JP2011017491A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem on increase of costs of components and a circuit as it is necessary to ensure a power source capacity and to prepare components ensured in sufficient dilating, as considerable inrush current flows and heavy load is applied to a switching power source when a capacitor is inserted to a load side for stabilizing the power source in recovering from a standby state.SOLUTION: This air conditioner includes a voltage converting means 2 for converting high-pressure DC voltage obtained by rectifying commercial power source into low-pressure output voltage, a motor 6 for an air blower, operated by applying DC voltage output from the voltage converting means as a control power source, and switching and applying the high-pressure direct current to a motor winding to control a rotational frequency of the motor, a variable means 7 for varying the motor control power source voltage, and a control part 8 having a microcomputer receiving an operation start command, outputting a rotational frequency command to the motor, and inputting a variable width signal to the variable means to vary the control power source voltage to the motor, as a core.

Description

  The present invention relates to an air conditioner that reduces standby power by controlling a control power supply of a blower motor.

  The motor for the blower employs a motor drive unit that employs a PWM drive method in which high-voltage direct current is turned on / off to create a three-phase alternating current and applied to the motor winding.

In this method, a PWM drive circuit in which a PWM control unit and a drive element are combined in the drive unit or an IC in which these are packaged is used. These circuits or ICs require a control power supply for operation. On the other hand, the control power supply for controlling the air conditioner using the control power supply or microcomputer as a core is a DC voltage obtained by full-wave rectification of a commercial power supply. Is used as a primary input to create a low-voltage output voltage on the secondary side.

  Since the switching power supply has a certain conversion efficiency when converted to the secondary output, the power that is added to the secondary power consumption by the conversion loss is consumed on the primary side.

  Even when the control circuit is not operating, the secondary circuit including the control circuit having the microcomputer as a core has a certain power loss as long as power is supplied. This state is defined as standby power loss.

  Conventional air-conditioning air has improved the conversion efficiency of the control power supply to reduce standby power loss, cuts unnecessary circuits, reduces the operation of the control circuit, and reduces the average power by intermittent operation of the load. It was.

  For example, Patent Literature 1 or Patent Literature 2 has two power sources, namely, a control circuit power source and a load driving power source, and attempts to reduce power by shutting off the load driving power source during standby.

  Moreover, in patent document 3, the electric power which a microcomputer consumes is reduced by making the operation speed of the microcomputer which controls an air conditioner at the time of a standby slower than operation.

  Moreover, in patent document 4, the electric power at the time of standby was reduced by interrupting | blocking the high voltage circuit of the motor drive IC for air blowers which is a power loss source.

The blower motor generally employs a drive system called a high voltage PWM system, and FIG. 7 shows a drive motor drive configuration diagram of an air conditioner according to the prior art. This blower motor controls a low-voltage DC voltage output by a voltage conversion means 2 typified by a switching power supply that converts a high-voltage DC voltage obtained by rectifying an AC voltage of a commercial power supply by a rectifier 1 into at least one low-voltage output voltage. Use as a power source. The PWM control unit 3 to which the control power is applied is activated by the low-voltage DC voltage and generates a PWM signal according to a command from the microcomputer. Further, the high-voltage direct current is turned on / off by the PWM signal to create a three-phase alternating current and is applied to the motor winding to constitute a motor drive unit 4 that performs PWM drive. In these configurations, a motor drive unit and a PWM control unit may be combined with individual components and circuits, or an IC that is packaged as a PWM drive IC may be used.

  On the other hand, this PWM drive unit requires a power supply for control as described above. This means that there is a slight power loss inside the circuit. Due to the characteristics of the air conditioner, the air conditioner is often stored with the outlet connected throughout the year. Therefore, even when not operating as air conditioning, there is a power loss, which causes a disadvantage to the user even though he does not work as standby power. Part of the cause of this standby power is the loss of the control power source that exists in the PWM drive unit of the blower motor described above.

  As a means for reducing the standby power, there is a method of providing a switch 15 such as a relay in the control power supply as shown in FIG. The problem with this method is the inrush of power when returning from the standby state. Generally, the control unit is provided with a capacitance component such as a capacitor for stabilizing the power supply in the power input unit. When the standby power reduction switch is configured to shut off the power supply during standby, the stabilization capacitor is charged when returning from standby. Therefore, a large inrush current flows at this moment, and this means that parts such as a rectifier diode with an inrush current resistance must be used to ensure a margin of power capacity so that the output of the voltage conversion means can withstand the inrush. It was the cause of the cost increase.

JP 2006-69992 A JP 2000-55439 A Japanese Patent No. 3483483 Japanese Patent No. 4153586

  As described above, in the air conditioners described in Patent Documents 1, 2 and 4, since the load is shut off during standby, an inrush current flows from the power source to the load when returning from the standby state. If a capacitor is inserted on the side to stabilize the power supply, a large inrush current occurs. Since the generation of a large inrush current results in a large load on the switching power supply, a component with sufficient derating is required to ensure that the power supply capacity is not necessary and damage caused by a large inrush current is required. And had problems that resulted in increasing the cost of the circuit.

  In addition, the air conditioner described in Patent Document 3 has a problem that it is necessary to adopt a microcomputer having a special function that can arbitrarily change the operation speed.

  The present invention has been made in view of such problems of the prior art, and does not generate a large inrush current when returning from standby, and also reduces power loss due to a microcomputer with a simple configuration. The purpose of the present invention is to provide an energy-saving air conditioner that reduces standby power without using parts with special functions and without applying unnecessary costs to circuits and parts.

In order to achieve the above object, the present invention provides voltage conversion means for converting a high-voltage DC voltage obtained by rectifying an AC voltage of a commercial power supply into at least one low-voltage output voltage, and a DC power output from the voltage conversion means. The fan motor that controls the rotational speed of the motor by switching the high-voltage direct current and applying it to the motor winding, the variable means that varies the motor control power supply voltage, and the operation start command are received to the motor. A control unit having a microcomputer as a core for outputting a rotational speed command and inputting a variable width signal to the variable means to vary a control power supply voltage to the motor is provided.

  The air conditioner of the present invention has a configuration that does not generate a large inrush current when returning from the standby state, so that standby power can be used without using parts with special functions and without applying unnecessary costs to circuits and parts. Can be reduced.

Air blower motor drive configuration diagram of the air conditioner in Embodiment 1 of the present invention (A) Detailed view of the control voltage circuit according to the first embodiment of the present invention (b) Characteristic diagram Configuration diagram of variable means in Embodiment 2 of the present invention Configuration diagram of variable means in Embodiment 3 of the present invention Another block diagram of the variable means in Embodiment 3 of this invention Configuration diagram of variable means in Embodiment 4 of the present invention Motor drive configuration diagram of air conditioner air blower in the prior art Detailed view of control voltage switching circuit in the prior art

  According to a first aspect of the present invention, there is provided voltage conversion means for converting a high-voltage DC voltage obtained by rectifying an AC voltage of a commercial power supply into at least one low-voltage output voltage, and the DC voltage output from the voltage conversion means is operated as a control power supply. A blower motor that controls the rotational speed of the motor by switching direct current and applying it to the motor winding, variable means that varies the motor control power supply voltage, and an operation start command are received and the rotational speed command is output to the motor In addition, a large inrush current generated at the time of return from standby can be reduced by providing a control unit having a microcomputer as a core for inputting a variable width signal to the variable means to vary the control power supply voltage to the motor. Can do.

  Further, the second invention has narrow pulse generating means comprising an oscillation circuit and a waveform shaping circuit, and supplies a control voltage necessary for the motor to operate stably during normal operation, and the narrow pulse during standby operation. Since the motor control voltage is reduced by the narrow width generated by the pulse generation means, it is possible to reduce a large inrush current that occurs at the time of return even when the microcomputer is not operating, so it is consumed by the microcomputer. Electric power can be reduced, and standby power can be further reduced.

  The third aspect of the invention is a first voltage stabilizing means for generating a control voltage necessary for the motor to stably operate a control power supply for the fan motor, and a second voltage for varying the control voltage. Voltage stabilizing means and connecting means for connecting the second stabilizing means to the control voltage generating circuit. During normal operation, the connecting means releases the second stabilizing means from the circuit, and during standby, the By adopting a configuration for connecting the connecting means, it is possible to reduce a large inrush current generated at the time of return and reduce standby power by an inexpensive and simple circuit configuration.

  The fourth aspect of the invention provides a voltage stabilizing means for generating a control voltage necessary for the motor to operate stably as a control power source for the motor for the blower and a small potential for constantly applying a small potential to the control power source of the motor. A potential generating means is used.

(Embodiment 1)
1 is a schematic configuration diagram of an air conditioner according to Embodiment 1 of the present invention, FIG. 2A is a detailed diagram of a control voltage circuit, and FIG. 1B is a characteristic diagram thereof.

  A voltage conversion means 2 for converting a high-voltage DC voltage obtained by rectifying an AC voltage of a commercial power supply into at least one low-voltage output voltage, and a low-voltage DC voltage output from the voltage conversion means are operated as a control power supply, and the high-voltage DC is switched. A fan motor 6 having a PWM drive unit 5 for controlling the number of revolutions of the motor by applying it to the motor winding, a variable means 7 for changing the motor control power supply voltage, and an operation start command. The low voltage output from the voltage conversion means 2 in the configuration of the control unit 8 having a microcomputer that outputs a rotation speed command and inputs a variable width signal to the variable means to vary the control power supply voltage to the motor. The variable voltage means 7 converts the DC voltage into a voltage V2 necessary for the PWM controller 3 to operate during normal operation. Applying to the PWM control unit 3 and holding the power consumed by the PWM control unit 3 at the lowest level V1 during standby, and charging the capacitor provided for power supply stabilization with a low voltage higher than 0V By suppressing the inrush current generated by charging the capacitor at the time of recovery from the power supply, the output capacity of the switching power supply, which is a voltage conversion means, is increased unnecessarily, or parts that withstand excessive power are used with overspec This can avoid unnecessary cost increases.

  As an example, when V2 = 20V, V1 is in the range of a control power supply voltage in which a voltage of about 0.5V to 2V can achieve both reduction of power consumption during standby and suppression of inrush current when returning from standby. . This value varies depending on the type of motor driving IC used.

  In general, an electrolytic capacitor is used as a capacitance component. However, when the voltage is applied from 0V, the internal impedance becomes almost zero, so a large charging current is generated as an inrush current. Since the internal impedance is constant and the charging current rises slowly, an excessive inrush current does not occur.

  As a voltage variable method, a pulse waveform shaping circuit is provided in the variable means, a narrow pulse is output from the microcomputer during standby, and a 100% pulse is output when returning from standby, and the voltage variable means configured from the pulse waveform shaping circuit. Thus, a configuration for generating a voltage according to the pulse width is conceivable.

(Embodiment 2)
FIG. 3 is a schematic configuration diagram of an air conditioner according to Embodiment 2 of the present invention.

  In the second embodiment, a narrow pulse generating means comprising an oscillation circuit 10 and a waveform shaping circuit 9 is provided, supplying a control voltage necessary for the motor to operate stably during normal operation, and the above-described operation during standby operation. By adopting a configuration in which the motor control voltage is lowered by the narrow width generated by the narrow pulse generating means, a pulse having a narrow width can be applied to the waveform shaping circuit even when the microcomputer is not operating during standby. Accordingly, since the control circuit including the microcomputer can be stopped during standby, the power consumed by these control circuits can be reduced, so that standby power can be further reduced.

(Embodiment 3)
FIG. 3 is a configuration diagram of variable means according to Embodiment 3 of the present invention.

In the third embodiment, first voltage stabilizing means 11 for generating a control voltage necessary for the motor to operate stably as a control power source for the blower motor, and the control voltage at the time of return from standby. Second voltage stabilizing means 12 for varying the voltage to minimize the generated inrush current and the standby loss, and connecting means 13 for connecting the second stabilizing means to the control voltage generating circuit. In the normal operation, the connection means 13 releases the second stabilization means from the circuit, and in the standby state, the second stabilization means is connected. Since the inrush current generated at the time of recovery is reduced, the power loss due to the PWM control unit 3 is reduced, and the control unit 8 having a microcomputer as a core can also be brought into a stopped state. Electric power can be greatly reduced.

  As a circuit example, two types of voltage stabilizing circuits using Zener diodes were prepared and connected in parallel. Here, a configuration is conceivable in which one circuit is always connected, and one circuit is connected to the circuit during standby by a switch such as a transistor.

  As another embodiment, as shown in FIG. 5, there is a configuration in which the voltage variable circuit is configured by a parallel circuit of a zener diode and a switch such as a transistor, and the voltage variable circuit is connected in series to the voltage stabilizing circuit. In this configuration, the switch is closed during normal operation and the switch is opened during standby to vary the supply voltage to the stable circuit, thereby achieving the functions and effects described above.

(Embodiment 4)
FIG. 6 is a block diagram of the variable means in Embodiment 4 of the present invention.

  The control power generation to the PWM control unit 3 includes the stable power generation unit 11 that generates a voltage originally required for the PWM control unit to operate, the inrush current that occurs when returning from standby, and the standby loss. Is constituted by a small potential generating means 14 for minimizing. During standby, since the current flowing through the small potential generating means is very small in order to minimize the voltage applied to the PWM controller, the impedance of the circuit is set very high and the loss is small. On the other hand, during normal operation after returning from standby, power is supplied from the voltage converter to the stable power generator by closing the switch connected to the stable power generator. At this time, as described above, since the circuit potential of the small potential generating means is very high, even if the outputs of the small potential generating means and the stabilized power generating means are always connected, the output voltage, that is, the supply potential to the PWM controller Can be stabilized at the output potential of the stable power supply generating means.

  With these configurations, a simple, inexpensive and simple control reduces the inrush current that occurs when returning from standby, reduces the power loss due to the PWM controller, and the control circuit has a microcomputer as the core. Since it can be stopped, the standby power can be significantly reduced as a whole.

  The air conditioner according to the present invention can also be applied to an air conditioner equipped with an air purifier, an air purifier, or a ventilator.

DESCRIPTION OF SYMBOLS 1 Rectifier 2 Voltage conversion means 3 PWM control part 4 Motor drive part 5 PWM drive part 6 Motor for ventilation 7 Variable means 8 Control part 9 Waveform shaping circuit 10 Oscillation circuit 11 1st voltage stabilization means 12 2nd voltage stabilization Means 13 Connection means 14 Low potential generating means 15 Switch

Claims (4)

Voltage conversion means for converting the AC voltage of the commercial power supply from at least one rectified high voltage DC voltage into at least one low voltage output voltage, and the DC voltage output from the voltage conversion means operates as a control power supply, and the high voltage DC is switched. A blower motor that controls the rotation speed of the motor by applying it to the motor winding, a variable means that varies the motor control power supply voltage, an operation start command and outputs a rotation speed command to the motor, An air conditioner including a control unit having a microcomputer as a core for inputting a variable width signal to the variable means to vary a control power supply voltage to the motor. It consists of an oscillation circuit and a waveform shaping circuit, and has a narrow pulse generation means that generates a pulse with a width that can reduce the inrush current when returning to normal operation while reducing power consumption during standby operation. The motor control voltage according to claim 1, wherein the motor control voltage is reduced by supplying a control voltage necessary for stable operation of the motor and by narrowing a generated pulse by the narrow pulse generating means during standby operation. Air conditioner. A first voltage stabilizing means for generating a control voltage required for the motor to stably operate a control power supply for the blower motor; and a second voltage stabilizing means for varying the control voltage; The second stabilizing means is connected to the control voltage generating circuit, and the second stabilizing means is released from the circuit by the connecting means during normal operation and the second by the connecting means during standby. The air conditioner according to claim 1, wherein the stabilizing means is connected to the control voltage generation circuit. The motor control power supply for the blower motor, voltage stabilizing means for generating a control voltage necessary for the motor to operate stably, and a small potential for suppressing the inrush current at the time of return from standby are always applied to the motor. The air conditioner according to claim 1, wherein the air conditioner is constituted by a small potential generating means applied to the control power source.

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