WO2019155539A1

WO2019155539A1 - Power conversion device, and motor driving apparatus and refrigerator using same

Info

Publication number: WO2019155539A1
Application number: PCT/JP2018/004152
Authority: WO
Inventors: 渉初瀬; 勇紀江幡; 正博田村; 橋本　浩之; 貴郎上田; 田村　建司
Original assignee: 日立ジョンソンコントロールズ空調株式会社
Priority date: 2018-02-07
Filing date: 2018-02-07
Publication date: 2019-08-15
Also published as: TW201935839A; JP7159227B2; TWI699085B; JPWO2019155539A1

Abstract

A power conversion device (1) is provided with: a power conversion circuit part that performs a boosting operation of converting AC power from an AC power supply (2) to DC power and converting DC output voltage to voltage higher than the voltage of the AC power supply, and that is provided with a short circuit (6) for short-circuiting the AC power supply via a reactor (4) and performs the boosting operation by switching the short circuit (6); and a control unit (10) that sets the conduction rate of the short circuit (6) according to the power supply voltage of the AC power supply (2) and the voltage of the reactor (4).

Description

Power conversion device, motor drive device and refrigeration equipment using the same

The present invention relates to a power conversion device that performs power conversion between AC power and DC power, a motor drive device that uses the power conversion device, and a refrigeration apparatus such as an air conditioner.

Recently, in order to drive electric power application equipment such as an air conditioner, a power conversion device that performs power conversion using a switching element is used. For power converters that perform power conversion between AC power in AC power supplies such as commercial AC power supplies and DC power in DC power supplies and loads, the current on the AC power supply side is used to improve efficiency and reduce harmonics. It is required to reduce waveform distortion.

In a power conversion device that performs a boost operation, the distortion of the current waveform is reduced by controlling the switching drive of the switching element for the boost operation. As conventional techniques for reducing distortion of a current waveform, techniques described in Patent Document 1 and Patent Document 2 are known.

In the technique described in Patent Document 1, a semiconductor switching element in an oscillation circuit connected to the primary side of a high-frequency transformer is controlled according to an AC power supply current, and the output of the high-frequency transformer includes a full-wave rectifier circuit and a waveform positive / negative conversion circuit. Are sequentially connected to an AC power source. As a result, a sinusoidal AC power supply current waveform is obtained. Furthermore, by stopping the driving of the switching elements constituting the positive / negative conversion circuit near the zero point of the AC power supply current, distortion of the waveform of the AC power supply current near the zero current can be suppressed.

In the technique described in Patent Document 2, the conduction factor signal of the switching element in the boost chopper circuit is set according to the instantaneous value of the AC power supply current and the boost ratio. As a result, the AC power supply current is sine wave without generating a reference waveform.

JP 2000-188876 A JP 2009-207282 A

In the technique described in Patent Document 1, since the stop of the driving of the switching element of the positive / negative conversion circuit adds disturbance to the operation of the semiconductor switching element of the oscillation circuit, an unexpected harmonic component is present in the AC power supply current waveform. Occur.

In the technique described in Patent Document 2, since the instantaneous value of the AC power supply current is used, the control may become unstable depending on the switching frequency.

Therefore, the present invention provides a power conversion device that can stably reduce the waveform distortion of an AC power supply current to make a sine wave, and a motor drive device and a refrigeration apparatus using the power conversion device.

In order to solve the above problems, a power conversion device according to the present invention performs a boosting operation for converting AC power from an AC power source into DC power and converting a DC output voltage to a voltage larger than the voltage of the AC power source. A power conversion circuit unit that includes a short circuit that short-circuits the AC power supply via the reactor, and that performs a boost operation by switching the short circuit, and a current ratio of the short circuit, the power supply voltage of the AC power supply and the reactor And a control unit that is set in accordance with the voltage.

In order to solve the above problem, the power conversion device according to the present invention converts the AC power from the AC power source into DC power and performs a boosting operation that converts the DC output voltage to a voltage larger than the voltage of the AC power source. A power conversion circuit unit that includes a semiconductor switching element and a reactor that stores energy when the semiconductor switching element is turned on, and performs a boosting operation by switching the semiconductor switching element; and a semiconductor switching element And a control unit for setting the conduction ratio of the semiconductor switching element according to a sine wave, and further comprising means for stopping the switching of the semiconductor switching element near the zero current of the power source current of the AC power source. Contains ingredients and higher order components.

In order to solve the above-described problems, a motor driving device according to the present invention drives a motor by a power converter, and the power converter converts AC power from an AC power source into DC power and outputs DC power. A first power conversion circuit unit that includes a short circuit that performs a step-up operation that converts a voltage to a voltage that is greater than the voltage of the AC power source, short-circuits the AC power source via a reactor, and performs the step-up operation by switching the short circuit A control unit that sets the conduction ratio of the short circuit according to the power supply voltage of the AC power supply and the voltage of the reactor, and a second power conversion circuit unit that converts the DC power into a variable voltage and variable frequency AC power And comprising.

In order to solve the above problems, a refrigeration apparatus according to the present invention includes a heat exchanger, a compressor that compresses and circulates a refrigerant, a fan that blows air to the heat exchanger, and a motor that drives the compressor or the fan. And a motor driving device for driving the motor, wherein the motor driving device is the motor driving device according to the present invention.

According to the present invention, since the waveform distortion of the AC power supply current can be stably reduced to a sine wave, it is possible to stably suppress harmonics generated by the power converter, the motor driving device using the power converter, and the refrigeration equipment. it can.

The circuit structure of the power converter device which is one Embodiment of this invention is shown. An example of a power supply current waveform is shown. The example of a waveform of a power supply current at the time of adding a tertiary component to a power supply current command value is shown. A waveform example of a power supply current when a tertiary component is added to the power supply current command value is shown. The circuit structure of the power converter device which is Example 1 is shown. The circuit structure of the motor drive device which is Example 2 is shown. It is a block diagram of the refrigeration equipment which is Example 3.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.

FIG. 1 shows a circuit configuration of a power conversion device according to an embodiment of the present invention.

As shown in FIG. 1, the power conversion circuit unit (main circuit unit) of the power conversion device 1 includes rectifier circuits configured by rectifier elements 3 a to 3 d to rectify AC power supplied from the AC power supply 2. In the present embodiment, the rectifying elements 3a to 3d are diodes. The AC power source 2 is connected to the AC input of the rectifier circuit via the reactor 4 in the power conversion device 1. Further, a short circuit 6 is connected between the AC inputs to short-circuit the AC input and control a short-circuit current flowing from the AC power supply 2 via the reactor 4. A smoothing capacitor 5 that smoothes the output voltage of the rectifier circuit is connected to the DC output of the rectifier circuit.

The power converter 1 includes an AC power source current detector 7 that detects an AC power source current (hereinafter referred to as “power source current”) input from the AC power source 2, and an AC power source that detects an AC power source voltage input from the AC power source 2. A voltage detector 8 and a DC output voltage detector 9 for detecting the DC output voltage of the rectifier circuit are provided. The short circuit control unit 10 creates a short circuit command signal 10A for the short circuit 6 based on the detection current of the AC power supply current detector 7 and the detection voltages of the AC power supply voltage detector 8 and the DC output voltage detector 9. Output. The pulse-off control unit 11 determines whether to stop the short-circuit command signal 10A, corrects the short-circuit command signal 10A according to the determination result, and outputs the corrected short-circuit command signal 11A. In addition, the short circuit 6 can perform ON / OFF control of the bidirectional current according to the positive / negative of the AC power supply voltage.

Next, the operation of this embodiment will be described.

The power converter 1 shown in FIG. 1 performs a boosting operation by driving the short circuit 6 by switching (on / off).

When the short circuit 6 is turned on, the AC power source 2 is short-circuited via the reactor 4, and thus a power source current flows through the closed circuit including the AC power source 2, the short circuit 6, and the reactor 4. At this time, the electric power from the AC power source 2, that is, electric energy, is stored in the reactor 4 as magnetic energy. Next, when the short circuit 6 is turned off, a power supply current flows through a path including the AC power supply 2, the rectifier circuit, the smoothing capacitor 5, and the reactor 4, and the energy accumulated in the reactor 4 is transferred to the smoothing capacitor 5 side through the rectifier circuit. Is released. At this time, an induced voltage proportional to the time change of the power supply current flowing through the reactor is generated in the reactor 4, so that a DC voltage larger than the voltage amplitude of the AC power supply 2 is output from the rectifier circuit.

When the short circuit 6 is turned off, the direction of the power supply current flowing to the AC side of the power converter 1 varies depending on the direction of the power supply current flowing when the short circuit 6 is turned on, that is, the voltage of the AC power supply 2. The rectifier circuit (full-wave rectifier circuit) composed of a bridge flows in one direction (the direction from the top to the bottom in the figure) through the DC side, that is, the smoothing capacitor. Thereby, the smoothing capacitor 5 is charged with a DC voltage larger than the voltage amplitude of the AC power supply 2.

The magnitude of the DC output voltage of the power conversion device 1 is controlled to a predetermined value by controlling the conduction rate (duty) when the short circuit 6 is ON. Here, the short circuit control unit 10 creates a command signal corresponding to the conduction ratio, and compares the command signal with a carrier signal (such as a triangular wave or a sawtooth wave) by pulse width modulation (PWM) to indicate the command signal indicated by the command signal. A short-circuit command signal 10A, which is a pulse signal having a flow rate, is created.

Considering the on / off operation of the short circuit 6 as described above, the circuit equation relating to the circuit configuration of FIG. 1 is approximately expressed by the equation (1).

In Expression (1), “d” is a conduction ratio (duty) when the short circuit 6 is ON, “i _s ” is an instantaneous value [A] of the power supply current, and “L” is The inductance value [H] of the reactor 4, “v _s ” is the instantaneous value [V] of the power supply voltage of the AC power supply 2, and “E _d ” is the voltage across the smoothing capacitor 5, that is, the DC output voltage [V]. “ΔE _d ” is the fluctuation component [V] of the DC output voltage.

The conduction rate d of the short circuit 6 is expressed as “d = t, where t _on and t _off are the times during which the short circuit 6 is on and off, respectively, during one switching period (T) of the short circuit 6. represented and _{_{_{on / (t on + t off}}} ) = t on / T ".

Here, when d = 1−K | i _s | (K: proportional gain), it is known that is can be controlled in a sine wave shape (see, for example, Patent Document 2 described above). Here, K is the amplitude of the supply current _{i _{s (I} s)} and the step-up ratio _{_{a (= E d / V s}} : V s is _v amplitude _s) is set from the (K = 1 / (a · I s )). Thereby, a predetermined DC output voltage is obtained.

In contrast, in conventional techniques, a voltage controller for matching the E _d to the command value E _d ^*, the current controller for matching the i _s the command value i _{s *} ^(sine wave), A power source current is converted into a sine wave and a predetermined DC output voltage is obtained.

Compared to such a general technique, the technique of setting d by “d = 1−K | i _s |” simplifies the configuration of the control device. However, according to the study by the present inventor, in such a means using the instantaneous value of the power supply current, the control may become unstable depending on the switching frequency (PWM frequency) (for example, when the frequency is lowered). .

Therefore, in this embodiment, the flow rate d is set as shown in Equation (2). According to the equation (2), the control is stabilized by using the voltage value.

In Equation (2), “K _pv ” is a proportional constant (voltage control gain), “v _s ^* ” is a power supply voltage command value [A], and “i _s ^* ” is a power supply current command value [A]. “E _d ^* ” is the DC output voltage command value [A], and “ΔE _d ^* ” is the DC output voltage fluctuation command value.

_{^{_{^{"V s * -L · (di s}}}} * / dt) " in equation (2) is the voltage portion of the circuit of FIG. 1 (instantaneous value), a voltage as it were related to the sinusoidal waveform of the power supply current _{i s} is there. L · (di _s ^* / dt) is the product of the inductance of the reactor 4 and the time rate of change of the power supply current, that is, the voltage of the reactor 4. “K _pv (E _d ^* + ΔE _d ^* )” relates to voltage control of the DC output voltage. Incidentally, "Delta] E _d ^*", the value of the deviation between the value of the "E _d" that is detected by the DC output voltage detector 9 as "E _d ^*" is set. The value of "K _pv", depending on the value of the "Delta] E _d ^*", increases as the value of the "Delta] E _d ^*" increases, and is set as smaller smaller.

Furthermore, in the equation (2), v _s ^* and i _s ^* are set by the equations (3) and (4), respectively.

In Expression (3), “V _s−1st ^* ” is the power supply voltage fundamental wave amplitude. In Expression (4), “I _s−1st ^* ” is the power source current fundamental wave amplitude. “Ω” is the power source angular frequency, and “t” is time.

Here, "v _s ^*" based on the "v _s" detected by the AC power supply voltage detector 8, the amplitude of the "v _s" amplitude and phase are measured, and are measured "v _s" And each value of the phase are set as “V _s−1st ^* ” and “ωt” in Equation (3), respectively. Furthermore, since the phase of the power supply current is controlled to be in phase with the power supply voltage, the measured phase value of “v _s ” is set as “ωt” in Equation (4). For "i _s ^*" based on the "i _s" detected by the AC power source current detector 7, "i _s" amplitude is measured, the value of the amplitude of the "i _s" as measurement formula ( It is set as “I _s-1st ^* ” in 4).

Although the description of a specific calculation process is omitted, it is understood that if is calculated by substituting equation (2) into equation (1), which is a circuit equation, is can be substantially sinusoidal. FIG. 2 shows an example of a power supply current waveform when the power conversion device of FIG. 1 is controlled by the conduction rate d according to the equation (2). As shown in FIG. 2, in this example, although there is a vibration component, the power supply current can be converted into a sine wave. The vibration component of the power supply current can be removed by a known filter circuit.

In this embodiment, the short circuit control unit 10 stops the switching of the short circuit 6 when the AC power supply current detector 7 detects a power supply current near zero. Thereby, the distortion of the power supply current waveform near zero current is reduced. Although this technique is a known technique, in the present embodiment, the slope (time change rate) of the power supply current near zero current is further reduced to approach zero. As a result, it is possible to suppress the occurrence of unexpected harmonics in the power supply current waveform due to the switching stop of the short circuit 6 becoming a disturbance to the boosting operation.

In the present embodiment, the magnitude of the slope of the supply current in the vicinity of zero current (time rate of change), in order to reduce than the sine wave (fundamental wave), high-order component in the "i _s ^*", for example, the formula Add tertiary components as shown in (5).

In Expression (5), “I _s-3rd ^* ” is the power supply current tertiary command amplitude. The magnitude of “I _s-3rd ^* ” is set to a value smaller than “I _s-1st ^* ”, for example, about one third of “I _s-1st ^* ”.

Figure 3 shows the i _s ^* to the power current command value, an example of the waveform of the power source current when added tertiary component as shown in Equation (5). However, the switching of the short circuit 6 is not stopped near the zero current.

As the waveform example of Fig. 3, by adding a tertiary component i _s ^* to the power current command value, the slope of the magnitude of the supply current of around zero current is reduced to a size close to zero. The vibration component in this waveform example can be removed by a known filter circuit (the waveform example in FIG. 4 is also the same).

Figure 4 shows the i _s ^* to the power current command value, an example of the waveform of the power source current when added tertiary component as shown in Equation (5). However, switching of the short circuit 6 is stopped in the vicinity of zero current.

As shown in the waveform example of FIG. 4, the switching of the short circuit 6 is stopped when the slope of the power supply current near zero current is reduced to near zero. Thereby, even if switching of the short circuit 6 is stopped, generation of unexpected harmonics in the power supply current waveform can be suppressed.

As described above, according to the present embodiment, by setting the conduction ratio (duty) according to the voltage of a predetermined part in the circuit, in this embodiment, the voltage of the AC power supply 2 and the reactor 4, the power supply current The waveform can be sine wave reliably. Thereby, the efficiency of a power converter device improves. Furthermore, even if the switching operation is stopped in the vicinity of the zero current to reduce the waveform distortion by reducing the time change rate of the power supply current related to the voltage value of the reactor 4 near the zero current, an unexpected harmonic wave Can be suppressed.

Incidentally, in the above embodiment, means for applying a high-order component current sine wave, in the case of conventional techniques, i.e., the command and the voltage controller for matching the E _d to the command value E _d ^*, the i _s The present invention can also be applied to the case where the power supply current is converted into a sine wave and a predetermined DC output voltage is obtained by using a current controller for matching the value i _s ^* (sine wave). The means for adding a high-order component to the current sine wave in the above embodiment can also be applied to the case of d = 1−K | i _s | (K: proportional gain). In these cases, the power conversion device has a reactor in which energy is stored when the semiconductor switching element (in the above-described embodiment, “short circuit 6”) is turned on, and the semiconductor switching element is switched (ON / OFF). A power conversion circuit unit that performs a boosting operation and a control unit that sets the conduction ratio of the semiconductor switching element according to a sine wave current including a fundamental wave component and a higher-order component are provided.

Hereinafter, examples related to the above-described embodiment will be described.

FIG. 5 shows a circuit configuration of the power conversion device that is Embodiment 1 of the present invention.

In the first embodiment, the rectifier elements 3a to 3d constituting the rectifier circuit of the power conversion device 1A are MOSFETs (Metal / Oxide / Semiconductor / Field / Effect / Transistors) which are semiconductor switching elements, and diodes connected in reverse parallel to the MOSFETs. Consists of As the diode, a MOSFET built-in diode may be used. Further, the power conversion device 1A performs a boosting operation by driving these MOSFETs on and off. That is, the rectifier circuit including the rectifier elements 3 a to 3 d also serves as the short circuit 6.

The step-up operation of the power conversion device 1A is as follows.

When the voltage direction of the AC power supply 2 is upward in the figure, when the rectifier element 3c (MOSFET) is turned on to turn on the short circuit 6, the AC power supply 2, the rectifier element 3a (diode), and the rectifier element 3c (MOSFET) The power supply current flows through the closed circuit including the reactor 4. Thereby, energy is accumulated in the reactor 4.

Next, when the rectifying element 3c (MOSFET) is turned off to turn off the short circuit 6, the power is supplied through a path including the AC power supply 2, the rectifying element 3a (diode), the smoothing capacitor 5, the rectifying element 3d (diode), and the reactor 4. A current flows, and the energy accumulated in the reactor 4 is released to the smoothing capacitor 5 side. At this time, since an induced voltage is generated in the reactor 4, a DC voltage larger than the voltage amplitude of the AC power supply 2 is output from the rectifier circuit.

The short circuit 6 in the first embodiment can supply a power supply current to both by a MOSFET full bridge circuit. For example, when the direction of the voltage of the AC power supply 2 is downward in the figure, when the rectifier element 3d (MOSFET) is turned on to turn on the short circuit 6, the AC power supply 2, the reactor 4, the rectifier element 3d (MOSFET), the rectifier A power supply current flows through a closed circuit including the element 3b (diode). Thereby, energy is accumulated in the reactor 4.

Next, when the rectifier 3d (MOSFET) is turned off to turn off the short circuit 6, the power is supplied through a path including the AC power supply 2, the reactor 4, the rectifier 3c (diode), the smoothing capacitor 5, and the rectifier 3b (diode). A current flows, and the energy accumulated in the reactor 4 is released to the smoothing capacitor 5 side. At this time, since an induced voltage is generated in the reactor 4, a DC voltage larger than the voltage amplitude of the AC power supply 2 is output from the rectifier circuit.

In the step-up operation as described above, when a power supply current flows through the rectifier element (diode), a pair of MOSFETs may be turned on. Thereby, the power loss which generate | occur | produces in 1 A of power converter devices can be reduced. The operation of the MOSFET is the same as the so-called synchronous rectification operation when the energy of the reactor 4 is released, that is, when the short circuit 6 operates as a rectification circuit.

The magnitude of the DC output voltage of the power conversion device 1A controls the conduction ratio (duty) when each of the short circuit 6, that is, the rectifying element 3c (MOSFET) and the rectifying element 3d (MOSFET) is ON. Thus, the predetermined value is controlled. Here, the short circuit control unit 10 creates a command signal corresponding to the conduction ratio, and compares the command signal with a carrier signal (such as a triangular wave or a sawtooth wave) by pulse width modulation (PWM) to indicate the command signal indicated by the command signal. A short-circuit command signal 10A, which is a pulse signal having a flow rate, is created. The conduction rate d is set by the above equation (2). Thereby, as described above, the power supply current waveform can be reliably converted into a sine wave, and thus the efficiency is improved.

Further, in the first embodiment, the switching operation of the rectifier element (MOSFET) is stopped in the vicinity of the zero current of the power supply current in order to reduce the waveform distortion, and the slope of the power supply current in the vicinity of the zero current (time change rate). and in order to reduce than the sine wave (fundamental wave), high-order component in the "i _s ^*" in the above equation (2), for example, as shown in the above equation (5) is added to the tertiary component. Thus, as described above, even if the switching operation is stopped in the vicinity of zero current to reduce waveform distortion, the generation of unexpected harmonics can be suppressed.

FIG. 6 shows a circuit configuration of a motor drive device that is Embodiment 2 of the present invention.

As shown in FIG. 6, the power conversion device 1 </ b> A of the first embodiment is connected as a DC power source to the DC side of the inverter device that drives the motor 100.

The main circuit of the inverter device is composed of a three-phase bridge circuit composed of six semiconductor switching elements 30a to 30f (MOSFETs in FIG. 6) each connected to a freewheeling diode. In the three-phase bridge circuit, the power converter 1A (FIG. 5) of the first embodiment is connected to the DC input side, and the motor 100 is connected to the AC output side.

AC power of constant voltage and constant frequency from the AC power source 2 is converted into DC power of a predetermined voltage by the power conversion device 1A. Further, the DC power is converted into AC power having a variable frequency and a variable voltage by driving the semiconductor switching elements 30a to 30f on and off. The motor 100 is driven at a variable speed by this AC power.

The inverter device controls the motor 100 to rotate at a desired speed. At this time, the inverter control unit 50 calculates a motor current necessary for making the speed of the motor 100 coincide with the speed command value, and the detected motor current, that is, the motor in which the three-phase output current I _{uvw of the} inverter device is calculated. The on / off driving of the semiconductor switching elements 30a to 30f is controlled so as to match the current.

As the motor 100, a three-phase AC motor such as an induction motor or a synchronous motor (for example, a permanent magnet synchronous motor) is applied. An IGBT (Insulated Gate Bipolar Transistor) may be applied as the semiconductor switching element used in the inverter device. When a MOSFET is applied as the semiconductor switching element, a built-in diode may be used as the freewheeling diode.

According to the second embodiment as described above, by using the power conversion device 1A (FIG. 5) that is the first embodiment of the present invention as the DC power source of the inverter device, the efficiency of the motor driving device is improved, Unexpected generation of harmonics in the motor drive device can be suppressed.

FIG. 7 is a configuration diagram of a refrigeration apparatus that is Embodiment 3 of the present invention. Here, the refrigeration equipment is a device that harmonizes temperatures, such as an air conditioner or a refrigerator. In the third embodiment, the fan motor is driven by the motor driving device (FIG. 6) according to the second embodiment described above.

As shown in FIG. 7, the refrigeration apparatus 300 includes

heat exchangers

301 and 302,

fans

303 and 304 for blowing air to these heat exchangers, a compressor 305 that compresses and circulates the refrigerant, It is arranged between the heat exchanger 301 and the heat exchanger 302, and between the compressor 305 and the

heat exchangers

301 and 302, and includes a pipe 306 through which a refrigerant flows and a motor driving device 307.

Permanent magnet synchronous motors are used as fan motors that rotationally drive the

fans

303 and 304. A compressor motor 308 that drives the compressor 305 is disposed inside the compressor 305. As the compressor motor 308, a permanent magnet synchronous motor or a three-phase induction motor is used.

The motor driving device 307 includes a DC power supply circuit that converts AC power from a commercial AC power supply into DC power, and a compressor motor that converts the DC power from the DC power supply circuit into AC power and supplies the AC power to the compressor motor 308. A drive inverter and a fan motor drive inverter that converts DC power into AC power from the DC power supply circuit and supplies the AC power to the fan motor are provided. The above-described first embodiment (FIG. 5) is applied to the DC power supply circuit. In addition, as the motor driving device 307 including the inverter, the above-described second embodiment (FIG. 6) is applied.

The first and second DC power supply circuits independent from each other are provided, and the compressor motor drive inverter and the compressor motor drive inverter are respectively connected to the first DC power supply circuit and the second DC power supply circuit. You may make it receive direct-current power.

According to the third embodiment, by using the motor driving device (FIG. 6) according to the second embodiment of the present invention as the motor driving device 307, the efficiency of the refrigeration equipment is improved and an unexpected harmonic in the refrigeration equipment. Wave generation can be suppressed.

In addition, this invention is not limited to the Example mentioned above, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

For example, IGBT (Insulated Gate Bipolar Transistor), SJ (Super Junction) -MOSFET or the like may be used as the semiconductor switching element in FIG. 5 or the semiconductor switching element for the inverter shown in FIG. However, when IGBT is used, the diode is externally attached. The semiconductor material constituting the semiconductor switching element may be a wide gap semiconductor such as SiC (Silicon Carbon) in addition to normal semiconductor silicon.

1, 1A ... Power converter, 2 ... AC power supply,
3a, 3b, 3c, 3d ... rectifier, 4 ... reactor,
5 ... smoothing capacitor, 6 ... short circuit, 7 ... AC power supply current detector,
8 ... AC power supply voltage detector, 9 ... DC output voltage detector,
10 ... Short circuit control unit, 10A ... Short circuit command signal,
11 ... Pulse-off control unit, 11A ... Corrected short-circuit command signal,
30a, 30b, 30c... Semiconductor switching element,
30d, 30e, 30f... Semiconductor switching element,
50 ... Inverter control unit, 100 ... Motor,
300 ... Refrigeration equipment, 301 ... Heat exchanger, 302 ... Heat exchanger,
303 ... Fan, 304 ... Fan, 305 ... Compressor,
306 ... Piping, 307 ... Motor driving device, 308 ... Compressor motor

Claims

In the power conversion device that converts the AC power from the AC power source to DC power and performs a boost operation that converts the DC output voltage to a voltage larger than the voltage of the AC power source,
A power conversion circuit unit that includes a short circuit that short-circuits the AC power supply via a reactor, and performs the boosting operation by switching the short circuit;
A control unit for setting a current conduction rate of the short circuit according to a power supply voltage of the AC power supply and a voltage of the reactor;
A power conversion device comprising:
In the power converter device described in Claim 1,
The voltage of the reactor is calculated by a product of an inductance of the reactor and a time change rate of a power source current of the AC power supply.
In the power converter device described in Claim 2,
The value of the power supply voltage is an instantaneous value of a sine wave,
The time conversion rate value of the power supply current is an instantaneous value calculated by assuming that the power supply current is composed of a sine wave component including a fundamental wave component in phase with the power supply voltage.
In the power converter device described in Claim 3,
A voltage detector for detecting the power supply voltage;
A current detector for detecting the power supply current;
With
The said control part sets the said duty ratio based on each detection value of the said voltage detector and the said current detector, The power converter device characterized by the above-mentioned.
The power conversion device according to claim 1,
The controller is
The power conversion device, wherein the conduction ratio is set so that the DC output voltage becomes a predetermined value.
The power conversion device according to claim 5,
The controller is
The power conversion device, wherein the conduction ratio is set according to the predetermined value and a deviation between the DC output voltage and the predetermined value.
In the power converter device described in Claim 6,
A DC voltage detector for detecting the DC output voltage;
The said control part sets the said duty ratio based on the detected value of the said DC voltage detector, The power converter device characterized by the above-mentioned.
In the power converter device described in Claim 1,
Furthermore, it comprises means for stopping the switching of the short circuit near the zero current of the power source current of the AC power source,
The power converter according to claim 1, wherein the power supply current waveform has a slope that is smaller than a slope of the sine wave in the vicinity of a zero current of the power supply current.
In the power converter device described in Claim 3,
Furthermore, comprising means for stopping the switching of the short circuit near the zero current of the power supply current,
The sine wave component includes a high-order component.
In the power converter device described in Claim 9,
The power converter according to claim 1, wherein the order of the higher order component is third order.
In the power conversion device that converts the AC power from the AC power source to DC power and performs a boost operation that converts the DC output voltage to a voltage larger than the voltage of the AC power source,
A power conversion circuit unit that includes a semiconductor switching element and a reactor that stores energy when the semiconductor switching element is turned on, and performs the boosting operation by switching the semiconductor switching element;
A control unit for setting the conduction rate of the semiconductor switching element according to a sine wave current;
With
Furthermore, a means for stopping the switching of the semiconductor switching element near the zero current of the power supply current of the AC power supply,
The sine wave current includes a fundamental wave component and a higher-order component.
In the power converter device described in Claim 11,
The power converter according to claim 1, wherein the order of the higher order component is third order.
In the power converter device described in Claim 11,
When the semiconductor switching element is turned on, the AC power supply is short-circuited through the reactor.
In a motor drive device that drives a motor by a power converter,
The power converter is
Along with converting AC power from the AC power source into DC power, performing a step-up operation that converts a DC output voltage to a voltage larger than the voltage of the AC power source, and comprising a short circuit that shorts the AC power source through a reactor, A first power conversion circuit unit that performs a boosting operation by switching the short circuit;
A control unit for setting a current conduction rate of the short circuit according to a power supply voltage of the AC power supply and a voltage of the reactor;
A second power conversion circuit unit for converting the DC power into AC power of variable voltage and variable frequency;
A motor drive device comprising:
A heat exchanger, a compressor that compresses and circulates the refrigerant, a fan that blows air to the heat exchanger, a motor that drives the compressor or the fan, a motor drive device that drives the motor, In refrigeration equipment comprising:
The motor driving device is
Along with converting AC power from the AC power source into DC power, performing a step-up operation that converts a DC output voltage to a voltage larger than the voltage of the AC power source, and comprising a short circuit that shorts the AC power source through a reactor, A first power conversion circuit unit that performs a boosting operation by switching the short circuit;
A control unit for setting a current conduction rate of the short circuit according to a power supply voltage of the AC power supply and a voltage of the reactor;
A second power conversion circuit unit for converting the DC power into AC power of variable voltage and variable frequency;
A refrigeration apparatus comprising: