JP7451075B2 - Control device, correction method and program - Google Patents

Description

The present invention relates to a control device, a correction method, and a program.

Converter devices are used in various fields. Patent Document 1 describes a technique for applying a converter device to an air conditioner to miniaturize and simplify the device.

Japanese Patent Application Publication No. 2014-150622

By the way, in the motor drive device described in Patent Document 1, a current according to a voltage difference between both ends of the reactor flows through the reactor in the converter device. Therefore, in the motor drive device described in Patent Document 1, distortion of the input current increases due to distortion of the power supply voltage.

Therefore, in a circuit where a current flows according to a voltage difference between both ends of the reactor, such as a reactor in a converter device as described in Patent Document 1, it is necessary to reduce the distortion of the input current caused by the distortion of the power supply voltage. There was a need for technology that could do this.

An object of the present invention is to provide a control device, a correction method, and a program that can solve the above problems.

According to the first aspect of the present invention, the control device determines the on-state and off-state of each of the plurality of switching elements included in the converter circuit based on the period in which the rotation speed of the compressor motor, which is the load of the converter circuit, fluctuates. a distortion measurement unit that measures the distortion of the input current by calculating from the ratio of each frequency component when changing the control signal that controls the state; and a distortion measurement unit that measures the distortion of the input current by calculating the distortion of the input current by an integer between 5 and 10. For each period calculated by A set of control signals is generated for each of three different values set for one of the phase difference or the amplitude of the harmonic component, and a plurality of sets of the control signals generated corresponding to the three different values are generated. A set of control signals with a small distortion of the input current waveform is identified from the set, and the on state and off state of the switching element are controlled based on the identified set of control signals, thereby controlling the input current. a control signal generation unit that corrects distortion, and generates the set of control signals by comparing a signal with a predetermined waveform serving as a reference and a voltage command generated for the set value, and calculating the comparison result. A plurality of control signals for respectively controlling the plurality of switching elements are generated as one set based on the above .

According to a second aspect of the present invention, in the control device according to the first aspect, the distortion measuring section measures the distortion of the input current for each period calculated by multiplying the period of variation of the rotational speed by an integer. It may be something that does .

According to a third aspect of the present invention, in the control device according to the first aspect or the second aspect , the cycle of fluctuations in the power of the converter circuit is such that the compressor rotates by the power supplied from the converter circuit. It may be the reciprocal of the rotation speed of the machine motor .

According to a fourth aspect of the present invention, in the first aspect or the second aspect , the period of fluctuation related to the power of the converter circuit is set per unit time of a single rotary in a compressor equipped with the compressor motor. It may be the reciprocal of the vibration frequency .

According to the fifth aspect of the present invention, the correction method determines the on-state and off-state of each of the plurality of switching elements of the converter circuit, based on the period in which the rotation speed of the compressor motor, which is the load of the converter circuit, fluctuates. measuring the distortion of the input current by calculating from the ratio of each frequency component when changing the control signal that controls the state; and multiplying the period by any integer from 5 to 10. For each calculated period, a phase difference between a voltage command that is a signal obtained by superimposing a sine wave input to the converter circuit and a harmonic component having the sine wave as a fundamental wave, and a voltage supplied to the converter circuit; Alternatively, a set of control signals is generated for each of three different values set for one of the amplitudes of the harmonic component, and a plurality of sets of control signals generated corresponding to the three different values are generated. A set of control signals with a small distortion of the input current waveform is identified from the set, and the on state and off state of the switching element are controlled based on the identified set of control signals, thereby controlling the input current. The generation of the set of control signals includes: comparing a signal with a predetermined waveform serving as a reference with a voltage command generated for the set value, and based on the comparison result. , a plurality of control signals for respectively controlling the plurality of switching elements are generated as one set .

According to the sixth aspect of the present invention , the program causes the computer to determine the on-state of each of the plurality of switching elements of the converter circuit based on the period in which the rotation speed of the compressor motor, which is the load of the converter circuit, fluctuates. measuring the distortion of the input current by calculating from the ratio of each frequency component when changing the control signal that controls the and off state, and multiplying the period by any integer from 5 to 10. For each period calculated by generating sets of the control signals for each of three different values set for one of the phase difference or the amplitude of the harmonic component; and generating the control signal sets corresponding to the three different values. By identifying one set of control signals with a small distortion of the input current waveform from among the plurality of sets, and controlling the on state and off state of the switching element based on the identified one set of control signals, the input current waveform is controlled. The control signal set is generated by comparing a reference signal with a predetermined waveform and the voltage command generated for the set value, and calculating the comparison result. A plurality of control signals for respectively controlling the plurality of switching elements are generated as one set based on the above .

According to the control device, correction method, and program according to the embodiments of the present invention, it is possible to reduce input current distortion caused by power supply voltage distortion in a circuit in which a current flows according to a voltage difference between both ends of a reactor.

1 is a diagram showing the configuration of a motor drive device according to an embodiment of the present invention. FIG. 2 is a diagram showing the configuration of a converter control section according to an embodiment of the present invention. FIG. 3 is a diagram for explaining generation of switching signals in an embodiment of the present invention. FIG. 3 is a diagram for explaining generation of a voltage command in an embodiment of the present invention. FIG. 2 is a first diagram showing a processing flow of a converter control unit according to an embodiment of the present invention. FIG. 2 is a second diagram showing a processing flow of a converter control unit according to an embodiment of the present invention. FIG. 1 is a schematic block diagram showing the configuration of a computer according to at least one embodiment.

<Embodiment>
Hereinafter, embodiments will be described in detail with reference to the drawings.
A motor drive device according to an embodiment of the present invention will be described.
In addition, in one embodiment of the present invention, it is assumed that the load of the converter device fluctuates in a constant cycle. FIG. 1 is a diagram showing the configuration of a motor drive device 1 according to an embodiment of the present invention. The motor drive device 1 is a device that converts AC power from an AC power source 4 into DC power, converts the DC power into three-phase AC power, and outputs the three-phase AC power to the compressor motor 20. As shown in FIG. 1, the motor drive device 1 includes a converter device 2 (an example of a circuit through which a current flows according to a voltage difference between both ends of a reactor, an example of a converter circuit), and an inverter device 3.

The converter device 2 is a device that converts AC power from the AC power source 4 into DC power and outputs the DC power to the inverter device 3. Converter device 2 includes a rectifier circuit 5, a switching circuit 10a, a switching circuit 10b, a smoothing capacitor 12, a converter control section 15, and an input current detection section 30.
The rectifier circuit 5 includes an input terminal, an input-side reference terminal, an output terminal, and an output-side reference terminal. The potential of the reference terminal on the input side is a potential that serves as a reference for the potential at the input terminal. The potential of the reference terminal on the output side is a potential that serves as a reference for the potential at the output terminal. The rectifier circuit 5 converts AC power input from the AC power supply 4 into DC power, and outputs the DC power to the switching circuit 10a and the switching circuit 10b.

The switching circuit 10 a causes a current to flow through the smoothing capacitor 12 and generates a voltage that is input to the inverter device 3 . The switching circuit 10a includes a reactor 6a, a diode 7a, and a switching element 8a.

The reactor 6a includes a first terminal and a second terminal.
The diode 7a includes an anode terminal and a cathode terminal.
The switching element 8a includes a first terminal, a second terminal, and a third terminal. The switching element 8a controls the current flowing from the second terminal to the third terminal by switching between an on-state period and an off-state period according to the signal received by the first terminal. Change the value of the flowing current. Examples of the switching element 8a include a field effect transistor (FET), an insulated gate bipolar transistor (IGBT), and the like. When the switching element 8a is, for example, an nMOS transistor, the first terminal of the switching element 8a is a gate terminal, the second terminal is a source terminal, and the third terminal is a drain terminal.

Similar to the switching circuit 10a, the switching circuit 10b causes current to flow through the smoothing capacitor 12 to generate a voltage that is input to the inverter device 3. The switching circuit 10b includes a reactor 6b, a diode 7b, and a switching element 8b.

The reactor 6b includes a first terminal and a second terminal.
Diode 7b includes an anode terminal and a cathode terminal.
Like the switching element 8a, the switching element 8b includes a first terminal, a second terminal, and a third terminal. The switching element 8b controls the current flowing from the second terminal to the third terminal by switching between an on-state period and an off-state period according to the signal received by the first terminal. Change the value of the flowing current. Examples of the switching element 8b include a field effect transistor, an IGBT, and the like. When the switching element 8b is, for example, an nMOS transistor, the first terminal of the switching element 8b is a gate terminal, the second terminal is a source terminal, and the third terminal is a drain terminal.

Smoothing capacitor 12 includes a first terminal and a second terminal. Smoothing capacitor 12 receives current from both switching circuit 10a and switching circuit 10b. That is, the voltage input to the inverter device 3 is determined by the sum of the current values flowing into the smoothing capacitor 12 from both the switching circuit 10a and the switching circuit 10b.

The input current detection section 30 includes an input terminal and an output terminal. The input current detection unit 30 detects a return current to the AC power supply 4 (hereinafter referred to as "input current"). Input current detection section 30 provides information on the detected input current to converter control section 15 .
Converter control unit 15 includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal. Converter control section 15 receives input current information from input current detection section 30 via the first input terminal, and observes the input current waveform. Converter control section 15 controls switching circuit 10a via the first output terminal. Further, the converter control unit 15 controls the converter 10b via the second output terminal. The converter control unit 15 identifies a control signal with a small distortion of the input current waveform from the input current waveform when changing the control signal Sg1 of the switching circuit 10a and the control signal Sg2 of the switching circuit 10b.

AC power supply 4 includes an output terminal and a reference terminal. AC power supply 4 supplies AC power to converter device 2 .

Zero-cross detection section 17 includes a first input terminal, a second input terminal, and an output terminal. The zero-cross detection unit 17 detects the zero-cross point of the voltage output by the AC power supply 4 via the first input terminal and the second input terminal. The zero crossing point indicates the time when the voltage output from the AC power supply 4 crosses zero volts, and that time becomes a reference time in the processing of the motor drive device 1. The zero-crossing detection unit 17 generates a zero-crossing signal including information on a zero-crossing point. Zero-cross detection section 17 outputs a zero-cross signal to converter control section 15 via an output terminal.

The inverter device 3 is a device that converts the DC power output from the converter device 2 into three-phase AC power and outputs it to the compressor motor 20. The inverter device 3 includes a bridge circuit 18 and an inverter control section 19.
As shown in FIG. 1, the bridge circuit 18 includes an input terminal, a first output terminal, a second output terminal, a third output terminal, and a reference terminal. The potential of the reference terminal is a potential that serves as a reference for the potentials at each of the input terminal, the first output terminal, the second output terminal, and the third output terminal. Bridge circuit 18 includes switching elements 181, 182, 183, 184, 185, and 186. The bridge circuit 18 is configured by each pair of switching elements 181 and 182, switching elements 183 and 184, and switching elements 185 and 186. Each of the switching elements 181 to 186 includes a first terminal, a second terminal, and a third terminal. Each of the switching elements 181 to 186 controls the current flowing from the second terminal to the third terminal by switching between an on state period and an off state period according to a signal received by the first terminal, Three-phase AC power that drives the compressor motor 20 is generated, and the generated three-phase AC power is output to the compressor motor 20. Examples of the switching elements 181, 182, 183, 184, 185, and 186 include power field effect transistors, IGBTs, and the like.

Inverter control section 19 includes a first output terminal, a second output terminal, a third output terminal, a fourth output terminal, a fifth output terminal, and a sixth output terminal. The first output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 181 a gate drive signal that switches between a period in which the switching element 181 is in an on state and a period in which it is in an off state. The second output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 182 a gate drive signal that switches the period in which the switching element 182 is in the on state and the period in which the switching element 182 is in the off state. The third output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 183 a gate drive signal that switches between a period in which the switching element 183 is in an on state and a period in which it is in an off state. The fourth output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 184 a gate drive signal that switches between an on-state period and an off-state period of the switching element 184. The fifth output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 185 a gate drive signal that switches between an on-state period and an off-state period of the switching element 185. The sixth output terminal of the inverter control unit 19 is a terminal for outputting to the first terminal of the switching element 186 a gate drive signal that switches between a period in which the switching element 186 is in an on state and a period in which it is in an off state. Note that in FIG. 1, the first to sixth output terminals of the inverter control section 19 are omitted. Further, in FIG. 1, the gate drive signals output from the first to sixth output terminals of the inverter control unit 19 to the bridge circuit 18 are collectively shown as a gate drive signal Spwm. Inverter control section 19 controls opening and closing of switching elements in bridge circuit 18 . The inverter control unit 19 generates gate drive signals Spwm for the switching elements 181 to 186 based on, for example, a required rotation speed command input from a host device (not shown). The inverter control unit 19 provides the gate drive signal Spwm to the bridge circuit 18 via the first to sixth output terminals. Note that specific examples of inverter control methods include vector control, sensorless vector control, V/F (Variable Frequency) control, overmodulation control, and one-pulse control.

Compressor motor 20 is rotated by three-phase AC power generated by each of switching elements 181-186. The direct load of the converter device 2 is the inverter device 3, and the required power of the inverter device 3 changes depending on the power supplied to the compressor motor 20. The load of the converter device 2 can therefore be seen as the compressor motor 20. In other words, the case where the load of the converter device 2 fluctuates at a substantially constant cycle is the case where the rotation speed of the compressor motor 20 fluctuates at a substantially constant cycle (an example of a variation related to the power of the converter circuit).

An input terminal of the rectifier circuit 5 is connected to an output terminal of the AC power supply 4 and a first input terminal of the zero-cross detection section 17. The reference terminal on the input side of the rectifier circuit 5 is connected to the reference terminal of the AC power supply 4 , the second input terminal of the zero-cross detection section 17 , and the input terminal of the input current detection section 30 . An output terminal of the rectifier circuit 5 is connected to a first terminal of a reactor 6a and a first terminal of a reactor 6b. The reference terminals on the output side of the rectifier circuit 5 are the third terminal of the switching element 8a, the third terminal of the switching element 8b, the second terminal of the smoothing capacitor 12, and the reference terminal of the inverter device 3 (switching elements 182, 184). , 186 respectively).
A second terminal of the reactor 6a is connected to an anode terminal of the diode 7a and a second terminal of the switching element 8a. The second terminal of the reactor 6b is connected to the anode terminal of the diode 7b and the second terminal of the switching element 8b.
The cathode terminal of the diode 7a is connected to the cathode terminal of the diode 7b, the first terminal of the smoothing capacitor 12, and the input terminal of the inverter device 3 (the second terminal of each of the switching elements 181, 183, and 185).
A first terminal of switching element 8 a is connected to a first output terminal of converter control section 15 . A first terminal of switching element 8b is connected to a second output terminal of converter control section 15.
A first terminal of converter control section 15 is connected to an output terminal of input current detection section 30 . A second terminal of converter control section 15 is connected to an output terminal of zero-cross detection section 17 .
A first terminal of switching element 181 is connected to a first output terminal of inverter control section 19 . A first terminal of switching element 182 is connected to a second output terminal of inverter control section 19 . A first terminal of switching element 183 is connected to a third output terminal of inverter control section 19 . A first terminal of switching element 184 is connected to a fourth output terminal of inverter control section 19 . A first terminal of switching element 185 is connected to a fifth output terminal of inverter control section 19 . A first terminal of switching element 186 is connected to a sixth output terminal of inverter control section 19 .
A third terminal of switching element 181 is connected to a second terminal of switching element 182 and a first terminal of compressor motor 20 . A third terminal of switching element 183 is connected to a second terminal of switching element 184 and a second terminal of compressor motor 20 . A third terminal of switching element 185 is connected to a second terminal of switching element 186 and a first terminal of compressor motor 20 .

Note that when realizing the above control, a DC voltage detection section and a motor current detection section may be provided as described in Patent Document 1.
The DC voltage detection section is a detection section that detects the input DC voltage Vdc of the bridge circuit 18.
The motor current detection section is a detection section that detects each phase current iu, iv, and iw flowing through the compressor motor 20. The motor current detection section inputs these detected values Vdc, iu, iv, and iw to the inverter control section 19. Note that the motor current detection section may detect the current flowing in the negative power line between the bridge circuit 18 and the smoothing capacitor 12, and obtain the phase currents iu, iv, and iw from this detection signal.

FIG. 2 is a functional block diagram of converter control section 15. As shown in FIG.
As shown in FIG. 2, the converter control section 15 includes a waveform observation section 21, a control signal generation section 22 (an example of a control section), a distortion measurement section 23, and a storage section 24.

The waveform observation section 21 receives from the zero-cross detection section 17 a zero-cross signal indicating the zero-cross point of the AC power supply 4 detected by the zero-cross detection section 17 . The waveform observation section 21 receives an input current waveform from the input current detection section 30. The waveform observation unit 21 observes the input current waveform with the zero-crossing point as a reference.

The control signal generation unit 22 generates a first switching signal Sg1 for controlling the switching circuit 10a and a second switching signal Sg2 for controlling the switching circuit 10b.
Specifically, the control signal generation unit 22 generates a predetermined triangular wave and a voltage command, as shown in FIGS. 3(a) and 3(c). The predetermined triangular wave is a reference waveform signal. The voltage command is a signal in which a sine wave and a harmonic component having the sine wave as a fundamental wave are superimposed. Then, the control signal generation unit 22 compares the triangular wave and the voltage command, and based on the comparison result, the first switching signal Sg1 and the first switching signal Sg1, which controls the switching element 8a as shown in FIGS. A second switching signal Sg2 that controls the switching element 8b is generated.
Note that the control signal generation unit 22 takes the absolute value of the signal obtained by superimposing the fundamental wave and the third harmonic shown in FIG. 4(a), for example, as shown in FIG. 4(b), and calculates the absolute value. The absolute value is used as the voltage command. Here, the control signal generation unit 22 normalizes the amplitude of the harmonic component by the amplitude of the fundamental wave.
The voltage command D in this case can be expressed as the following equation (1).

In equation (1), the phase difference f1t indicates the phase difference between the power supply voltage and the voltage command. The amplitude f3s indicates the amplitude of the sine component of the third harmonic. The amplitude f3c indicates the amplitude of the cosine component of the third harmonic.
In addition, although the example shown here shows the case where the third harmonic is used as the harmonic to be superimposed on the fundamental wave, in another embodiment of the present invention, the fifth harmonic, the seventh harmonic, and the ninth harmonic are used. Like waves, even harmonic components of arbitrary odd orders may be superimposed.
In addition, since grid voltage distortion is normally a distortion that includes only odd-order harmonic components, odd-order harmonic components are superimposed, but in another embodiment of the present invention, even-order harmonic components are superimposed. Waves may also be superimposed. For example, if it is known that even-order harmonics are superimposed due to external interference, even-order harmonics may be superimposed on the fundamental wave.

When the control signal generation section 22 changes the voltage command using the phase difference f1t, the amplitude f3s, and the amplitude f3c as parameters, the distortion measurement section 23 changes the first switching signal Sg1 and the second switching signal Sg2. Measure the input current distortion that occurs when Here, the distortion measurement unit 23 measures the distortion of the input current for each period calculated by multiplying the fluctuation period of the load of the converter device 2 by any integer from 5 to 10. Specifically, when the compressor motor 20 in an air conditioner rotates at about 20 [rps], the strain measurement unit 23 measures the frequency at a period of (1/20 [rps]) x 5 times = 0.25 [s]. Measure distortion. Also, considering the stabilization time of the current waveform, 10 times the current waveform is more stable than 5 times, so preferably, the distortion measurement unit 23 Distortion is measured at a cycle of .5 [s]. However, in reality, if the control cycle is long, it will take time for the entire adjustment, so it is better to adjust at a cycle calculated by about 5 to 10 times. Then, the converter control unit 15 corrects the distortion of the input current for each calculated period. By measuring the distortion of the input current at the period calculated in this way, the distortion measuring section 23 can stabilize the measured value of the distortion, and reduce the time required for correcting the input current distortion by the converter control section 15. Can be shortened. This has been confirmed by experiment. Note that when the distortion measurement unit 23 periodically measures the distortion of the input current at a cycle shorter than five times, the time from when the distortion of the input current is corrected to when the input current waveform actually becomes stable is It will run out. As a result, the distortion of the next input current is corrected while the input current waveform is unstable, and the overall correction time becomes longer. Furthermore, when the distortion measuring section 23 periodically measures the distortion of the input current at a cycle longer than 10 times, the adjustment is not made after the distortion of the input current has been corrected and the input current waveform actually becomes stable. There will be a waiting time. As a result, the entire correction time becomes longer.
The measurement of the distortion of the input current performed by the distortion measurement unit 23 is based on the input current waveform received by the waveform observation unit 21, and for example, the distortion is calculated from the ratio of each frequency component by Fourier transformation. It may be calculated using other techniques.
Note that the distortion here is a distortion rate μ expressed by the following equation (2).

In equation (2), _I1 is a fundamental current component, _I2 is a second harmonic current component, _I3 is a third harmonic current component, and _I4 is a fourth harmonic current component.
Then, the control signal generation unit 22 can cancel the distortion in the input current by generating the voltage command using the parameter when the distortion of the input current measured by the distortion measurement unit 23 is the smallest.

Storage unit 24 stores various information necessary for processing performed by converter control unit 15. For example, the storage unit 24 stores the measurement results of the distortion measurement unit 23.

Next, processing of the motor drive device 1 according to an embodiment of the present invention will be described.
Here, the processing flow of converter control section 15 shown in FIGS. 5 and 6 will be described.
Note that the processing of the converter control unit 15 shown in FIGS. 5 and 6 is processing performed when the input current is flowing. Further, the rotation speed of the compressor motor 20, which is the load of the converter device 2, fluctuates at a constant cycle, and even if not specifically stated, the strain measurement unit 23 measures the rotation speed of the compressor motor 20. The distortion of the input current is measured for each period calculated by multiplying the reciprocal of the value by any integer between 5 and 10. The control signal generation section 22 generates the first switching signal Sg1 and the second switching signal Sg2 every measurement cycle by the distortion measurement section 23 to correct distortion of the input current.

As shown in FIG. 5, the converter control unit 15 performs a process of step S1 to set a phase difference f1t, which is a parameter. The process of step S1 is performed as shown in the process flow shown in FIG. Specifically, the process of step S1 for setting the phase difference f1t is the process of steps S11a to S27a described below.

The control signal generation unit 22 generates initial parameters of the voltage command regarding the phase difference f1t, the amplitude f3s, and the amplitude f3c (step S11a). Note that the initial parameter of the phase difference f1t is the phase value f1t1, the initial parameter of the amplitude f3s is the amplitude f3s1, and the initial parameter of the amplitude f3c is the amplitude f3c1. Further, the combination of the initial parameter phase value f1t1, amplitude f3s1, and amplitude f3c1 at this time is set as parameter Param1. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param1 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param1 to the distortion measurement section 23.

The waveform observation unit 21 receives an input current from the input current detection unit 30 (step S12a). The waveform observation section 21 outputs the value of the input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param1 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S13a). The distortion measurement unit 23 associates the measurement result of the distortion of the input current with the parameter Param1 and stores them in the storage unit 24 (step S14a). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives the notification of completion of measurement from the distortion measurement unit 23, the control signal generation unit 22 generates a value larger than the phase difference f1t1 by the minimum setting width Δf1t of the phase difference f1t without changing the amplitude f3s1 and the amplitude f3c1, which are the parameters. A voltage command is generated for the phase difference f1t2 set to (step S15a). The combination of the parameters in this case, phase difference f1t2, amplitude f3s1, and amplitude f3c1, is set as parameter Param2. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param2 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param2 to the distortion measurement section 23.

The waveform observation section 21 receives an input current from the input current detection section 30 (step S16a). The waveform observation section 21 outputs the value of the received input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param2 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S17a). The distortion measurement unit 23 associates the measurement result of the distortion of the input current with the parameter Param2 and stores them in the storage unit 24 (step S18a). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives the notification of completion of measurement from the distortion measurement unit 23, the control signal generation unit 22 sets the amplitude f3s1 and the amplitude f3c1, which are the parameters, to a value smaller than the phase difference f1t1 by the minimum setting width Δf1t. A voltage command is generated for the phase difference f1t3 (step S19a). The combination of the parameters in this case, phase difference f1t3, amplitude f3s1, and amplitude f3c1, is set as parameter Param3. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param3 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param3 to the distortion measurement section 23.

The waveform observation section 21 receives an input current from the input current detection section 30 (step S20a). The waveform observation section 21 outputs the value of the received input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param3 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S21a). The distortion measurement unit 23 associates the measurement result of the distortion of the input current with the parameter Param3 and stores them in the storage unit 24 (step S22a). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives the notification of completion of measurement from the distortion measurement unit 23, it reads the measurement results of input current distortion associated with each of the parameters Param1, Param2, and Param3 from the storage unit 24. The control signal generation unit 22 sets the input current distortion for the parameter Param1 as a first input current distortion, the input current distortion for the parameter Param2 as a second input current distortion, and the input current distortion for the parameter Param3 as a first input current distortion. It is written into the storage unit 24 as the third input current distortion. The control signal generation unit 22 compares the measurement results of the distortion of the first to third input currents and determines whether the distortion of the first input current is the minimum (step S23a).
When the control signal generation unit 22 determines that the distortion of the first input current is the minimum (YES in step S23a), the control signal generation unit 22 selects an intermediate value (this In this case, if it is determined that the distortion takes a minimum value when using the phase difference f1t1), the parameter (in this case, parameter Param1) that provides the distortion of the first input current is set as the parameter to be set as a fixed value. (Step S24a) The process proceeds to setting the amplitude f3s, which is a parameter.

Further, when determining that the distortion of the first input current is not the minimum (NO in step S23a), the control signal generation unit 22 determines whether the distortion of the second input current is the minimum (step S25a). ).
When the control signal generation unit 22 determines that the distortion of the second input current is the minimum (YES in step S25a), the control signal generation unit 22 selects a parameter from which the distortion of the second input current can be obtained as a parameter to be set as a fixed value (in this case , Param2) are set, for example, by writing them into the storage unit 24 (step S26a), and the process proceeds to setting the amplitude f3s, which is a parameter.

In addition, when the control signal generation unit 22 determines that the distortion of the second input current is not the minimum (NO in step S25a), the control signal generation unit 22 selects a parameter (this If so, the parameter Param3) is set (step S27a), and the process proceeds to the process of setting the parameter amplitude f3s.

Next, the converter control unit 15 performs the process of step S2 shown in FIG. 5 to set the phase difference f3s, which is a parameter. The process of step S2 is a process of setting the amplitude f3s as a parameter without changing the parameters other than the amplitude f3s set in the process of step S1. The process of step S2 shown in FIG. 5 is performed as shown in the process flow shown in FIG. Specifically, the process of step S2 for setting the amplitude f3s is the process of steps S11b to S27b shown below.

The control signal generation unit 22 generates voltage command parameters using the phase difference f1t, amplitude f3s, and amplitude f3c set in the process of step S1 as initial parameters (step S11b). For convenience of explanation, the phase difference f1t set in the process of step S1 is referred to as the phase value f1t1, the amplitude f3s set in the process of step S1 is referred to as the amplitude f3s1, and the amplitude f3c set in the process of step S1 is referred to as the amplitude f3c1. shall be. Further, the combination of the initial parameter phase value f1t1, amplitude f3s1, and amplitude f3c1 at this time is set as parameter Param1. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param1 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param1 to the distortion measurement section 23.

The waveform observation section 21 receives the input current from the input current detection section 30 (step S12b). The waveform observation section 21 outputs the value of the input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param1 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S13b). The distortion measurement unit 23 associates the measurement result of the distortion of the input current with the parameter Param1 and stores them in the storage unit 24 (step S14b). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives a notification of completion of measurement from the distortion measurement unit 23, the control signal generation unit 22 sets the amplitude f3s to a value larger than the amplitude f3s1 by the minimum setting width Δf3s without changing the parameters phase difference f1t1 and amplitude f3c1. A voltage command is generated for the set amplitude f3s2 (step S15b). The combination of the parameters in this case, phase difference f1t1, amplitude f3s2, and amplitude f3c1, is set as parameter Param2. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param2 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param2 to the distortion measurement section 23.

The waveform observation section 21 receives the input current from the input current detection section 30 (step S16b). The waveform observation section 21 outputs the value of the received input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param2 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S17b). The distortion measurement unit 23 stores the measurement result of the distortion of the input current in association with the parameter Param2 in the storage unit 24 (step S18b). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives a notification of completion of measurement from the distortion measurement unit 23, the control signal generation unit 22 generates an amplitude set to a value smaller than the amplitude f3s1 by the minimum setting width Δf3s without changing the parameters phase difference f1t1 and amplitude f3c1. A voltage command is generated for f3s3 (step S19b). The combination of the parameters in this case, phase difference f1t1, amplitude f3s3, and amplitude f3c1, is set as parameter Param3. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param3 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param3 to the distortion measurement section 23.

The waveform observation section 21 receives the input current from the input current detection section 30 (step S20b). The waveform observation section 21 outputs the value of the received input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param3 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S21b). The distortion measurement unit 23 associates the measurement result of the distortion of the input current with the parameter Param3 and stores them in the storage unit 24 (step S22b). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives the notification of completion of measurement from the distortion measurement unit 23, it reads the measurement results of input current distortion associated with each of the parameters Param1, Param2, and Param3 from the storage unit 24. The control signal generation unit 22 sets the input current distortion for the parameter Param1 as a first input current distortion, the input current distortion for the parameter Param2 as a second input current distortion, and the input current distortion for the parameter Param3 as a first input current distortion. It is written into the storage unit 24 as the third input current distortion. The control signal generation unit 22 compares the measurement results of the distortion of the first to third input currents and determines whether the distortion of the first input current is the minimum (step S23b).
When the control signal generation unit 22 determines that the distortion of the first input current is the minimum (YES in step S23b), the control signal generation unit 22 generates an intermediate value among the three different amplitudes f3s1, f3s1−Δf3s, and f3s1+Δf3s (in this case, , amplitude f3s1), the parameter (parameter Param1 in this case) from which the distortion of the first input current can be obtained is stored as a parameter to be set as a fixed value. It is set by writing in the section 24 (step S24b), and the process proceeds to setting the amplitude f3c, which is a parameter.

Further, when determining that the distortion of the first input current is not the minimum (NO in step S23b), the control signal generation unit 22 determines whether the distortion of the second input current is the minimum (step S25b). ).
When the control signal generation unit 22 determines that the distortion of the second input current is the minimum (YES in step S25b), the control signal generation unit 22 selects a parameter from which the distortion of the second input current can be obtained as a parameter to be set as a fixed value (in this case , parameter Param2) (step S26b), and the process proceeds to setting the parameter amplitude f3c.

In addition, when the control signal generation unit 22 determines that the distortion of the second input current is not the minimum (NO in step S25b), the control signal generation unit 22 selects a parameter from which the distortion of the third input current is obtained (this If so, the parameter Param3) is set (step S27b), and the process proceeds to the process of setting the parameter amplitude f3c.

Next, the converter control unit 15 performs the process of step S3 shown in FIG. 5 to set a phase difference f3c as a parameter. The process of step S3 is a process of setting the amplitude f3c as a parameter without changing the parameters other than the amplitude f3c set in the process of step S2. The process in step S3 shown in FIG. 5 is performed as shown in the process flow shown in FIG. Specifically, the process of step S3 for setting the amplitude f3c is the process of steps S11c to S27c shown below.

The control signal generation unit 22 generates voltage command parameters using the phase difference f1t, amplitude f3s, and amplitude f3c set in the process of step S2 as initial parameters (step S11c). For convenience of explanation, the phase difference f1t set in the process of step S2 is referred to as the phase value f1t1, the amplitude f3s set in the process of step S2 is referred to as the amplitude f3s1, and the amplitude f3c set in the process of step S2 is referred to as the amplitude f3c1. shall be. Further, the combination of the initial parameter phase value f1t1, amplitude f3s1, and amplitude f3c1 at this time is set as parameter Param1. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param1 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param1 to the distortion measurement section 23.

The waveform observation unit 21 receives an input current from the input current detection unit 30 (step S12c). The waveform observation section 21 outputs the value of the input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param1 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S13c). The distortion measurement unit 23 associates the measurement result of the distortion of the input current with the parameter Param1 and stores them in the storage unit 24 (step S14c). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives the notification of completion of measurement from the distortion measurement unit 23, the control signal generation unit 22 sets the amplitude f3c to a value larger than the amplitude f3c1 by the minimum setting width Δf3c without changing the parameters phase difference f1t1 and amplitude f3s1. A voltage command is generated for the set amplitude f3c2 (step S15c). The combination of the parameters in this case, phase difference f1t1, amplitude f3s1, and amplitude f3c2, is set as parameter Param2. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param2 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param2 to the distortion measurement section 23.

The waveform observation section 21 receives the input current from the input current detection section 30 (step S16c). The waveform observation section 21 outputs the value of the received input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param2 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S17c). The distortion measurement unit 23 stores the measurement result of the distortion of the input current in association with the parameter Param2 in the storage unit 24 (step S18c). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives the notification of completion of measurement from the distortion measurement unit 23, the control signal generation unit 22 generates an amplitude set to a value smaller than the amplitude f3c1 by the minimum setting width Δf3c without changing the parameters phase difference f1t1 and amplitude f3s1. A voltage command is generated for f3c3 (step S19c). The combination of the parameters in this case, phase difference f1t1, amplitude f3s1, and amplitude f3c3, is set as parameter Param3. The control signal generation unit 22 outputs the first switching signal Sg1 generated for the parameter Param3 to the switching circuit 10a, and outputs the generated second switching signal Sg2 to the switching circuit 10b. The control signal generation section 22 outputs the value of the parameter Param3 to the distortion measurement section 23.

The waveform observation section 21 receives an input current from the input current detection section 30 (step S20c). The waveform observation section 21 outputs the value of the received input current to the distortion measurement section 23.

The distortion measuring section 23 receives the value of the parameter Param3 from the control signal generating section 22. Further, the distortion measuring section 23 receives the value of the input current from the waveform observing section 21 . The distortion measuring unit 23 measures the distortion of the input current based on the value of the input current (step S21c). The distortion measurement unit 23 associates the measurement result of the distortion of the input current with the parameter Param3 and stores them in the storage unit 24 (step S22c). The distortion measuring section 23 notifies the control signal generating section 22 of the completion of the measurement.

When the control signal generation unit 22 receives the notification of completion of measurement from the distortion measurement unit 23, it reads the measurement results of input current distortion associated with each of the parameters Param1, Param2, and Param3 from the storage unit 24. The control signal generation unit 22 sets the input current distortion for the parameter Param1 as a first input current distortion, the input current distortion for the parameter Param2 as a second input current distortion, and the input current distortion for the parameter Param3 as a first input current distortion. It is written into the storage unit 24 as the third input current distortion. The control signal generation unit 22 compares the measurement results of the distortion of the first to third input currents and determines whether the distortion of the first input current is the minimum (step S23c).
When the control signal generation unit 22 determines that the distortion of the first input current is the minimum (YES in step S23c), the control signal generation unit 22 generates an intermediate value among the three different amplitudes f3c1, f3c1−Δf3c, and f3c1+Δf3c (in this case , amplitude f3c1), the parameter (parameter Param1 in this case) that provides the distortion of the first input current is stored as a parameter to be set as a fixed value (in this case, parameter Param1). The settings are made by writing in the section 24 (step S24c).
Then, the control signal generation unit 22 proceeds to the process of step S4 in which it is determined whether the parameter Param1 has been set in all steps of step S1, step S2, and step S3 shown in FIG.

Further, when determining that the distortion of the first input current is not the minimum (NO in step S23c), the control signal generation unit 22 determines whether the distortion of the second input current is the minimum (step S25c). ).
When the control signal generation unit 22 determines that the distortion of the second input current is the minimum (YES in step S25c), the control signal generation unit 22 selects a parameter from which the distortion of the second input current can be obtained as a parameter to be set as a fixed value (in this case , Param2) are set (step S26c).
Then, the control signal generation unit 22 proceeds to the process of step S4 in which it is determined whether the parameter Param1 has been set in all steps of step S1, step S2, and step S3 shown in FIG.

In addition, when the control signal generation unit 22 determines that the distortion of the second input current is not the minimum (NO in step S25c), the control signal generation unit 22 selects a parameter from which the distortion of the third input current is obtained (this If so, the parameter Param3) is set (step S27c).
Then, the control signal generation unit 22 proceeds to the process of step S4 in which it is determined whether the parameter Param1 has been set in all steps of step S1, step S2, and step S3 shown in FIG.

If the control signal generation unit 22 determines in the process of step S4 that the parameter Param1 is not set in at least one of step S1, step S2, and step S3, the process returns to step S1.
Further, in the process of step S4, if the control signal generation unit 22 determines that the parameter Param1 has been set in all steps of step S1, step S2, and step S3, the control signal generation unit 22 completes the process.
The control signal generation unit 22 generates a voltage command using the set phase difference f1t, amplitude f3c, and amplitude f3s as parameters.

In addition, in the processing of the motor drive device 1 according to the embodiment of the present invention described using FIGS. 5 and 6 , the input current is determined by averaging the measurement results of a natural number of input currents to eliminate noise and compression. The influence of load fluctuations on the machine motor 20 can be reduced.

The motor drive device 1 according to one embodiment of the present invention has been described above.
In the motor drive device 1 according to the embodiment of the present invention, the control signal generation unit 22 (control unit) is configured to control a first current flowing in a converter circuit in which a current flows according to a voltage difference between both ends of the reactors 6a and 6b. A switching signal Sg1 and a second switching signal Sg2 (control signal) are generated. The distortion measurement unit 23 measures the distortion of the current flowing through the converter circuit with respect to the plurality of first switching signals Sg1 and second switching signals Sg2 (control signals) generated by the control signal generation unit 22.
By doing so, the motor drive device 1 connects the control signal generation unit 22 and the converter circuit through which a current flows according to the voltage difference between both ends of the reactors 6a and 6b using the generated first switching signal Sg1 and the second switching signal. It becomes possible to control using Sg2 (control signal), and distortion of the input current caused by distortion of the power supply voltage can be reduced.

Note that in one embodiment of the present invention, an example was shown in which the converter control unit 15 calculates the minimum value of distortion, but in another embodiment of the present invention, the converter control unit 15 may calculate the minimum value of distortion. . In another embodiment of the present invention, converter control unit 15 may, for example, measure input current distortion for all possible parameters and identify the minimum value of distortion. Further, the converter control unit 15 may specify the minimum value of distortion using another method.
Further, in one embodiment of the present invention, the method by which the converter control unit 15 identifies the minimum value of distortion is not limited to the above method. In one embodiment of the present invention, the converter control unit 15 may use another method such as Newton's method to identify the minimum value of distortion.

Note that in one embodiment of the present invention, an example was shown in which distortion (distortion rate μ) is calculated, but in another embodiment of the present invention, the total power factor PF shown in the following equation (3) is calculated instead of distortion. It may be used.

In equation (3), the symbol φ is the phase difference between the voltage and current in the AC power supply 4. When using the total power factor in this way, it is possible to make adjustments to reduce the input current including the power factor cosφ. This is because the input active power VI cosφ of the converter device 2 is determined by the inverter device 3 regardless of the operation of the converter device 2, so when the power factor of the converter device 2 improves, the reactive power VI cosφ of the input of the converter device 2 increases. This is based on the idea that the apparent power VI, which is the square root of the sum of the squares of active power and reactive power, is also reduced.

In addition, in one embodiment of the present invention, an example was shown in which the AC power supply 4 is a single-phase power supply, but in another embodiment of the present invention, the AC power supply 4 may be a three-phase power supply. When the AC power source 4 is a three-phase power source, the harmonic components to be superimposed on the fundamental wave may be (6n-1)th and (6n+1)th harmonics (where n is an integer of 1 or more).

In one embodiment of the present invention, the distortion measurement unit 23 measures the distortion of the input current for each period calculated by multiplying the reciprocal of the rotation speed of the compressor motor 20 by any integer between 5 and 10. The explanation has been made assuming that the control signal generation unit 22 corrects the distortion of the input current by generating the first switching signal Sg1 and the second switching signal Sg2 at each measurement cycle by the distortion measurement unit 23. However, in another embodiment of the present invention, the strain measuring unit 23 sets an integer of 5 to 10 to the reciprocal of the frequency of vibration per unit time of the single rotary in the compressor (an example of fluctuations related to the power of the converter circuit). The control signal generation section 22 measures the distortion of the input current at each period calculated by multiplying one of the two, and the control signal generation section 22 generates the first switching signal Sg1 and the second switching signal Sg2 at each measurement period by the distortion measurement section 23. The input current may be generated to correct distortion of the input current. Note that the frequency of vibration per unit time of the single rotary corresponds to the number of rotations of the compressor motor 20. In another embodiment of the present invention, the distortion measurement unit 23 multiplies the reciprocal of the frequency fluctuation of the voltage on the power grid side (an example of fluctuation related to the power of the converter circuit) by any integer between 5 and 10. The control signal generation section 22 generates and inputs the first switching signal Sg1 and the second switching signal Sg2 every measurement period by the distortion measurement section 23. It may also be something that corrects current distortion. Note that the reciprocal of the frequency fluctuation of the voltage on the grid power supply side (50 [Hz], 60 [Hz]) is of the same order as the reciprocal of the rotation speed of the compressor motor 20 (20 ~ [rps]), so the grid Even if the frequency fluctuation of the voltage on the power supply side, the rotation speed fluctuation of the compressor motor 20, and the frequency of vibration per unit time of the single rotary occur at the same time, the strain measurement unit 23 calculates the reciprocal of these to be between 5 and 10. The control signal generating section 22 measures the distortion of the input current at each period calculated by multiplying by any integer, and the control signal generating section 22 generates the first switching signal Sg1 and the second switching signal Sg1 at each period of measurement by the distortion measuring section 23. A signal Sg2 can be generated to correct distortions in the input current.

Note that the storage unit 24 and other storage units in each embodiment of the present invention may be provided anywhere as long as appropriate information is transmitted and received. Further, the storage unit 24 and other storage units may exist in plurality and store data in a distributed manner within a range where appropriate information is transmitted and received.

Note that the order of the processing in the embodiment of the present invention may be changed as long as appropriate processing is performed.

The storage unit 24 and the storage device (including registers and latches) in the embodiment of the present invention may be provided anywhere as long as appropriate information is transmitted and received. Further, each of the storage unit 24 and the storage device may exist in plurality and store data in a distributed manner within a range where appropriate information is transmitted and received.

Although the embodiment of the present invention has been described, the converter control unit 15, inverter control unit 19, and other control devices described above may have a computer system inside. The above-described processing steps are stored in a computer-readable recording medium in the form of a program, and the above-mentioned processing is performed by reading and executing this program by the computer. A specific 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 50 includes a CPU 60, a main memory 70, a storage 80, and an interface 90, as shown in FIG.
For example, each of the above-mentioned converter control section 15, inverter control section 19, and other control devices is implemented in the computer 50. The operations of each processing section described above are stored in the storage 80 in the form of a program. The CPU 60 reads the program from the storage 80, expands it to the main memory 70, and executes the above processing according to the program. Further, the CPU 60 secures storage areas corresponding to each of the above-mentioned storage units in the main memory 70 according to the program.

Examples of the storage 80 include HDD (Hard Disk Drive), SSD (Solid State Drive), magnetic disk, magneto-optical disk, CD-ROM (Compact Disc Read Only Memory), and DVD-ROM (Digital Versatile). (Disc Read Only Memory) , semiconductor memory, etc. Storage 80 may be an internal medium connected directly to the bus of computer 50, or may be an external medium connected to computer 50 via interface 90 or a communication line. Furthermore, when this program is distributed to the computer 50 via a communication line, the computer 50 that received the distribution may develop the program in the main memory 70 and execute the above processing. In at least one embodiment, storage 80 is a non-transitory, tangible storage medium.

Further, the program may realize some of the functions described above. Furthermore, the program may be a file that can realize the above-described functions in combination with a program already recorded in the computer system, a so-called difference file (difference program).

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

1... Motor drive device 2... Converter device 3... Inverter device 4... AC power supply 5... Rectifier circuit 6a, 6b... Reactor 7a, 7b... Diode 8a, 8b... - Switching elements 10a, 10b...Switching circuit 12...Smoothing capacitor 15...Converter control section 17...Zero cross detection section 21...Waveform observation section 22...Control signal generation section 23... Distortion measurement section 24...Storage section 30...Input current detection section 50...Computer 60...CPU
70...Main memory 80...Storage 90...Interface Lp...Positive bus bar

Claims (6)

Each frequency when the control signal that controls the on state and off state of each of the plurality of switching elements included in the converter circuit is changed based on the period in which the rotation speed of the compressor motor, which is the load of the converter circuit, fluctuates. a distortion measurement unit that measures the distortion of the input current by calculating from the ratio of the components;
The signal is a signal in which a sine wave input to the converter circuit and a harmonic component having the sine wave as a fundamental wave are superimposed for each period calculated by multiplying the period by any integer from 5 to 10. A set of control signals is generated for each of three different values set for one of the phase difference between the voltage command and the voltage supplied to the converter circuit, or the amplitude of the harmonic component, and One set of control signals with a small distortion of the input current waveform is identified from among the plurality of sets of the control signals generated corresponding to different values, and the on-state of the switching element is determined based on the identified one set of control signals. a control signal generation unit that corrects distortion of the input current by controlling the input current and the off state;
Equipped with
The generation of the set of control signals involves comparing a reference signal with a predetermined waveform with a voltage command generated for the set value, and controlling each of the plurality of switching elements based on the comparison result. It generates a plurality of control signals as one set,
Control device. The strain measuring section includes:
measuring the distortion of the input current for each period calculated by multiplying the period in which the rotational speed fluctuates by an integer;
The control device according to claim 1. The cycle of fluctuations in the power of the converter circuit is:
is the reciprocal of the rotation speed of the compressor motor rotated by the electric power supplied from the converter circuit;
The control device according to claim 1 or claim 2. The cycle of fluctuations in the power of the converter circuit is:
is the reciprocal of the frequency of vibration per unit time of a single rotary in a compressor equipped with the compressor motor,
The control device according to claim 1 or claim 2. Each frequency when the control signal that controls the on state and off state of each of the plurality of switching elements included in the converter circuit is changed based on the period in which the rotation speed of the compressor motor, which is the load of the converter circuit, fluctuates. The distortion of the input current is measured by calculating from the ratio of the components, and the sine wave input to the converter circuit is calculated for each period calculated by multiplying the period by any integer from 5 to 10. and a harmonic component having the sine wave as a fundamental wave, which is set for either the phase difference between the voltage command and the voltage supplied to the converter circuit, or the amplitude of the harmonic component. generating sets of the control signals for three different values, and selecting one set of control signals with a small distortion of the input current waveform from among the plurality of sets of the control signals generated corresponding to the three different values. correcting the distortion of the input current by specifying a signal and controlling an on state and an off state of the switching element based on the specified set of control signals;
including;
The generation of the set of control signals involves comparing a reference signal with a predetermined waveform with a voltage command generated for the set value, and controlling each of the plurality of switching elements based on the comparison result. It generates a plurality of control signals as one set,
Correction method. to the computer,
Each frequency when the control signal that controls the on state and off state of each of the plurality of switching elements included in the converter circuit is changed based on the period in which the rotation speed of the compressor motor, which is the load of the converter circuit, fluctuates. The distortion of the input current is measured by calculating from the ratio of the components, and the sine wave input to the converter circuit is calculated for each period calculated by multiplying the period by any integer from 5 to 10. and a harmonic component having the sine wave as a fundamental wave, which is set for either the phase difference between the voltage command and the voltage supplied to the converter circuit, or the amplitude of the harmonic component. generating sets of the control signals for three different values, and selecting one set of control signals with a small distortion of the input current waveform from among the plurality of sets of the control signals generated corresponding to the three different values. correcting the distortion of the input current by specifying a signal and controlling an on state and an off state of the switching element based on the specified set of control signals;
run the
The generation of the set of control signals involves comparing a reference signal with a predetermined waveform with a voltage command generated for the set value, and controlling each of the plurality of switching elements based on the comparison result. It generates a plurality of control signals as one set,
program.

Images