting the constant current value to be large to some extent, for example, when an IGBT is used as the transistor in the storage battery conversion device 101, the circuit can be operated with a low on-resistance of the IGBT. The efficiency of the apparatus 101 can be increased.

  In the storage battery conversion device according to the embodiment of the present invention, the control unit 12 controls the transistors 33 and 34 so that the current Ibdc measured by the measurement unit 11 becomes a predetermined value in the charging operation of the storage battery 106. In the discharging operation of the storage battery 106, the transistors 33 and 34 are controlled so that the current Ibdc measured by the measuring unit 11 becomes a predetermined value.

  With such a configuration, constant current discharge and constant current charge of the storage battery 106 can be performed by a simple and appropriate method for controlling the switching of the transistors 33 and 34 in the voltage conversion unit 13.

  Moreover, in the storage battery converter according to the embodiment of the present invention, the charge stop threshold value and the discharge stop threshold value are median values of the charge start threshold value and the discharge start threshold value.

  With such a configuration, it is possible to suppress the occurrence of a difference in the length of the stop time of the discharge operation and the charge operation due to the voltage increase and the voltage decrease of the line 151. Therefore, the storage battery 106 during the stop period of the discharge operation and the charge operation. Can be stably calculated. Further, since the threshold value for stopping charging and the threshold value for stopping discharging can be made common, it is possible to simplify the control of the charging operation and the discharging operation based on the voltage of the line 151.

  Moreover, in the power supply system according to the embodiment of the present invention, when the voltage on the line 151 rises and becomes equal to or higher than the first limit threshold value that is larger than the charging start threshold value, the power generator conversion device 103 causes the voltage on the line 151 to increase. Output suppression control is performed so as not to exceed a predetermined upper limit value.

  With such a configuration, in a configuration in which DC power is supplied via a line, it is possible to prevent the voltage on the line from becoming excessive and to supply more stable power. The upper limit value is set to a value larger than the charging start threshold value, for example.

  Moreover, in the power supply system according to the embodiment of the present invention, when the voltage on line 151 rises and becomes equal to or higher than the second limit threshold value that is larger than the charging start threshold value, converter 151 for AC power supply increases the voltage on line 151. Output suppression control is performed so as not to exceed a predetermined upper limit value.

  With such a configuration, in a configuration in which DC power is supplied via a line, it is possible to prevent the voltage on the line from becoming excessive and to supply more stable power. The upper limit value is set to a value larger than the charging start threshold value, for example.

  Further, in the power supply system according to the embodiment of the present invention, the load converter 107 outputs the output of the voltage converter at a cycle shorter than the start and stop cycles of the charging or discharging operation of the storage battery converter 101. Control the voltage.

  With such a configuration, the control of the load converter 107 can follow the voltage change of the line 151, so that the supply voltage to the load device 108 can be controlled to be constant.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 11,41 Measurement part 12 Control part 13,43 Voltage conversion part 20,42 PI calculating part 21 Charge / discharge determination part 22 Battery remaining charge calculation part 23,51 PWM circuit 24,52 Buck-boost chopper circuit 31,35,61,65 Capacitor 32, 62 Coil 33, 34, 63 Transistor 36, 37, 66, 67 Voltage measuring device 38, 68 Current measuring device 64 Diode 101 Storage battery conversion device 102 Power generation device 103 Power generation device conversion device 104 AC power source 105 AC power source Converter 106 Storage battery 107 Converter for load 201 Power supply system

Claims (12)

A voltage converting unit capable of performing a discharging operation for converting a DC voltage from the storage battery and supplying the line to the line; and a charging operation for converting the DC voltage from the line and supplying the line to the storage battery;
A control unit for controlling the charging operation and the discharging operation of the voltage conversion unit,
The control unit starts the charging operation when the voltage of the line rises and becomes equal to or higher than a charging start threshold, stops the charging operation when the voltage of the line drops and becomes lower than a charging stop threshold, When the voltage drops and falls below the discharge start threshold, the discharge operation is started, and when the voltage of the line rises above the discharge stop threshold, the discharge operation is stopped,
The charge stop threshold and the discharge stop threshold are values between the charge start threshold and the discharge start threshold,
The control unit controls a current flowing from the voltage conversion unit to the storage battery in the charging operation to a constant value, and controls a current flowing from the storage battery to the voltage conversion unit in the discharge operation to a constant value. Conversion device. The storage battery conversion device further includes:
The storage battery conversion device according to claim 1, further comprising a measurement unit that measures a voltage of the storage battery when the charging operation and the discharging operation are stopped.   The storage battery conversion device according to claim 2, wherein the control unit calculates a remaining storage amount of the storage battery based on the voltage measured by the measurement unit.   The said control part is a storage battery converter of Claim 3 which does not start the said charge operation or the said discharge operation irrespective of the voltage of the said line | wire, when the calculated said electrical storage residual amount satisfy | fills predetermined conditions.   The control unit controls a current flowing from the voltage conversion unit to the storage battery in the charging operation to a predetermined value, and controls a current flowing from the storage battery to the voltage conversion unit in the discharging operation to a predetermined value. The storage battery converter according to any one of claims 1 to 4. The storage battery conversion device further includes:
A measurement unit for measuring a current flowing between the storage battery and the voltage conversion unit;
The voltage conversion unit includes a switch element,
The control unit controls the switch element so that the current measured by the measuring unit becomes a predetermined value in the charging operation, and the current measured by the measuring unit in the discharging operation is predetermined. The storage battery conversion device according to claim 5, wherein the switch element is controlled to have a value.   The storage battery conversion device according to any one of claims 1 to 6, wherein the charge stop threshold value and the discharge stop threshold value are median values of the charge start threshold value and the discharge start threshold value. A converter for a power generator that converts the DC voltage from the power generator and supplies it to the line;
A power supply comprising: a discharging operation for converting a DC voltage from a storage battery and supplying the line to the line; and a converter for a storage battery capable of performing a charging operation for converting the DC voltage from the line and supplying the line to the storage battery A system,
The storage battery conversion device starts the charging operation when the voltage on the line rises to be equal to or higher than a charging start threshold, stops the charging operation when the voltage on the line drops below a charging stop threshold, When the voltage of the line decreases and becomes less than the discharge start threshold, the discharge operation is started, and when the voltage of the line rises and becomes the discharge stop threshold or more, the discharge operation is stopped,
The power supply system, wherein the charge stop threshold and the discharge stop threshold are values between the charge start threshold and the discharge start threshold.   The power generating device conversion device performs output suppression control so that the voltage of the line does not exceed a predetermined upper limit value when the voltage of the line rises and exceeds a first limit threshold value that is greater than the charging start threshold value. The power supply system according to claim 8. The power supply system further includes:
An AC power source conversion device that converts an AC voltage from an AC power source into a DC voltage and supplies it to the line,
The converter for AC power supply performs output suppression control so that the voltage of the line does not exceed a predetermined upper limit value when the voltage of the line rises and exceeds a second limit threshold value that is greater than the charging start threshold value. The power supply system according to claim 8 or 9. The power supply system further includes:
A load conversion device that converts the DC voltage from the line and supplies it to the load,
The load conversion device includes a voltage conversion unit, and controls the output voltage of the voltage conversion unit at a cycle shorter than the start and stop cycles of the charging operation or the discharge operation of the storage battery conversion device. The power supply system according to any one of claims 8 to 10. A power supply control method in a storage battery conversion device capable of performing a discharge operation for converting a DC voltage from a storage battery and supplying the line to a line, and a charging operation for converting a DC voltage from the line and supplying the line to the storage battery There,
Starting the charging operation when the voltage of the line rises and exceeds a charging start threshold;
Stopping the charging operation when the voltage of the line drops below a charging stop threshold; and
Starting the discharge operation when the voltage of the line drops below the discharge start threshold;
The discharge operation is stopped when the voltage of the line rises to a discharge stop threshold value or more,
The power supply control method, wherein the charge stop threshold and the discharge stop threshold are values between the charge start threshold and the discharge start threshold.

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