JP2019122060A - Three-phase voltage doubler rectifier circuit, air conditioning device, and control method using air conditioning device - Google Patents

Abstract

To provide a three-phase voltage doubler circuit capable of improving the power efficiency of a device using the three-phase voltage doubler circuit.SOLUTION: A three-phase voltage doubler includes a first transistor and a second transistor which are connected between an output terminal of a bridge circuit for rectifying three-phase AC voltage and an input terminal for inputting a return current, and are connected in series, in which a third transistor is provided between a first capacitor and the first transistor in the first capacitor and the second capacitor, which are connected in series, and a fourth transistor is provided between the second capacitor and the second transistor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a three-phase voltage doubler rectifier circuit, an air conditioner, and a control method using the air conditioner.

As a circuit for converting alternating current power supplied from a three-phase alternating current power supply into direct current power, there is a three-phase voltage doubler rectifier circuit.
Patent Document 1 discloses, as a related technology, a technology related to a three-phase voltage doubler rectifier circuit using diodes generally called FRD (Fast Recovery Diode) (diodes indicated by reference numerals D7 and D8 in Patent Document 1). Is described.

JP 2008-012586 A

By the way, the FRD is an element that realizes a short reverse recovery time as compared to a general diode in order to increase the efficiency of the device. Therefore, when the technology described in Patent Document 1 is used in an apparatus such as an air conditioner, a voltage drop corresponding to a forward voltage occurs in the FRD, which may lower the power efficiency of the apparatus compared to a general diode. There is. The reverse recovery time is the time taken for the diode to go from the on state to the complete off state.
Therefore, there is a need for a technique that can improve the power efficiency of a device in which a three-phase voltage doubler rectifier circuit is used.

  An object of the present invention is to provide a three-phase voltage doubler rectifier circuit, an air conditioner, and a control method using the air conditioner that can solve the above-mentioned problems.

  According to a first aspect of the present invention, a three-phase voltage doubler rectifier circuit is a first transistor having a first terminal, a second terminal, and a third terminal, and is configured to receive an alternating voltage supplied from a three-phase alternating voltage. A first terminal to which the second terminal through which a current according to a voltage applied to the first terminal flows is connected to an output terminal for outputting a rectified voltage of the bridge circuit for rectifying; A second transistor having a second terminal and a third terminal, wherein the current corresponding to the voltage applied to the first terminal of the second transistor is input to the input terminal to which the return current of the bridge circuit is input. A second terminal connected to the third terminal of the second transistor through which the second current flows, and the second terminal of the second transistor connected to the third terminal of the first transistor A third transistor having a first terminal, a second terminal, and a third terminal, wherein a voltage applied to the first terminal of the third transistor is applied to the second terminal of the first transistor. A third transistor connected to the third terminal of the third transistor through which a current corresponding to the third transistor flows, and a fourth transistor having a first terminal, a second terminal, and a third terminal, the second transistor A fourth transistor to which the second terminal of the fourth transistor to which a current according to the voltage applied to the first terminal of the fourth transistor flows is connected to the third terminal of the fourth transistor; A first capacitor having one terminal and a second terminal, wherein the first terminal of the first capacitor is connected to the second terminal of the third transistor. A second capacitor having a first terminal, a first terminal, and a second terminal, wherein the third terminal of the first transistor is connected to the second terminal of the first capacitor; The first terminal of the second capacitor is connected to the third terminal of one transistor, and the second terminal of the second capacitor is connected to the third terminal of the fourth transistor. And a second capacitor.

  According to a second aspect of the present invention, in the three-phase voltage doubler rectifier circuit according to the first aspect, each of the first transistor, the second transistor, the third transistor, and the fourth transistor includes: 1 terminal is a first control signal that switches between ON state and OFF state at each timing when the voltage of the output terminal of the bridge circuit becomes a minimum value when the number of revolutions of the motor is equal to or greater than a predetermined number of revolutions And the first terminal of the first transistor and the first terminal of the fourth transistor are the first terminal of the second transistor and the first terminal of the third transistor. When the first control signal in the on state is received, the first control signal in the off state is received, and the first transistor of the second transistor is When the first terminal having a child with the said third transistor receives said first control signal of the OFF state may be one that receives the first control signal of the ON state.

  According to a third aspect of the present invention, in the three-phase voltage doubler rectifier circuit according to the first or second aspect, the first terminal of each of the first transistor and the second transistor is a motor Is a terminal that always receives the second control signal that indicates the off state when the number of rotations of the second transistor is less than a predetermined number of rotations, and the first terminal of each of the third and fourth transistors is The terminal may receive the second control signal that always indicates the on state when the number of rotations of the motor is less than the predetermined number of rotations.

  According to a fourth aspect of the present invention, in the three-phase voltage doubler rectifier circuit according to any one of the first to third aspects, at least one of the third transistor and the fourth transistor is a super junction MOSFET. (Metal-Oxide-Semiconductor Field-Eeffect Transistor) may be used.

  According to a fifth aspect of the present invention, an air conditioner includes the three-phase voltage doubler rectifier circuit according to any one of the first to fourth aspects, and an AC voltage supplied from the three-phase AC voltage as a bridge circuit. The control signal that switches between on and off at each timing when the rectified voltage rectified by the voltage becomes the minimum value is the first transistor, the second transistor, the third transistor, and the third transistor provided in the three-phase voltage doubler rectifier circuit. And a control unit that outputs the first terminal of each of the fourth transistors.

  According to a sixth aspect of the present invention, in the air conditioner according to the fifth aspect, the three-phase voltage doubler rectifier circuit is provided between an output terminal of the bridge circuit and the second terminal of the first transistor. A reactor for improving ripples in the output of the bridge circuit, and the control unit changes a timing at which the control signal is switched on and off based on a phase difference of voltage between both terminals of the reactor It may be

  According to a seventh aspect of the present invention, a control method by an air conditioner is a first transistor having a first terminal, a second terminal, and a third terminal, wherein an AC voltage supplied from a three-phase AC voltage is A first terminal to which the second terminal through which a current according to a voltage applied to the first terminal flows is connected to an output terminal for outputting a rectified voltage of the bridge circuit for rectifying; A second transistor having a second terminal and a third terminal, wherein the current corresponding to the voltage applied to the first terminal of the second transistor is input to the input terminal to which the return current of the bridge circuit is input. Is connected to the third terminal of the second transistor, and the second terminal of the second transistor is connected to the third terminal of the first transistor. A third transistor having a transistor, a first terminal, a second terminal, and a third terminal, wherein a voltage applied to the first terminal of the third transistor is applied to the second terminal of the first transistor. A third transistor connected to the third terminal of the third transistor through which a current corresponding to the third transistor flows, and a fourth transistor having a first terminal, a second terminal, and a third terminal, the second transistor A fourth transistor to which the second terminal of the fourth transistor to which a current according to the voltage applied to the first terminal of the fourth transistor flows is connected to the third terminal of the fourth transistor; A first capacitor having one terminal and a second terminal, wherein the first terminal of the first capacitor is the second terminal of the third transistor. A second capacitor having a first terminal, a first terminal, and a second terminal connected to each other and to which the second terminal of the first capacitor is connected to the third terminal of the first transistor; The first terminal of the second capacitor is connected to the third terminal of the first transistor, and the second terminal of the second capacitor is connected to the third terminal of the fourth transistor. A control method using an air conditioner having a control unit and a three-phase voltage doubler rectifier circuit including the second capacitor, wherein the control unit is configured to control the number of rotations of the motor to be equal to or greater than a predetermined number of rotations. Control for outputting, to the three-phase voltage doubler rectifier circuit, a first control signal that switches between an on state and an off state at each timing when the voltage at the output terminal of the bridge circuit becomes a minimum value. A second portion of the second transistor when the first control signal in the off state is output to the first terminal of the first transistor and the first terminal of the fourth transistor. The first control signal in the on state is output to the first terminal of the first terminal and the third transistor, and the first terminal of the first transistor and the first terminal of the fourth transistor are output. When the first control signal in the on state is output, the first control signal in the off state is output to the first terminal of the second transistor and the first terminal of the third transistor; A control unit that outputs the second control signal always indicating the off state to the three-phase voltage doubler rectifier circuit when the number of rotations of the second motor is less than a predetermined number of rotations, The second control signal indicating the on state is always output to the first terminal of each of the third transistor and the fourth transistor when the number of rotations of the data is less than the predetermined number of rotations. .

  The three-phase voltage doubler rectifier circuit according to the embodiment of the present invention can improve the power efficiency of a device using the three-phase voltage doubler rectifier circuit.

It is a figure which shows the structure of the air conditioner by one Embodiment of this invention. It is a figure for demonstrating the 1st control signal in one embodiment of the present invention, and the 2nd control signal. It is a figure which shows the processing flow of the air conditioner by one Embodiment of this invention. It is a figure for demonstrating the effect by the three-phase voltage doubler rectifier circuit by one Embodiment of this invention. It is a figure for demonstrating the 1st control signal in another embodiment of this invention. It is a schematic block diagram showing composition of a computer concerning at least one embodiment.

Embodiment
Hereinafter, a configuration of an air conditioner (hereinafter, referred to as “air conditioner”) motor drive device according to an embodiment of the present invention will be described.
The air conditioner 1 according to one embodiment of the present invention rectifies an alternating current supplied from a three-phase alternating current power supply to generate a direct current voltage, and converts the generated direct current voltage into an alternating current voltage for rotating a compressor motor. The compressor motor is rotated to generate compressed air, and heat exchange of the air through the refrigerant is performed to realize at least one of cooling and heating. As shown in FIG. 1, the air conditioner 1 includes a three-phase voltage doubler rectifier circuit 10, an inverter 20, a compressor motor 30, a first control unit 40, a second control unit 50, and a rotation speed detection unit 60.
A three-phase alternating current power supply 70 shown in FIG. 1 is a power supply that supplies power to the air conditioner 1. Three-phase alternating current power supply 70 outputs three alternating current voltages whose phases are different by 120 degrees. Three-phase alternating current power supply 70 is, for example, a commercial power supply.

  The three-phase voltage doubler rectifier circuit 10 includes a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, a sixth terminal, a seventh terminal, and an eighth terminal. The inverter 20 includes a first terminal, a second terminal, a third terminal, a fourth terminal, and a fifth terminal. The compressor motor 30 includes a first terminal, a second terminal, and a third terminal. The first control unit 40 includes a first terminal, a second terminal, a third terminal, a fourth terminal, and a fifth terminal. The second control unit 50 includes a first terminal and a second terminal. The rotation speed detection unit 60 includes a first terminal and a second terminal. The three-phase alternating current power supply 70 includes a first terminal, a second terminal, a third terminal, and a fourth terminal.

The first terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the first terminal of the inverter 20. The second terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the second terminal of the inverter 20 and the first terminal of the second control unit 50. The third terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the first terminal of the first control unit 40. The fourth terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the second terminal of the first control unit 40. The fifth terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the third terminal of the first control unit 40. The sixth terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the fourth terminal of the first control unit 40. The seventh terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the first terminal of the three-phase AC power supply 70. The eighth terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the second terminal of the three-phase AC power supply 70. The ninth terminal of the three-phase voltage doubler rectifier circuit 10 is connected to the third terminal of the three-phase AC power supply 70.
The third terminal of the inverter 20 is connected to the second terminal of the second control unit 50. The fourth terminal of the inverter 20 is connected to the first terminal of the compressor motor 30. The fifth terminal of the inverter 20 is connected to the second terminal of the compressor motor 30. The sixth terminal of the inverter 20 is connected to the third terminal of the compressor motor 30.
A first terminal of the rotation number detection unit 60 detects the rotation number of the compressor motor 30 and receives information on the rotation number. The second terminal of the rotational speed detector 60 is connected to the fifth terminal of the first controller 40.

  Three-phase voltage doubler rectifier circuit 10 is a circuit for converting a three-phase AC voltage supplied from three-phase AC power supply 70 with a phase difference of 120 degrees to a DC voltage according to a control signal received from first control unit 40. is there. As shown in FIG. 1, the three-phase voltage doubler rectifier circuit 10 includes diodes D1, D2, D3, D4, D5, D6, a reactor L1, power transistors Q1, Q2, M1, M2, and capacitors C1, C2.

  Each of the diodes D1, D2, D3, D4, D5, D6 comprises an anode and a cathode. Each of reactor L1 and capacitors C1 and C2 has a first terminal and a second terminal. Each of the power transistors Q1 and Q2 is, for example, an IGBT (Insulated Gate Bipolar Transistor), and includes an emitter, a gate, and a collector. Each of the power transistors M1 and M2 is, for example, a SJ-MOSFET (Super Junction-Metal-Oxide-Semiconductor Field-Eeffect Transistor), and includes a source, a gate, and a drain. Each of the power transistors M1 and M2 is an nMOS transistor, and in each of the power transistors M1 and M2, the substrate is connected to the source. As a result, since the same potential is applied to the p region of the substrate and the n region of the source, the pn connection between the substrate and the source does not become a parasitic diode. On the other hand, in each of the power transistors M1 and M2, different potentials are applied to the p region of the substrate and the n region of the drain, so the pn connection between the substrate and the drain constitutes a parasitic diode.

The anode of the diode D1 is connected to the cathode of the diode D2. The anode of the diode D1 serves as the ninth terminal of the three-phase voltage doubler rectifier circuit 10. The cathode of the diode D1 is connected to the cathode of the diode D3, the cathode of the diode D5, and the first terminal of the reactor L1.
The anode of the diode D2 is connected to the anode of the diode D4, the anode of the diode D6, the emitter of the power transistor Q2, and the drain of the power transistor M2.
The anode of the diode D3 is connected to the cathode of the diode D4. The anode of the diode D3 is the eighth terminal of the three-phase voltage doubler rectifier circuit 10.
The anode of the diode D5 is connected to the cathode of the diode D6. The anode of the diode D5 is the seventh terminal of the three-phase voltage doubler rectifier circuit 10.

The second terminal of reactor L1 is connected to the collector of power transistor Q1 and the source of power transistor M1.
The gate of the power transistor Q1 is the sixth terminal of the three-phase voltage doubler rectifier circuit 10. The emitter of the power transistor Q1 is connected to the collector of the power transistor Q2, the first terminal of the capacitor C1, and the first terminal of the capacitor C2.
The gate of the power transistor Q2 is the fifth terminal of the three-phase voltage doubler rectifier circuit 10.
The gate of the power transistor M1 is the third terminal of the three-phase voltage doubler rectifier circuit 10. The drain of the power transistor M1 is connected to the second terminal of the capacitor C1. The drain of the power transistor M1 serves as the first terminal of the three-phase voltage doubler rectifier circuit 10.
The gate of the power transistor M2 is the fourth terminal of the three-phase voltage doubler rectifier circuit 10. The source of the power transistor M2 is connected to the second terminal of the capacitor C2. The source of the power transistor M2 is the second terminal of the three-phase voltage doubler rectifier circuit 10.

The diodes D1, D2, D3, D4, D5 and D6 constitute a three-phase bridge circuit. The diodes D 1, D 2, D 3, D 4, D 5 and D 6 constituting the three-phase bridge circuit rectify the current supplied from the three-phase AC power supply 70 to generate a DC voltage.
Reactor L1 constitutes a ripple removal filter with capacitors C1 and C2.

Each of power transistors Q 1, Q 2, M 1 and M 2 is turned on or off in response to a control signal received from first control unit 40. Then, the capacitors C1 and C2 are charged by the voltage generated by the diodes D1, D2, D3, D4, D5, and D6 constituting the three-phase bridge circuit.
At this time, the first control unit 40 acquires the number of rotations of the compressor motor 30. In addition, the first control unit 40 holds information indicating a predetermined number of revolutions serving as a determination reference for switching between the first control signal and the second control signal. Then, the first control unit 40 compares the acquired number of rotations with a predetermined number of rotations indicated by the information to be held. The first control unit 40 outputs, to the three-phase voltage doubler rectifier circuit 10, a first control signal that causes the DC voltage to be output twice as large as the amplitude of the three-phase AC voltage when the acquired rotational speed is equal to or higher than a predetermined rotational speed. Do. The first control unit 40 outputs, to the three-phase voltage doubler rectifier circuit 10, a second control signal that causes the DC voltage to be output that is one time the amplitude of the three-phase AC voltage when the acquired rotational speed is less than the predetermined rotational speed. Do. Depending on the difference between the first control signal and the second control signal, the charge stored in the capacitors C1 and C2 is different depending on whether the number of rotations of the compressor motor 30 is equal to or greater than the predetermined number of rotations. Differently, when receiving the first control signal from the first control unit 40, the three-phase voltage doubler rectifier circuit 10 outputs a DC voltage twice as large as the amplitude of the three-phase AC voltage to the inverter 20. When the second control signal is received, the DC voltage that is one time the amplitude of the three-phase AC voltage is output to the inverter 20.
The DC voltage that is one time the amplitude of the three-phase AC voltage is calculated from the effective value, for example, when the effective value of the rectified voltage output from the three-phase AC power supply 70 is 200 volts, The DC voltage that is one time the amplitude of the three-phase AC voltage is (200 ・ 2) volts. Further, a DC voltage twice as large as the amplitude of the three-phase AC voltage is (400 · √2) volts.

  Here, for the case where the first control unit 40 outputs the first control signal to the three-phase voltage doubler rectifier circuit 10 and the case where the first control unit 40 outputs the second control signal to the three-phase voltage doubler rectifier circuit 10, a three-phase voltage doubler rectifier circuit The operation of generating a direct current 10 will be described with reference to FIG.

First, the operation of the three-phase voltage doubler rectifier circuit 10 when the first control unit 40 outputs the first control signal to the three-phase voltage doubler rectifier circuit 10 will be described.
The waveform V1 described in the portion of FIG. 2 (a) is a voltage at the cathode of the diode D1, and after being rectified by the diodes D1, D2, D3, D4, D5, D6 constituting the three-phase bridge circuit. It is a voltage. Further, the waveform indicating on or off described in the portion of FIG. 2A is a first control signal. In the part of FIG. 2A, the vertical direction represents the amplitude. Also, the horizontal direction represents time. Further, in the portion of FIG. 2A, each of the waveforms Q1, Q2, M1, and M2 represents a control signal applied to each gate of the power transistors Q1, Q2, M1, and M2. As shown in the portion of FIG. 2A, each of the waveforms Q1, Q2, M1, and M2 has an on state (high level) and an off state (low level) at the timing when the voltage V1 becomes the minimum value. Switch. Also, the waveforms Q1 and M2 change similarly between the on state and the off state. Further, the waveforms Q2 and M1 are in the off state when the waveforms Q1 and M2 are in the on state, and are in the on state when the waveforms Q1 and M2 are in the off state. The on resistance of each of the power transistors M1 and M2 is smaller than the impedance of the parasitic diode. Therefore, when each of the power transistors M1 and M2 is in the on state, almost no current flows in the parasitic diode, and almost all current flows from the source to the drain, which constitutes the transistor.

While the waveforms Q1 and M2 are in the off state and the waveforms Q2 and M1 are in the on state, the power transistors Q1 and M2 are opened by the first control signal, and the parasitic diode of the power transistor M2 becomes conductive. In the transistors Q2 and M1, only a voltage drop corresponding to the on resistance occurs. In this case, a current flows from the node at the cathode of the diode D1 to the node at the anode of the diode D2 via the reactor L1, the power transistor M1, the capacitor C1 and the power transistor Q2, and the capacitor C1 is charged. Also, in this case, assuming that the on resistance of the power transistors Q2 and M1 is 0 ohm, a voltage after being rectified by the diodes D1, D2, D3, D4, D5 and D6 is applied to the capacitor C1.
Also, while the waveforms Q1 and M2 are in the on state and the waveforms Q2 and M1 are in the off state, the first control signal causes only a voltage drop in the power transistors Q1 and M2 according to the on resistance. M1 is opened and the parasitic diode of the power transistor M1 becomes conductive. In this case, a current flows from the node at the cathode of the diode D1 to the node at the anode of the diode D2 via the reactor L1, the power transistor Q1, the capacitor C2 and the power transistor M2, and the capacitor C2 is charged. Also, in this case, assuming that the on resistance of the power transistors Q1 and M2 is 0 ohm, the voltage rectified by the diodes D1, D2, D3, D4, D5, D6 is applied to the capacitor C2.
Therefore, when first control unit 40 repeatedly switches on and off the first control signal at every timing when voltage V1 becomes the minimum value, each of capacitors C1 and C2 becomes a fully charged voltage, that is, three. It is charged to a DC voltage which is one time the amplitude of the phase AC voltage. Here, the capacitors C1 and C2 are connected in series. Therefore, in the case where the first control unit 40 outputs the first control signal to the three-phase voltage doubler rectifier circuit 10, the three-phase voltage doubler rectifier circuit 10 has one amplitude of the three-phase AC voltage applied to the capacitor C2. A DC voltage twice as large as the amplitude of the three-phase AC voltage is output to the inverter 20, in which a DC voltage one time as large as the amplitude of the three-phase AC voltage applied to the capacitor C1 is added to the double DC voltage.

Next, the operation of the three-phase voltage doubler rectifier circuit 10 when the first control unit 40 outputs the second control signal to the three-phase voltage doubler rectifier circuit 10 will be described. When the first control unit 40 outputs the second control signal to the three-phase voltage doubler rectifier circuit 10, the three-phase voltage doubler rectifier circuit 10 is rectified by the diodes D1, D2, D3, D4, D5, D6. It outputs the subsequent DC voltage as it is (ie, a voltage of 1 ×).
The waveform V1 described in the portion of FIG. 2 (b) is the voltage at the cathode of the diode D1 similarly to the waveform V1 described in the portion of FIG. 2 (a), and constitutes a three-phase bridge circuit It is a voltage rectified by the diodes D1, D2, D3, D4, D5 and D6. Also, the two waveforms indicating on and off described in the portion of FIG. 2B are the second control signal. In the part of FIG. 2 (b), the vertical direction represents the amplitude. Also, the horizontal direction represents time. Further, in the portion of FIG. 2B, each of the waveforms Q1 and Q2 is a control signal applied to the gate of each of the power transistors Q1 and Q2, and is a control that indicates that each of the power transistors Q1 and Q2 is always off. It is a signal. Further, each of the waveforms M1 and M2 is a control signal applied to the gate of each of the power transistors M1 and M2, and is a control signal that always indicates ON. That is, the three-phase voltage doubler rectifier circuit 10 outputs the voltage applied to the serially connected capacitors C1 and C2 charged by the voltage rectified by the diodes D1, D2, D3, D4, D5, D6. .

  The on resistance of each of the power transistors M1 and M2 is smaller than the impedance of the parasitic diode. Therefore, when the control signal applied to the gate of each of power transistors M1 and M2 is a control signal always indicating ON, almost no current flows in the parasitic diode, and in each of power transistors M1 and M2, As the voltage Vsd between drains, only a voltage drop corresponding to the on resistance occurs. Also, each of the power transistors Q1 and Q2 is in an open state. A voltage at which the capacitors C1 and C2 connected in series are fully charged by the voltage of the waveform V1 is applied to the inverter 20. Therefore, the three-phase voltage doubler rectifier circuit 10 outputs, to the inverter 20, a DC voltage that is one time the amplitude of the three-phase AC voltage.

  The second control unit 50 acquires the current value of the compressor motor 30 flowing to the second terminal of the inverter 20. The second control unit 50 outputs a control signal for controlling a voltage applied to the compressor motor 30 to the inverter 20 based on the received current value.

  The rotation speed detection unit 60 detects the rotation speed of the compressor motor 30. The rotation speed detection unit 60 is, for example, a rotary encoder. The rotation speed detection unit 60 outputs the detected rotation speed to the first control unit 40.

Next, a process flow in which the three-phase voltage doubler rectifier circuit 10 generates a direct current when the first control unit 40 changes the control signal shown in FIG. 3 will be described.
When the air conditioner 1 starts up, the first control unit 40 acquires the number of rotations of the compressor motor 30 from the number-of-rotations detection unit 60 (step S1). The first control unit 40 compares a predetermined rotation number indicated by information held in advance with the rotation number acquired from the rotation number detection unit, and determines whether the acquired rotation number is equal to or more than a predetermined rotation number. Is determined (step S2).
The first control unit 40 generates a first control signal when it is determined that the acquired rotation speed is equal to or more than a predetermined rotation speed (YES in step S2) (step S3).
In addition, the first control unit 40 generates a second control signal, when it is determined that the acquired rotation speed is less than the predetermined rotation speed (NO in step S2).
Then, the first control unit 40 outputs the generated control signal (that is, the first control signal or the second control signal) to the three-phase voltage doubler rectifier circuit 10 (step S5).

The three-phase voltage doubler rectifier circuit 10 receives a control signal from the first control unit 40 (step S6).
Three-phase voltage doubler rectifier circuit 10 generates a DC voltage according to the received control signal (step S7). Specifically, when the received control signal is the first control signal, three-phase voltage doubler rectifier circuit 10 outputs a DC voltage twice the amplitude of the three-phase AC voltage to inverter 20. Further, when the received control signal is the second control signal, the three-phase voltage doubler rectifier circuit 10 outputs a DC voltage that is one time the amplitude of the three-phase AC voltage to the inverter 20 (step S8).

Inverter 20 receives a DC voltage from three-phase voltage doubler rectifier circuit 10 (step S9). At this time, the second control unit 50 acquires the current value of the compressor motor 30. The second control unit 50 generates a control signal for controlling the output voltage of the inverter 20 according to the acquired current value of the compressor motor 30. The second control unit 50 outputs the generated control signal to the inverter 20. The inverter 20 receives a control signal from the second control unit 50 (step S10). Inverter 20 generates an alternating voltage according to the received control signal (step S11). The inverter 20 outputs the generated alternating voltage to the compressor motor 30 (step S12).
Compressor motor 30 receives an AC voltage from inverter 20 (step S13). When the compressor motor 30 receives an alternating voltage, a current flows in the compressor motor 30. The compressor motor 30 rotates at a rotational speed corresponding to the flowing current (step S14). As a result, compressed air is generated in the air conditioner 1.
The inductor L1 is not necessary when the change in the output voltage of the bridge circuit constituted by the diodes D1, D2, D3, D4, D5, and D6 is small. In this case, the cathode of the diode D1 may be connected to the collector of the power transistor Q1 and the source of the power transistor M1.

Hereinabove, the air conditioner 1 including the three-phase voltage doubler rectifier circuit 10 according to the embodiment of the present invention has been described.
A three-phase voltage doubler rectifier circuit 10 according to an embodiment of the present invention is a first transistor having a first terminal, a second terminal, and a third terminal, and is a bridge that rectifies an AC voltage supplied from a three-phase AC voltage. The first transistor to which the second terminal through which a current according to the voltage applied to the first terminal flows is connected to an output terminal for outputting a rectified voltage of the circuit, a first terminal, and a second terminal A second transistor having a third terminal, wherein a current corresponding to a voltage applied to the first terminal of the second transistor flows to an input terminal to which a return current of the bridge circuit is input The second transistor is connected to the third terminal of the second transistor, and the second terminal of the second transistor is connected to the third terminal of the first transistor. A third transistor having a first terminal, a second terminal, and a third terminal, wherein a voltage applied to the first terminal of the third transistor is applied to the second terminal of the first transistor. A third transistor connected to the third terminal of the third transistor through which a current corresponding to the third transistor flows, and a fourth transistor having a first terminal, a second terminal, and a third terminal, the second transistor A fourth transistor to which the second terminal of the fourth transistor to which a current according to the voltage applied to the first terminal of the fourth transistor flows is connected to the third terminal of the fourth transistor; A first capacitor having one terminal and a second terminal, wherein the first terminal of the first capacitor is connected to the second terminal of the third transistor. A second capacitor having a first terminal, a first terminal, and a second terminal, wherein the third terminal of the first transistor is connected to the second terminal of the first capacitor; The first terminal of the second capacitor is connected to the third terminal of one transistor, and the second terminal of the second capacitor is connected to the third terminal of the fourth transistor. And a second capacitor.
That is, the three-phase voltage doubler rectifier circuit 10 according to one embodiment of the present invention includes the power transistor M1 between the collector of the power transistor Q1 and the first terminal of the capacitor C1, and the emitter of the power transistor Q2 and the capacitor C2. A power transistor M2 is provided between it and the first terminal.
On the other hand, for example, in the three-phase voltage doubler rectifier circuit described in Patent Document 1, a diode called FRD (Fast Recovery Diode) replaces the power transistors M1 and M2 in the embodiment of the present invention (in Patent Document 1) Diodes denoted by D7 and D8 are used.
The characteristics showing the relationship between the ON voltage and current of the FRD and the relationship between the ON voltage and current of the power transistors M1 and M2 are, for example, the characteristics shown in FIG. The characteristics described as the source-drain voltage Vsd in FIG. 4 are the characteristics of the power transistors M1 and M2. Further, the characteristic described as Vf in FIG. 4 is the characteristic of the FRD. As can be seen from FIG. 4, the FRD has an offset in the on voltage direction, and a voltage drop corresponding to the offset necessarily occurs. On the other hand, in the power transistors M1 and M2, no voltage drop occurs due to the offset.
That is, in the three-phase voltage doubler rectifier circuit 10 according to one embodiment of the present invention, the voltage drop is improved by 2 (Vf-Vsd) compared to the three-phase voltage doublet rectifier circuit using FRD. It is improved by (Vf-Vsd) x (the current flowing to the compressor motor 30 which is a load). The voltage Vf is a forward voltage of FRD. Further, the voltage Vsd is a value obtained by multiplying the on-resistance of the power transistor M1 or M2 by the current flowing to the compressor motor 30, that is, the voltage between the source and the drain.
Therefore, the three-phase voltage doubler rectifier circuit 10 according to an embodiment of the present invention has better power efficiency than, for example, the three-phase voltage doubler rectifier circuit described in Patent Document 1 and the like.

  In the embodiment of the present invention, it has been described that the first control unit 40 switches on and off of the first control signal at each timing when the voltage V1 becomes the minimum value. However, in another embodiment of the present invention, as shown in FIG. 5, the ON and OFF states of the first control signal and the second control signal are shifted by θ from the timing at which the voltage V1 becomes the minimum value. It is also good. When the reactor L1 is present, an induced voltage is generated when a current flows through the reactor L1. Therefore, the timing at which the voltage waveform between the first terminal and the second terminal of reactor L1 becomes the minimum value differs. The value of θ may be determined to correct the timing difference.

  In the embodiment of the present invention, the first control unit 40 has been described as receiving information on the rotation speed of the compressor motor 30 from the rotation speed detection unit 60. However, in another embodiment of the present invention, the first control unit 40 may receive information on the rotation speed of the compressor motor 30 from the second control unit 50. Specifically, for example, the first control unit 40 acquires a control signal from the second control unit 50. The control signal of the second control unit 50 controls the number of rotations of the compressor motor 30. Therefore, the first control unit 40, for example, holds in advance information indicating the relationship between the control signal and the number of revolutions corresponding to the control signal, and thus the compressor motor is obtained from the control signal acquired from the second control unit 50. 30 revolutions can be identified.

  In the process according to the embodiment of the present invention, the order of the processes may be switched as long as the appropriate process is performed.

Although the embodiment of the present invention has been described, the above-described first control unit 40, second control unit 50, and other control devices may have a computer system inside. The process of the process described above is stored in the form of a program in a computer readable recording medium, and the process is performed by the computer reading and executing the program. An example of a computer is shown below.
FIG. 6 is a schematic block diagram showing the configuration of a computer according to at least one embodiment.
The computer 5 includes a CPU 6, a main memory 7, a storage 8 and an interface 9, as shown in FIG.
For example, each of the first control unit 40, the second control unit 50, and the other control devices described above is mounted on the computer 5. The operation of each processing unit described above is stored in the storage 8 in the form of a program. The CPU 6 reads a program from the storage 8 and develops it in the main memory 7 and executes the above processing according to the program. Further, the CPU 6 secures a storage area corresponding to each storage unit described above in the main memory 7 in accordance with a program.

  Examples of the storage 8 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magnetooptical disk, a compact disc read only memory (CD-ROM), and a digital versatile disc read only memory (DVD-ROM). , Semiconductor memory and the like. The storage 8 may be internal media directly connected to the bus of the computer 5 or may be external media connected to the computer 5 via the interface 9 or a communication line. When the program is distributed to the computer 5 by a communication line, the computer 5 that has received the distribution may expand the program in the main memory 7 and execute the above processing. In at least one embodiment, storage 8 is a non-transitory tangible storage medium.

  Also, the program may realize part of the functions described above. Furthermore, the program may be a file capable of realizing the above-described functions in combination with a program already recorded in a computer system, a so-called difference file (difference program).

  While several embodiments of the present invention have been described, these embodiments are examples and do not limit the scope of the invention. Various additions, omissions, replacements and changes may be made to these embodiments without departing from the scope of the invention.

1 · · · air conditioner 5 · · · computer 6 · · · CPU
7 main memory 8 storage 9 interface 10 three-phase voltage doubler rectifier circuit 20 inverter 30 compressor motor 40 first control unit 50 first 2 control unit 60 ... rotation speed detection unit 70 ... three-phase AC power supply

Claims (7)

The first transistor having a first terminal, a second terminal, and a third terminal, the output terminal outputting the rectified voltage of a bridge circuit for rectifying an alternating voltage supplied from a three-phase alternating voltage, The first transistor to which the second terminal through which a current according to a voltage applied to one terminal flows is connected;
A second transistor having a first terminal, a second terminal, and a third terminal, wherein a voltage applied to the first terminal of the second transistor is input to an input terminal to which a return current of the bridge circuit is input. And the second terminal of the second transistor is connected to the third terminal of the first transistor. The second terminal of the second transistor is connected to the third terminal of the second transistor. When,
A third transistor having a first terminal, a second terminal, and a third terminal, wherein a voltage applied to the first terminal of the third transistor is applied to the second terminal of the first transistor. The third transistor to which the third terminal of the third transistor through which current flows is connected;
A fourth transistor having a first terminal, a second terminal, and a third terminal, wherein the voltage is applied to the third terminal of the second transistor according to the voltage applied to the first terminal of the fourth transistor. The fourth transistor to which the second terminal of the fourth transistor through which current flows is connected;
A first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is connected to the second terminal of the third transistor, and the third terminal of the first transistor is connected. The first capacitor to which the second terminal of the first capacitor is connected;
A second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is connected to the third terminal of the first transistor, and the third terminal of the fourth transistor is connected. The second capacitor to which the second terminal of the second capacitor is connected;
Three-phase voltage doubler rectifier circuit. The first terminal of each of the first transistor, the second transistor, the third transistor, and the fourth transistor is:
A terminal that receives a first control signal that switches between the on state and the off state at each timing when the voltage of the output terminal of the bridge circuit becomes a minimum value when the number of revolutions of the motor is equal to or greater than a predetermined number of revolutions. Yes,
The first terminal of the first transistor and the first terminal of the fourth transistor are:
When the first terminal of the second transistor and the first terminal of the third transistor receive the first control signal of the on state, the first control signal of the off state is received; When the first terminal of the two transistors and the first terminal of the third transistor receive the first control signal in the off state, the first control signal in the on state is received.
The three-phase voltage doubler rectifier circuit according to claim 1. The first terminal of each of the first transistor and the second transistor is:
A terminal that receives the second control signal that always indicates the off state when the number of rotations of the motor is less than a predetermined number of rotations,
The first terminal of each of the third transistor and the fourth transistor is
A terminal that receives the second control signal that always indicates the on state when the number of rotations of the motor is less than the predetermined number of rotations;
The three-phase voltage doubler rectifier circuit according to claim 1 or 2. At least one of the third transistor and the fourth transistor is
It is a super junction MOSFET (Metal-Oxide-Semiconductor Field-Eeffect Transistor),
The three-phase voltage doubler rectifier circuit according to any one of claims 1 to 3. The three-phase voltage doubler rectifier circuit according to any one of claims 1 to 4.
The three-phase voltage doubler rectifier circuit is provided with a control signal that switches between on and off at each timing when the voltage after rectified by alternating current voltage supplied from a three-phase alternating voltage is reduced to a minimum value by the bridge circuit. A control unit that outputs the first terminal of each of the transistor, the second transistor, the third transistor, and the fourth transistor;
An air conditioner equipped with The three-phase voltage doubler circuit is
The reactor which improves the ripple in the output of the bridge circuit is provided between the output terminal of the bridge circuit and the second terminal of the first transistor,
The control unit
The timing at which the control signal is switched on and off is changed based on a phase difference of voltage between both terminals of the reactor.
The air conditioner according to claim 5. The first transistor having a first terminal, a second terminal, and a third terminal, the output terminal outputting the rectified voltage of a bridge circuit for rectifying an alternating voltage supplied from a three-phase alternating voltage, The first transistor to which the second terminal through which a current according to a voltage applied to one terminal flows is connected;
A second transistor having a first terminal, a second terminal, and a third terminal, wherein a voltage applied to the first terminal of the second transistor is input to an input terminal to which a return current of the bridge circuit is input. And the second terminal of the second transistor is connected to the third terminal of the first transistor. The second terminal of the second transistor is connected to the third terminal of the second transistor. When,
A third transistor having a first terminal, a second terminal, and a third terminal, wherein a voltage applied to the first terminal of the third transistor is applied to the second terminal of the first transistor. The third transistor to which the third terminal of the third transistor through which current flows is connected;
A fourth transistor having a first terminal, a second terminal, and a third terminal, wherein the voltage is applied to the third terminal of the second transistor according to the voltage applied to the first terminal of the fourth transistor. The fourth transistor to which the second terminal of the fourth transistor through which current flows is connected;
A first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is connected to the second terminal of the third transistor, and the third terminal of the first transistor is connected. The first capacitor to which the second terminal of the first capacitor is connected;
A second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is connected to the third terminal of the first transistor, and the third terminal of the fourth transistor is connected. The second capacitor to which the second terminal of the second capacitor is connected;
A control method by an air conditioner having a three-phase voltage doubler rectifier circuit comprising:
The control unit
The three-phase first control signal is switched between the on state and the off state at each timing when the voltage of the output terminal of the bridge circuit becomes a minimum value when the number of revolutions of the motor is equal to or greater than a predetermined number of revolutions. A control unit that outputs to the voltage doubler rectification circuit, and
When the first control signal in the off state is output to the first terminal of the first transistor and the first terminal of the fourth transistor, the first terminal of the second transistor and the first terminal of the second transistor may Outputting the first control signal in the on state to the first terminal of the three transistors;
When the first control signal in the on state is output to the first terminal of the first transistor and the first terminal of the fourth transistor, the first terminal of the second transistor and the first terminal of the second transistor may Outputting the first control signal in the off state to the first terminal of the three transistors;
When the number of revolutions of the motor is less than a predetermined number of revolutions, the second control signal is switched between the on state and the off state at each timing when the voltage of the output terminal of the bridge circuit becomes a minimum value. A control unit that outputs to the voltage doubler rectification circuit, and
The second control signal indicating the on state is always output to the first terminal of each of the third transistor and the fourth transistor when the number of rotations of the motor is less than the predetermined number of rotations. ,
The first terminal of the first transistor is:
When the second control signal in the on state is output to the first terminal of the second transistor, the second control signal in the off state is output, and the first terminal of the second transistor is output. When the second control signal in the off state is output, the second control signal in the on state is output.
Control method by air conditioner.

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