JP7034670B2 - Rectifier, power supply, motor and air conditioner - Google Patents

Description

The present invention relates to a rectifier, a power supply, an electric motor, and an air conditioner.

In recent years, a rectifying device (converter) that rectifies alternating current is connected to an inverter device to generate alternating current having a frequency different from the frequency of alternating current supplied to the rectifying device, and is used for driving a motor or the like. Such motors are widely used in air conditioners (air conditioners), refrigerators (refrigerators), and the like.

In Patent Document 1, an inductance is connected to the (+), (-) side terminal or one of the terminals of the bridge rectifying circuit connected to the AC power supply, and the (+), (-) of the bridge rectifying circuit is passed through the inductance. ) Connect the first and second semiconductor switches connected in series in parallel to the side terminal, and further connect the first diode and the first and second in parallel to the (+) and (-) side terminals through the inductance. The series circuit of the second capacitor or battery is connected to the series circuit of the second diode, and the middle point of the series circuit of the semiconductor switch is connected to the middle point of the series circuit of the capacitor or battery. A double voltage rectifying circuit is described.

Japanese Unexamined Patent Publication No. 58-207870

By the way, in a voltage doubler rectifier that rectifies alternating current and boosts it to a DC voltage that is twice the input AC voltage, power factor control (PFC: Power Factor Control) that effectively suppresses harmonic currents as well as boosting is performed. ) Technology is becoming important. In particular, as the output and density of the rectifier increase, the electrical and thermal load of the members for improving the power factor increases, so a voltage doubler rectifier that can improve the power factor even more efficiently is required. Has been done.
An object of the present invention is to provide a rectifier or the like in which a harmonic current is suppressed while controlling an output voltage to a predetermined value.

For this purpose, the rectifier to which the present invention is applied includes a plurality of capacitors connected in series and supplying a plurality of output voltages between both terminals and from a connection point. Then, a plurality of switching elements for switching the rectified direct current of the supplied alternating current are provided so as to individually charge the plurality of the capacitors. Further, it includes a plurality of voltage detection units for detecting each of the plurality of output voltages, and a current detection unit for detecting the alternating current or the direct current. Further, the plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values set for the plurality of output voltages, respectively, and , A control unit for setting a control amount for controlling a plurality of the switching elements is provided based on a current waveform command value set so as to correspond to a standard for harmonics. The current waveform command value is represented by the value obtained by adding an offset value to the absolute value of the sine wave having a frequency three times the frequency of the supplied AC, or the absolute value of the sine wave having the frequency of the supplied AC. Will be done.
As a result, harmonics can be easily suppressed as compared with the case where the current waveform is not represented by the command value.

In such a rectifying device, the current detecting unit may be provided on the side to which alternating current is supplied from the plurality of voltage detecting units.

Each output voltage target value of the plurality of output voltages may be set for each of the plurality of output voltages.
As a result, an intermediate output voltage can be taken out from the connection point as compared with the case where the output voltage is not set for each of the plurality of output voltages.

Then, the control unit divides a unit period set to include at least one cycle of the waveform representing the current waveform command value into a plurality of divisions, and controls the switching element for each division. It can be characterized by setting.
As a result, harmonics can be suppressed more accurately than in the case of not dividing into categories.

Further, the control unit uses the control amount in the division as a value obtained by calculating the difference between the current detected in the unit period immediately before the unit period and the current waveform command value by the integral element. It can be characterized by setting.
As a result, harmonics can be suppressed more accurately.
The rectifier to which the present invention is applied includes a plurality of capacitors connected in series and supplying a plurality of output voltages between both terminals and from a connection point. Then, a plurality of switching elements for switching the rectified direct current of the supplied alternating current are provided so as to individually charge the plurality of the capacitors. Further, it includes a plurality of voltage detection units for detecting each of the plurality of output voltages, and a current detection unit for detecting the alternating current or the direct current. Further, the plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values set for the plurality of output voltages, respectively, and , A plurality of control units for setting a control amount for controlling a plurality of the switching elements are provided based on a current waveform command value set to correspond to a standard for harmonics. Then, each output voltage target value of the plurality of output voltages is set for each output voltage by the plurality of independent control units, and is individually controlled.

From another point of view, the power supply device to which the present invention is applied includes a rectifying unit and an inverter unit to which the output voltage of the rectifying unit is supplied to generate alternating current. The rectifying unit is connected in series and includes a plurality of capacitors that supply a plurality of output voltages between both terminals and from the connection point. Further, the rectifying unit includes a plurality of switching elements that switch the supplied alternating current to the rectified direct current so as to individually charge the plurality of the capacitors. Further, the rectifying unit includes a plurality of voltage detecting units for detecting each of the plurality of output voltages, and a current detecting unit for detecting the alternating current or the direct current. Further, the plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values set for the plurality of output voltages, respectively, and , A control unit for setting a control amount for controlling a plurality of the switching elements is provided based on a current waveform command value set so as to correspond to a standard for harmonics. The current waveform command value is represented by the value obtained by adding an offset value to the absolute value of the sine wave having a frequency three times the frequency of the supplied AC, or the absolute value of the sine wave having the frequency of the supplied AC. Will be done.

Further, the magnitude of the current waveform command value can be set based on the voltage value supplied to the connected load.

From another point of view, in the motor device to which the present invention is applied, a rectifying section, an inverter section to which the output voltage of the rectifying section is supplied, and an alternating current generated to the inverter section are supplied. It is equipped with an electric motor. The rectifying unit is connected in series and includes a plurality of capacitors that supply a plurality of output voltages between both terminals and from the connection point. Further, the rectifying unit includes a plurality of switching elements that switch the supplied alternating current to the rectified direct current so as to individually charge the plurality of the capacitors. Further, the rectifying unit includes a plurality of voltage detecting units for detecting each of the plurality of output voltages, and a current detecting unit for detecting the alternating current or the direct current. Further, the plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values set for the plurality of output voltages, respectively, and , A control unit for setting a control amount for controlling a plurality of the switching elements is provided based on a current waveform command value set so as to correspond to a standard for harmonics. The current waveform command value is represented by the value obtained by adding an offset value to the absolute value of the sine wave having a frequency three times the frequency of the supplied AC, or the absolute value of the sine wave having the frequency of the supplied AC. Will be done.

Further, the control unit can be characterized in that the control amount for controlling a plurality of the switching elements is set by using the motor harmonic suppression correction value for suppressing the harmonics generated by the motor.
As a result, harmonics can be suppressed more accurately.

Furthermore, from another point of view, the air conditioner to which the present invention is applied includes the motor device and regulates air.

According to the present invention, it is possible to provide a rectifier device that suppresses harmonic current while controlling the output voltage to a predetermined value.

It is a figure which shows an example of the electric motor apparatus to which 1st Embodiment is applied. It is a figure explaining the basic operation of the rectifying part in a power-source part. (A) is an inductor and capacitor charge mode, (b) is an inductor discharge mode, (c) is an inductor and capacitor charge mode, and (d) is an inductor discharge mode. It is a block diagram of the control part in a power-source part. It is a figure explaining the operation of the storage device in a current control block. It is a figure explaining an Example. (A) is the AC phase voltage supplied by the power supply to the motor device, (b) is the input current A input to the motor device when not controlled by the control unit of FIG. 3, and (c) is the input current A of FIG. When the voltage control block and the current control block are used in the control unit, the input currents B and (d) input to the motor device are the motor harmonics in addition to the voltage control block and the current control block in the control unit of FIG. The input currents C and (e) input to the motor device when the wave control block is used include a current waveform control block in addition to the voltage control block, the current control block and the motor harmonic control block in the control unit of FIG. It is a waveform of the input current D input to the motor device when used. It is a figure which shows an example of the electric motor apparatus to which the 2nd Embodiment is applied. It is a figure which shows an example of the electric motor apparatus to which the 3rd Embodiment is applied.

In order to satisfy the IEC standard (standard for high frequency) regarding the harmonic current of the power supply, the rectifier (converter) generally takes a harmonic suppression measure by a passive component such as a reactor. However, when the rectifier is applied to equipment that uses three-phase alternating current, such as a large air conditioner, the size of the reactor becomes large. For this reason, various disadvantages such as loss and heat generation due to the reactor and enormous size of the device occur. Therefore, in the present embodiment, the output voltage (DC link voltage) is controlled to a predetermined value, and the harmonic current is controlled to be suppressed. The air conditioner contains a refrigerator, a blower (fan), a heat exchanger, a humidifier, an air filter, etc., and adjusts the temperature, humidity, cleanliness, air flow, etc. of the air. The refrigerator is driven by a compressor.

In addition, due to recent advances in device performance and cost demands from the market, the cost of rectifiers is being reduced. For example, in a rectifier device used for three-phase alternating current, when a 400 V system power supply is used, the device used in the rectifier device has a withstand voltage of 1200 V. When the rectifier is applied to a large air conditioner, if the output voltage (DC link voltage) that drives the compressor is also used as the power source for driving the fan, the inverter device that drives the fan will inevitably have a device with a withstand voltage of 1200 V. It will be the one used. Since the power required for a fan is smaller than that of a compressor, it is desirable to apply a device with a low withstand voltage to reduce costs.

Two 1200V rectifiers are often used in series for the purpose of ensuring the withstand voltage of the electrolytic capacitor for smoothing, and a plurality of 1200V rectifiers are often used in parallel. As a result, the output voltage (DC link voltage) is divided by the capacitor. Therefore, it is conceivable to supply electric power to a load such as a fan by using a voltage divided by a capacitor connected in series. However, when power is supplied from one capacitor to a load such as a fan, the voltage becomes unbalanced with the other capacitor. Eventually, the voltage of one capacitor becomes 0V and the voltage of the other capacitor becomes the output voltage (DC link voltage), which not only cannot supply power to the load as it is, but also exceeds the withstand voltage of the capacitor.

Therefore, in the rectifier or the like described in the present embodiment, the output voltage (DC link voltage) is controlled to a predetermined value by controlling the voltage of the capacitors connected in series, and the capacitors connected in series are controlled. It is possible to supply power to the loads connected to each. That is, the voltage divided by the capacitor is used to stably control the voltage of the capacitor even if the load is unbalanced. This makes it possible to use a device with a low withstand voltage on the load side that uses the divided voltage.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a diagram showing an example of an electric motor device 100 to which the first embodiment is applied.
The electric motor device 100 according to the first embodiment includes a power supply unit 1 and an electric motor (motor) 2. The motor device 100 is connected to a three-phase alternating current power supply 200. The power supply 200 is an example of an AC power supply. The power supply unit 1 is an example of a power supply device.

The power supply unit 1 includes an electromagnetic interference (EMI: Electromagnetic Interference) suppression filter 10 (hereinafter referred to as an EMI suppression filter 10) connected to the power supply 200, and a rectifier (converter) unit 20 connected to the EMI suppression filter 10. , A control unit 30 connected to the rectifying unit 20 and controlling the rectifying unit 20, and an inverter unit 40 connected to the rectifying unit 20. The power supply unit 1 includes a control unit (not shown) that controls the inverter unit 40. Further, a current detection unit 50 that detects a current supplied from the power supply unit 1 to the electric motor 2 may be provided.

The rectifying unit 20 is an example of a rectifying device. The rectifying device may include an EMI suppression filter 10 in addition to the rectifying unit 20.
The electric motor 2 is connected to the inverter unit 40. The electric motor 2 is, for example, a DC brushless motor.
The current detection unit 50 detects (measures the current value) the current flowing in any two phases of the three-phase alternating current (U phase, V phase, W phase) supplied from the inverter unit 40 to the motor 2. In FIG. 1, the U phase and the W phase are detected. In the case of three-phase alternating current, the sum of the current values flowing through the three phases is 0, so the current values of the three phases can be obtained by detecting the currents of the two phases (measuring the current values).
This will be described in order below.

[EMI suppression filter 10]
The EMI suppression filter 10 is a member that removes EMI, and is, for example, a choke coil that blocks the passage of high-frequency noise. It may be another member.

[Rectifier 20]
The rectifying unit 20 rectifies the three-phase alternating current supplied from the power supply 200 to direct current. The rectifying unit 20 includes inductors L1, L2, L3, a diode bridge DB, switching elements SW1, SW2, diodes D1 and D2, feedback diodes Df1, Df2, and capacitors C1 and C2. The diode bridge DB includes diodes D11, D12, D13, D14, D15 and D16. Further, the rectifying unit 20 includes a current detecting unit 23 that detects the current (output current) of the diode bridge DB. Further, the rectifying unit 20 includes a voltage detecting unit 21 that detects the output voltage of the rectifying unit 20 and a voltage detecting unit 22 that detects the voltage of the capacitor C2. Instead of the current detection unit 23, a current detection unit 24 that detects the current of the power supply 200 may be provided.

The diode bridge DB is configured by connecting three sets of two diodes connected in series in parallel. That is, the diodes D11 and D12 are connected in series at the connection point a, the diodes D13 and D14 are connected in series at the connection point b, and the diodes D15 and D16 are connected in series at the connection point c. Then, these are connected in parallel between the connection point d and the connection point e. The diodes D11 to D16 are connected so that a current flows in the direction from the connection point e to the connection point d.

One terminal of the inductors L1, L2, and L3 is connected to the R phase, the S phase, and the T phase of the power supply 200, respectively, via the EMI suppression filter 10. The other terminal of the inductor L1 is connected to the connection point a, the other terminal of the inductor L2 is connected to the connection point b, and the other terminal of the inductor L3 is connected to the connection point c.

The switching elements SW1 and SW2 are connected in series at the connection point h, the switching element SW1 side is connected to the connection point f connected to the connection point d, and the switching element SW2 side is connected to the connection point g connected to the connection point e. The feedback diodes Df1 and Df2 are connected in parallel to the switching elements SW1 and SW2. The feedback diodes Df1 and Df2 are connected in a direction in which a current flows from the connection point g to the connection point f. The direction in which the current flows in the feedback diodes Df1 and Df2 is opposite to the direction in which the current flows in the switching elements SW1 and SW2. The connection point d and the connection point f have the same potential. Further, the connection point e and the connection point g have the same potential.

The switching elements SW1 and SW2 are switching elements for high withstand voltage power. For example, a field effect transistor, an insulated gate bipolar transistor (IGBT), or the like can be applied to the switching elements SW1 and SW2. The switching elements SW1 and SW2 are three-terminal elements, and the terminals that control on / off are called gates.

In the diode D1, one terminal (anode) is connected to the connection point f, and the other terminal (cathode) is connected to the connection point i. Further, in the diode D2, one terminal (cathode) is connected to the connection point j and the other terminal (anode) is connected to the connection point g.

The capacitors C1 and C2 are connected in series at the connection point k, the capacitor C1 side is connected to the connection point i, and the capacitor C2 side is connected to the connection point j. The connection point k between the capacitor C1 and the capacitor C2 is connected to the connection point h between the switching element SW1 and the switching element SW2. That is, the connection point h and the connection point k have the same potential.

In the rectifying unit 20, two voltages, a potential (voltage) of the connection point i with reference to the connection point j and a potential (voltage) of the connection point k with reference to the connection point j, can be taken out. That is, the rectifying unit 20 constitutes a multi-level boost converter. Since the potential of the connection point k is lower than the potential of the connection point i, it is called an intermediate potential ( _Vhalf ). The connection points i and j are connected to the input terminals P and N of the inverter unit 40.
Here, the potential of the connection point i with respect to the connection point j may be referred to as an output potential (output voltage), and the potential of the connection point k with respect to the connection point j may be referred to as an intermediate potential (intermediate voltage).

The connection point j in the rectifying unit 20 is a reference potential. The connection point i in the rectifying unit 20 is called a DC link. Therefore, the potential (voltage) of the connection point i with respect to the potential (reference voltage) of the connection point j may be referred to as a DC link voltage. That is, the DC link voltage is the sum of the voltage of the capacitor C1 (voltage between the connection point i and the connection point k) and the voltage of the capacitor C2 (voltage between the connection point k and the connection point j). Is. Then, the DC link voltage is supplied to the inverter unit 40 as the output voltage of the rectifying unit 20.

The current detection unit 23 is provided between the connection point d and the connection point f, and detects (measures the current value) the current (output current) of the diode bridge DB. Since the current of the diode bridge DB is a pulsating current that reflects the three-phase alternating current, the current of each phase in the three-phase alternating current can be known from the waveform of the current.

The voltage detection unit 21 is provided at the connection point i (between the connection point i and the input terminal P of the inverter unit 40), and is a voltage obtained by adding the voltage of the capacitor C1 and the voltage of the capacitor C2 connected in series, that is, Detects (measures the voltage value) the output voltage (DC link voltage) of the rectifying unit 20. Further, the voltage detection unit 22 detects (measures the voltage value) the voltage of the capacitor C2, that is, the intermediate potential (V _half ).

The current detection unit 24 provided in place of the current detection unit 23 detects the current flowing in any two phases of the three-phase alternating current (R phase, S phase, T phase) supplied from the power supply 200 to the EMI suppression filter 10 ( Measure the current value). In FIG. 1, the R phase and the T phase are detected. As described above, in the case of three-phase alternating current, the sum of the current values flowing through the three phases is 0, so the current values of the three phases can be obtained by detecting the currents of the two phases (measuring the current values).

The current detection unit 23 or the current detection unit 24 is provided on the power supply side (upstream side) that supplies alternating current from the voltage detection units 21 and 22.

Instead of the inductors L1, L2, and L3, inductors may be provided between the connection point d and the connection point f and between the connection point e and the connection point g.

[Control unit 30]
The control unit 30 is configured as a computer including a CPU, a memory, and the like. Then, the control unit 30 is a switching element of the rectifying unit 20 based on the current detected by the current detecting unit 23 (or the current detecting unit 24) of the rectifying unit 20 and the voltage detected by the voltage detecting units 21 and 22. Controls the on / off of SW1 and SW2. That is, a pulse width modulation (PWM) signal that controls on / off of the switching elements SW1 and SW2 is generated by the program stored in the memory.

The control unit 30 includes two control units 30A and 30B. The control units 30A and 30B have the same configuration as described later. Then, as shown in FIG. 1, the control unit 30A is connected to the voltage detection unit 21 that detects the potential (DC link voltage) of the connection point i. On the other hand, the control unit 30B is connected to the voltage detection unit 22 that detects the potential (intermediate potential (V _half )) of the connection point k. A voltage (DC link voltage-intermediate potential (V _half )) applied to the capacitor C1 obtained by subtracting the potential of the connection point k detected by the control unit 30B from the potential of the connection point i is input to the control unit 30A. It is supposed to be done. Further, the voltage applied to the capacitor C2, which is obtained by subtracting the potential (reference potential) of the connection point j from the potential of the connection point k, is input to the control unit 30B. The voltage can be detected by providing resistances between the connection point i and the connection point j and between the connection point k and the connection point j and measuring the voltage value generated by the flowing current.

Then, the control unit 30 is connected to a current detection unit 23 that detects (measures the current value) the current flowing between the connection point d (output of the diode bridge DB) and the connection point f (switching element SW1 side). There is. The current (measured current value) detected by the current detection unit 23 is input to the control units 30A and 30B. As described above, the current detection unit 24 may be used instead of the current detection unit 23. The current detection unit 23 or the current detection unit 24 may be connected to each of the control units 30A and 30B of the control unit 30.
The current detection (measurement of the current value) may be performed by a current sensor provided in the path through which the current flows. The current sensor is, for example, a coil provided so as to surround the path of the current. Then, the current can be detected by measuring the voltage induced in the coil or the like.

Then, the control unit 30A generates and supplies a PWM signal for controlling on / off of the switching element SW2 to the gate of the switching element SW2. On the other hand, the control unit 30B generates and supplies a PWM signal for turning on / off the switching element SW1 at the gate of the switching element SW1. That is, the control unit 30A detects the voltage of the capacitor C1 and turns on / off the switching element SW2 to control the voltage of the capacitor C1. The control unit 30B detects the voltage of the capacitor C2, turns on / off the switching element SW1, and controls the voltage of the capacitor C2.

The control units 30A and 30B may be configured by different computers (microcomputers), or may be configured by one computer (microcomputer), and the control units 30A and 30B may be virtually configured.

[Inverter unit 40]
The inverter unit 40 switches the direct current supplied by the rectifying unit 20 to generate an alternating current that drives the electric motor 2 that is a load. Here, the inverter unit 40 generates three-phase alternating current (U phase, V phase, and W phase).
The inverter unit 40 includes switching elements SW3 to SW8 and a feedback diode (unsigned) connected in parallel to them. Then, three sets of two switching elements connected in series are connected in parallel. That is, the switching elements SW3 and SW4 are connected in series, the switching elements SW5 and SW6 are connected in series, and the switching elements SW7 and SW8 are connected in series. Then, these are connected in parallel between the input terminals P and N of the inverter unit 40. The switching elements SW3 to SW8 and the feedback diodes (unsigned) connected in parallel to them are connected in the direction in which a current flows from the input terminal P to the input terminal N. The direction in which the current flows in the feedback diode is opposite to the direction in which the current flows in the switching elements SW3 to SW8.

The connection points of the switching elements SW3 and SW4 are connected to the motor 2 as the U phase, the connection points of the switching elements SW5 and SW6 as the V phase, and the connection points of the switching elements SW7 and SW8 as the W phase.
A PWM signal is supplied to the gates of the switching elements SW3 to SW8 by the control unit that controls the inverter unit 40. As a result, the inverter unit 40 generates three-phase alternating current (U phase, V phase, and W phase).

[Operation of motor device 100]
The operation of the electric motor device 100 will be described.
When alternating current is supplied from the power supply 200 via the EMI suppression filter 10, the rectifying unit 20 rectifies the alternating current and generates a direct current output voltage (DC link voltage) between the connection point i and the connection point j. do. At this time, the rectifying unit 20 is provided with switching elements SW1 and SW2 and capacitors C1 and C2, and is arbitrarily set with a boost ratio of 1 or more with respect to the voltage obtained when the AC voltage is rectified by the diode bridge DB. The voltage is obtained. For example, when the line effective value of the AC voltage supplied by the power supply 200 is 380 Vrms, the peak value of the DC voltage obtained when the AC voltage is rectified by the diode bridge DB is ideally 537 V. On the other hand, the DC output voltage (DC link voltage) obtained by the rectifying unit 20 can be an arbitrarily set voltage of 537 V or higher.

The inverter unit 40 uses the DC output voltage (DC link voltage) generated by the rectifying unit 20 as a three-phase alternating current (U-phase, V-phase, and W) by turning on / off a set of three switching elements connected in series. Phase) is generated. Then, the inverter unit 40 supplies three-phase alternating current (U phase, V phase, and W phase) to the motor 2. The three sets of switching elements are a set of switching elements SW3 and SW4, a set of switching elements SW5 and SW6, and a set of switching elements SW7 and SW8.
The electric motor 2 is rotated by the alternating current (U phase, V phase, and W phase) supplied by the inverter unit 40. The rotation speed of the motor 2 is changed by changing the frequency of the alternating current (U phase, V phase and W phase) supplied by the inverter unit 40 by the control unit (not shown) that controls the inverter unit 40.
Since the operation of the inverter unit 40 is known, detailed description thereof will be omitted, and the operation of the rectifying unit 20 in the power supply unit 1 will be described in detail below.

(Operation of rectifying unit 20)
FIG. 2 is a diagram illustrating the basic operation of the rectifying unit 20 in the power supply unit 1. 2A is a charge mode of the inductors L1 and L3 and the capacitor C1, FIG. 2B is a discharge mode of the inductors L1 and L3, and FIG. 2C is a charge mode of the inductors L1 and L3 and the capacitor C2. 2 (d) shows the discharge modes of the inductors L1 and L3. 2 (a) to 2 (d) are cases where the potential of the R phase is higher than the potential of the T phase. This will be described in order below.

The voltage of the capacitor C1 (voltage between the connection point i and the connection point k) and the voltage of the capacitor C2 (the connection point k and the connection point j) connected in series to the inverter section 40 (between the input terminals P and N) A voltage is applied that is the sum of the voltage between them).

(A) Charging mode of inductors L1, L3 and capacitor C1 In the charging mode of inductors L1, L3 and capacitor C1 shown in FIG. 2A, the switching element SW1 is turned off by the control unit 30 (see FIG. 1), and the switching element is switched. SW2 is set to on. Then, from the R phase of the power supply 200 (see FIG. 1), the current passes through the inductor L1, the diode D11, the diode D1, the capacitor C1, the switching element SW2, the diode D16, and the inductor L3 in this order, and returns to the T phase of the power supply 200. Flows. At this time, electromagnetic energy is accumulated in the inductors L1 and L3, and the capacitor C1 is charged. Charges are supplied to the capacitor C1 from the DC voltage obtained when the AC voltage of the power supply 200 is rectified by the diode bridge DB during the time (on-duty time) when the switching element SW2 is on. The on-duty time is a time during which the switching element SW2 is repeatedly turned on and off. That is, the capacitor C1 can be voltage-controlled depending on the time when the switching element SW2 is on.

At this time, since the diode D2 is connected in the direction opposite to the path through which the current flows, the capacitor C2 does not discharge.

(B) Discharge Modes of Inductors L1 and L3 In the discharge modes of the inductors L1 and L3 shown in FIG. 2B, the control unit 30 sets the switching element SW2 that was on to off. That is, both the switching elements SW1 and SW2 are turned off. When the switching element SW2 shifts from on to off, the current path via the switching element SW2 is cut off. Therefore, a current flows from the R phase of the power supply 200 via the inductor L1, the diode D1, the capacitors C1, C2, the diode D2, the diode D16, and the inductor L3 to return to the T phase of the power supply 200, so that the inductor L1 , The electromagnetic energy stored in L3 is released (discharged). As a result, the capacitors C1 and C2 connected in series are further charged. Depending on the value of the inductance of the inductors L1 and L3, the voltage of the capacitors C1 and C2 connected in series (the voltage between the connection point i and the connection point j) rises.

(C) Charging Mode of Inductors L1, L3 and Capacitor C2 In the charging mode of the inductors L1, L3 and the capacitor C2 shown in FIG. 2C, the control unit 30 sets the switching element SW1 that was off to ON. .. That is, the switching element SW1 is turned on and the switching element SW2 is turned off. Then, a current flows from the R phase of the power supply 200 through the inductor L1, the diode D11, the switching element SW1, the capacitor C2, the diode D2, the diode D16, and the inductor L3 in this order, and returns to the T phase of the power supply 200. At this time, electromagnetic energy is accumulated in the inductors L1 and L3, and the capacitor C2 is charged. Charges are supplied to the capacitor C2 from the DC voltage obtained when the AC voltage of the power supply 200 is rectified by the diode bridge DB during the time (on-duty time) when the switching element SW1 is on. That is, the capacitor C2 can be voltage-controlled depending on the time when the switching element SW1 is on.
From the above, since the voltage of the capacitor C1 and the capacitor C2 can be controlled respectively, not only the voltage of each of the capacitor C1 and the capacitor C2 can be controlled to an arbitrary set voltage, but also the connection point i and the connection point j. The voltage between and (DC link voltage) can be controlled to a voltage with a boost ratio of 1 or more.

(D) Discharge Mode of Inductors L1 and L3 In the discharge mode of the inductor L1 shown in FIG. 2D, the control unit 30 sets the switching element SW1 that was on to off. That is, both the switching elements SW1 and SW2 are turned off. When the switching element SW1 shifts from on to off, the current path via the switching element SW1 is cut off. Therefore, a current flows from the R phase of the power supply 200 via the inductor L1, the diode D1, the capacitors C1, C2, the diode D2, the diode D16, and the inductor L3 to return to the T phase of the power supply 200, so that the inductor L1 , The electromagnetic energy stored in L3 is released (discharged). As a result, the capacitors C1 and C2 connected in series are further charged. Depending on the value of the inductance of the inductors L1 and L3, the voltage of the capacitors C1 and C2 connected in series (the voltage between the connection point i and the connection point j) rises.

In the above, it has been explained that the potential of the R phase is higher than the potential of the T phase between the R phase and the T phase, but in the three phases (R phase, S phase and T phase), the potential relationship is other. The same applies to the case of a combination. Therefore, the description will be omitted.

As described above, the rectifying unit 20 can control the respective voltages of the capacitors C1 and C2 by controlling the time (on-duty time) when each of the switching elements SW1 and SW2 is on. Therefore, when a load is connected to each of the capacitors C1 and C2, it is possible to maintain a stable voltage even when the voltage is unbalanced between the capacitors C1 and C2. Then, the sum of the voltage of the capacitor C1 and the voltage of the capacitor C2 (the voltage between the connection point i and the connection point j) becomes the output voltage (DC link voltage) of the rectifying unit 20, and the input voltage (input terminal) of the inverter unit 40. The voltage between P and N).

Here, the inductors L1, L2, and L3 are provided. The inductors L1, L2, and L3 store electromagnetic energy when either the switching element SW1 or the switching element SW2 is on, and discharge (discharge) the stored electromagnetic energy when both the switching elements SW1 and SW2 are off. ), And charges the capacitors C1 and C2. That is, although it is affected by the power supplied to the load, when the on time of the switching elements SW1 and SW2 is controlled when the load is extremely small, it is rectified although it depends on the inductance values of the inductors L1, L2 and L3. Since the output voltage (DC link voltage) of unit 20 is the sum of the voltage of the capacitor C1 and the voltage of the capacitor C2 (voltage between the connection point i and the connection point j), it is the peak value of the AC voltage of the power supply 200. It can be easily boosted up to twice or more. At this time, for example, when the peak value of the DC voltage obtained by rectifying the AC voltage with the diode bridge DB is 537V (380V * √2) and the target value of the output voltage (DC link voltage) from the rectifying unit 20 is 600V, the peak value is set. Since the value of 537V can be supplied to each of the capacitors C1 and C2 when the switching elements SW1 and SW2 are on, the voltage of each of the capacitors C1 and C2 can be set to a maximum of 537V. Therefore, the supply of energy from the inductors L1, L2, and L3 can be almost unnecessary in principle. In addition, "*" represents a product.

As a method of providing a boosting function to the rectifying unit 20, there is a method of using one capacitor instead of the two capacitors C1 and C2 and boosting the voltage with an inductor. In this method, the energy for boosting the AC voltage from the peak voltage of the DC voltage rectified by the diode bridge DB is supplied from the inductor. For example, when the peak value of the DC voltage rectified by the diode bridge DB is 537V (380V * √2) and the target value of the output voltage (DC link voltage) from the rectifying unit 20 is 600V, the inductor is based on 537V. It is necessary to supply the energy for boosting more than that. Therefore, in the method using one capacitor, the energy supplied from the inductor is larger than in the case of using the above two capacitors C1 and C2. That is, in the method using one capacitor, it is necessary to use a large inductance value, that is, an inductor having a large shape.

As described above, an inductor having a small inductance value may be used for the inductors L1, L2, and L3 of the rectifying unit 20 in the motor device 100 to which the first embodiment is applied, and the size can be reduced.

Further, since the voltage applied across each of the switching elements SW1 and SW2 is equal to the voltage divided by the capacitors C1 and C2, the switching elements SW1 and SW2 are used even when the 400V power supply 200 is used. Only 1/2 of the DC link voltage (voltage between connection points i and j) is applied to. Therefore, even if the target value of the output voltage (DC link voltage) is 1000 V at the maximum, the withstand voltage of the switching elements SW1 and SW2 may be 500 V or more. That is, a switching element with a withstand voltage of 600 V can be used.
On the other hand, when there is only one switching element, 1000V is applied to the switching element, and it is necessary to use a switching element having a withstand voltage of 1200V. Since the switching element has a higher speed as the withstand voltage is lower, the method using two capacitors C1 and C2 to which the first embodiment is applied also has an advantage that the speed can be increased.

Next, the operation of the control unit 30 that controls the rectifying unit 20 in the power supply unit 1 will be described in detail.
(Operation of control unit 30)
FIG. 3 is a block diagram of the control unit 30 in the power supply unit 1. As described above, the control unit 30 includes two control units (control units 30A and 30B). The block diagram shown here shows the control unit 30A out of the two control units (control units 30A and 30B). The control unit 30B is also represented by a block diagram similar to that of the control unit 30A, except for the portion shown below. Therefore, the description of the control unit 30B will be omitted.

The control unit 30A includes a voltage control block 31 that controls the DC output voltage output by the rectifying unit 20, a current waveform control block 32 that controls the current waveform to control harmonics generated in the current, and a current that controls the current. The control block 33 and the electric machine harmonic control block 34 for controlling the harmonics generated from the electric motor 2 are provided. The motor harmonic control block 34 is used when controlling the motor 2. Therefore, when the motor 2 is not controlled, it is not necessary to provide the motor harmonic control block 34. This will be described in order below.

As described above, the control unit 30A detects the voltage at the connection point i of the rectifying unit 20, controls the duty ratio of the PWM signal that sets the on / off of the switching element SW2, and controls the voltage of the capacitor C1 (connection point). The voltage between the voltage i and the connection point k) is controlled to a specified voltage, and the harmonics appearing in the current are controlled to conform to the IEC standard. The duty ratio is the ratio of the on time to the on and off repetition period.

{Voltage control block 31}
The voltage control block 31 outputs a voltage difference value as a control amount for controlling the voltage of the capacitor C1. The voltage control block 31 includes a comparator 311, an integrator (integrator) 312, a proportional element (proportional device) 313, and an adder 314. Then, the voltage target value (output voltage target value) determined for the capacitor C1 in the comparator 311 and the voltage (voltage measured value) of the capacitor C1 detected (measured) by the voltage detection unit 21 (see FIG. 1). ) And is entered. Then, the comparator 311 calculates the difference (deviation) between the voltage target value and the voltage measured value. The integration element 312 is an element represented by a transfer function (Ki_v * 1 / s), and an integral calculation is performed on the difference obtained by the comparator 311. The proportional element 313 is an element represented by the transfer function (Kp_v), and is proportionally calculated with respect to the difference obtained by the comparator 311. Then, the adder 314 adds the result of the integral calculation by the integral element 312 and the result of the proportional calculation by the proportional element 313, and outputs a voltage difference value as a control value to be controlled.
That is, the voltage control block 31 performs proportional integral (PI) control for controlling the voltage of the capacitor C1 to a predetermined voltage.

Even if the voltage of the capacitor C1 (DC link voltage) drops due to the magnitude of the output power (output power), the voltage difference value is controlled so that the voltage becomes the voltage target value. Therefore, the voltage difference value corresponds to the output power. Further, the voltage of the capacitor C1 (DC link voltage) is controlled so that the efficiency of the motor 2 is maximized. Therefore, even if the output power is small, when a high voltage is required, the voltage difference value is set accordingly, and the efficiency can be improved in the control of the motor 2.

In the control unit 30B, the comparator 311 has a voltage target value determined for the capacitor C2 instead of the capacitor C1 and a capacitor C2 detected (measured) by the voltage detection unit 21 (see FIG. 1). The voltage (measured voltage) is input.
By setting the voltage target values to different values for the control units 30A and 30B, it is possible to control the voltage (V _half ) divided by the capacitors C1 and C2 while controlling the DC link voltage. can. Therefore, it is possible to supply electric power to the load from the connection point k (pressure dividing point) with the capacitors C1 and C2.

{Current waveform control block 32}
The current waveform control block 32 controls the current waveform in order to make the harmonics appearing in the current waveform conform to the IEC standard. The IEC standard stipulates that Total Harmonic Distortion (THD) and Partial Weighted Harmonic Distortion (PWHD) should be less than or equal to the specified values.

The current waveform control block 32 includes a current waveform setting element 321 and an adder 322. When the power supply 200 is a three-phase alternating current, the current waveform setting element 321 is calculated by an element represented by a transfer function of an absolute value (A * | sin (3θ) |) of a frequency component three times that of the three-phase alternating current. Outputs the current waveform correction value. The current waveform setting element 321 functions as a proportional device. Here, θ is an angle representing the time of the AC voltage. One cycle is θ = 2π. Then, the adder 322 adds the current waveform correction value and the voltage difference value obtained by the voltage control block 31 to output the current waveform command value. The voltage difference value is an offset value with respect to the current. That is, the current waveform command value is represented by (A * | sin (3θ) |) + an offset value with respect to the current. The current waveform correction value sets the current waveform, and the offset value with respect to the current sets the magnitude of the current by the voltage difference value obtained by the voltage control block 31 (bias). Here, the average value of the current waveform command values represented by (A * | sin (3θ) |) + offset value with respect to the current is referred to as the magnitude of the current waveform command value. In FIG. 3, the offset value with respect to the current is referred to as an offset value.

The amplitude A is a parameter for setting the amplitude of the current waveform and can be changed. That is, if the current becomes large, it is necessary to set the amplitude A to be large in order to satisfy the standard for harmonics. Therefore, the amplitude A can be changed according to the voltage difference value. The amplitude A may be obtained by calculation from the voltage value supplied to the load (output voltage target value), or may be obtained by referring to a table provided for the voltage value supplied to the load.
That is, the control unit 30 changes the amplitude A in association with the voltage difference value (offset value with respect to the current). In other words, the control unit 30 changes the magnitude of the current waveform command value. As a result, a slight phase shift of the current waveform with respect to the AC voltage waveform can be corrected.

As described above, the current waveform control block 32 outputs a current command value for setting the current waveform so that the harmonics appearing in the current waveform conform to a defined standard. Then, the current waveform control block 32 converts the voltage difference value that controls the input voltage into the current command value that controls the current.

Here, the current waveform setting element 321 has an absolute value (A * | sin (3θ) |) of a frequency component three times as large as that of the three-phase alternating current as a transfer function to the voltage difference value obtained by the voltage control block 31. .. This is an example, and the current waveform correction value that corrects the current waveform so that the harmonics appearing in the current satisfy the standard may be output. Here, a waveform in which the harmonics appearing in the current satisfy the standard may be set, and the current waveform correction value may be output so as to have this waveform. That is, the harmonics are added so as to satisfy the harmonic standard. Therefore, the current waveform correction value may be output by calculation from the function representing the current waveform as described above, or may be given by a table for setting a predetermined current waveform. The current waveform correction value and the current waveform command value will be described in detail later.

{Current control block 33}
The current control block 33 outputs a current difference value as a control amount for controlling the current flowing through the rectifying unit 20. The current control block 33 includes a comparator 331, a proportional element (proportional device) 332, an integrator element (integrator) 333, and a storage device (memory) 334 and an adder 335. Then, the current waveform command value output by the current waveform control block 32 and the current value (current measurement value) detected (measured) by the current detection unit 23 are input to the comparator 331. Then, the comparator 331 calculates the difference between the current command value and the current measured value. The proportional element 332 is an element represented by the transfer function (Kp_i), and the difference obtained by the comparator 331 is proportionally calculated. The integration element 333 is an element represented by a transfer function (Ki_i * 1 / s), and the difference obtained by the comparator 331 is integrated. Then, the storage device 334 accumulates the result of the integration calculation for each timing of the AC voltage of the power supply 200 (the division described later), and the next division already accumulated for the next timing (the next division). Outputs the result of the integral operation of. The adder 335 adds the result of the proportional operation by the proportional element 332 and the result of the integral operation output from the storage device 334, and outputs a current difference value as a control value to be controlled. That is, proportional integral control is performed for each division. The classification will be described later.
The storage device 334 is configured as a memory included in the control unit 30.

Also in the control unit 30B, the current value (current measurement value) detected (measured) by the current detection unit 23 is input to the comparator 331.
As described above, the current measurement value may be the current value detected by the current detection unit 24 instead of the current detection unit 23.

{Motor harmonic control block 34}
The electric motor 2 tends to generate a harmonic wave (6f) 6 times the frequency (f) of the electric angle indicating a change in the magnetic field, and this harmonic wave (6f) may flow to the power supply unit 1. The current is detected by the current detection unit 23 (see FIG. 1) provided on the power supply side 200 side of the capacitors C1 and C2. Therefore, a harmonic (6f) having a cycle different from the cycle of the AC voltage of the power supply 200 is mixed in the detected current as a disturbance. Therefore, a motor harmonic control block 34 is provided to suppress a 6-fold harmonic (6f) generated from the motor 2. By doing so, it becomes possible to obtain a stable periodic current waveform in the current control block 33. Therefore, the stability of control in the current control block 33 is improved.

The motor harmonic control block 34 includes a comparator 341. The comparator 341 outputs the difference between the current difference value output by the current control block 33 and the correction value for suppressing the 6-fold harmonic (6f) (harmonic (6f) suppression correction value). The frequency of the harmonic (6f) of the motor 2 can be known by detecting the current on the motor 2 side. Therefore, the harmonic (6f) suppression correction value is set based on the frequency of the harmonic (6f) of the motor 2 detected (measured) by the current detection unit 50. Then, a signal (PWM signal) as a control amount for controlling the on / off of the switching element SW2 is generated. In other words, the control amount is the duty ratio of the PWM signal that turns on / off the switching element SW2.

The control unit 30A does not have to include all of the voltage control block 31, the current waveform control block 32, the current control block 33, and the motor harmonic control block 34. When the motor harmonic control block 34 is not provided, the current difference value output by the current control block 33 may be configured to be a signal (PWM signal) for controlling on / off of the switching element SW2. When the current waveform control block 32 is not provided, the voltage difference value output by the voltage control block 31 may be configured as a current command value and input to the current control block 33.
The same applies to the control unit 30B.

{Operation of storage device 334 in current control block 33}
Hereinafter, the operation of the storage device 334 in the current control block 33 will be described in detail.
The current control block 33 improves the power factor as described above. In power factor improvement (PFC), the current waveform is controlled according to the waveform of the AC phase voltage (AC phase voltage waveform). That is, it is necessary to set the current waveform by matching the phase with the AC phase voltage waveform.

FIG. 4 is a diagram illustrating the operation of the storage device 334 in the current control block 33. FIG. 4 shows one cycle of one phase (AC phase voltage waveform) in the voltage waveform of the three-phase AC of the power supply 200. The current waveform command value output from the current waveform control block 32 is also shown. The current waveform command value is a current waveform correction value (A * | sin (3θ) |) + an offset value with respect to the current. The offset value with respect to the current has a smaller fluctuation than the current waveform correction value. Therefore, the current waveform command value has the periodicity of the current waveform correction value. Further, the lower part of FIG. 4 shows a part of the storage device 334 and a part of the PWM signal output by the motor harmonic control block 34 to the gate of the switching element SW2.

Here, the current waveform command value has a periodicity of a frequency three times that of the AC voltage of the power supply 200, and is matched in phase with the AC phase voltage waveform (referred to as AC phase voltage in FIG. 4). ing. That is, the time point when the current waveform command value becomes 0 coincides with the time point (zero cross) when the AC phase voltage waveform becomes 0V.

Here, as an example, one cycle (phase) of the AC phase voltage waveform is set as a repeating unit period, and one unit period is divided into 266 sections. That is, one cycle of the AC phase voltage waveform is divided into 266, and a PWM signal for controlling the switching element SW2 is set for each divided section. The storage device 334 has a storage area of 266. Here, the divided sections are referred to as sections 1 to 266, and the start points of the sections 1 to 266 are referred to as times t ₁ to t ₂₆₆ . Then, each of the storage areas is described as storage areas # 1 to # 266. In addition, one cycle of the current having periodicity (in FIG. 4, one cycle of the current waveform correction value and 1/3 of one cycle of the AC phase voltage) may be set as a unit period. That is, the unit period may be set to include at least one cycle of the waveform representing the current waveform command value.

In the following, FIG. 4 will be described with reference to FIG.
At time t ₁ , the measured current value actually measured is input to the comparator 331. Then, the integration element 333 integrates the difference (error) between the current waveform command value output by the comparator 331 and the current measurement value by the transfer function (Ki_i * 1 / s). Then, the integrated current value N (1) with respect to the time t ₁ newly calculated and obtained is stored in the storage area # 1 of the storage device 334. On the other hand, the storage device 334 outputs the current integral value O (2) already stored in the storage area # 2 to the adder 335. Then, the adder 335 outputs the current difference value of the section ₂ starting from the time t2 based on the current integral value O (2). The current difference value is converted into a PWM signal by the motor harmonic control block 34 and output. The current integral value newly calculated by the current measurement value measured at time t _x (x is an integer of 1 to 266) is set as the current integral value N (x), and the storage device 334 has already been set at time t _x . Let the current integral value stored in the current integral value O (x) be.

The current integral value O ( ₂ ) stored in the storage device 334 corresponds to the current integral value stored one unit period (here, one cycle of the AC phase voltage waveform) from time t2. The reason for using the current integral value O (x) one unit period ago will be described below in the case of x = 1.
Ideally, the current integral value applied to the section 1 is calculated based on the current measured value measured at time t1 and applied to the section ₁ . However, it takes time for the control unit 30 to calculate the current integral value. Therefore, the timing at which the current integral value for the section 1 is calculated and output by the control unit 30 may be too late to be applied to the section 1. If the current integrated value to be applied to the section 1 is applied to a section other than the section 1 such as the section 2, the phase of the AC phase voltage waveform and the current waveform will be out of phase. Here, the current waveform command value is set so as to include a frequency component (A * | sin (3θ) |) that is three times that of the three-phase alternating current. Therefore, as shown in FIG. 4, the change in current is large. Therefore, if the current integrated value to be applied to section 1 is applied to a section other than section 1 such as section 2, the phase of the AC phase voltage waveform and the current waveform will be out of phase, and the standard for harmonics will not be satisfied. It ends up. That is, it is required that the phase shift between the AC phase voltage waveform and the current waveform is small.

Therefore, in the first embodiment, the current integrated value calculated based on the measured current measurement value is stored in the storage device 334, and the storage device is stored one unit period (here, one cycle of the AC phase voltage waveform). The current difference value is calculated using the current integrated value accumulated in 334. This is because even if there is a difference in the current measurement value between adjacent unit periods, it is easier to satisfy the standard for harmonics as compared with the case where the above-mentioned phase shift occurs.

That is, the current integral value N (x) is calculated from the current measurement value at time t _x and stored in the storage area # x, and the current integral value O (one unit period before) stored in the storage area # (x + 1) is used. x + 1) is output, and the current command value applied to the interval (x + 1) from the time t _{x + 1} is calculated. In this way, in the storage area # x in the storage device 334, a new current integral value N (x) is accumulated after the accumulated current integral value O (x) is output.

As an example, one cycle (phase) of the AC phase voltage is divided into 266 sections as one unit period, but the larger the number of sections, the better. That is, the current integral value calculated by the integral element 333 uses the value one unit period before. However, as shown in the current control block 33 of FIG. 3, the current proportional value calculated by the proportional element 332 does not have a storage device. Therefore, the value of the section where the current is actually measured will be used in the next section. Therefore, the current difference value is the sum of the current integral value one unit time ago and the current proportional value one section before. That is, since the current proportional value includes an error for one section, the accuracy of the current difference value improves as the number of sections increases. The number of sections may be determined by this accuracy and the computing power of the control unit 30.

As described above, if the current waveform has periodicity, the actual current waveform can be controlled to the waveform set by the current waveform command value. According to this method, harmonics can be suppressed without performing a heavy calculation load such as a fast Fourier transform (FFT). Therefore, the program that executes this algorithm can be implemented on an inexpensive microcomputer with low computing power.

{Example}
FIG. 5 is a diagram illustrating an embodiment. 5A shows an AC phase voltage supplied by the power supply 200 to the motor device 100, and FIG. 5B shows an input current A input to the motor device 100 when the control unit 30 of FIG. 3 does not control the current. 5 (c) shows the input current B input to the motor device 100 when the voltage control block 31 and the current control block 33 are used in the control unit 30 of FIG. 3, and FIG. 5 (d) shows the control of FIG. In the unit 30, in addition to the voltage control block 31 and the current control block 33, the input current C to be input to the motor device 100 when the motor harmonic control block 34 is used, FIG. 5 (e) is the control unit of FIG. 30 is a waveform of an input current D input to the motor device 100 when the current waveform control block 32 is used in addition to the voltage control block 31, the current control block 33, and the motor harmonic control block 34.

As shown in FIG. 5A, here, two cycles of the AC phase voltage waveform of the sine wave are shown.
When the control shown in FIG. 3 shown in FIG. 5B is not performed, the waveform of the input current A input to the motor device 100 is a harmonic (6f) 6 times the frequency (f) of the electric angle of the motor 2. The waveform has poor followability to the AC phase voltage waveform. The harmonic (6f) is a high-frequency vibration that appears in the input current A.

When the voltage control block 31 and the current control block 33 are used in the control unit 30 of FIG. 3 shown in FIG. 5 (c), the waveform of the input current B input to the motor device 100 is slightly close to the AC phase voltage waveform. , The waveform includes a harmonic (6f) that is 6 times the frequency (f) of the electric angle of the electric motor 2. The input current may be transmitted due to the resonance between the impedance of the power supply 200 and the capacitors C1 and C2. Here, the input current B suppresses resonance by using the current control block 33, and suppresses fluctuations in the DC link voltage by the voltage control block 31. This enables stable voltage control and / or current control even when the impedance of the power supply 200 is different.

When the motor harmonic control block 34 is used in addition to the voltage control block 31 and the current control block 33 in the control unit 30 of FIG. 3 shown in FIG. 5 (d), the waveform of the input current C input to the motor device 100. Suppresses a harmonic (6f) that is 6 times the frequency (f) of the electric angle of the motor 2.

When the current waveform control block 32 is used in addition to the voltage control block 31, the current control block 33, and the electric motor harmonic control block 34 in the control unit 30 of FIG. 3 shown in FIG. 5 (e), the current waveform control block 32 is input to the electric motor device 100. The waveform of the input current D is a waveform having high followability to the AC phase voltage waveform.

That is, by using the voltage control block 31 and the current control block 33 in the control unit 30, the current waveform (input currents B and C) approaches the waveform that follows the AC phase voltage waveform, but the current waveform control block 32 is added. As a result, it can be seen that the current waveform (input current D) becomes a waveform that more closely follows the AC phase voltage waveform.

Here, in the current waveform control block 32, a current waveform command value having a frequency three times that of the AC voltage is added. This is because when the power supply 200 is a three-phase alternating current, there is a timing (period) in which no current flows in each phase. For example, in the sections 1, 2 and 3 in FIGS. 5 (b) to 5 (e), no current is flowing. Therefore, by controlling the current waveform by applying a current waveform command value having a frequency three times that of the AC voltage, the standard regarding harmonics is satisfied.

<Second embodiment>
In the first embodiment, the power supply 200 was a three-phase alternating current. In the second embodiment, the power supply 210 is single-phase alternating current.
FIG. 6 is a diagram showing an example of the motor device 110 to which the second embodiment is applied.
The electric motor device 110 in the second embodiment includes a power supply unit 1 and an electric motor (motor) 2. The motor device 100 is connected to a single-phase alternating current power supply 210. The power supply 210 is another example of an AC power supply. Since the other configurations are the same as those in the first embodiment except for the portion where the three phases become a single phase, the same reference numerals are given and the description thereof will be omitted.

In the second embodiment, in the block diagram shown in FIG. 3, the transfer function of the current waveform setting element 321 in the current waveform control block 32 may be A * | sin (θ) |. In the case of single-phase alternating current, there is no period during which no current flows in each phase, so it is easy to meet the standards for harmonics.

<Third embodiment>
The electric motor device 120 of the third embodiment has a different configuration of the rectifying unit 20 from the electric motor device 100 to which the first embodiment is applied.
FIG. 7 is a diagram showing an example of the motor device 120 to which the third embodiment is applied. The same parts as those of the electric motor device 100 to which the first embodiment is applied are designated by the same reference numerals, and the description thereof will be omitted. As in the first embodiment, the power supply 200 is a three-phase alternating current.

The rectifying unit 20 of the electric motor device 120 further includes diodes D21 to D26 in the rectifying unit 20 of the electric motor device 100 to which the first embodiment is applied. Then, the diodes D21 and D22 are connected in series at the connection point l, the diodes D23 and D24 are connected in series at the connection point m, and the diodes D25 and D26 are connected in series at the connection point n. These are connected in parallel between the connection point o and the connection point p. The diodes D21 to D26 are connected in a direction in which a current flows from the connection point p toward the connection point o. Then, the connection point l of the diodes D21 and D22 connected in series is connected to the R phase of the power supply 200 via the inductor L1 and the EMI suppression filter 10. The connection point m of the diodes D23 and D24 connected in series is connected to the S phase of the power supply 200 via the inductor L2 and the EMI suppression filter 10. The connection point n of the diodes D25 and D26 connected in series is connected to the T phase of the power supply 200 via the inductor L3 and the EMI suppression filter 10.

The switching elements SW1 and SW2 connected in series are connected between the connection point o and the connection point p. The capacitors C1 and C2 connected in series are connected between the connection point i and the connection point j, as in the motor device 100 to which the first embodiment is applied. Then, the connection point h of the switching elements SW1 and SW2 and the connection point k of the capacitors C1 and C2 are connected. Then, the intermediate potential V _half can be taken out from the connection point k.

The operation of the motor device 120 will be described.
Here, as shown in FIG. 2, the case where the potential of the R phase is higher than the potential of the T phase will be described.
When the switching element SW1 is off and the switching element SW2 is on, electromagnetic energy is accumulated in the inductors L1 and L3, and the capacitor C1 is charged. That is, a current flows from the R phase to the T phase via the inductor L1, the capacitor C1, the switching element SW2, the diode D26, and the inductor L3. As a result, electromagnetic energy is accumulated in the inductors L1 and L3, and the capacitor C1 is charged by the AC voltage of the power supply 200.

Here, when the switching elements SW2 are turned off and the switching elements SW1 and SW2 are turned off, the electromagnetic energy stored in the inductors L1 and L3 is discharged (released). That is, a current flows from the R phase to the T phase via the inductor L1, the diode D11, the capacitors C1, C2, the diode D16, and the inductor L3. As a result, the capacitors C1 and C2 are charged.

Next, when the switching element SW1 is turned on, the switching element SW1 is turned on, and the switching element SW2 is turned off, electromagnetic energy is accumulated in the inductors L1 and L3, and the capacitor C2 is charged. .. That is, a current flows from the R phase to the T phase via the inductor L1, the diode D21, the switching element SW1, the capacitor C2, the diode D16, and the inductor L3. As a result, electromagnetic energy is accumulated in the inductors L1 and L3, and the capacitor C2 is charged by the AC voltage of the power supply 200.

Here, when the switching elements SW1 are turned off and the switching elements SW1 and SW2 are turned off, the electromagnetic energy stored in the inductors L1 and L3 is discharged (released). That is, a current flows from the R phase to the T phase via the inductor L1, the diode D11, the capacitors C1, C2, the diode D16, and the inductor L3. As a result, the capacitors C1 and C2 are charged.

The voltage between both terminals (connection point i and connection point j) of the capacitors C1 and C2 connected in series is controlled by the time (on-duty time) when each of the switching elements SW1 and SW2 is on. (Boosted). Further, the intermediate potential V _half can be taken out from the connection point k of the capacitors C1 and C2 connected in series.

As described above, the rectifying unit 20 of the motor device 120 also includes the capacitors C1 and C2 connected in series as in the motor device 100 to which the first embodiment is applied, and each of the capacitors C1 and C2 is provided. It is designed to be switched and charged by the switching elements SW1 and SW2. Therefore, the electric motor device 120 includes the same control unit 30 (control units 30A, 30B) as the electric motor device 100 to which the first embodiment is applied, so that the electric motor device 120 to which the first embodiment is applied. It is controlled in the same way as 100. The control unit 30 (control units 30A and 30B) is configured to detect the current flowing between the connection point d and the connection point i of the rectifying unit 20.

The motor device 120 to which the third embodiment is applied is connected to the power supply 200 of the three-phase alternating current, but like the motor device 110 to which the second embodiment is applied, the single-phase alternating current It may be changed to be connected to the power supply 210 of.

The capacitors C1 and C2 of the rectifying unit 20 in the power supply unit 1 of the electric motor device 100 and 110.120 to which the first to third embodiments are applied may be electrolytic capacitors, but the control unit. Since the capacitors C1 and C2 are constantly charged by 30, a stable DC link voltage can be obtained even with a film capacitor or a ceramic capacitor having a smaller capacity than the electrolytic capacitor. Film capacitors and ceramic capacitors are smaller and have a longer life than electrolytic capacitors. Further, as described above, a small inductor having a small inductance can be used for the inductors L1, L2, and L3. Therefore, the motor devices 100, 110, 120 and the like can be miniaturized and the life can be extended.

Further, in the rectifying unit 20 in the power supply unit 1 of the motor device 100 and 110.120 to which the first to third embodiments are applied, the two capacitors C1 and C2 and the two switching elements SW1 are used. , SW2 was used to obtain an arbitrary output voltage (DC link voltage) having a boost ratio of 1 or more. A higher voltage output voltage (DC link voltage) may be obtained by using a capacitor and a switching element having more than two each.

The three-phase alternating current power supply 200 shown in FIGS. 1 and 7 has a star connection, but may be a circular (delta) connection. Then, the phase of the input current may be adjusted so as to satisfy the standard for harmonics.

Then, although the motor devices 100, 110, and 120 are set from the first embodiment to the third embodiment, the power supply unit 1 may supply an output to other than the motor 2 as a power supply device. Further, the rectifying unit 20 of the power supply unit 1 may be used as a rectifying device.
Further, the motor devices 100, 110, and 120 are used by being incorporated in an air conditioner (air conditioner) or the like.

1 ... Power supply unit, 2 ... Electric motor (motor), 10 ... EMI suppression filter, 20 ... Rectifier (converter) unit, 21, 22 ... Voltage detection unit, 23, 24 ... Current detection unit, 30 ... Control unit, 30A, 30B ... control unit, 31 ... voltage control block, 32 ... current waveform control block, 33 ... current control block, 34 ... electric machine harmonic control block, 40 ... inverter unit, 100, 110, 120 ... electric motor device, 200, 210 ... power supply , 311, 331, 341 ... comparer, 312, 333 ... integrating element (integrator), 313, 332 ... proportional element (proportional device), 314, 322, 335 ... adder, 321 ... current waveform setting element, 334 ... Storage (memory), C1, C2 ... Condenser, D1, D2, D11 to D16, D21 to D26 ... Diode, DB ... Diode bridge, Df1, Df2 ... Feedback diode, L1 to L3 ... Inductor, SW1 to SW8 ... Switching element , V _half ... Intermediate potential

Claims (11)

Multiple capacitors that are connected in series and supply multiple output voltages between both terminals and from the connection point,
A plurality of switching elements for switching a rectified direct current of the supplied alternating current so as to individually charge the plurality of the capacitors, and a plurality of switching elements.
A plurality of voltage detectors that detect each of the plurality of output voltages, and
A current detector that detects alternating current or direct current , and
The plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values and harmonics set for each of the plurality of output voltages. A control unit for setting a control amount for controlling a plurality of the switching elements based on a current waveform command value set to correspond to a standard for waves is provided .
The current waveform command value is represented by a value obtained by adding an offset value to an absolute value of a sine wave having a frequency three times the frequency of the supplied AC, or an absolute value of a sine wave having a frequency of the supplied AC.
Rectifier. The rectifying device according to claim 1, wherein the current detecting unit is provided on the side to which alternating current is supplied from the plurality of voltage detecting units. The rectifier according to claim 1 , wherein each output voltage target value of the plurality of output voltages is set for each of the plurality of output voltages. The control unit divides a repeating unit period set to include at least one cycle of a waveform representing the current waveform command value into a plurality of divisions, and controls the switching element for each division. The rectifying device according to claim 1 , wherein the rectifying device is set. The control unit sets the control amount in the category by using a value calculated by an integral element of the difference between the current detected in the unit period immediately before the unit period and the current waveform command value. The rectifying device according to claim 4 , wherein the rectifying device is characterized by the above. Multiple capacitors that are connected in series and supply multiple output voltages between both terminals and from the connection point,
A plurality of switching elements for switching a rectified direct current of the supplied alternating current so as to individually charge the plurality of the capacitors, and a plurality of switching elements.
A plurality of voltage detectors that detect each of the plurality of output voltages, and
A current detector that detects alternating current or direct current, and
The plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values and harmonics set for each of the plurality of output voltages. A plurality of control units for setting a control amount for controlling a plurality of the switching elements based on a current waveform command value set to correspond to a standard for waves are provided.
Each output voltage target value of the plurality of output voltages is set for each output voltage by the plurality of independent control units and is individually controlled.
Rectifier. Multiple capacitors that are connected in series and supply multiple output voltages between both terminals and from the connection point, and multiple switches that switch the supplied alternating current to rectified direct current so as to charge the plurality of capacitors individually. An element, a plurality of voltage detectors for detecting each of a plurality of the output voltages, and a current detector for detecting the alternating current or the direct current.
The plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values and harmonics set for each of the plurality of output voltages. A control unit for setting a control amount for controlling a plurality of the switching elements based on a current waveform command value set to correspond to a standard for waves is provided .
The current waveform command value is represented by a value obtained by adding an offset value to an absolute value of a sine wave having a frequency three times the frequency of the supplied AC, or an absolute value of a sine wave having a frequency of the supplied AC. The rectifying part and
A power supply unit including an inverter unit to which the output voltage of the rectifying unit is supplied and an alternating current is generated. The power supply device according to claim 7 , wherein the magnitude of the current waveform command value is set based on the voltage supplied to the connected load. Multiple capacitors that are connected in series and supply multiple output voltages between both terminals and from the connection point, and multiple switches that switch the supplied alternating current to rectified direct current so as to charge the plurality of capacitors individually. An element, a plurality of voltage detectors for detecting each of a plurality of the output voltages, and a current detector for detecting the alternating current or the direct current.
The plurality of output voltages detected by the plurality of voltage detectors, the current detected by the current detectors, and the output voltage target values and harmonics set for each of the plurality of output voltages. A control unit for setting a control amount for controlling a plurality of the switching elements based on a current waveform command value set to correspond to a standard for waves is provided .
The current waveform command value is represented by a value obtained by adding an offset value to an absolute value of a sine wave having a frequency three times the frequency of the supplied AC, or an absolute value of a sine wave having a frequency of the supplied AC. The rectifying part and
An inverter unit to which the output voltage of the rectifying unit is supplied to generate alternating current,
An electric motor device including an electric motor to which an alternating current generated by the inverter unit is supplied. The motor according to claim 9 , wherein the control unit sets the control amount for controlling the plurality of the switching elements by using the motor harmonic suppression correction value for suppressing the harmonics generated by the motor. Device. An air conditioner comprising the motor device according to claim 9 or 10 for adjusting air.

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