JP4282365B2 - Automotive power equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel consumption by dispensing with weak field operation even at high revolution, for continuously charging a battery regardless of the revolution number of a synchronous motor, with loss from a weak field current suppressed. <P>SOLUTION: The DC power source on the input side of an inverter 1 that drives an M/G 20 comprises a series connection of a battery 30 and a capacitor 31, and a DC/DC converter 10 for delivery of electric power between the battery 30 and the capacitor 31. By this power supply configuration, generated power is supplied to the capacitor 31 and the battery 30 while a three-phase short is released, and energy accumulated in the capacitor 31 is transported to the battery 30 by the DC/DC converter 10 during the three-phase short for charging the battery 30, by repeating, at an appropriate time interval, the three-phase shorting and its releasing by turning on all switching elements of an upper side arm or a lower side arm of the inverter 1 while the revolution number of the M/G20 is high more than specified numbers. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automobile power device, and more particularly, to an automobile power device that starts and accelerates an automobile engine and generates electric power.
[0002]
[Prior art]
As a drive system for an electric vehicle, a type in which an electric motor is directly connected to an engine crankshaft is known. In this type of drive system, a battery is connected as an input power source of an inverter that drives an electric motor, and the shaft of the electric motor is connected to a wheel via a transmission to drive it.
[0003]
In a conventional automobile power device, when a permanent magnet type synchronous motor is used as an electric motor, a field-weakening operation method is used in a high-speed range of a predetermined number of revolutions or more, and a DC circuit from a battery to an inverter is generated during vehicle travel. When an abnormality such as opening occurs, the switching elements of the upper arm or lower arm of the inverter that drives the permanent magnet type synchronous motor for driving the vehicle are collectively turned on to output a zero voltage vector, or the inverter After the smoothing capacitor and the inverter unit are separated by the switching means provided on the DC input side, the power supply from the synchronous motor is stopped by short-circuiting the DC terminals on the inverter input side by the second switching means. An example of preventing a voltage more than necessary from being applied to the smoothing capacitor has been proposed (see, for example, Patent Document 1). .
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-47055
[0005]
FIG. 2 of the above-mentioned Patent Document 1 shows the former example, which is a case where the switching elements of the upper arm are collectively turned on, and the direction of each phase current flowing through the input terminal of the permanent magnet type synchronous motor Is indicated by an arrow. In this case, a short circuit is constituted by the transistor and the diode. Thus, by turning on all the switching elements of the upper arm, a short circuit can be configured regardless of the direction of the three-phase current. The same effect can be obtained even if all the switching elements of the lower arm are turned on.
[0006]
FIG. 3 of the above-mentioned patent document 1 shows the latter example, and an opening / closing means for separating the switching unit and the smoothing capacitor of the inverter and an opening / closing means for short-circuiting the input side of the inverter are added. ing. By disconnecting the smoothing capacitor from the inverter by the switching means and then short-circuiting the input side of the inverter by the switching means, the current of the permanent magnet synchronous motor can be short-circuited via the diode of the inverter.
[0007]
[Problems to be solved by the invention]
In an automobile power device using a permanent magnet type synchronous motor as described in Patent Document 1 described above, field-weakening operation is required in a high-speed range of a certain number of revolutions or more, and control is complicated. In addition, in order to prevent loss due to field weakening current and to apply a voltage exceeding the allowable voltage to the smoothing capacitor, while outputting the zero voltage vector or shorting between the DC terminals on the inverter input side In addition, a short circuit is constituted by the transistor and the diode, and all the power generated by the permanent magnet type synchronous motor is lost, and the battery cannot be charged during the short circuit configuration.
[0008]
The present invention has been made to solve such a problem, and does not require field-weakening operation even at a high speed, and can continuously charge a battery regardless of the rotational speed of the permanent magnet type synchronous motor. An object of the present invention is to obtain an automobile power device that can reduce the loss caused by the field weakening current and improve the fuel consumption.
[0009]
[Means for Solving the Problems]
The present invention is an automotive power device for starting, accelerating and generating electric power of an automobile engine, which drives the engine when starting and accelerating the engine and receives the power of the engine during steady running and deceleration. A synchronous motor that generates electric power, an inverter that drives the synchronous motor when the engine of the synchronous motor is driven, and that performs a rectifying operation when the synchronous motor generates power; and an input terminal of the inverter that is connected to the synchronous motor. A power source that supplies DC power to the inverter when the engine is driven, and is charged by the generated power of the synchronous motor when the synchronous motor generates power. The power source includes a first energy storage source and a second power source. A series-connected power supply in which the energy storage sources are connected in series with each other, the first energy storage source and the second energy storage source. A DC / DC converter that transports energy between energy storage sources, and during the period when the rotational speed of the synchronous motor exceeds a predetermined rotational speed during power generation of the synchronous motor, the input terminal of the synchronous motor or its By repeatedly performing a short circuit on the input side of the inverter connected to the input terminal and releasing it at a predetermined time interval, the power supply is stopped and supplied from the synchronous motor to the series-connected power source via the inverter. It is repeated at the predetermined time interval, and when the power supply is stopped, the DC / DC converter is connected from the second energy storage source to the first energy storage source or the first energy storage source. Transport energy to the load.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a circuit diagram showing a configuration of an automotive power device according to an embodiment of the present invention. In FIG. 1, an inverter 1 is a three-phase inverter device for driving an M / G (motor / generator) 20 or rectifying an output when the generator of the M / G 20 is operated. A power semiconductor element is generally used for the switch. Although it is described as a MOSFET in FIG. 1, it may be another power semiconductor element such as an IGBT. The same applies hereinafter. Sx1, Sx3, Sx5 are upper arms. The switches Sx2, Sx4, and Sx6 are switches for the lower arm. In an electric vehicle such as a hybrid vehicle or a fuel cell vehicle, the M / G 20 operates as a motor to drive the engine when assisting the engine at the time of starting or accelerating, and drives the engine during steady running or deceleration. The motor / generator that operates as a generator for receiving power and is directly connected to the crankshaft of the engine or is connected to the crankshaft of the engine via a belt or gear. As the M / G 20, a claw pole type permanent magnet or a permanent magnet type synchronous motor or induction motor can be considered.
[0011]
The battery 30 and the capacitor 31 are first and second energy storage sources, respectively. The battery 30 and the capacitor 31 constitute a series-connected power source connected in series with each other. As shown in the figure, an in-vehicle load 33 to be supplied with power is connected to the battery 30. The DC / DC converter 10 that exchanges energy between the battery 30 and the capacitor 31 includes an upper switch Qx1, a lower switch Qx2, and a reactor Lx. Dx1 and Dx2 in FIG. It is. The battery 30, the capacitor 31, and the DC / DC converter 10 are connected to the input terminal of the inverter 10, and supply DC power to the inverter 1 when the engine of the M / G 20 is driven, and are synchronized when the M / G 20 generates power. It constitutes a “power source” that is charged by the electric power generated by the motor.
[0012]
The capacitor 31 is a large-capacity capacitor, and an electric double layer capacitor, an aluminum electrolytic capacitor, or the like is used. A smoothing capacitor 15 is connected in parallel between the inverter 1 and the DC / DC converter 10. The control circuit 32 is a device that detects the rotational speed of the motor of the M / G 20 and the voltage of the capacitor 31 and sends an operation control signal to the power semiconductor elements constituting the inverter 1 and the DC / DC converter 10 based on the detected number.
[0013]
First, a description will be given first of the conventional operation at the start of the electric vehicle or at the time of power generation of the circuit shown in FIG. Great for torque assist during engine restart after idling stop (including initial start-up when engine temperature is low and engine temperature is sufficient if torque is sufficient) It is necessary to supply current to the motor, and for this purpose, it is necessary to supply a large current from the battery to the inverter input. For this reason, in an electric vehicle, since it is necessary to mount a large capacity battery according to the required starting torque, the battery is expensive. On the other hand, in an inverter, it may be considered that the steady-state loss is almost proportional to the output current (when IGBT is used as a switching element) or is almost proportional to its square (when MOSFET is used as a switching element). Because switching devices (power semiconductor devices) that make up inverters need to be large in capacity and multi-parallel, the inverter output current can be reduced and the input voltage can be increased to reduce the size and cost of the inverter. It has been demanded.
[0014]
A conventional method for solving these problems is proposed in Japanese Patent Application Laid-Open No. 2002-218667. In this publication, the time required for restart after an idle stop is a short time of about 1 second or less, and is about 10 seconds including the torque assist by the motor during subsequent acceleration. In addition, as shown in the circuit of FIG. 1, a low-voltage battery such as an existing 12V battery and a large-capacitance capacitor are connected in series, and in the short-time high-current output region at the time of restart or torque assist after the above-described idle stop, By supplying energy from the capacitor to the inverter as well, the current supplied from the battery can be reduced, and the battery can be reduced in size and cost by lowering the voltage and capacity, or the life can be extended by reducing the instantaneous current draw. Expecting. Further, since the input voltage of the inverter can be increased by increasing the capacitor voltage, the output current can be reduced with the same output power.
[0015]
On the other hand, when the M / G 20 is operated as a generator, the inverter 1 functions as a rectifier. When an induction motor is used as the M / G 20, there is a problem that an excitation current for supplying the rotating magnetic flux is necessary, the power factor is bad, and the starting current becomes large. Therefore, in the following description, the operation of the generator when a permanent magnet type synchronous motor or a claw pole type synchronous motor with a permanent magnet is used as the M / G 20 which is a feature of the present invention will be described.
[0016]
FIG. 2 shows a charging / discharging state of the capacitor 31 when the M / G 20 is operating as a generator. Here, Vc on the vertical axis is a voltage between terminals of the capacitor 31, and Vcmax is a maximum rated voltage of the capacitor 31. When the M / G 20 is operating as a generator and the rotation speed is controlled to an output voltage suitable for charging the battery 30 below a certain value, the control circuit 32 detects the motor rotation speed. Thus, a signal for turning on the upper switch Qx1 and turning off the lower switch Qx2 is output, and the battery 30 is charged through the upper switch Qx1. Since no switching operation is performed during this period, the loss of the upper switch Qx1 can be minimized. In this operating state, no charge is accumulated in the capacitor 31 and the voltage across it is zero. When the rotational speed increases and reaches a certain rotational speed, the control circuit 32 detects this and outputs a signal for operating the DC / DC converter 10 as a step-down converter to the upper switch Qx1 and the lower switch Qx2, and the battery Step down to a voltage suitable for charging 30. In order to keep the DC / DC converter 10 below the allowable temperature, it is necessary to suppress the heat generation of the upper switch Qx1 and the lower switch Qx2, and for this purpose, the control circuit 32 reduces the operating time and duty of the DC / DC converter 10. Control to limit or stop. At this time, the capacitor 31 is charged by the M / G 20 (period (a) in FIG. 2). In this case, since the charging current of the capacitor 31 also flows to the battery 30, the battery 30 is charged simultaneously with the charging of the capacitor 31.
[0017]
When the rotational speed of M / G 20 further increases, charging of capacitor 31 continues (the period of (a) is further extended), and exceeds the maximum rated voltage Vcmax of capacitor 31 as shown by the dotted line in the figure. Here, when the voltage Vc of the capacitor 31 reaches a certain predetermined voltage that is lower than Vcmax (point (A) in the figure), the control circuit 32 detects this, and FIG. By turning on all the switches of the power semiconductor elements Sx1, Sx3, Sx5 of the upper arm of the inverter 1 or turning on all the switches of the power semiconductor elements Sx2, Sx4, Sx6 of the lower arm in FIG. If the phase short circuit is configured, the capacitor 31 is not charged any more and the voltage Vc does not exceed Vcmax.
[0018]
The idea of configuring this three-phase short circuit is also described in Patent Document 1. According to the publication, when a permanent magnet type synchronous motor rotates at a certain speed or higher, the permanent magnet type synchronous motor is operated to weaken the field so that the charging voltage of the smoothing capacitor does not exceed the rated voltage. In the case where an abnormality occurs during operation, an idea of configuring a three-phase short circuit as a means for preventing an excessive voltage from being applied to the smoothing capacitor is proposed. In this publication, the battery side circuit is not configured as shown in FIG. 1 according to the present embodiment, but the battery is directly connected to the input side of the inverter, and the battery cannot be charged during the configuration of the three-phase short circuit. It is.
[0019]
However, in the present embodiment, the circuit of FIG. 1 forms a three-phase short circuit after the period of FIG. 2A, and is stored in the capacitor 31 by the DC / DC converter 10 during the configuration. It is possible to charge the discharged battery 30 by supplying power to the in-vehicle load 33 with the generated energy, or to supply power to the in-vehicle load 33 directly connected to the battery 30 ((c) in FIG. 2). If the control circuit 32 detects that the voltage of the capacitor 31 has dropped due to charging of the battery 30 or power supply to the in-vehicle load 33 and canceling the configuration of the three-phase short circuit, the M / An operation mode (period (a) in FIG. 2) in which the energy generated by G20 is stored in the capacitor 31 can be entered. That is, even when the rotational speed of the M / G 20 is equal to or greater than a certain value, it is possible to continue charging the battery by repeating the above operation at appropriate time intervals without performing field-weakening operation. Therefore, the control by the field weakening current in the high-speed rotation region becomes unnecessary, the control becomes easy, the loss due to the field weakening current does not occur, and the heat generation on the inverter side can be reduced.
[0020]
It should be noted that the field weakening current in the high speed rotation region of M / G20 must be increased as the number of rotations increases, but in a region where a relatively small current may be used, the terminal voltage of M / G20 is controlled by field weakening current control. Controlling the battery and charging the battery is more complicated, but there are cases where the loss of the entire system can be reduced rather than repeating the three-phase short circuit and its release. In such a rotation region, the field-weakening operation may be performed first, and in a higher rotation region, the operation may be switched to a method in which a three-phase short circuit and its release are repeated.
[0021]
Further, in the power source in which the capacitor 31 is connected in series to the battery 30 as shown in FIG. 1, there is no problem even if the terminal voltage of the permanent magnet type synchronous motor is higher by the rated voltage of the capacitor 31 than in the case of the power source of the battery alone. The battery 30 can be charged. This means that the field weakening current can be kept low, or that the battery 30 can be charged up to higher speed rotation with the same field current, and the loss can be reduced accordingly. Therefore, using the circuit shown in FIG. 1, it is conceivable to further increase the efficiency of the entire system in an operation mode of repeated field-weakening operation and three-phase short circuit in a high-speed rotation region.
[0022]
Further, even when the inverter 1 is in a running state in which field-weakening operation becomes impossible due to the rated current limitation of the inverter 1 and a three-phase short circuit must be continuously formed, the three-phase short circuit and the release thereof are used. The battery 30 can be continuously charged.
[0023]
In FIG. 2, an appropriate time (period (b) in FIG. 2) is taken between the timing of forming the short circuit and the timing of causing the DC / DC converter 10 to perform the step-down converter operation. This is the time taken to lower the temperature to a sufficiently low temperature when the power semiconductor elements Qx1, Qx2, Dx1, and Dx2 constituting the DC / DC converter 10 operate. If there is no problem in operation, the operation pattern of FIG. As shown in FIG. 5, the period of (b) may be eliminated, and the DC / DC converter 10 may be caused to perform the step-down converter operation almost simultaneously with the configuration of the short circuit.
[0024]
The period (a) in FIG. 2 is a period in which energy is stored in the capacitor 31. If components such as the power semiconductor element of the DC / DC converter 10 are in a thermally operable state, the step-down operation is performed. It is also possible to store energy in the capacitor 31 at the same time.
[0025]
Further, in the configuration in which the capacitor 31 is stacked on the battery 30 as shown in FIG. 1, even if the power semiconductor element constituting the inverter 1 is destroyed and short-circuited, the capacitor 31 is discharged, but the battery 30 Since the terminals are not short-circuited, the system is highly reliable.
[0026]
In the description so far, the method of constructing the three-phase short circuit as an example of preventing the application of an excessive voltage to the smoothing capacitor has been described as an example. The method of short-circuiting the input side of the inverter as shown in FIG.
[0027]
As described above, in the automobile power device according to the present embodiment, the DC power source on the input side of the inverter 1 that drives the permanent magnet type synchronous motor (M / G 20) is used as the battery 30 (first energy storage source). And a capacitor 31 (second energy storage source) in series, and a DC / DC converter 10 that exchanges power between the battery 30 and the capacitor 31. When this power supply configuration is used, when the rotational speed of the permanent magnet type synchronous motor is high enough to be higher than a certain value, the three-phase short-circuit due to all the switching elements of the upper arm or the lower arm of the inverter 1 being turned on and the release thereof for an appropriate time. By repeating the operation at intervals, the generated power is supplied to the capacitor 31 and the battery 30 while the three-phase short circuit is released, and the energy stored in the capacitor 31 is transported to the battery 30 by the DC / DC converter 10 when all of the power is on. Thus, the battery 30 can be charged (in addition, the energy may be transported not only to the battery 30 but also to the in-vehicle load 33 connected to the battery 30 during all-on). When energy is transported to the battery 30, the voltage across the capacitor 31 decreases, and the operation mode for charging the capacitor 31 and the battery 30 is resumed by releasing the three-phase short-circuit state at the upper arm or the lower arm of the inverter 1 again. enter. In this method, field-weakening operation is not required even at high rotation, and by repeating this operation, the battery 30 can be continuously charged regardless of the rotation speed of the permanent magnet type synchronous motor. Since no current flows, the loss is reduced and the fuel efficiency is improved. Furthermore, when the vehicle is decelerated using an engine brake or the like while using a high-speed rotation region, the kinetic energy of the automobile can be effectively regenerated. Furthermore, the use of the capacitor 31 as one of the energy storage sources that repeatedly charge and discharge has the effect that the life of the system can be extended as compared with a battery that is extremely susceptible to aging when the discharge depth is increased. Further, a three-phase short circuit is caused by turning on all the power semiconductor elements Sx1, Sx3, Sx5 of the upper arm of the inverter 1 or turning on all the switches of the power semiconductor elements Sx2, Sx4, Sx6 of the lower arm. Since this is performed, a three-phase short circuit can be configured at low cost, and on / off timing can be easily controlled.
[0028]
Embodiment 2. FIG.
In the present embodiment, a more reliable system can be obtained by selecting the withstand voltage of each component of the DC / DC converter 10 in the circuit of FIG. 1 so as to satisfy the following inequality.
[0029]
Vcmax> Vemfmax−Vb (1)
VQx1> Vemfmax (2)
VQx2> Vemfmax (3)
[0030]
Here, Vemfmax is the no-load induced voltage at the maximum rotational speed of the permanent magnet type synchronous motor, Vcmax is the maximum rated voltage of the capacitor 31, VQx1 and VQx2 are power semiconductor elements (here, they are drawn as MOSFETs, but other power such as IGBTs) The maximum rated voltage between the drain and source of Qx1 and Qx2 may be a semiconductor element. FIG. 4 shows the charging / discharging status of the capacitor 31 during traveling. Similarly to the first embodiment, when the M / G 20 enters the power generation mode and the rotation speed becomes a certain value or more, charging of the capacitor 31 is started (period (a) in FIG. 4), and the rotation speed of the MG is constant. Then, the voltage Vc across the capacitor 31 is
[0031]
Vc = Vemf−Vb (4)
[0032]
(Period (b) in FIG. 4). Here, Vb is a voltage between the terminals of the battery 30, and Vemf is an output voltage generated between the terminals of the inverter 1 operating as a rectifier circuit by the induced voltage of the M / G 20 at the rotation speed. Since the maximum rated voltage Vcmax of the capacitor 31 satisfies the relationship (1), even if the M / G 20 continues to rotate at the maximum rotation speed, the voltage Vc of the capacitor 31 does not exceed Vcmax, and dielectric breakdown does not occur. Since it is not, it becomes a highly reliable device.
[0033]
In this way, in a drive / power generation system using a permanent magnet type synchronous motor or a claw pole type synchronous motor with a permanent magnet for the M / G 20, a capacitor 31 satisfying the relationship of formula (1) is connected in series to the battery 30. Furthermore, if the relations of the expressions (2) and (3) are satisfied, depending on the charge state of the battery 30 and the temperature of the components constituting the DC / DC converter 10 regardless of the rotational speed of the M / G 20, The operation limitation or temporary stop of the DC / DC converter 10 can be performed. Thereby, it is not necessary to require the DC / DC converter 10 to have an unnecessarily high cooling performance or low heat generation, and the DC / DC converter 10 can be reduced in size and cost.
[0034]
Further, if the withstand voltage of the power semiconductor elements constituting inverter 1 is sufficient, all the power semiconductor elements in the upper arm or the lower arm of inverter 1 described in the first embodiment are turned on. It is not always necessary to short-circuit the three-phase or the DC input side of the inverter unit, and control becomes easy. In this case, the DC / DC converter 10 may be operated when battery charging is required. On the other hand, even when there is a relationship of formulas (1), (2), and (3), when using a power semiconductor element having a low maximum rated voltage for the inverter 1 in order to reduce component costs and loss of the inverter 1 The above short circuit may be configured so that these elements are not subjected to a voltage exceeding the maximum rated voltage.
[0035]
As described above, according to the present embodiment, the voltage that can be applied to both ends of the series-connected power source in which the battery 30 (first energy storage source) and the capacitor 31 (second energy storage source) are connected in series with each other. Since it is set to be greater than the no-load induced voltage at the maximum rotational speed of the M / G 20, depending on the state of charge of the battery 30 and the temperature of the components constituting the DC / DC converter 10 regardless of the rotational speed of the M / G 20 In addition, the operation limitation or temporary stop of the DC / DC converter 10 can be performed. Thereby, it is not necessary to require the DC / DC converter 10 to have an unnecessarily high cooling performance or low heat generation, and the DC / DC converter 10 can be reduced in size and cost. Furthermore, the effect that the means for short-circuiting the input terminal of the M / G 20 becomes unnecessary is obtained.
[0036]
Embodiment 3 FIG.
1 to 3, all the power semiconductor elements of the upper arm or the lower arm of the inverter 1 are repeatedly turned on and off, or the input terminals of the inverter 1 are repeatedly short-circuited and opened. On both sides of the period in which the converter 10 operates and the capacitor 31 is repeatedly charged and discharged, Qx1 is on and the capacitor 31 is not charged (that is, “Qx1 on” at both ends in FIGS. 2 and 3). ”And a period in which Vc is 0). During this period, the permanent magnet type synchronous motor or the claw pole type synchronous motor with a permanent magnet has a relatively low rotational speed, and the battery 30 can be charged with the output rectified by the diode of the inverter 1, or weakened by the inverter 1. It shows a situation where the battery 30 can be charged with a voltage appearing on the inverter input side by performing field operation. Thus, when the rotational speed of the permanent magnet type synchronous motor is relatively low, the switching element Qx1 constituting the DC / DC converter 10 is always turned on. In this way, loss due to switching does not occur and heat generation of the DC / DC converter 10 can be reduced.
[0037]
As described above, according to the present embodiment, DC / DC converter 10 mutually transports energy between battery 30 (first energy storage source) and capacitor 31 (second energy storage source). Therefore, at least two switching elements Qx1 and Qx2 are configured, and of these switching elements Qx1 and Qx2, the high voltage side terminal of the DC voltage input / output terminal of the inverter 1 and the battery 30 are connected via the reactor Lx. Since the element Qx1 is always in an ON state when the M / G 20 is below a certain rotational speed during the power generation operation by the M / G 20, it is possible to suppress the heat generation in the DC / DC converter 10 portion during power generation to a low level.
[0038]
【The invention's effect】
The present invention is an automotive power device for starting, accelerating and generating electric power of an automobile engine, which drives the engine when starting and accelerating the engine and receives the power of the engine during steady running and deceleration. A synchronous motor that generates electric power, an inverter that drives the synchronous motor when the engine of the synchronous motor is driven, and that performs a rectifying operation when the synchronous motor generates power; and an input terminal of the inverter that is connected to the synchronous motor. A power source that supplies DC power to the inverter when the engine is driven, and is charged by the generated power of the synchronous motor when the synchronous motor generates power. The power source includes a first energy storage source and a second power source. A series-connected power supply in which the energy storage sources are connected in series with each other, the first energy storage source and the second energy storage source. A DC / DC converter that transports energy between energy storage sources, and during the period when the rotational speed of the synchronous motor exceeds a predetermined rotational speed during power generation of the synchronous motor, the input terminal of the synchronous motor or its By repeatedly performing a short circuit on the input side of the inverter connected to the input terminal and releasing it at a predetermined time interval, the power supply is stopped and supplied from the synchronous motor to the series-connected power source via the inverter. It is repeated at the predetermined time interval, and when the power supply is stopped, the DC / DC converter is connected from the second energy storage source to the first energy storage source or the first energy storage source. Since energy is transported to the load, the field-weakening operation is not required even at high speeds, and the rotational speed of the permanent magnet type synchronous motor is reduced. Razz can be continuously charge the battery, reducing the losses due to field weakening current, it is possible to improve the fuel economy.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of an automotive power device according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing an example according to the first embodiment of a capacitor charging / discharging operation pattern provided in the automobile power device according to the embodiment of the present invention;
FIG. 3 is an explanatory diagram showing another example according to the first embodiment of a capacitor charging / discharging operation pattern provided in the automobile power device according to the embodiment of the present invention;
FIG. 4 is an explanatory diagram showing an example according to the second embodiment of a capacitor charging / discharging operation pattern provided in the automobile power device according to the embodiment of the present invention.
[Explanation of symbols]
1 inverter, 10 DC / DC converter, 15 smoothing capacitor, 20 M / G (motor / generator), 30 battery, 31 capacitor, 32 control circuit, 33 load, Sx1 to Sx6 power semiconductor element, Qx1 upper switch, Qx2 lower side Switch, Dx1, Dx2 Freewheel diode, Lx reactor.

Claims (5)

An automotive power device for starting and accelerating and generating power for an automobile engine,
A synchronous motor that drives the engine at the time of starting and accelerating the engine and generates power by receiving the power of the engine during steady running and deceleration;
An inverter that drives the synchronous motor when driving the engine of the synchronous motor, and performs a rectifying operation when generating power of the synchronous motor;
A power source connected to an input terminal of the inverter, supplying DC power to the inverter when the engine of the synchronous motor is driven, and charged by the generated power of the synchronous motor when generating power of the synchronous motor;
The above power supply
A series-connected power source in which a first energy storage source and a second energy storage source are connected in series with each other;
A DC / DC converter for transporting energy between the first energy storage source and the second energy storage source;
In a period in which the rotational speed of the synchronous motor exceeds a predetermined rotational speed during power generation of the synchronous motor, a short circuit on the input side of the synchronous motor or the input side of the inverter connected to the input terminal and the release thereof are predetermined. By repeatedly performing the power supply from the synchronous motor to the series-connected power source via the inverter at the predetermined time interval. When the power supply is stopped, the DC / DC An automotive power device, wherein a converter transports energy from the second energy storage source to the first energy storage source or a load connected to the first energy storage source. The short circuit on the input side of the synchronous motor or the input side of the inverter connected to the input terminal is performed by collectively turning on the switching elements of the upper arm or the lower arm provided in the inverter. The automobile power device according to claim 1, wherein 3. The automobile power device according to claim 1, wherein the first energy storage source includes a battery, and the second energy storage source includes a capacitor. 4. 4. The automobile power device according to claim 1, wherein a voltage that can be applied to both ends of the series-connected power source is greater than a no-load induced voltage at the maximum number of rotations of the synchronous motor. 5. The DC / DC converter includes at least two switching elements including a first switching element that connects a high voltage side terminal of a DC voltage input / output terminal of the inverter and the first energy storage source via a reactor. And
5. The first switching element according to claim 1, wherein the first switching element is always in an on state during a period when the rotational speed of the synchronous motor is equal to or lower than a predetermined rotational speed during the power generation by the synchronous motor. The automobile power device according to Item 1.

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