JP6486488B2 - Power conversion device and refrigeration cycle device including the same - Google Patents

Description

  The present invention relates to a three-phase full-wave rectification type power conversion device and a refrigeration cycle device including the same.

  In a large-capacity power converter that drives a motor such as a compressor and a fan of a refrigeration air conditioner, a three-phase full-wave rectification type power converter with improved power factor and power current harmonic has been proposed. (For example, refer to Patent Document 1).

  Patent Document 1 includes a three-phase rectifier that rectifies a three-phase AC power source, a reactor, a switching element, and a backflow prevention element, and includes a boost converter section that boosts the output voltage of the three-phase rectifier by chopping, and a boost converter section. A switching control unit that controls the switching element, a smoothing capacitor that smoothes the output of the boost converter unit, an inverter circuit that converts the DC voltage that is the output of the boost converter unit into an AC voltage, and supplies the AC voltage to the motor, and an inverter And an inverter driving means for driving the circuit, and the switching control unit controls the on-duty of the switching element so that the power supply current becomes a rectangular wave.

  In Patent Document 1, since the power supply current is a rectangular wave, the fifth-order harmonic component of the power supply current harmonic is particularly reduced compared to the case where a DC reactor is used immediately after the three-phase rectifier, which is advantageous from the viewpoint of harmonic regulation. It is.

JP 2010-187521 A

  In the conventional power converter described in Patent Document 1, the voltage immediately after the three-phase rectifier is input to the boost converter unit. In general, it is known that the voltage immediately after the three-phase rectifier pulsates at a frequency six times the power supply frequency (360 Hz at a commercial frequency of 60 Hz). Since the input voltage of the boost converter unit does not become constant due to the pulsation, the voltage applied to both ends of the reactor, that is, the reactor voltage does not become constant, and the reactor current of the boost converter unit is controlled to a constant value. Difficult to do.

  In order to control the reactor current to a constant value while pulsation occurs, it is necessary to sufficiently increase the response of the current control system. Therefore, when the carrier frequency is increased in order to increase the response of the current control system, there is a problem that an increase in loss of the power conversion device and an increase in noise occur. Further, when the carrier frequency is increased, the control cycle is shortened, so that the calculation needs to be completed within a more limited time. Therefore, a high-performance control device is required, which causes an increase in cost. Therefore, it is possible to reduce the carrier frequency by using repetitive control, but if a power supply phase shift occurs, there is a problem that the controllability of repetitive control in which control is performed using past information deteriorates. there were.

  The present invention has been made to solve the above-described problems, and provides a power conversion device that improves the current control performance while reducing the carrier frequency, and a refrigeration cycle device including the power conversion device. It is an object.

A power conversion device according to the present invention includes a voltage detector that detects at least one line voltage or phase voltage of a three-phase AC power supply, a three-phase rectifier that rectifies the three-phase AC power supply, a reactor, and a switching element. A converter for stepping up or down the output of the three-phase rectifier, a smoothing capacitor for smoothing the output voltage of the converter, a switching controller for controlling the switching element, and a voltage detected by the voltage detector. A phase angle calculation unit that calculates a power supply phase angle; and a current detector that detects a reactor current, wherein the switching control unit calculates a current deviation from the reactor current and outputs the current deviation; and the current deviation And an integrator for accumulating the current deviation output from the subtractor in the integrator, and a timing based on the power supply phase angle. A repeat control unit that outputs the current deviation from the integrator, an adder that adds and outputs the current deviation output from the subtractor and the current deviation output from the repeat control unit, and the adder A switching signal determining unit that generates an ON / OFF signal of the switching element based on a value output from the subtractor, and adding the current deviation output from the subtractor and the current deviation output from the repetitive control unit The process of adding in the vessel is repeated for each cycle of the three-phase AC power supply.

  According to the power conversion device of the present invention, the switching signal determination unit that generates the ON / OFF signal of the switching element after adding the current deviation output from the subtractor repeatedly with the current deviation output from the control unit by the adder. To enter. Then, by repeating this process at regular intervals, the current control performance can be improved while reducing the carrier frequency.

It is a block diagram of the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the phase angle calculation part of the power converter device which concerns on Embodiment 1 of this invention. It is operation | movement explanatory drawing of the phase angle calculation part of the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the switching control part of the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the boost converter part periphery of the power converter device which concerns on Embodiment 1 of this invention. It is a waveform which shows the characteristic of the current control response of the power converter device which concerns on Embodiment 1 of this invention. It is a waveform which shows the characteristic of the repetition control of the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram of the switching control part of the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram of the power converter device which concerns on Embodiment 3 of this invention. It is a block diagram of the phase angle calculation part of the power converter device which concerns on Embodiment 4 of this invention. It is a block diagram of the air conditioner which concerns on Embodiment 7 of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings, the relationship of the size of each component may be different from the actual one.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a power conversion device according to Embodiment 1 of the present invention.
The power conversion device according to the first embodiment includes a repetitive control unit 24 (see FIG. 4 described later) that performs repetitive control as feedback control means for current control of the boost converter unit 3, and a phase angle calculation used for repetitive control. Part 11.

  As shown in FIG. 1, the power converter includes a three-phase rectifier 2, a boost converter unit 3, a smoothing capacitor 4, an inverter 5, a phase angle calculation unit 11, a switching control unit 10, and a voltage detector 12. , 14 and a current detector 13. And the three-phase alternating current power supply 1 is connected to the power converter device as an input, and the motor 6 is connected as a load.

The step-up converter unit 3 is a step-up converter including a reactor 7, a switching element 8 such as an IGBT, and a backflow prevention element 9 such as a fast recovery diode. In step-up converter unit 3, reactor 7 and backflow prevention element 9 are connected in series, one end of reactor 7 is connected to the three-phase rectifier 2 side, and one end of backflow prevention element 9 is connected to the smoothing capacitor 4 side. . The switching element 8 is configured such that one end is connected between the reactor 7 and the backflow prevention element 9 and is connected in parallel with the smoothing capacitor 4.
Note that switching of the switching element 8 of the boost converter unit 3 is performed by the switching control unit 10.

The phase angle calculation unit 11 receives the power supply voltage v _rs from the voltage detector 12 that detects the power supply voltage, and outputs the power supply phase angle θ to the switching control unit 10. There are three inputs to the switching control unit 10, the power source phase angle θ output from the phase angle calculation unit 11, the current flowing through the reactor 7 detected by the current detector 13 (hereinafter referred to as the reactor current i _L ), and the voltage A voltage v _dc (hereinafter referred to as a smoothing capacitor voltage v _dc ) applied across the smoothing capacitor 4 detected by the detector 14. The output of the switching control unit 10 is an ON / OFF signal to the switching element 8.

Next, the operation of the power conversion device according to the first embodiment will be described with reference to FIG.
The AC voltage supplied from the three-phase AC power source 1 is rectified by the three-phase rectifier 2 and converted into a DC voltage. The DC voltage is boosted to an arbitrary value by the switching control unit 10 controlling ON / OFF of the switching element 8 of the boost converter unit 3. Further, the switching element 8, the reactor current i _L is controlled to be a constant value. Finally, the inverter 5 converts the DC voltage back to an AC voltage, and the motor 6 is driven by the AC voltage converted in reverse.

  Here, in the boost converter unit 3, when the switching element 8 is turned on, the backflow prevention element 9 is prevented from conducting, and the voltage rectified by the three-phase rectifier 2 is applied to the reactor 7. On the other hand, when the switching element 8 is turned off, the backflow prevention element 9 is conducted, and a voltage in the direction opposite to that when the switching element 8 is turned on is induced in the reactor 7. At this time, from the viewpoint of energy, it can be seen that the energy accumulated in the reactor 7 when the switching element 8 is turned on is transferred to the inverter 5 which is a load when the switching element 8 is turned off. Therefore, the output voltage of the boost converter unit 3 can be controlled by controlling the on-duty of the switching element 8.

FIG. 2 is a configuration diagram of the phase angle calculation unit 11 of the power conversion device according to Embodiment 1 of the present invention.
The phase angle calculation unit 11 includes a zero cross detection unit 15, a control frequency clock 16, a phase counter A17, a counter maximum value calculation unit 18, and a phase counter B19. The phase angle calculator 11 receives the power supply voltage v _rs from the voltage detector 12 and outputs the power supply phase angle θ to the switching controller 10.

  The phase counter A17 corresponds to the “first phase counter” of the present invention, and the phase counter B19 corresponds to the “second phase counter” of the present invention.

FIG. 3 is an operation explanatory diagram of the phase angle calculation unit 11 of the power conversion device according to Embodiment 1 of the present invention.
Next, the operation of the phase angle calculation unit 11 will be described with reference to FIGS.
The control frequency clock 16 is a clock that operates for each control cycle used for calculating the on-duty of the switching element 8. Here, the control frequency is a frequency for calculating the on-duty of the switching element 8 of the boost converter unit 3, and the control period is a period for calculating the on-duty of the switching element 8 of the boost converter unit 3. On the other hand, the carrier frequency is a frequency when the calculated on-duty is converted into a pulse width (Pulse Width Modulation), and the switching element 8 is turned ON / OFF at the cycle of the carrier frequency.

  In general, when the carrier frequency is 18 KHz, the control frequency is often calculated at 18 KHz which is the same as the carrier frequency. Note that the calculation may be performed at 36 KHz, which is twice the carrier frequency, and 9 KHz, which is half the carrier frequency. Further, the clock 16 having the control frequency shown in FIG. 3 is difficult to understand when the counter value increases, and is 400 Hz, although it deviates from the actual value for simplification.

The zero-cross detection unit 15 determines the zero-cross signal z _rs that is the output signal, as shown in the equation (1), based on the sign of the power supply voltage v _rs that is the input signal.

As a method of generating the zero cross signal z _rs , there is a method of inputting the power supply voltage v _rs and the zero voltage to the comparator. This is a method of configuring with hardware. Apart from this method, there is a method in which the value of the power supply voltage v _rs is detected by an A / D converter mounted in the microcomputer and then described by a program. This is a method of configuring with software. Note that the method for generating the zero cross signal z _rs is not limited to this as long as the periodicity of the current can be detected.

The phase counter A17 is a counter that counts up with a clock 16 having a control frequency. From the timing when the zero cross signal z _rs rises, the phase counter A17 is reset in the next control cycle, and further counted up from the next control cycle.

Next, the counter maximum value calculation unit 18 determines the reset value of the phase counter B19. Calculation is performed before the zero cross signal z _rs rises and the phase counter A17 is reset. In other words, at the timing of rising of the zero-crossing signal _{z rs,} compares the counter A output _{N A} is the output of the phase counter A17, and a reset value _{N max,} which is determined from the maximum value of the output of the phase counter A17, (2 ) Determine the reset value N _max as shown in the equation.

If towards the counter A output _{N A} is greater than the reset value _{N max} adds 1 reset value _{N max.} Further, if the counter A output _{N A} and the reset value _{N max} is the same does not change the reset value _{N max.} Also, if the direction of the counter A output _{N A} is less than the reset value _{N max} subtracts 1 from the reset value _{N max.}
In this way, the value of the reset value _Nmax , which is the reset value of the phase counter B, is changed little by little by using the counter maximum value calculation unit 18.

The phase counter B19 is a counter that counts up with the clock 16 of the control frequency. When the count value of the phase counter B19 reaches the reset value _Nmax calculated by the counter maximum value calculation unit 18, the phase counter B is reset in the next control cycle.

FIG. 4 is a configuration diagram of the switching control unit 10 of the power conversion device according to Embodiment 1 of the present invention.
Next, the operation of the switching control unit 10 will be described with reference to FIG.
The switching control unit 10 includes a voltage control system that controls the smoothing capacitor voltage v _dc as a feedback loop, and a current control system that controls the reactor current i _L as a minor loop.

The voltage control system receives the smoothing capacitor voltage v _dc detected by the voltage detector 14 and the output voltage command value v ^* _dc, and includes a subtracter 20 and a PID control unit 21. The output voltage command value v ^* _dc is a target value of the voltage boosted by the boost converter unit 3, and the output voltage command value v ^* _dc is determined from the breakdown voltage of the smoothing capacitor 4, the motor specifications, and the motor operating state. It is not limited to. The PID control unit 21 is a combination of proportional control, integral control, and derivative control. The PID control unit 21 may be only proportional control, or may be a combination of proportional control, integral control, and derivative control.

The current control system has a reactor current command value i ^* _L as an input, and includes a subtractor 22, a PID control unit 23, a repetition control unit 24, and an adder 25. Of course, in the current control system, the PID control unit 23 may be only proportional control, or may be a combination of proportional control, integral control, and differential control.

  The switching control unit 10 includes a switching signal determination unit 26.

The subtractor 20 calculates a voltage deviation from the output voltage command value v ^* _dc for the boost converter unit 3 and the smoothing capacitor voltage v _dc which is the output voltage of the boost converter unit 3 detected by the voltage detector 14. Specifically, the smoothing capacitor voltage v _dc is subtracted from the output voltage command value v ^* _dc . The voltage deviation output from the subtracter 20 is subjected to PID control by the PID control unit 21 and then becomes a reactor current command value i ^* _L , which is input to the subtractor 22.

The subtracter 22, and the reactor current command value i ^* _L, and a reactor current i _L detected by the current detector 13, calculates a current deviation of the reactor 7. Specifically, subtracting the reactor current i _L from the reactor current command value i ^* _L. The current deviation output from the subtractor 22 branches into two, one of which is PID controlled by the PID control unit 23 and then input to the adder 25, and the other is the error accumulating unit 29 of the repetitive control unit 24. Is input. That is, the switching control unit 10 includes the first path 61 in which the current deviation is input to the switching signal determination unit 26 without passing through the repetitive control unit 24, and the current deviation through the repetitive control unit 24. And a second path 62 that is input to the determination unit 26.

  The adder 25 calculates an on-duty input to the switching signal determination unit 26 from the current deviation output from the PID control unit 23 and the current deviation output from the error accumulation unit 29. Specifically, the current deviation output from the PID control unit 23 and the current deviation output from the error accumulation unit 29 are added.

The switching signal determination unit 26 generates the ON / OFF signal S ₁ for the switching element 8 from the on-duty that is the output of the adder 25.

  The repetition control unit 24 includes an input address determination unit 27, an output address determination unit 28, and an error accumulation unit 29. Inside the error accumulating unit 29, a plurality of integrators 30, one of the plurality of integrators 30 is selected, an input address connecting unit 31 connected to the input side, and an output address connecting unit 32 connected to the output side. It consists of. The repetitive control unit 24 accumulates the current deviation output from the subtractor 22 in any one integrator 30 based on the power supply phase angle θ input from the phase angle calculation unit 11, and any one integrator. The operation of outputting the current deviation accumulated in 30 is performed.

  The plurality of integrators 30 has an address for each integrator 30, and each phase angle is associated with the address of each integrator 30. The input address determination unit 27 determines the address of the integrator 30 that accumulates the current deviation input from the subtractor 22 to the error accumulation unit 29 from the power supply phase angle θ input from the phase angle calculation unit 11. The input address connection unit 31 connects the output side of the subtractor 22 to the input side of the integrator 30 having the determined address, and causes the integrator 30 to store the output side. Further, the output address determination unit 28 determines the address of the integrator 30 that outputs the accumulated current deviation from the power supply phase angle θ input from the phase angle calculation unit 11. The output address connection unit 32 connects the output side of the integrator 30 with the determined address to the input side of the adder 25 and causes the integrator 30 to output it.

  The configuration of the control system including the voltage control system and the current control system in the minor loop is an ordinary control configuration of the boost converter, but it is special to use the control unit 24 repeatedly.

FIG. 5 is a configuration diagram around the boost converter unit 3 of the power conversion device according to the first embodiment of the present invention, and FIG. 6 is a characteristic of the current control response of the power conversion device according to the first embodiment of the present invention. It is a waveform which shows. 6A is a waveform showing characteristics before the current control system of the reactor 7 is made to respond at high speed, and FIG. 6B is a waveform after the current control system of the reactor 7 is made to respond at high speed. It is a waveform which shows a characteristic.
In the case of the configuration using the boost converter unit 3 immediately after the three-phase rectifier 2, the reactor current cannot be controlled constant unless the current control response is increased. The reason for this will be described with reference to FIGS.

When the voltage immediately after the three-phase rectifier 2 and the input voltage v _in, the waveform of FIG. 6 (a) and the input voltage v _in and the reactor current i _L. Input voltage v _in, since the difference between the maximum value and the minimum value of each phase of the power supply voltage is output, varies the phase angle of the voltage source, which is six times the frequency of the power supply, 360 Hz (power supply frequency 60Hz In this case, pulsation occurs.

Pulsation is generated in the input voltage _{v in,} the voltage applied across the reactor 7 for (hereinafter, referred to as reactor voltage _{v L)} is changed, the 360Hz to reactor current _{i L} as shown in FIG. 6 (a) Pulsation occurs. Therefore, in order to prevent this, it was essential to make the current control system of the reactor 7 respond at high speed and to make it sufficiently higher than 360 Hz. If a faster current control response can be confirmed that the FIG. 6 (b), and the pulsation of the reactor current i _L is smaller.

Since the reactor control response must be made fast, it is necessary to set the carrier frequency at a high speed, leading to an increase in switching loss of the power conversion device.
Even at slow reactor control response, the development of control methods pulsation of reactor current i _L decreases were problems. As a means for solving this, the control of the reactor current i _L using the repetitive control unit 24 is applied.

Next, the operation principle of repetitive control will be described.
One cycle of the power supply voltage (hereinafter referred to as one power supply cycle) is divided into a plurality of power supply phase angles, and is made to correspond to the plurality of integrators 30 of the repetitive control unit 24. For example, when the control frequency is 18000 Hz and the power supply frequency is 60 Hz, 18000 ÷ 60 = 300, and N = 300 integrators 30 are prepared. The 300 integrators 30 correspond to each power supply phase angle, and here, the power supply phase angle corresponding to 1.2 deg (360 deg ÷ 300) per integrator 30.

Here, the operation of the repetitive control will be considered for a certain power supply phase angle α.
The repetitive control unit 24 accumulates the current deviation in the integrator 30 associated with the power supply phase angle α. Then, the current deviation accumulated in the integrator 30 is output in accordance with the timing of the power supply phase angle α after one cycle of the power supply.

  Then, by adding the current deviation output from the repetitive control unit 24 to the current deviation of the power supply phase angle α output from the PID control unit 23 in the adder 25, the power supply phase angle α one cycle before the power supply is added. Current deviation can be made closer to zero than timing.

The above processing is repetitive control. By repeating this repetitive control every power supply voltage cycle (hereinafter referred to as power supply cycle), the current deviation finally becomes zero. By realizing this with a separate integrator 30 for every power supply phase angle, the current deviation of all power supply phase angles can be made zero. In other words, it is possible to control to enhance the current control performance, the on-duty that is input to the switching signal determining section 26 for generating ON / OFF signals S ₁ of the switching element 8. In this way, even if the carrier frequency is reduced and a power phase shift occurs, highly accurate current control can be realized.

Next, the control block of the repetition control unit 24 will be described.
The power supply phase angle θ calculated by the phase angle calculation unit 11 is input to the input address determination unit 27 and the output address determination unit 28. Then, the address of the integrator 30 that accumulates the input current deviation is determined by the input address determination unit 27, and the output side of the subtractor 22 is connected to the integrator 30 of the determined address by the input address connection unit 31. Connecting. The output address determination unit 28 determines the address of the integrator 30 that outputs the accumulated current deviation, and the output address connection unit 32 inputs the output side of the integrator 30 at the determined address to the input of the adder 25. Connect to the side.

  Next, the relationship between the input address and the output address will be described. The algorithm of the iterative control unit 24 needs to consider a delay. There are two types of delay, a delay due to dead time and a delay due to current control. The delay due to the dead time is caused by a calculation time delay of a controller such as a microcomputer, and generally corresponds to one control cycle.

Next, delay due to current control will be described. Relationship between the reactor current i _L and reactor voltage v _L is a voltage equation of (3). Reactor current i _L is represented by integration of reactor voltage v _L. Therefore, even if output as the boost converter unit 3 becomes a reactor voltage v _L, it takes time to propagate as a current value. Therefore, it is necessary to consider a delay of one control cycle.

As described above, since the delay is two times of the control cycle, the output outputs an address two ahead of the input.
The error accumulation unit 29, a subtractor 22 the current deviation obtained by subtracting the reactor current i _L from the reactor current command value i ^* _L is input, the current deviation to the respective integrators 30 in the error accumulation unit 29, which is the calculated Is accumulated.

  The values accumulated in each integrator 30 are output after one cycle of the power source, and the output of the repetition control unit 24 is added to the current deviation output from the PID control unit 23 by the adder 25. Thus, the result of the repeat control unit 24 is reflected.

FIG. 7 is a waveform showing the characteristics of the repetition control unit 24 of the power conversion device according to the first embodiment of the present invention. FIG. 7 is a diagram showing the effect of the repetitive control, showing the power supply voltage v _rs , the reactor current i _L , and the repetitive control output i _error which is the control amount of the repetitive control in order from the top.
As shown in FIG. 7, the pulsation of the reactor current i _L can be confirmed to have been reduced to every power cycle. This is because the repetitive control unit 24 accumulates the pulsation of one power supply cycle in each integrator 30 and cancels the error after the next power supply cycle, that is, one power supply cycle.

  As described above, in the power conversion device according to the first embodiment, the current deviation approaches zero by performing repeated control and adding the current deviation of the same power supply phase angle, so that the pulsation of the reactor current can be reduced. it can. Therefore, even if the carrier frequency is reduced and a power phase shift occurs, the current control performance can be improved. For this reason, the control response of the PID control unit 23 can be lowered, the carrier frequency can be reduced, the loss of the power conversion device can be reduced, and noise can be suppressed. In addition, since the control cycle is extended by reducing the carrier frequency, it is easy to mount on an inexpensive microcomputer with a low calculation speed.

  Further, repetitive control is applied to the current deviation of the reactor 7 on the DC side, and the pulsation for one cycle of the power source is accumulated in each integrator 30. The harmonic component of the reactor current on the DC side is characterized by having the same frequency characteristics as the power cycle, and the power phase can be monitored on the AC side. Therefore, the periodicity of the reactor current can be detected by a relatively simple method such as detecting the zero cross of the power supply voltage, and the circuit can be configured at low cost.

  Further, the correct power phase can be detected even under the adverse effect that noise is superimposed on the zero cross detection of the power supply voltage and the detection of the zero cross of the power supply voltage cannot be detected correctly. For this reason, highly accurate current control is realizable. In addition, by limiting the number of corresponding addresses to ± 1, it is possible to suppress the corresponding address from changing suddenly and to suppress the influence of the power supply environment.

  Furthermore, since the control system is configured as PID control + repetitive control, the resistance to disturbance is improved in PID control, and the repetitive control follows the target value, that is, the harmonics are suppressed. By tuning the control gain, it is possible to realize highly accurate control compared to conventional control using only PID control. For example, in the repetitive control using an error for one cycle of the past power supply, the periodicity of the current is important, but the control gain is tuned as described above for fluctuations in the power supply environment where the periodicity is lost, for example, instantaneous interruption . By doing so, the PID control mainly operates when the power supply environment changes, and the power converter can improve the resistance to the change of the power supply environment.

Embodiment 2. FIG.
Hereinafter, although Embodiment 2 will be described, the same elements as those in Embodiment 1 are omitted, and the same or corresponding parts as those in Embodiment 1 are denoted by the same reference numerals.
FIG. 8 is a configuration diagram of a power conversion device according to Embodiment 2 of the present invention.
In the second embodiment, the circuit configuration is changed and a multilevel converter is applied.

  The power converter includes a three-phase rectifier 2, a multi-level converter unit 33, a smoothing capacitor 4, an inverter 5, a phase angle calculation unit 11, a switching control unit 39, voltage detectors 12 and 14, and current detection. And a container 13. And the three-phase alternating current power supply 1 is connected to the power converter device as an input, and the motor 6 is connected as a load.

  The multilevel converter unit 33 is a multilevel converter including the reactor 7, two switching elements 34 and 35, two backflow prevention elements 36 and 37, and an intermediate capacitor 38. In the multilevel converter section 33, the two switching elements 34 and 35 and the two backflow prevention elements 36 and 37 are connected in series, and are connected in parallel with the smoothing capacitor 4. The reactor 7 has one end connected to the three-phase rectifier 2 side and the other end connected between the switching element 34 and the backflow prevention element 37. The intermediate capacitor 38 has one end connected between the switching element 34 and the switching element 35 and the other end connected between the backflow prevention element 36 and the backflow prevention element 37.

Switching of the switching elements 34 and 35 of the multilevel converter unit 33 is performed by a switching control unit 39. The switching control unit 39 has four inputs, and is applied to both ends of the smoothing capacitor 4 detected by the voltage detector 14, the power source phase angle θ output from the phase angle calculation unit 11, the reactor current i _L detected by the current detector 13. V _dc and a voltage v _m applied to both ends of the intermediate capacitor 38 detected by the newly added voltage detector 40 (hereinafter referred to as an intermediate capacitor voltage v _m ). The output of the switching control unit 39 is an ON / OFF signal to the switching elements 34 and 35.

The basic function of the multi-level converter unit 33 is the same as that of the boost converter unit 3, but the multi-level converter unit 33 is characterized in that the input voltage level to the switching control unit 39 is three levels. Specifically, when the voltage of the intermediate capacitor 38 is controlled to ½ v _dc that is half of the smoothing capacitor voltage v _dc , the multilevel converter unit 33 has three levels of voltages 0, ½ v _dc , and v _dc. Can output. Therefore, switching loss can be reduced and the carrier ripple current of reactor 7 can be reduced, so that the power conversion device can be made highly efficient.

The configuration of the phase angle calculation unit 11 is the same as that of the first embodiment and is shown in FIG. The phase angle calculation unit 11 includes a zero cross detection unit 15, a control frequency clock 16, a phase counter A17, a counter maximum value calculation unit 18, and a phase counter B19. The phase angle calculator 11 receives the power supply voltage v _rs from the voltage detector 12 and outputs the power supply phase angle θ to the switching controller 10.

FIG. 9 is a configuration diagram of the switching control unit 39 of the power conversion device according to the second embodiment of the present invention.
Next, the operation of the switching control unit 39 will be described with reference to FIG.
The switching control unit 39 according to the second embodiment has a voltage control system for the intermediate capacitor 38 as compared with the first embodiment, but the other configuration is the same.

Hereinafter, a voltage applied to both ends of the intermediate condenser 38 newly added in the second embodiment, a description will be given of a control system of the intermediate condenser voltage v _m.
The intermediate voltage control system has an intermediate capacitor voltage command value v ^* _m as input, and includes a subtracter 41 and a PID control unit 42. The PID control unit 42 may be a controller with only proportional control, or may be a controller in which any of proportional control, integral control, and differential control is combined.

The subtractor 41 calculates a voltage deviation from the intermediate capacitor voltage command value v ^* _m and the intermediate capacitor voltage v _m detected by the voltage detector 40. Specifically, subtracting the intermediate condenser voltage v _m from the intermediate condenser voltage command value v ^* _m. The voltage deviation output from the subtractor 41 is subjected to PID control by the PID control unit 42, becomes on-duty, and is input to the subtractor 43.

  The subtractor 43 calculates the on-duty D obtained from the current control system and the output of the intermediate voltage control system. Specifically, the on-duty D1 of the switching element 34 is calculated by subtracting the on-duty output from the PID control unit 42 from the on-duty D output from the adder 25.

  Similarly to the subtractor 43, the adder 44 calculates the on-duty D obtained from the current control system and the output of the intermediate voltage control system. Specifically, the on-duty D2 output from the adder 25 and the on-duty output from the PID control unit 42 are added to calculate the on-duty D2 of the switching element 35.

The switching signal determination unit 45 generates ON / OFF signals S ₁ and S ₂ for the switching elements 34 and 35 from the on-duty D 1 that is the output of the subtracter 43 and the on-duty D 2 that is the output of the adder 44.

  In the power conversion device according to the second embodiment, it is possible to reduce the pulsation of the reactor current by repeatedly performing the control as in the first embodiment. Therefore, even if the carrier frequency is reduced and a power phase shift occurs, the current control performance can be improved. For this reason, the control response of the PID control unit 23 can be lowered, the carrier frequency can be reduced, the loss of the power converter can be reduced, and noise can be suppressed. In addition, since the control cycle is extended by reducing the carrier frequency, it is easy to mount on an inexpensive microcomputer with a low calculation speed.

  Further, repetitive control is applied to the current deviation of the reactor 7 on the DC side, and the pulsation for one cycle of the power source is accumulated in each integrator 30. The harmonic component of the reactor current on the DC side is characterized by having the same frequency characteristics as the power cycle, and the power phase can be monitored on the AC side. Therefore, the periodicity of the reactor current can be detected by a relatively simple method such as detecting the zero cross of the power supply voltage, and the circuit can be configured at low cost.

  Further, the correct power phase can be detected even under the adverse effect that noise is superimposed on the zero cross detection of the power supply voltage and the detection of the zero cross of the power supply voltage cannot be detected correctly. For this reason, highly accurate current control is realizable. In addition, by limiting the number of corresponding addresses to ± 1, it is possible to suppress the corresponding address from changing suddenly and to suppress the influence of the power supply environment.

  Furthermore, since the control system is configured as PID control + repetitive control, the resistance to disturbance is improved in PID control, and the repetitive control follows the target value, that is, the harmonics are suppressed. By tuning the control gain, it is possible to realize highly accurate control compared to conventional control using only PID control. For example, in the repetitive control using an error for one cycle of the past power supply, the periodicity of the current is important, but the control gain is tuned as described above for fluctuations in the power supply environment where the periodicity is lost, such as a momentary power failure. . By doing so, the PID control mainly operates when the power supply environment changes, and the power converter can improve the resistance to the change of the power supply environment.

Further, in the second embodiment, the multi-level converter unit 33 is controlled to 0, 1/2 v _dc , v by controlling the intermediate capacitor voltage v _m to 1/2 v _dc which is half of the smoothing capacitor voltage v _{dc. Since} it can output with the voltage of 3 levels of _dc , a switching loss can be made small and the carrier ripple current of the reactor 7 becomes small, so that the power converter can be made highly efficient.

Embodiment 3 FIG.
Hereinafter, although Embodiment 3 will be described, the same elements as those in Embodiments 1 and 2 are omitted, and the same or corresponding parts as those in Embodiments 1 and 2 are denoted by the same reference numerals.
FIG. 10 is a configuration diagram of a power conversion device according to Embodiment 3 of the present invention.
The third embodiment is an example in which the circuit configuration is changed and a step-down converter is applied.

  The power converter includes a three-phase rectifier 2, a step-down converter unit 46, a smoothing capacitor 4, an inverter 5, a phase angle calculation unit 11, a switching control unit 49, voltage detectors 12 and 14, and a current detector. 13. And the three-phase alternating current power supply 1 is connected to the power converter device as an input, and the motor 6 is connected as a load.

  The step-down converter unit 46 is a step-down converter that includes a reactor 7, a switching element 47, and a backflow prevention element 48. In step-down converter 46, switching element 47 and reactor 7 are connected in series, one end of switching element 47 is connected to the three-phase rectifier 2 side, and one end of reactor 7 is connected to the smoothing capacitor 4 side. The backflow prevention element 48 is configured such that one end is connected between the switching element 47 and the reactor 7 and is connected in parallel with the smoothing capacitor 4.

  In the first embodiment, the boost converter unit 3 is provided and has a function of boosting the voltage. However, in the third embodiment, the step-down converter unit 46 is provided and has a function of stepping down the voltage. Also in such a converter configuration, the same phase angle calculation unit 11 of FIG. 2 as that of the first embodiment and the control block shown in FIG. 4 can be used.

  In the power conversion device according to the third embodiment, it is possible to reduce the pulsation of the reactor current by repeatedly performing the control as in the first embodiment. Therefore, even if the carrier frequency is reduced and a power phase shift occurs, the current control performance can be improved. For this reason, the control response of the PID control unit 23 can be lowered, the carrier frequency can be reduced, the loss of the power converter can be reduced, and noise can be suppressed. In addition, since the control cycle is extended by reducing the carrier frequency, it is easy to mount on an inexpensive microcomputer with a low calculation speed.

  Further, repetitive control is applied to the current deviation of the reactor 7 on the DC side, and the pulsation for one cycle of the power source is accumulated in each integrator 30. The harmonic component of the reactor current on the DC side is characterized by having the same frequency characteristics as the power cycle, and the power phase can be monitored on the AC side. Therefore, the periodicity of the reactor current can be detected by a relatively simple method such as detecting the zero cross of the power supply voltage, and the circuit can be configured at low cost.

  Further, the correct power phase can be detected even under the adverse effect that noise is superimposed on the zero cross detection of the power supply voltage and the detection of the zero cross of the power supply voltage cannot be detected correctly. For this reason, highly accurate current control is realizable.

  Furthermore, since the control system is configured as PID control + repetitive control, the resistance to disturbance is improved in PID control, and the repetitive control follows the target value, that is, the harmonics are suppressed. By tuning the control gain, it is possible to realize highly accurate control compared to conventional control using only PID control. For example, in the repetitive control using an error for one cycle of the past power supply, the periodicity of the current is important, but the control gain is tuned as described above for fluctuations in the power supply environment where the periodicity is lost, such as a momentary power failure. . By doing so, the PID control mainly operates when the power supply environment changes, and the power converter can improve the resistance to the change of the power supply environment.

Embodiment 4 FIG.
Hereinafter, although Embodiment 4 will be described, the same elements as those in Embodiments 1 to 3 are omitted, and the same or corresponding parts as those in Embodiments 1 to 3 are denoted by the same reference numerals.
In the fourth embodiment, a circuit configuration including the same boost converter unit 3 as in the first embodiment is used, and the circuit diagram of FIG. 1 is used. Note that the description of the operation of the circuit is the same as that in Embodiment 1, and is therefore omitted.

FIG. 11 is a configuration diagram of the phase angle calculation unit 11 of the power conversion device according to the fourth embodiment of the present invention.
Since the configuration of the power conversion device according to the fourth embodiment is the same as that of the first embodiment, it is shown in FIG. 1, but the configuration of the contents of the phase angle calculation unit 11 is partially different as shown in FIG. 11. ing.
The phase angle calculation unit 11 according to the fourth embodiment includes a zero cross detection unit 15, a control frequency clock 16, a phase counter A17, a counter maximum value calculation unit 18, a phase counter B19, a subtractor 50, A PID control unit 51.

The phase angle calculation unit 11 is different from the first embodiment from the output of the counter maximum value calculation unit 18, and the reset value of the phase counter B19 is reset to a fixed value of the reset value command value N ^* _max. . The zero-cross detection unit 15, the control frequency clock 16, the phase counter A17, and the counter maximum value calculation unit 18 operate in the same manner as in the first embodiment.

The phase angle calculator 11 receives the power supply voltage v _rs from the voltage detector 12 and outputs the power supply phase angle θ to the switching controller 10. Further, the subtracter 50 calculates the reset value N _max and the reset value command value N ^* _max , which are the outputs of the counter maximum value calculator 18. Specifically, the reset value deviation is calculated by subtracting the reset value N _max from the reset value command value N ^* _max . The reset value deviation output from the subtractor 50, after being PID controlled by PID control unit 51, is output as the control frequency f _c. Reset value command value N ^* _max is determined by N ^* _max determination means 63. Since the power supply frequency varies depending on the region, N ^* _max varies depending on the region. _Therefore , N ^* _max is investigated when the power is turned on. For example, in a region where the power supply frequency is 60 Hz, if the control frequency is 18000 Hz, N ^* _max is 18000 ÷ 60 = 300.

In other words, the PID control unit 51 _controls the control frequency _{f c} such that _{N ^max =} N _* ^max, based on the value of the control frequency _{f c,} to generate a clock 16 of the control frequency.
The PID control unit 51 is a controller for proportional control, integral control, and differential control. Note that the PID control unit 51 may be a controller with only proportional control, or may be a controller in which any of proportional control, integral control, and differential control is combined.
The PID control unit 51 corresponds to a “proportional control unit” of the present invention.

If the control frequency is the carrier frequency, if the reset value command value ^N _* max = 300, the carrier frequency _{f c} can be calculated by the power source frequency _{f s} and ^N _{* max} (4) equation.

When the power supply frequency f _s = 60 Hz, the control frequency is f _c = 18 kHz.
While designing the control frequency and the carrier frequency the same as is common, the carrier frequency is half the or _f c = 9 kHz for _{f c} of the control frequency, twice 36 kHz, 1/3 times the 6kHz The frequency can be tripled to 54 kHz.
The control frequency and the carrier frequency have a relationship, and controlling the control frequency controls the carrier frequency.

  The configuration of the contents of the switching control unit 10 is also shown in FIG. 4 as in the first embodiment. However, it is necessary to operate the switching signal determination unit 26 in consideration that the carrier frequency changes.

  In the power conversion device according to the fourth embodiment, the pulsation of the reactor current can be reduced by performing repeated control, as in the first embodiment. Therefore, even if the carrier frequency is reduced and a power phase shift occurs, the current control performance can be improved. For this reason, the control response of the PID control unit 23 can be lowered, the carrier frequency can be reduced, the loss of the power converter can be reduced, and noise can be suppressed. In addition, since the control cycle is extended by reducing the carrier frequency, it is easy to mount on an inexpensive microcomputer with a low calculation speed.

  Further, repetitive control is applied to the current deviation of the reactor 7 on the DC side, and the pulsation for one cycle of the power source is accumulated in each integrator 30. The harmonic component of the reactor current on the DC side is characterized by having the same frequency characteristics as the power cycle, and the power phase can be monitored on the AC side. Therefore, the periodicity of the reactor current can be detected by a relatively simple method such as detecting the zero cross of the power supply voltage, and the circuit can be configured at low cost.

  Further, the correct power phase can be detected even under the adverse effect that noise is superimposed on the zero cross detection of the power supply voltage and the detection of the zero cross of the power supply voltage cannot be detected correctly. For this reason, highly accurate current control is realizable.

  Furthermore, since the control system is configured as PID control + repetitive control, the resistance to disturbance is improved in PID control, and the repetitive control follows the target value, that is, the harmonics are suppressed. By tuning the control gain, it is possible to realize highly accurate control compared to conventional control using only PID control. For example, in the repetitive control using an error for one cycle of the past power supply, the periodicity of the current is important, but the control gain is tuned as described above for fluctuations in the power supply environment where the periodicity is lost, such as a momentary power failure. . By doing so, the PID control mainly operates when the power supply environment changes, and the power converter can improve the resistance to the change of the power supply environment.

Embodiment 5. FIG.
Hereinafter, although Embodiment 5 will be described, the same elements as those in Embodiments 1 to 4 are omitted, and the same or corresponding parts as those in Embodiments 1 to 4 are denoted by the same reference numerals.
In the fifth embodiment, the method of calculating the power supply phase angle θ of the fourth embodiment is applied to a multilevel converter.
The circuit configuration of the power conversion device according to the fifth embodiment is the same as that of the second embodiment shown in FIG. The configuration of the phase angle calculation unit 11 is the same as that of the fourth embodiment shown in FIG. The operation of the power conversion device is the same as in the second and fourth embodiments, and a description thereof will be omitted.

  In the power conversion device according to the fifth embodiment, the pulsation of the reactor current can be reduced by repeatedly performing the control. Therefore, even if the carrier frequency is reduced and a power phase shift occurs, the current control performance can be improved. For this reason, the control response of the PID control unit 23 can be lowered, the carrier frequency can be reduced, the loss of the power converter can be reduced, and noise can be suppressed. In addition, since the control cycle is extended by reducing the carrier frequency, it is easy to mount on an inexpensive microcomputer with a low calculation speed.

  Further, repetitive control is applied to the current deviation of the reactor 7 on the DC side, and the pulsation for one cycle of the power source is accumulated in each integrator 30. The harmonic component of the reactor current on the DC side is characterized by having the same frequency characteristics as the power cycle, and the power phase can be monitored on the AC side. Therefore, the periodicity of the reactor current can be detected by a relatively simple method such as detecting the zero cross of the power supply voltage, and the circuit can be configured at low cost.

  Further, the correct power phase can be detected even under the adverse effect that noise is superimposed on the zero cross detection of the power supply voltage and the detection of the zero cross of the power supply voltage cannot be detected correctly. For this reason, highly accurate current control is realizable.

  Furthermore, since the control system is configured as PID control + repetitive control, the resistance to disturbance is improved in PID control, and the repetitive control follows the target value, that is, the harmonics are suppressed. By tuning the control gain, it is possible to realize highly accurate control compared to conventional control using only PID control. For example, in the repetitive control using an error for one cycle of the past power supply, the periodicity of the current is important, but the control gain is tuned as described above for fluctuations in the power supply environment where the periodicity is lost, such as a momentary power failure. . By doing so, the PID control mainly operates when the power supply environment changes, and the power converter can improve the resistance to the change of the power supply environment.

Embodiment 6 FIG.
Hereinafter, although Embodiment 6 will be described, the same elements as those in Embodiments 1 to 5 are omitted, and the same or corresponding parts as those in Embodiments 1 to 5 are denoted by the same reference numerals.
In the sixth embodiment, the method of calculating the power supply phase angle θ of the fourth embodiment is applied to a step-down converter.
The circuit configuration of the power conversion device according to the sixth embodiment is the same as that of the third embodiment shown in FIG. The configuration of the phase angle calculation unit 11 is the same as that of the fourth embodiment shown in FIG. The operation of the power conversion device is the same as in the third and fourth embodiments, and a description thereof will be omitted.

  In the power conversion device according to the sixth embodiment, the pulsation of the reactor current can be reduced by performing repeated control. Therefore, even if the carrier frequency is reduced and a power phase shift occurs, the current control performance can be improved. For this reason, the control response of the PID control unit 23 can be lowered, the carrier frequency can be reduced, the loss of the power converter can be reduced, and noise can be suppressed. In addition, since the control cycle is extended by reducing the carrier frequency, it is easy to mount on an inexpensive microcomputer with a low calculation speed.

  Further, repetitive control is applied to the current deviation of the reactor 7 on the DC side, and the pulsation for one cycle of the power source is accumulated in each integrator 30. The harmonic component of the reactor current on the DC side is characterized by having the same frequency characteristics as the power cycle, and the power phase can be monitored on the AC side. Therefore, the periodicity of the reactor current can be detected by a relatively simple method such as detecting the zero cross of the power supply voltage, and the circuit can be configured at low cost.

  Further, the correct power phase can be detected even under the adverse effect that noise is superimposed on the zero cross detection of the power supply voltage and the detection of the zero cross of the power supply voltage cannot be detected correctly. For this reason, highly accurate current control is realizable. In addition, by limiting the number of corresponding addresses to ± 1, it is possible to suppress the corresponding address from changing suddenly and to suppress the influence of the power supply environment.

  Furthermore, since the control system is configured as PID control + repetitive control, the resistance to disturbance is improved in PID control, and the repetitive control follows the target value, that is, the harmonics are suppressed. By tuning the control gain, it is possible to realize highly accurate control compared to conventional control using only PID control. For example, in the repetitive control using an error for one cycle of the past power supply, the periodicity of the current is important, but the control gain is tuned as described above for fluctuations in the power supply environment where the periodicity is lost, such as a momentary power failure. . By doing so, the PID control mainly operates when the power supply environment changes, and the power converter can improve the resistance to the change of the power supply environment.

Embodiment 7 FIG.
Hereinafter, although Embodiment 7 will be described, the same elements as those in Embodiments 1 to 6 are omitted, and the same or corresponding parts as those in Embodiments 1 to 6 are denoted by the same reference numerals.
In the seventh embodiment, an example in which the power conversion device according to the first to sixth embodiments is applied to the compressor 101 and the air conditioner will be described.

(Configuration and operation of air conditioner)
FIG. 12 is a configuration diagram of an air conditioner according to Embodiment 7 of the present invention.
Hereinafter, the case where the power converter device which concerns on Embodiment 1-6 is applied to the compressor 101 and an air conditioner is demonstrated using FIG.

  A power conversion device 100 shown in FIG. 12 is a power conversion device according to Embodiments 1 to 6, and receives power supply from the three-phase AC power supply 1 and supplies it to the motor 6 for rotational driving. The motor 6 is connected to the compression element 101a, and the motor 6 and the compression element 101a constitute a compressor 101 that compresses the refrigerant.

  The air conditioner according to the seventh embodiment includes a compressor 101, a four-way valve 102, an outdoor heat exchanger 103, an expansion device 104, an indoor heat exchanger 105, a four-way valve 102, and a compressor 101 in this order. Connected to form a refrigeration cycle. Among these, the outdoor unit 106 includes a power conversion device 100, a compressor 101, a four-way valve 102, an outdoor heat exchanger 103, and an expansion device 104, and the indoor unit 107 includes an indoor heat exchanger 105. Has been.

  The outdoor heat exchanger 103 corresponds to the “evaporator” of the present invention.

Next, the operation of the air conditioner according to the seventh embodiment will be described by taking cooling operation as an example.
When the cooling operation is performed, the four-way valve 102 causes the refrigerant discharged from the compressor 101 to go to the outdoor heat exchanger 103 in advance, and the refrigerant flowing out of the indoor heat exchanger 105 to the compressor 101. It is assumed that the flow path is switched so as to go.

  When the motor 6 of the compressor 101 is rotationally driven by the power conversion device 100, the compression element 101a of the compressor 101 connected to the motor 6 compresses the refrigerant, and the compressor 101 discharges the high-temperature and high-pressure refrigerant. The high-temperature and high-pressure refrigerant discharged from the compressor 101 flows into the outdoor heat exchanger 103 via the four-way valve 102 and performs heat exchange with outside air in the outdoor heat exchanger 103 to radiate heat. The refrigerant that has flowed out of the outdoor heat exchanger 103 is expanded and depressurized by the expansion device 104, becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant, flows into the indoor heat exchanger 105, and performs heat exchange with the air in the air-conditioning target space. The refrigerant evaporates into a low-temperature and low-pressure gas refrigerant and flows out of the indoor heat exchanger 105. The gas refrigerant flowing out from the indoor heat exchanger 105 is sucked into the compressor 101 via the four-way valve 102 and compressed again. The above operation is repeated.

  In addition, in FIG. 12, although the example which applied the power converter device which concerns on Embodiment 1-6 to the compressor 101 of an air conditioner was shown, it is not limited to this, Other than an air conditioner Needless to say, the present invention is applicable to heat pump devices, refrigeration devices and other refrigeration cycle devices in general.

  By using this Embodiment 7, the power converter device which concerns on Embodiment 1-6 can be applied to the compressor 101 and an air conditioner, and even if it makes carrier frequency and a current control response small, it is highly accurate. Current control can be realized, and the power converter with low power loss and low noise can be obtained.

1 three-phase AC power source, 2 three-phase rectifier, 3 boost converter, 4 smoothing capacitor, 5 inverter, 6 motor, 7 reactor, 8 switching element, 9 backflow prevention element, 10 switching control unit, 11 phase angle calculation unit, 12 Voltage detector, 13 Current detector, 14 Voltage detector, 15 Zero cross detector, 16 Control frequency clock, 17 Phase counter A, 18 Counter maximum value calculator, 19 Phase counter B, 20 Subtractor, 21 PID controller , 22 subtractor, 23 PID control unit, 24 repetition control unit, 25 adder, 26 switching signal determination unit, 27 input address determination unit, 28 output address determination unit, 29 error accumulation unit, 30 integrator, 31 input address connection Part, 32 output address connection part, 33 multi-level converter part, 34 switch Switching element, 35 Switching element, 36 Backflow prevention element, 37 Backflow prevention element, 38 Intermediate capacitor, 39, Switching control unit, 40 Voltage detector, 41 Subtractor, 42 PID control unit, 43 Subtractor, 44 Adder, 45 Switching signal determination unit, 46 step-down converter unit, 47 switching element, 48 backflow prevention element, 49 switching control unit, 50 subtractor, 51 PID control unit, 61 first path, 62 second path, 63 N ^* _max determination means, DESCRIPTION OF SYMBOLS 100 Power converter, 101 Compressor, 101a Compression element, 102 Four way valve, 103 Outdoor heat exchanger, 104 Expansion apparatus, 105 Indoor heat exchanger, 106 Outdoor unit, 107 Indoor unit.

Claims (13)

A voltage detector for detecting at least one line voltage or phase voltage of the three-phase AC power supply;
A three-phase rectifier for rectifying the three-phase AC power supply;
A converter unit having a reactor and a switching element, and boosting or stepping down the output of the three-phase rectifier;
A smoothing capacitor for smoothing the output voltage of the converter unit;
A switching control unit for controlling the switching element;
A phase angle calculation unit for calculating a power supply phase angle of the voltage detected by the voltage detector;
A current detector for detecting the reactor current,
The switching controller is
A subtractor that calculates and outputs a current deviation from the reactor current; and
An integrator for accumulating the current deviation;
Accumulating the current deviation output from the subtractor in the integrator, and repeatedly outputting the current deviation from the integrator at a timing based on the power supply phase angle;
An adder for adding and outputting the current deviation output by the subtractor and the current deviation output by the repetitive control unit;
A switching signal determining unit that generates an ON / OFF signal of the switching element based on a value output from the adder,
The subtracter power converter processing of adding at the output to the current deviation of the current deviation outputted is the repetitive control unit has the adder in which repeats every one period of the three-phase AC power source. The phase angle calculator is
Having a first phase counter and a second phase counter with the control period of the converter as a clock;
The first phase counter outputs a value counted up for each clock, and the counted up value is reset every one cycle of a zero cross signal generated from the output of the voltage detector,
The second phase counter outputs a value counted up for each clock as the power supply phase angle, and the counted up value is the same as a reset value determined from the maximum output value of the first phase counter. The power conversion device according to claim 1, wherein the power conversion device is reset when it becomes. Comparing the reset value with the value of the first phase counter one clock before the first phase counter is reset;
If the reset value is larger, subtract 1 from the reset value,
The power converter according to claim 2, wherein when the reset value is smaller, 1 is added to the reset value. The phase angle calculator is
A proportional control unit that outputs a control frequency from a deviation obtained by subtracting the reset value from a reset value command value;
The proportional control unit includes:
The control frequency is controlled so that the reset value command value and the reset value are equal, and the clock is generated based on the control frequency.
The power converter according to claim 2 or 3. The repeat control unit
A plurality of integrators associated with the power supply phase angle and an address;
An input address determination unit that determines an address of the integrator that accumulates the input current deviation from the input power supply phase angle; an input address connection unit that accumulates the current deviation in the integrator;
An output address determination unit that determines an address of the integrator that outputs the accumulated current deviation from the input power supply phase angle; and an output address connection unit that outputs the current deviation from the integrator. The power converter device as described in any one of Claims 1-4. The repeat control unit
The current deviation accumulated in the integrator associated with the address of the power supply phase angle α is output at the timing of the power supply phase angle α after one cycle of the three-phase AC power supply. The power converter described. The switching controller is
The current deviation of the power supply phase angle α output from the subtractor is added to the current deviation output from the integrator at the timing of the power supply phase angle α after one cycle of the three-phase AC power supply. Item 7. The power conversion device according to Item 6. The converter part is
The reactor;
The switching element;
A backflow prevention element,
The reactor and the backflow prevention element are connected in series,
One end of the reactor is connected to the three-phase rectifier side, one end of the backflow prevention element is connected to the smoothing capacitor side,
The switching element is a boost converter having one end connected between the reactor and the backflow prevention element and connected in parallel with the smoothing capacitor. The power converter device described in 1. The converter part is
The reactor;
Two switching elements connected in series with each other;
Two backflow prevention elements connected in series with each other;
An intermediate condenser, and
The two switching elements and the two backflow prevention elements are connected in series, and connected in parallel with the smoothing capacitor,
The reactor has one end connected to the three-phase rectifier side and the other end connected between the switching element and the backflow prevention element.
The intermediate capacitor is a multi-level converter having one end connected between the two switching elements and the other end connected between the two backflow prevention elements. The power conversion device according to one item. The converter part is
The reactor;
The switching element;
A backflow prevention element,
The switching element and the reactor are connected in series,
One end of the switching element is connected to the three-phase rectifier side, one end of the reactor is connected to the smoothing capacitor side,
8. The step-down converter is configured as a step-down converter having one end connected between the switching element and the reactor and connected in parallel with the smoothing capacitor. The power converter device described in 1. A refrigerant circuit in which a compressor, a condenser, an expansion device, and an evaporator are annularly connected by a refrigerant pipe;
A refrigeration cycle apparatus comprising: the power conversion device according to any one of claims 1 to 10 that is driven by supplying electric power to the compressor. A voltage detector for detecting at least one line voltage or phase voltage of the three-phase AC power supply;
A three-phase rectifier for rectifying the three-phase AC power supply;
A converter unit having a reactor and a switching element, and boosting or stepping down the output of the three-phase rectifier;
A smoothing capacitor for smoothing the output voltage of the converter unit;
A switching control unit for controlling the switching element;
A phase angle calculation unit for calculating a power supply phase angle of the voltage detected by the voltage detector;
A current detector for detecting the reactor current,
The switching controller is
A subtractor that calculates and outputs a current deviation from the reactor current; and
Accumulating the current deviation output by the subtracter, and repeatedly outputting the current deviation at a timing based on the power supply phase angle;
An adder for adding and outputting the current deviation output by the subtractor and the current deviation output by the repetitive control unit;
A switching signal determining unit that generates an ON / OFF signal of the switching element based on a value output from the adder,
Is intended to repeat the process of adding the subtractor and said current deviation of the current deviation outputted to output said repetitive control unit by the adder for each cycle of the three-phase AC power source,
The phase angle calculator is
Having a first phase counter and a second phase counter with the control period of the converter as a clock;
The first phase counter outputs a value counted up for each clock, and the counted up value is reset every one cycle of a zero cross signal generated from the output of the voltage detector,
The second phase counter outputs a value counted up for each clock as the power supply phase angle, and the counted up value is the same as a reset value determined from the maximum output value of the first phase counter. Power converter that is reset when it becomes. A voltage detector for detecting at least one line voltage or phase voltage of the three-phase AC power supply;
A three-phase rectifier for rectifying the three-phase AC power supply;
A converter unit having a reactor and a switching element, and boosting or stepping down the output of the three-phase rectifier;
A smoothing capacitor for smoothing the output voltage of the converter unit;
A switching control unit for controlling the switching element;
A phase angle calculation unit for calculating a power supply phase angle of the voltage detected by the voltage detector;
A current detector for detecting the reactor current,
The switching controller is
A subtractor that calculates and outputs a current deviation from the reactor current; and
Accumulating the current deviation output by the subtracter, and repeatedly outputting the current deviation at a timing based on the power supply phase angle;
An adder for adding and outputting the current deviation output by the subtractor and the current deviation output by the repetitive control unit;
A switching signal determining unit that generates an ON / OFF signal of the switching element based on a value output from the adder,
Is intended to repeat the process of adding the subtractor and said current deviation of the current deviation outputted to output said repetitive control unit by the adder for each cycle of the three-phase AC power source,
The repeat control unit
A plurality of integrators associated with the power phase angle and an address;
An input address determination unit that determines an address of the integrator that accumulates the input current deviation from the input power supply phase angle; an input address connection unit that accumulates the current deviation in the integrator;
An output address determination unit that determines an address of the integrator that outputs the accumulated current deviation from the input power supply phase angle; and an output address connection unit that outputs the current deviation from the integrator. Power conversion device.

Images