JP2011045218A - Power conversion device, motor drive controller equipped with the same, compressor and blower mounted with motor drive controller, and air conditioner, refrigerator and freezer mounted with the compressor or blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a power conversion device capable of reducing a current capacity of each element by dispersing the current by forming a chopper circuit into a bridge connection structure having a plurality of systems. <P>SOLUTION: The other end of a reactor 4 of which one end is located on an input positive electrode side of the chopper circuit 3 is connected to a connection line between an anode side of a diode 7a and a collector side of a switching element 7d, the connection line between the anode side of the diode 7b and the collector side of the switching element 7e, and the connection line between the anode side of the diode 7c and the collector side of the switching element 7f, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power conversion device, a motor drive control device including the power conversion device, a compressor and a blower equipped with the power conversion device, an air conditioner equipped with the compressor or blower, a refrigerator, and a freezer.

  Conventionally, in equipment that supports three-phase AC power supply, as a three-phase full-wave rectifier converter, a three-phase rectifier circuit that rectifies three-phase AC voltage, and a reactor and a capacitor are used to filter the output voltage of the three-phase rectifier circuit And a filter circuit that includes an inverter circuit that converts the output voltage of the filter circuit into an AC voltage and drives a motor.

  In addition, as a method for improving the power factor of the power source with respect to the conventional three-phase full-wave rectifier converter, for example, “a three-phase rectifier circuit for rectifying a three-phase AC voltage and an output voltage of the three-phase rectifier circuit Boost chopper circuit that boosts by chopping, smoothing element that smoothes output signal of boost chopper circuit, voltage detector that detects output voltage of smoothing element, voltage command for output voltage of boost chopper circuit and detection of voltage detector DC current command generation circuit for generating a DC current command for suppressing a deviation from the output to zero and flowing a DC current to the output of the three-phase rectifier circuit, and DC current detection for detecting an output current of the three-phase rectifier circuit And a pulse signal generation circuit for generating a pulse signal for suppressing the deviation between the DC current command and the detection output of the DC current detector to zero, and the step-up chopper circuit includes a rectifier circuit And a switching element that controls charging / discharging of the charge accumulated in the reactor in accordance with the pulse width of the pulse signal has been proposed (see, for example, Patent Document 1). ).

Japanese Patent No. 2869498 (page 3, FIG. 1)

  The above-described three-phase full-wave rectification method has a problem that the power supply current is pulsed and the power supply power factor is low. In the above-described three-phase full-wave rectification converter, the output DC voltage depends on the power supply voltage. For example, when the inverter and the motor are used as loads, the DC voltage is insufficient when the motor is driven at high speed. There are also problems.

  Further, according to the invention described in Patent Document 1, a technique for improving the power factor of a power source is described for a three-phase full-wave rectifier converter by controlling the output voltage of the boost chopper circuit to be constant. However, for example, when applied to a large load exceeding 10 kW, a large current flows through the switching element and the backflow prevention element. There is a problem that an element for industrial use is used and the cost is increased. In addition, since elements for large current use need to be connected by screwing a metal plate on the circuit board, it is difficult to mount on the circuit board and there is a problem that the cost increases in terms of mounting cost. .

  In addition, it is necessary to perform wiring on the circuit board, and pattern wiring is performed at locations where a large current flows, which increases the mounting area and complexity of the pattern, increases costs, increases the size of the circuit, Since the wiring length also becomes long, there is a problem that it causes a surge voltage due to wiring inductance.

  Further, when a plurality of systems are configured by discrete elements, variations in element characteristics due to different temperature conditions of each element and unbalance of current flowing through each element are likely to occur. Since the loss is also unbalanced, the temperature condition further varies, and there is a problem that the current unbalance is accelerated.

The present invention has been made to solve the above-described problems, and a first object is to reduce the current capacity of each element by distributing the current by providing a chopper circuit with a plurality of bridge connection configurations. It is to obtain a power conversion device that can do.
A second object is to provide a motor drive control device that includes the power conversion device described above, and that can increase the voltage output to the inverter circuit by the chopper circuit to solve the shortage of the output voltage of the inverter circuit. .
And the 3rd objective is to obtain the compressor, air blower, air conditioner, refrigerator, and freezer provided with said function by providing said power converter device.

  The power conversion device according to the present invention is configured by a series circuit of a rectifier that rectifies an AC voltage, at least one pair of diodes, and a switching element having one end connected to the anode side of the diodes, and the cathode side of each of the diodes is A multi-phase bridge circuit connected to each other (hereinafter, the connection line is referred to as “connection line A”), and the other ends of the switching elements are connected to each other (hereinafter, the connection line is referred to as “connection line B”); A chopper circuit composed of a reactor having one end connected to each connection line between the diode and the switching element in the multiphase bridge circuit, one end connected to the connection line A, and the other end connected to the connection line B. A smoothing capacitor connected to the switching element, and a switching control means for controlling an ON / OFF operation of the switching element. The output positive side of the flow device is connected to the other end of the reactor, the output negative side is connected to the connection line B, and the switching control means controls the ON / OFF operation of the switching element to control the chopper. The output voltage of the circuit is boosted.

  According to the power conversion device of the present invention, since the chopper circuit has a multiple-system bridge connection configuration with diodes and switching elements, the current can be distributed, so that the current capacity required for each element can be reduced. Therefore, it is not necessary to use an element for industrial use, and an increase in circuit size can be suppressed.

It is a block diagram of the power converter device which concerns on Embodiment 1 of this invention. It is a block block diagram of the switching control means 11 in the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the chopper circuit 3 in the power converter device which concerns on Embodiment 1 of this invention. It is a figure which shows the example of a block diagram in case the bridge circuit 19 is comprised by a discrete element. It is a block diagram of the bridge circuit 19 modularized in the power converter device which concerns on Embodiment 1 of this invention. It is a figure which shows the waveform of the drive pulse applied to the electric current of the reactor 4 in the power converter device which concerns on Embodiment 1 of this invention, and switching element 7d-7f. It is a block diagram of the chopper circuit 3a in the power converter device which concerns on Embodiment 1 of this invention. It is a figure which shows the example which bypasses a chopper circuit in the power converter device which concerns on Embodiment 1 of this invention. It is a figure which shows the example which bypasses a chopper circuit in the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the chopper circuit 3b in the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the chopper circuit 3c in the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the chopper circuit 3d in the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the chopper circuit 3e in the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram of the chopper circuit 3f in the power converter device which concerns on Embodiment 2 of this invention. It is a figure which shows the waveform of the drive pulse applied to the electric current of the reactors 4-6 in the continuous mode of the power converter device which concerns on Embodiment 2 of this invention, and the switching elements 7d-7f. It is a figure which shows the drive pulse waveform applied to the electric current of the reactors 4-6 in the critical mode of the power converter device which concerns on Embodiment 2 of this invention, and the switching elements 7d-7f. It is a figure which shows the drive pulse waveform applied to the electric current of the reactors 4-6 in the discontinuous mode of the power converter device which concerns on Embodiment 2 of this invention, and the switching elements 7d-7f. It is a block diagram of the chopper circuit 3g in the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram of the chopper circuit 3h in the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram of the chopper circuit 3i in the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram of the chopper circuit 3j in the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram of the chopper circuit 3k in the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram of the motor drive control apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the example of the whole structure of the air conditioner which concerns on Embodiment 4 of this invention. It is a figure which shows the example of the whole structure of the refrigerator which concerns on Embodiment 5 of this invention.

Embodiment 1 FIG.
(Overall configuration of power converter)
FIG. 1 is a configuration diagram of a power conversion device according to Embodiment 1 of the present invention.
As shown in FIG. 1, the three output lines extending from the three-phase AC power source 1 are a connection line between the anode side of the rectifier diode 2a and the cathode side of the rectifier diode 2d, the anode side of the rectifier diode 2b, and the rectifier diode 2e. Are connected to the cathode side of the rectifier diode and the anode side of the rectifier diode 2c and the cathode side of the rectifier diode 2f. A three-phase rectifier 2 is constituted by these rectifier diodes 2a to 2f. The cathode sides of the rectifier diodes 2 a to 2 c are connected to each other, and the connection line is connected to the input positive electrode side of the chopper circuit 3. The anode sides of the rectifier diodes 2 d to 2 f are connected to each other, and the connection line is connected to the input negative side of the chopper circuit 3. A smoothing capacitor 8 is connected in parallel to the output side of the chopper circuit 3. A bus current detector 9 is installed on a connection line connecting the anode side of the rectifier diodes 2 d to 2 f and the input negative side of the chopper circuit 3. An output voltage detector 10 is connected in parallel to both ends of the smoothing capacitor 8 described above. The bus current detector 9 and the output voltage detector 10 are connected to the switching control unit 11, and transmit the input current of the chopper circuit 3 and the voltage across the smoothing capacitor 8 to the switching control unit 11, respectively. The switching control means 11 is connected to the chopper circuit 3 for ON / OFF control of switching elements in the chopper circuit 3 to be described later.

In FIG. 1, the bus current detector 9 is installed on the connection line on the input negative side of the chopper circuit 3, but is not limited to this, and is installed on the connection line on the input positive side. Also good.
Further, as the rectifier diodes 2a to 2f in the three-phase rectifier 2, elements such as SiC Schottky barrier diodes may be used. This makes it possible to reduce loss by taking advantage of the low resistance during conduction.
The three-phase rectifier 2 corresponds to a “rectifier” in the present invention.

(Block configuration and operation of the switching control means 11)
FIG. 2 is a block configuration diagram of the switching control means 11 in the power conversion device according to Embodiment 1 of the present invention.
As shown in FIG. 2, the output side of the bus current command value calculation unit 21 for inputting the output voltage command value for the output voltage of the chopper circuit 3 from the outside is connected to the input side of the on-duty calculation unit 22. The output side of the on-duty calculation unit 22 is connected to the input side of the drive pulse generation unit 23.

Next, the operation of the switching control means 11 configured as described above will be described.
The bus current command value calculation unit 21 for inputting an output voltage command value for the output voltage of the chopper circuit 3 from the outside further outputs the output voltage of the chopper circuit 3 detected by the output voltage detector 10 (the voltage across the smoothing capacitor 8). (Hereinafter, referred to as an output voltage detection value) is input, a bus current command value is calculated based on the output voltage command value and the output voltage detection value, and the bus current command value is output to the on-duty calculation unit 22. Next, the on-duty calculation unit 22 having received the bus current command value further inputs the bus current detected by the bus current detector 9 (the input current of the chopper circuit 3) (hereinafter referred to as the bus current detection value). Then, the on-duty is calculated based on the bus current command value and the bus current detection value, and the on-duty is output to the drive pulse generator 23. Here, the on-duty indicates the ON time for the switching element in the chopper circuit 3 to be described later, and the ratio of the sum of the ON time and the OFF time. Further, the drive pulse generator 23 that has received this on-duty generates a drive pulse for performing an ON / OFF operation of a switching element in the chopper circuit 3 to be described later based on this on-duty.

  The on-duty calculation by the on-duty calculation unit 22 is performed as follows, for example. The bus current command value calculation unit 21 determines the bus current command value so that the deviation between the output voltage command value and the output voltage detection value becomes zero. Next, the on-duty calculation unit 22 determines the on-duty so that the deviation between the bus current command value and the bus current detection value becomes zero.

(Configuration of chopper circuit 3)
FIG. 3 is a configuration diagram of the chopper circuit 3 in the power conversion device according to the first embodiment of the present invention.
As shown in FIG. 3, the other end of the reactor 4 whose one end is the input positive side of the chopper circuit 3 is connected to the anode side of the diode 7a and the collector side of the switching element 7d, and is switched to the anode side of the diode 7b. The connection line is connected to the collector side of the element 7e, and the connection line between the anode side of the diode 7c and the collector side of the switching element 7f. The switching elements 7d to 7f are, for example, IGBTs (Insulated Gate Bipolar Transistors). The cathode sides of the diodes 7 a to 7 c are connected to each other, and the connection line forms the output positive side of the chopper circuit 3. The emitter sides of the switching elements 7d to 7f are connected to each other, and the connection line forms the output negative side of the chopper circuit 3, and the output negative side and the input negative side of the chopper circuit 3 are common. It has become. In other words, each of the series circuits of the diodes 7a to 7c and the switching elements 7d to 7f is connected in a multiphase bridge. The chopper circuit 3 configured as described above constitutes a boost type chopper circuit. The diodes 7a to 7c and the switching elements 7d to 7f form a bridge circuit 19, and the bridge circuit 19 is modularized. Further, although not shown, the gate sides of the switching elements 7d to 7f are connected to the switching control means 11, and the switching control means 11 controls the ON / OFF operation of the switching elements 7d to 7f. Thus, the output voltage of the chopper circuit 3 is controlled.

  For example, when the chopper circuit 3 having the above configuration is applied to a load having a large capacity exceeding 10 kW, if the chopper circuit 3 is configured by one system, the diode and the switching element include Since a large current flows, a general-purpose element cannot be used for each, and an element for industrial use needs to be used, resulting in an increase in cost. In addition, since these elements for industrial use for large currents need to be connected by screwing a metal plate on the circuit board, it is difficult to mount on the circuit board, and the cost of mounting is also low. Accompanying up. On the other hand, in the chopper circuit 3 according to the present embodiment, since the three-system bridge connection configuration is provided by the diodes 7a to 7c and the switching elements 7d to 7f, the current can be dispersed. The required current capacity can be reduced, it is not necessary to use an element for industrial use, and since the bridge circuit 19 is modularized, it can be mounted on a circuit board by soldering. Cost increase can be suppressed.

FIG. 4 is a diagram showing an example of a configuration diagram when the bridge circuit 19 is configured by discrete elements.
As shown in FIG. 4, the anode sides of the diodes 31a to 31c are connected to the collector sides of the switching elements 32a to 32c by the pattern wiring 34, respectively. Further, the cathode sides of the diodes 31 a to 31 c are connected to each other by the pattern wiring 34. Further, the emitter sides of the switching elements 32a to 32c are also connected by the pattern wiring 34, respectively. Furthermore, the radiation fin 33 is installed in the vicinity of the diode 31a and the switching element 32a, the diode 31b and the switching element 32b, and the diode 31c and the switching element 32c.

When a chopper circuit of a plurality of systems is constituted by such discrete elements, wiring between each element needs to be performed on a circuit board. Further, when the capacity of a load connected to the chopper circuit is large, pattern wiring Since a large current flows through 34, an increase in mounting area and a complicated pattern increase costs and increase the circuit size. Furthermore, since the wiring length becomes long, it may cause a surge voltage due to wiring inductance.
In addition, when multiple systems are configured by discrete elements in a bridge circuit, each element is affected by variations in element characteristics due to different temperature conditions of each element, and variations in wiring impedance of each system due to complicated patterns. Unbalance tends to occur in the flowing current. In this case, since the energy loss in each element is also unbalanced, the temperature condition further varies and the current unbalance is accelerated. Considering the occurrence of this current imbalance, the current capacity of each element or the number of systems must be selected, so that the current capacity of the entire element is larger than the current capacity in the case of one system, and the cost Accompanying upsizing and circuit enlargement.
Furthermore, when radiating fins are installed in common in a plurality of elements, the height of each element needs to be equalized at the time of mounting, which increases the number of man-hours for mounting and increases the cost of mounting.

FIG. 5 is a block diagram of the modularized bridge circuit 19 in the power conversion apparatus according to Embodiment 1 of the present invention.
The module 41 is obtained by modularizing the bridge circuit 19. The diodes 42a to 42c correspond to the diodes 7a to 7c in FIG. 3, and the switching elements 43a to 43c are the switching elements 7d to 7f in FIG. Equivalent to. The module 41 is provided with heat radiating fins 44. The diodes 42 a to 42 c and the switching elements 43 a to 43 c in the module 41 are wired by the metal wiring 45 to form the bridge circuit 19. That is, the metal wiring 45 corresponds to the pattern wiring 34 in FIG. 4 described above, and is wired inside the module 41.

As described above, when the bridge circuit 19 is modularized, the mounting area can be significantly reduced, and the cost increase and the circuit size can be suppressed. Furthermore, since the wiring length is also shortened, wiring inductance that causes a surge voltage can be reduced.
Further, by making the bridge circuit 19 modular, it is possible to mount the circuit on the circuit board by soldering, so that an increase in mounting cost can be suppressed.
In addition, since each element in the module 41 has the same temperature condition, there is no variation in element characteristics, and as described above, there is no variation in the wiring impedance of each system because the wiring length is short. Therefore, since current imbalance is less likely to occur, the current capacity of each element, the number of systems, and the radiation fins can be optimally selected, and cost increase and circuit enlargement can be suppressed.
Then, as described with reference to FIG. 4, man-hours such as height alignment for attaching the heat dissipating fins when using the discrete elements can be reduced, so that an increase in cost can be suppressed.

(Operation of power converter)
Next, the operation of the power conversion device according to the present embodiment configured as described above will be described.
First, as shown in FIG. 1, the AC voltage from the three-phase AC power source 1 is rectified by a three-phase rectifier 2. The rectified voltage is input to the chopper circuit 3.

FIG. 6 is a diagram showing the current of the reactor 4 and the waveform of the drive pulse applied to the switching elements 7d to 7f in the power conversion device according to Embodiment 1 of the present invention.
Here, first, description will be made by paying attention to the diode 7a and the switching element 7d shown in FIG. A current flows through the reactor 4 by the voltage input to the chopper circuit 3 described above. At this time, the ON / OFF operation of the switching element 7d is controlled by the driving pulse applied to the gate side of the switching element 7d (hereinafter referred to as driving pulse a) by the switching control means 11, but the switching element 7d is in the ON state. In this case, the current flowing through the reactor 4 (hereinafter referred to as the reactor current) flows through the switching element 7d, and the current value increases linearly. Next, when the switching element 7d is turned off by the driving pulse a, the reactor current flows through the diode 7a, and a voltage having a polarity opposite to that when the switching element 7d is turned on is applied to the reactor 4. The current value of the reactor current decreases linearly. The ON / OFF operation of the switching element 7d as described above is repeated, and the reactor current has a waveform that fluctuates up and down. Here, the above operation will be described from the viewpoint of energy. When the switching element 7d is in the ON state, energy is accumulated in the reactor 4 due to the increasing reactor current, while the switching element 7d is in the OFF state. The energy accumulated in the reactor 4 is transferred to the output side and accumulated in the smoothing capacitor 8, and the output voltage, which is a direct current in the chopper circuit 3, becomes higher than the input voltage and boosted. At this time, the switching control means 11 can control the magnitude of the output voltage of the chopper circuit 3 by controlling the on-duty.

In addition, the operations of the diode 7a and the switching element 7d as described above are performed in the diode 7b and the switching element 7e, and also in the diode 7c and the switching element 7f. At this time, if the driving pulse applied by the switching control means 11 is the driving pulse b applied to the switching element 7e and the driving pulse c is applied to the switching element 7f, the switching control means 11 The switching elements 7d to 7f are simultaneously turned ON and OFF by the drive pulses a to c applied from 11, respectively.
As described above, the switching control means 11 does not apply the drive pulses a to c separately to drive the switching elements 7d to 7f simultaneously ON and OFF, but drives the same signals. May be applied.

Although the above operation has been described based on the circuit configuration of the chopper circuit 3 shown in FIG. 3, the present invention is not limited to this, and the chopper circuit 3a shown in FIG. 7 may be applied. In the chopper circuit 3a shown in FIG. 7, the diodes 7a to 7c in the chopper circuit 3 shown in FIG. 3 are respectively replaced with switching elements 18a to 18c in which freewheeling diodes are connected in reverse parallel, and the switching elements 7d to 7f are respectively The freewheeling diodes are replaced with switching elements 18d to 18f connected in antiparallel, and the switching circuit 18a to 18f constitutes a bridge circuit 19a. Further, although not shown, the gate side of these switching elements 18 a to 18 f is connected to the switching control means 11. In such a configuration, the switching control means 11 controls the switching elements 18a to 18c to be always in an OFF state, so that the free-wheeling diodes connected in reverse parallel in the switching elements 18a to 18c become diodes in the chopper circuit 3. It assumes the same function as 7a-7c. Then, the switching control means 11 controls the ON / OFF operations of the switching elements 18d to 18f in the same manner as the switching elements 7d to 7f in the chopper circuit 3, so that the output voltage is changed in the same manner as the chopper circuit 3 described above. Boosted.
As the bridge circuit 19a, for example, a general-purpose module such as IPM (Intelligent Power Module) can be used. Therefore, it is not necessary to create a new module, and cost and development load can be reduced. It is. This can also be applied to the bridge circuit 19 described above.

  The bridge circuit 19 and the bridge circuit 19a correspond to the “polyphase bridge circuit” in the present invention.

(Effect of Embodiment 1)
As in the configuration and operation as described above, the chopper circuit 3 has a three-system bridge connection configuration with the diodes 7a to 7c and the switching elements 7d to 7f, or the chopper circuit 3a with the switching elements 18a to 18f. Since the current can be distributed, the current capacity required for each element can be reduced, there is no need to use an element for industrial use, and the bridge circuit 19 and the bridge circuit 19a are modularized. Since the circuit can be prevented from being enlarged and mounted on the circuit board by soldering, the increase in mounting cost can be suppressed.
Further, since the wiring length is shortened, wiring inductance that causes a surge voltage can be reduced.
In addition, since each element in the module 41 has the same temperature condition, there is no variation in element characteristics, and as described above, there is no variation in the wiring impedance of each system because the wiring length is short. Therefore, since current imbalance is less likely to occur, the current capacity of each element, the number of systems, and the radiation fins can be optimally selected, and cost increase and circuit enlargement can be suppressed.
Further, as the bridge circuit 19 or the bridge circuit 19a, for example, a general-purpose module such as IPM (Intelligent Power Module) can be used. Development load can be reduced.

  In the case where it is not necessary to perform the step-up operation by the chopper circuit depending on the load, that is, the switching elements 7d to 7f in the chopper circuit 3 in FIG. 3 are turned off by the switching control means 11, or the chopper circuit in FIG. Even when the switching elements 18d to 18f in 3a are turned off, the reactor 4 and the free-wheeling diodes connected in reverse parallel to the diodes 7a to 7c or the switching elements 18a to 18c serve as current paths. In No. 4, copper loss due to the resistance component, and conduction loss due to a forward voltage drop during conduction occurs in the free-wheeling diode connected in reverse parallel with the diodes 7a to 7c and the switching elements 18a to 18c. Therefore, as shown in FIG. 8, the backflow prevention element 16 may be newly connected in parallel with the chopper circuit 3 or the chopper circuit 3a. In this case, the number of elements in the current path can be reduced, and loss can be reduced.

  Further, as shown in FIG. 9, even if an open / close element 17 such as a relay is connected instead of the backflow prevention element 16 in FIG. 8, loss in the chopper circuit 3 or chopper circuit 3a is similarly reduced. It becomes possible. At this time, the opening / closing operation of the opening / closing element 17 may be controlled by the switching control means 11. Furthermore, in this configuration, even if the switching element 17 and the switching elements 7d to 7f or the switching elements 18d to 18f are turned on when the DC voltage is increased by the switching control means 11, a current path can be formed. It is also possible to prevent element destruction.

  Further, as the switching elements 7d to 7f of the bridge circuit 19 or the switching elements 18a to 18f of the bridge circuit 19a, a SiC-based semiconductor or a super junction structure switching element may be used. As a result, the loss can be reduced as compared with the case where a conventionally used Si-based switching element is used. In particular, a switching element having a super junction structure has a problem that recovery is large, but the configuration of the chopper circuit 3 or the chopper circuit 3a as in the present embodiment is suitable for a switching element having a super junction structure because the recovery is small. It is a use, and it is possible to enhance the loss reduction effect by making the best use of its characteristics.

Further, the case of the step-up chopper circuit shown in FIGS. 3 and 7 has been described as the chopper circuit according to the present embodiment, but the present invention is not limited to this, and the step-down type chopper as shown in FIG. The chopper circuit 3 or the chopper circuit 3a may be replaced by the circuit 3b. As shown in FIG. 10, the collector sides of the switching elements 7d to 7f are connected to each other, and the connection lines form the input positive electrode side of the chopper circuit 3b. The emitter sides of the switching elements 7d to 7f are connected to the cathode sides of the diodes 7a to 7c, respectively. The anode sides of the diodes 7a to 7c are connected to each other, and the connection line forms the output negative side of the chopper circuit 3b. The output negative side and the input negative side of the chopper circuit 3b are common. It has become. The connecting line between the emitter side of the switching element 7d and the cathode side of the diode 7a, the connecting line between the emitter side of the switching element 7e and the cathode side of the diode 7b, and the emitter side of the switching element 7f and the cathode side of the diode 7c. Are connected to one end of the reactor 4, and the other end forms the output positive side of the chopper circuit 3b. The chopper circuit 3b configured as described above constitutes a step-down chopper circuit. The switching elements 7d to 7f and the diodes 7a to 7c form a bridge circuit 19b. The bridge circuit 19b is modularized. Further, although not shown, the gate sides of the switching elements 7d to 7f are connected to the switching control means 11, and the switching control means 11 controls the ON / OFF operation of the switching elements 7d to 7f. Thus, the output voltage of the chopper circuit 3b may be controlled. The switching elements 7d to 7f are simultaneously turned ON and OFF by the switching control means 11, respectively.
Note that, as described above, in order to simultaneously turn on and off the switching elements 7d to 7f, the switching control means 11 does not apply the drive pulse to the switching elements 7d to 7f separately, but to the same signal. The drive pulse may be applied.

By applying the chopper circuit 3b as shown in FIG. 10 above, since the three-system bridge connection configuration is achieved by the switching elements 7d to 7f and the diodes 7a to 7c, the current can be dispersed. The current capacity required for the circuit can be reduced, and it is not necessary to use an element for industrial use. Further, since the bridge circuit 19b is modularized, it can be miniaturized and mounted on a circuit board by soldering. Therefore, the increase in mounting cost can be suppressed as in the case of applying the step-up chopper circuit shown in FIGS.
Further, for example, when the motor is connected as a load of the chopper circuit 3b, it is possible to improve the efficiency when the load is small, such as when the motor is driven at a low speed.

  Further, instead of the step-down chopper circuit 3b shown in FIG. 10, the chopper circuit 3c shown in FIG. 11 may be applied. In the chopper circuit 3c shown in FIG. 11, the diodes 7a to 7c in the chopper circuit 3b shown in FIG. 10 are respectively replaced with switching elements 18d to 18f in which freewheeling diodes are connected in antiparallel, and the switching elements 7d to 7f are respectively The switching elements 18a to 18c in which the freewheeling diodes are connected in reverse parallel are replaced, and a bridge circuit 19c is configured by these switching elements 18a to 18f. Further, although not shown, the gate side of these switching elements 18 a to 18 f is connected to the switching control means 11. In such a configuration, the switching control unit 11 controls the switching elements 18d to 18f so as to be always in an OFF state, so that the free-wheeling diodes connected in reverse parallel in the switching elements 18d to 18f become diodes in the chopper circuit 3b. It assumes the same function as 7a-7c. Then, the switching control means 11 controls the ON / OFF operations of the switching elements 18a to 18c similar to those of the switching elements 7d to 7f in the chopper circuit 3b, respectively, so that the output voltage is similar to the chopper circuit 3b described above. Step down.

  Further, as the chopper circuit according to the present embodiment, a step-up / step-down chopper circuit 3d as shown in FIG. 12 may be applied. As shown in FIG. 12, the collector sides of the switching elements 7d to 7f are connected to each other, and the connection lines form the input positive electrode side of the chopper circuit 3d. The emitter sides of the switching elements 7d to 7f are connected to the cathode sides of the diodes 7a to 7c, respectively. The anode sides of the diodes 7a to 7c are connected to each other, and the connecting line forms the output positive side of the chopper circuit 3d. The connecting line between the emitter side of the switching element 7d and the cathode side of the diode 7a, the connecting line between the emitter side of the switching element 7e and the cathode side of the diode 7b, and the emitter side of the switching element 7f and the cathode side of the diode 7c. Are connected to one end of the reactor 4, and the other end forms the output negative side of the chopper circuit 3d. The output negative side and the input negative side of the chopper circuit 3d are common. Yes. The chopper circuit 3d configured as described above constitutes a step-up / down type chopper circuit. Further, a bridge circuit 19d is formed by the switching elements 7d to 7f and the diodes 7a to 7c, and the bridge circuit 19d is modularized. Further, although not shown, the gate sides of the switching elements 7d to 7f are connected to the switching control means 11, and the switching control means 11 controls the ON / OFF operation of the switching elements 7d to 7f. Thus, the output voltage of the chopper circuit 3d may be controlled. The switching elements 7d to 7f are simultaneously turned ON and OFF by the switching control means 11, respectively. In addition, as described above, in order to simultaneously perform the ON operation and the OFF operation of the switching elements 7d to 7f, the switching control unit 11 does not separately apply the drive pulses to the switching elements 7d to 7f, A drive pulse of the same signal may be applied.

By applying the chopper circuit 3d as shown in FIG. 12 above, since the three-system bridge connection configuration is achieved by the switching elements 7d to 7f and the diodes 7a to 7c, the current can be dispersed. The current capacity required for the circuit can be reduced, and it is not necessary to use an element for industrial use. Further, since the bridge circuit 19d is modularized, it can be miniaturized and mounted on a circuit board by soldering. Therefore, the increase in mounting cost can be suppressed as in the case of applying the step-up chopper circuit shown in FIGS.
Further, in the configuration shown in FIG. 12, it is possible to arbitrarily increase and decrease the voltage, so that it is needless to say that the effect of the above-described increase or decrease can be obtained.

  Further, instead of the step-down chopper circuit 3d shown in FIG. 12, the chopper circuit 3e shown in FIG. 13 may be applied. In the chopper circuit 3e shown in FIG. 13, the switching elements 7d to 7f in the chopper circuit 3d shown in FIG. 12 are replaced with switching elements 18a to 18c in which freewheeling diodes are connected in antiparallel, and the diodes 7a to 7c are respectively The switching elements 18d to 18f in which the reflux diodes are connected in reverse parallel are replaced with each other, and the switching circuit 18a to 18f constitutes a bridge circuit 19e. Further, although not shown, the gate side of these switching elements 18 a to 18 f is connected to the switching control means 11. In such a configuration, the switching control unit 11 controls the switching elements 18d to 18f so as to be always in an OFF state, whereby the free-wheeling diodes connected in reverse parallel in the switching elements 18d to 18f are replaced with the diodes in the chopper circuit 3d. It assumes the same function as 7a-7c. Then, the switching control means 11 controls the ON / OFF operations of the switching elements 18a to 18c similar to those of the switching elements 7d to 7f in the chopper circuit 3d, respectively, so that the output voltage of the switching elements 18a to 18c is the same as that of the chopper circuit 3d described above. Boosted or stepped down.

  Furthermore, for example, the three-phase AC power source 1 and the three-phase rectifier 2 can obtain the same effect even when the number of phases is different, such as single phase or four phase, for example, two-phase including four switching elements. Needless to say, the same effect can be obtained in this case.

  The bridge circuits 19b to 19e correspond to the “polyphase bridge circuit” in the present invention.

Embodiment 2. FIG.
The power conversion device according to the present embodiment will be described focusing on differences from the power conversion device according to the first embodiment.

  The overall configuration of the power conversion device according to the present embodiment and the block configuration and operation of the switching control means 11 are the same as those in the first embodiment.

(Configuration of chopper circuit 3f)
FIG. 14 is a configuration diagram of the chopper circuit 3f in the power conversion device according to the second embodiment of the present invention.
As shown in FIG. 14, one end of each of the reactors 4 to 6 is connected to each other, and the connection line forms the input positive electrode side of the chopper circuit 3f. The connection line between the anode side of the diode 7 a and the collector side of the switching element 7 d is connected to the other end of the reactor 4. Similarly, the connection line between the anode side of the diode 7b and the collector side of the switching element 7e is connected to the other end of the reactor 5, and the connection line between the anode side of the diode 7c and the collector side of the switching element 7f. Is connected to the other end of the reactor 6. The cathode sides of the diodes 7a to 7c are connected to each other, and the connection line forms the output positive side of the chopper circuit 3f. The emitter sides of the switching elements 7d to 7f are connected to each other, and the connection line forms the output negative side of the chopper circuit 3f. The output negative side and the input negative side of the chopper circuit 3f are common. It has become. In other words, each of the series circuits of the diodes 7a to 7c and the switching elements 7d to 7f is connected in a multiphase bridge. The chopper circuit 3f configured as described above constitutes a step-up chopper circuit. Further, a bridge circuit 19f is formed by the diodes 7a to 7c and the switching elements 7d to 7f, and the bridge circuit 19f is modularized. Further, although not shown, the gate sides of the switching elements 7d to 7f are connected to the switching control means 11, and the switching control means 11 controls the ON / OFF operation of the switching elements 7d to 7f. Thus, the output voltage of the chopper circuit 3f is controlled.

  When the chopper circuit 3f having the above configuration is applied to a load having a large capacity exceeding 10 kW, for example, if the chopper circuit 3f is configured by one system, a diode, a switching element, and a reactor Since a large current flows in each of them, a general-purpose element cannot be used for each, and an element for industrial use needs to be used, resulting in an increase in cost. In addition, since these elements for industrial use for large currents need to be connected by screwing a metal plate on the circuit board, it is difficult to mount on the circuit board, and the cost of mounting is also low. Accompanying up. On the other hand, in the chopper circuit 3f according to the present embodiment, the diodes 7a to 7c, the switching elements 7d to 7f, and the reactors 4 to 6 have a three-system bridge connection configuration, so that the current can be dispersed. Therefore, the current capacity required for each element can be reduced, it is not necessary to use an element for industrial use, and since the bridge circuit 19f is modularized, it can be mounted on a circuit board by soldering. Therefore, an increase in mounting cost can be suppressed.

Note that the bridge circuit 19f in the chopper circuit 3f according to the present embodiment may have a modularized configuration as shown in FIG. It goes without saying that by adopting such a configuration, it is possible to obtain the same effect as that of the modularized bridge circuit 19 shown in FIG.
In addition, since reactors 4 to 6 are respectively provided in each phase arm, the current flowing per reactor is small and can be realized with a small current capacity. It becomes possible to use the core material. For example, in this embodiment, since switching is performed in the bridge circuit 19f, this frequency component is also included in the current flowing through the reactor. In general, high-frequency current flows only to the outside of the conductor due to the skin effect, increasing the AC resistance of the conductor and increasing copper loss. However, using a winding such as a litz wire increases the AC resistance due to the skin effect. Can be suppressed. Since this litz wire is a stranded wire, it is difficult to manufacture for large currents. However, in this embodiment, the current capacity per reactor can be reduced, so the litz wire should be applied. It is possible to reduce the loss in the reactor and improve the circuit efficiency.

(Operation of power converter)
Next, the operation of the power conversion device according to the present embodiment configured as described above will be described.
First, as shown in FIG. 1, the AC voltage from the three-phase AC power source 1 is rectified by a three-phase rectifier 2. The rectified voltage is input to the chopper circuit 3.

FIG. 15 is a diagram illustrating waveforms of the driving pulses applied to the currents of the reactors 4 to 6 and the switching elements 7 d to 7 f in the continuous mode of the power conversion device according to the second embodiment of the present invention.
Here, first, description will be made by paying attention to the diode 7a, the switching element 7d, and the reactor 4 shown in FIG. A current flows through the reactor 4 by the voltage input to the chopper circuit 3 f described above. At this time, a driving pulse a is applied to the gate side of the switching element 7d by the switching control means 11, and the ON / OFF operation of the switching element 7d is controlled. When the switching element 7d is in the ON state, the reactor 4 (Hereinafter referred to as reactor current A) flows through the switching element 7d, and the current value increases linearly. Next, when the switching element 7d is turned off by the drive pulse a, the reactor current A flows through the diode 7a, and a voltage having a polarity opposite to that when the switching element 7d is turned on is applied to the reactor 4. Thus, the current value of the reactor current A decreases linearly. The ON / OFF operation of the switching element 7d as described above is repeated, and the reactor current A has a waveform that fluctuates up and down. Here, the above operation will be described from the viewpoint of energy. When the switching element 7d is in the ON state, energy is accumulated in the reactor 4 by the increasing reactor current A, while the switching element 7d is in the OFF state. In this case, the energy accumulated in the reactor 4 is transferred to the output side and accumulated in the smoothing capacitor 8, and the output voltage which is a direct current in the chopper circuit 3f is higher than the input voltage and boosted. At this time, the switching control means 11 can control the magnitude of the output voltage of the chopper circuit 3f by controlling the on-duty.

  The above-described operations of the diode 7a, the switching element 7d, and the reactor 4 are also performed in the diode 7b, the switching element 7e, and the reactor 5, and the diode 7c, the switching element 7f, and the reactor 6. At this time, a current flowing through the reactor 5 is a reactor current B, and a current flowing through the reactor 6 is a reactor current C. Further, as described above, among the drive pulses applied by the switching control means 11, the pulse applied to the switching element 7e is defined as the drive pulse b, and the pulse applied to the switching element 7f is defined as the drive pulse c. As shown in FIG. 15, the drive pulses a to c applied from the switching control means 11 have the same frequency and are controlled by shifting the timing of the ON / OFF operation.

With the above operation, the input current of the chopper circuit 3f is the sum of the reactor currents A to C flowing in the reactors 4 to 6, respectively. Therefore, the frequency component resulting from the switching operation included in the input current is high frequency. Since ripples are reduced, noise can be reduced.
In addition, for example, if the drive pulses have a phase difference of 120 degrees, the frequency component resulting from the switching operation is three times the frequency and the ripple is minimized. be able to.
Further, even if the switching frequency of the switching elements 7d to 7f is lowered, it can be equivalent to the frequency component resulting from the switching operation in the input current of the chopper circuit 3 according to the first embodiment, that is, the reactor current. If this is utilized, the switching frequency of the switching elements 7d-7f can be lowered without increasing the frequency component resulting from the switching operation in the input current. In this case, since the number of times of switching in the switching elements 7d to 7f can be reduced, switching loss in the switching elements 7d to 7f can be reduced and high efficiency can be achieved.

  In the operation of the chopper circuit 3f described above, the drive pulses a to c applied from the switching control means 11 are controlled by shifting the ON / OFF operation timings of the switching elements 7d to 7f with the same frequency. However, the present invention is not limited to this, and it goes without saying that the ON / OFF operations may be performed simultaneously.

FIG. 16 is a diagram illustrating currents of reactors 4 to 6 and driving pulse waveforms applied to switching elements 7d to 7f in a critical mode (described later) of the power conversion device according to the second embodiment of the present invention. It is a figure which shows the drive pulse waveform applied to the electric current of the reactors 4-6 in the discontinuous mode (after-mentioned) of the power converter device, and the switching elements 7d-7f.
Here, the operation state that does not become 0 even when the current flowing in the reactors 4 to 6 decreases, that is, the operation state shown in FIG. 15 is referred to as a continuous mode. On the other hand, the operation state in which there is a section in which the current flowing through the reactors 4 to 6 decreases to 0, that is, the operation state shown in FIG. 16 is referred to as a discontinuous mode. In addition, when the switching elements 7d to 7f are in the OFF state, the operating state in which the switching elements 7d to 7f are turned on at the moment when the current flowing through the reactors 4 to 6 decreases to zero, that is, as shown in FIG. The operating state is called a critical mode in the sense of a boundary between continuous mode and discontinuous mode.

In the first embodiment described above, when the switching elements 7d to 7f are simultaneously turned ON and OFF, the input current is the same as the reactor current. Therefore, in an application that is handled with a large current, the reactor current is When controlled by the critical mode as shown in FIG. 17 or the discontinuous mode as shown in FIG. 18, the harmonic components included in the input current will increase, which is shown in FIG. It is preferable to be controlled by such a continuous mode.
On the other hand, in the present embodiment, since the ON / OFF operation timing of each of the switching elements 7d to 7f is controlled to be shifted, the input current is the sum of the reactor currents A to C. Therefore, the criticality shown in FIG. Even if controlled by the mode or the discontinuous mode shown in FIG. 17, the input current has a waveform in which the current does not become zero like the reactor currents A to C in the continuous mode shown in FIG. Can be reduced. Further, in the critical mode or the discontinuous mode, since the inductance value required for the reactors 4 to 6 may be made smaller than that in the continuous mode, the reactors 4 to 6 can be downsized.

The above operation has been described based on the circuit configuration of the chopper circuit 3f shown in FIG. 14. However, the present invention is not limited to this, and the chopper circuit 3g shown in FIG. 18 may be applied. In the chopper circuit 3g shown in FIG. 18, the diodes 7a to 7c in the chopper circuit 3f shown in FIG. 14 are replaced with switching elements 18a to 18c in which freewheeling diodes are connected in antiparallel, and the switching elements 7d to 7f are respectively The switching elements 18d to 18f in which the freewheeling diodes are connected in antiparallel are replaced, and the switching circuit 18a to 18f constitutes a bridge circuit 19g. Further, although not shown, the gate side of these switching elements 18 a to 18 f is connected to the switching control means 11. In such a configuration, the switching control means 11 controls the switching elements 18a to 18c so as to be always in an OFF state, whereby the free-wheeling diodes connected in reverse parallel in the switching elements 18a to 18c become diodes in the chopper circuit 3f. It assumes the same function as 7a-7c. Then, the switching control means 11 controls the ON / OFF operation of the switching elements 18d to 18f in the same manner as the switching elements 7d to 7f in the chopper circuit 3f, so that the output voltage is changed similarly to the chopper circuit 3f described above. Boosted.
As the bridge circuit 19g, for example, a general-purpose module such as IPM (Intelligent Power Module) can be used. Therefore, it is not necessary to create a new module, and cost and development load can be reduced. It is. This can also be applied to the bridge circuit 19f described above.

  The bridge circuit 19f and the bridge circuit 19g correspond to the “polyphase bridge circuit” in the present invention.

(Effect of Embodiment 2)
As described above, the chopper circuit 3f includes the diodes 7a to 7c, the switching elements 7d to 7f and the reactors 4 to 6, or the chopper circuit 3g includes the switching elements 18a to 18f and the reactors 4 to 6. Since a three-system bridge connection configuration is used, the current can be distributed, so that the current capacity required for each element can be reduced, and it is not necessary to use an industrial element, and the bridge circuit 19f and the bridge Since the circuit 19g is modularized, it can be mounted on a circuit board by soldering, so that an increase in mounting cost can be suppressed.
In addition, since the input currents of the chopper circuit 3f and the chopper circuit 3g are the addition of the reactor currents A to C flowing in the reactors 4 to 6, respectively, the frequency component resulting from the switching operation included in the input current is increased and the ripples are increased. Therefore, the noise can be reduced.
Further, the timing shift of the switching operation of the switching elements 7d to 7f in the bridge circuit 19f or the switching elements 18d to 18f in the bridge circuit 19g is, for example, switched if each drive pulse has a phase difference of 120 degrees. The frequency component resulting from the operation is three times the frequency, and the ripple can be minimized.
Even if the switching frequency of the switching elements 7d to 7f in the bridge circuit 19f or the switching elements 18d to 18f in the bridge circuit 19g is lowered, the switching operation in the input current, that is, the reactor current of the chopper circuit 3 according to the first embodiment is achieved. It can be equivalent to the resulting frequency component. By utilizing this, the switching frequency of the switching elements 7d to 7f or the switching elements 18d to 18f can be lowered without increasing the frequency component resulting from the switching operation in the input current. In this case, since the number of times of switching in the switching elements 7d to 7f or the switching elements 18d to 18f can be reduced, switching loss in the switching elements 7d to 7f or the switching elements 18d to 18f can be reduced, and high efficiency can be achieved.
Further, the bridge circuit 19f in the chopper circuit 3f according to the present embodiment or the bridge circuit 19g in the chopper circuit 3g has a modularized configuration as shown in FIG. It goes without saying that the same effect as that of the bridge circuit 19 can be obtained.
In addition, since reactors 4 to 6 are respectively provided in each phase arm, the current flowing per reactor is small and can be realized with a small current capacity. It becomes possible to use the core material.
Further, when the ON / OFF operation timing of each of the switching elements 7d to 7f or the switching elements 18d to 18f is controlled as in the present embodiment, the input current is the addition of the reactor currents A to C. 16, even if controlled by the critical mode shown in FIG. 16 or the discontinuous mode shown in FIG. 17, the input current has a waveform in which the current does not become zero like the reactor currents AC in the continuous mode shown in FIG. 15. Therefore, harmonic components can be reduced.
Further, in the critical mode or the discontinuous mode, the inductance value required for the reactors 4 to 6 may be smaller than that in the continuous mode, so that the reactors 4 to 6 can be downsized.
Furthermore, as the bridge circuit 19f and the bridge circuit 19g, for example, a general-purpose module such as IPM (Intelligent Power Module) can be used, so there is no need to create a new module, and the cost and development load are reduced. Can be reduced.

Although the step-up type chopper circuit shown in FIGS. 14 and 18 has been described as the chopper circuit according to the present embodiment, the present invention is not limited to this, and the step-down type chopper as shown in FIG. The chopper circuit 3f or the chopper circuit 3g may be replaced by the circuit 3h. As shown in FIG. 19, the collector sides of the switching elements 7d to 7f are connected to each other, and the connection lines form the input positive electrode side of the chopper circuit 3h. The emitter sides of the switching elements 7d to 7f are connected to the cathode sides of the diodes 7a to 7c, respectively. The anode sides of the diodes 7a to 7c are connected to each other, and the connection line forms the output negative side of the chopper circuit 3b. The output negative side and the input negative side of the chopper circuit 3 are common. It has become. A connection line between the emitter side of the switching element 7 d and the cathode side of the diode 7 a is connected to one end of the reactor 4. Similarly, the connection line between the emitter side of the switching element 7e and the cathode side of the diode 7b is connected to one end of the reactor 5, and the connection line between the emitter side of the switching element 7f and the cathode side of the diode 7c is , Connected to one end of the reactor 6. The other ends of the reactors 4 to 6 are connected to each other, and the connection line forms the output positive electrode side of the chopper circuit 3h. The chopper circuit 3h configured as described above constitutes a step-down chopper circuit. The switching elements 7d to 7f and the diodes 7a to 7c form a bridge circuit 19h, and the bridge circuit 19h is modularized. Further, although not shown, the gate sides of the switching elements 7d to 7f are connected to the switching control means 11, and the switching control means 11 controls the ON / OFF operation of the switching elements 7d to 7f. Thus, the output voltage of the chopper circuit 3h may be controlled. The switching elements 7d to 7f are controlled by the switching control means 11 with the same frequency and shifted ON / OFF operation timing.
As described above, the switching control means 11 controls the switching element 7d-7f by shifting the ON / OFF operation timing at the same frequency. However, the present invention is not limited to this, and is simultaneously turned on. Needless to say, the operation and the operation for the OFF operation may be used.

By applying the chopper circuit 3h as shown in FIG. 19 as described above, a three-system bridge connection configuration is formed by the switching elements 7d to 7f, the diodes 7a to 7c, and the reactors 4 to 6, so that the current can be dispersed. Therefore, the current capacity required for each element can be reduced, there is no need to use an element for industrial use, and since the bridge circuit 19h is modularized, it is possible to reduce the size, and by soldering Since it can be mounted on a circuit board, an increase in mounting cost can be suppressed as in the case of applying the step-up chopper circuit shown in FIGS.
In addition, for example, when the motor is connected as a load of the chopper circuit 3h, the efficiency can be improved when the load is small, such as when the motor is driven at a low speed.

  Further, instead of the step-down chopper circuit 3h shown in FIG. 19, the chopper circuit 3i shown in FIG. 20 may be applied. In the chopper circuit 3i shown in FIG. 20, the diodes 7a to 7c in the chopper circuit 3h shown in FIG. 19 are respectively replaced with switching elements 18d to 18f in which freewheeling diodes are connected in antiparallel, and the switching elements 7d to 7f are respectively The switching elements 18a to 18c in which the freewheeling diodes are connected in antiparallel are replaced, and a bridge circuit 19i is configured by these switching elements 18a to 18f. Further, although not shown, the gate side of these switching elements 18 a to 18 f is connected to the switching control means 11. In such a configuration, the switching control means 11 controls the switching elements 18d to 18f so as to be always in an OFF state, whereby the free-wheeling diodes connected in reverse parallel in the switching elements 18d to 18f are replaced with the diodes in the chopper circuit 3h. It assumes the same function as 7a-7c. Then, the switching control means 11 controls the ON / OFF operations of the switching elements 18a to 18c similar to those of the switching elements 7d to 7f in the chopper circuit 3h, respectively, so that the output voltage is similar to that of the chopper circuit 3h described above. Step down.

Further, as the chopper circuit according to the present embodiment, a step-up / step-down chopper circuit 3j as shown in FIG. 21 may be applied. As shown in FIG. 21, the collector sides of the switching elements 7d to 7f are connected to each other, and the connection line forms the input positive electrode side of the chopper circuit 3j. The emitter sides of the switching elements 7d to 7f are connected to the cathode sides of the diodes 7a to 7c, respectively. The anode sides of the diodes 7a to 7c are connected to each other, and the connection line forms the output positive side of the chopper circuit 3j. A connection line between the emitter side of the switching element 7 d and the cathode side of the diode 7 a is connected to one end of the reactor 4. Similarly, the connection line between the emitter side of the switching element 7e and the cathode side of the diode 7b is connected to one end of the reactor 5, and the connection line between the emitter side of the switching element 7f and the cathode side of the diode 7c is , Connected to one end of the reactor 6. The other ends of the reactors 4 to 6 are connected to each other, and the connection line forms the output positive side of the chopper circuit 3j, and the output negative side and the input negative side of the chopper circuit 3j are common. It has become. The chopper circuit 3j configured as described above constitutes a step-up / down type chopper circuit. Further, a bridge circuit 19j is formed by the switching elements 7d to 7f and the diodes 7a to 7c, and the bridge circuit 19j is modularized. Further, although not shown, the gate sides of the switching elements 7d to 7f are connected to the switching control means 11, and the switching control means 11 controls the ON / OFF operation of the switching elements 7d to 7f. Thus, the output voltage of the chopper circuit 3j may be controlled. The switching elements 7d to 7f are controlled by the switching control means 11 with the same frequency and shifted ON / OFF operation timing.
As described above, the switching control means 11 controls the switching element 7d-7f by shifting the ON / OFF operation timing at the same frequency. However, the present invention is not limited to this, and is simultaneously turned on. Needless to say, the operation and the OFF operation may be performed.

By applying the chopper circuit 3j as shown in FIG. 21 as described above, a three-system bridge connection configuration is formed by the switching elements 7d to 7f, the diodes 7a to 7c, and the reactors 4 to 6, so that the current can be dispersed. Therefore, the current capacity required for each element can be reduced, it is not necessary to use an element for industrial use, and since the bridge circuit 19j is modularized, it is possible to reduce the size, and by soldering Since it can be mounted on a circuit board, an increase in mounting cost can be suppressed as in the case of applying the step-up chopper circuit shown in FIGS.
Further, in the configuration shown in FIG. 21, it is possible to arbitrarily increase and decrease the voltage, so that it is needless to say that the above-described effect of the voltage increase or decrease can be obtained.

  Further, instead of the step-down chopper circuit 3j shown in FIG. 21, the chopper circuit 3k shown in FIG. 22 may be applied. In the chopper circuit 3k shown in FIG. 22, the switching elements 7d to 7f in the chopper circuit 3j shown in FIG. 21 are replaced with switching elements 18a to 18c in which freewheeling diodes are connected in antiparallel, and the diodes 7a to 7c are respectively replaced. The switching elements 18d to 18f in which the freewheeling diodes are connected in reverse parallel are replaced with each other, and a bridge circuit 19k is configured by these switching elements 18a to 18f. Further, although not shown, the gate side of these switching elements 18 a to 18 f is connected to the switching control means 11. In such a configuration, the switching control unit 11 controls the switching elements 18d to 18f so as to be always in an OFF state, so that the free-wheeling diodes connected in reverse parallel in the switching elements 18d to 18f become diodes in the chopper circuit 3j. It assumes the same function as 7a-7c. Then, the switching control means 11 controls the ON / OFF operations of the switching elements 18a to 18c similar to the switching elements 7d to 7f in the chopper circuit 3j, respectively, so that the output voltage is similar to that of the chopper circuit 3j described above. Increased or decreased pressure.

  Furthermore, for example, the three-phase AC power source 1 and the three-phase rectifier 2 can obtain the same effect even when the number of phases is different, such as single phase or four phase, for example, two-phase including four switching elements. Needless to say, the same effect can be obtained in this case even when the bridge circuit configuration is used.

  The bridge circuits 19h to 19k correspond to the “polyphase bridge circuit” in the present invention.

Embodiment 3 FIG.
(Overall configuration of motor drive control device)
FIG. 23 is a configuration diagram of a motor drive control device according to Embodiment 3 of the present invention. The motor drive control device according to the present embodiment will be described focusing on differences from the above-described power conversion device according to the first embodiment.
As shown in FIG. 23, the motor drive control device according to the present embodiment outputs the output from the chopper circuit 3 to the AC voltage at the output side of the power converter shown in FIG. The inverter circuit 12 is connected to the motor 15 described later. In the inverter circuit 12, the collector sides of the switching elements 12 a to 12 c to which the reflux diodes are connected in reverse parallel are connected to each other, and the connection line forms the input positive electrode side of the inverter circuit 12. The emitter sides of the switching elements 12a to 12c are connected to the collector sides of the switching elements 12d to 12f, respectively, to which the reflux diodes are connected in antiparallel. The emitter sides of the switching elements 12 d to 12 f are connected to each other, and the connection line forms the input negative side of the inverter circuit 12. An inverter circuit 12 is formed by the switching elements 12a to 12f. Also, a connection line between the emitter side of the switching element 12a and the collector side of the switching element 12d, a connection line between the emitter side of the switching element 12b and the collector side of the switching element 12e, and an emitter side of the switching element 12c and the switching element 12f The output lines of the inverter circuit 12 extend from the connection lines to the collector side of the two, and these three output lines are connected to the motor 15. A motor current detector 13 for detecting a current supplied to the motor 15 is installed on the output line. The motor current detector 13 and the output voltage detector 10 for detecting the voltage across the smoothing capacitor 8 are connected to the inverter driving means 14. This inverter driving means 14 switches the inverter circuit 12 based on the voltage across the smoothing capacitor 8 detected by the output voltage detector 10 and the current supplied to the motor 15 detected by the motor current detector 13. A drive signal for controlling the ON / OFF operation of the elements 12a to 12f is generated.

  Needless to say, the chopper circuit 3 shown in FIG. 23 may be replaced by the chopper circuits 3a to 3k in the first and second embodiments.

(Relationship between motor current I, winding resistance R and energy loss in the motor 15)
Generally, when the number of turns N of the motor winding in the motor 15 is increased, the winding resistance R is proportional to the square of the number of turns N, as shown by the following equation (1). The proportionality constant at this time is k _1.

R = k ₁ · N ² (1)

Further, the motor current I flowing in the output line of the inverter circuit 12 and the motor winding is inversely proportional to the number of turns N as shown in the following equation (2). The proportionality constant at this time is k _2.

I = k ₂ / N (2)

At this time, the motor copper loss Loss _motorcp in the winding resistance R does not depend on the number of turns N as shown in the following formula (3).

Loss _motorcp = R · I ² = k ₁ · k ₂ ² (3)

At this time, if the motor current I is reduced, the conduction loss in the switching elements 12a to 12f in the inverter circuit 12 can be reduced. However, as shown in the above equation (2), the number N of turns of the motor winding is set as follows. By increasing the motor current I, the conduction loss in the inverter circuit 12 can be reduced. Furthermore, as shown in the above equation (4), even if the number of turns N increases, the motor copper loss Loss _motorcp does not increase.

Further, when the number of turns N of the motor winding of the motor 15 is increased, the induced voltage Φ generated increases in proportion to the number of turns N as shown in the following equation (4). The proportionality constant at this time is k ₃ .

Φ = k ₃ · N (4)

  At this time, the increase in the induced voltage Φ due to the increase in the number of turns N decreases the high-speed driving range of the motor 15, but according to the present embodiment, as described in the first and second embodiments. Since the output voltage of the inverter circuit 12 can be increased by boosting the voltage by the chopper circuit 3 or the like, the number of turns of the motor 15 can be increased without reducing the high-speed driving range of the motor 15.

(Effect of Embodiment 3)
The configuration of the inverter circuit 12 in the present embodiment is the same as that of the bridge circuit 19a shown in FIG. 7 in the first embodiment and the bridge circuit 19g in FIG. 18 in the second embodiment. Can be used. Furthermore, if the driver circuit for driving each switching element has a common configuration, the configurations of the chopper circuit and the inverter circuit on each substrate can be largely the same. This makes it possible to reduce production costs or reduce development load.
Further, when the motor 15 is driven at a high speed, the output voltage of the inverter circuit 12 is insufficient, so that the high-speed driving range is limited. However, according to the present embodiment, the voltage is boosted by the chopper circuit 3 and the like, Since the input DC voltage also increases, the shortage of the output voltage of the inverter circuit 12 can be resolved, the high-speed driving range can be expanded, and a high-performance motor drive control device can be obtained.
Further, since the motor current of the motor 15 is reduced by increasing the output voltage of the inverter circuit 12 by the boosting function of the chopper circuit 3 or the like, the current flows when the switching elements 12a to 12f constituting the inverter circuit 12 are turned on. Since the current is reduced, the conduction loss in the inverter circuit 12 can be reduced, and the efficiency can be improved when the motor 15 is driven at high speed.
Further, since the motor current is reduced by increasing the number of turns of the motor winding, it is possible to reduce the conduction loss in the inverter circuit 12. At this time, even if the number of turns is increased, the motor copper loss in the motor 15 is increased. There is nothing. At this time, if the number of turns is increased, the induced voltage increases and the high-speed driving range of the motor 15 is decreased. However, according to the present embodiment, the voltage is boosted by the chopper circuit 3 or the like, and the output of the inverter circuit 12 is increased. Since the voltage can be increased, the number of turns of the motor 15 can be increased without reducing the high-speed driving range of the motor 15.
Further, when the motor 15 is driven at a low speed and the load is small and the output voltage of the inverter circuit 12 is low, the switching control means 11 turns off the switching elements 7d to 7f to operate the chopper circuit 3 and the like. It is possible to stop and suppress conduction loss in the chopper circuit 3 or the like.
Furthermore, when the motor 15 is driven at a low load, such as when driving at a low speed, the DC voltage generated by the three-phase full-wave rectification method is higher than the output voltage of the inverter circuit 12 required for driving. For this reason, the loss of the switching elements in the chopper circuit 3 and the inverter circuit 12 is large, and noise due to a voltage error due to dead time becomes a problem in the inverter circuit 12. At this time, when the chopper circuits 3b to 3e according to the first embodiment or the chopper circuits 3h to 3k according to the second embodiment are applied as the chopper circuit and the output voltage is stepped down, the chopper circuits 3b to 3e are applied to the inverter circuit 12. Therefore, by optimizing the DC voltage, it is possible to reduce noise by reducing loss in switching elements in the bridge circuit and the inverter circuit 12 and reducing voltage error due to dead time in the inverter circuit 12.

Embodiment 4 FIG.
(Overall configuration of the air conditioner 101)
FIG. 24 is a diagram illustrating an example of the overall configuration of an air conditioner according to Embodiment 4 of the present invention.
As shown in FIG. 24, the air conditioner 101 according to the present embodiment includes an outdoor unit 102 and an indoor unit 105. The outdoor unit 102 includes a compressor 103 that is connected to a refrigerant circuit (not shown) and forms a part of the refrigeration cycle, a heat exchanger (not shown), and a blower 104 that blows air to the heat exchanger. The compressor 103 and the blower 104 are rotationally driven by a motor controlled by the motor drive control device according to the third embodiment described above.

(Effect of Embodiment 4)
Needless to say, the above-described configuration can provide the same effects as those of the first to third embodiments.
Moreover, since the motor current is reduced by increasing the voltage by the chopper circuit or increasing the number of turns of the motor as described above, heat generation in the compressor 103 and the blower 104 can be suppressed.

Embodiment 5 FIG.
(Overall configuration of refrigerator 111)
FIG. 25 is a diagram showing an example of the overall configuration of the refrigerator according to Embodiment 5 of the present invention.
As shown in FIG. 25, a refrigerator 111 according to the present embodiment includes a compressor 112 connected by a refrigerant circuit (not shown) and constituting a part of a refrigeration cycle, and a cooler 114 provided in a cooling chamber 113. And a blower 115 for sending the cold air generated by the cooler 114 to the refrigerating room and the freezing room. The compressor 112 and the blower 115 are rotationally driven by a motor controlled by the motor drive control device according to the third embodiment described above.

(Effect of Embodiment 5)
Needless to say, the above-described configuration can provide the same effects as those of the first to third embodiments.
Further, as described above, since the motor current is reduced by increasing the voltage by the chopper circuit or increasing the number of turns of the motor, heat generation in the compressor 112 and the blower 115 can be suppressed.

  In addition, although the refrigerator 111 was demonstrated in this Embodiment, it is not restricted to this, For example, about a freezer, the compressor which is rotationally driven by the motor controlled by the motor drive control apparatus which concerns on Embodiment 3, or It is good also as a structure to which an air blower is applied.

  DESCRIPTION OF SYMBOLS 1 3 phase alternating current power supply, 2 3 phase rectifier, 2a-2f rectifier diode, 3, 3a-3k chopper circuit, 4-6 reactor, 7a-7c diode, 7d-7f switching element, 8 smoothing capacitor, 9 bus current detector DESCRIPTION OF SYMBOLS 10 Output voltage detector, 11 Switching control means, 12 Inverter circuit, 12a-12f Switching element, 13 Motor current detector, 14 Inverter drive means, 15 Motor, 16 Backflow prevention element, 17 Open / close element, 18a-18f Switching element 19, 19a to 19k bridge circuit, 21 bus current command value calculation unit, 22 on-duty calculation unit, 23 drive pulse generation unit, 31a to 31c diode, 32a to 32c switching element, 33 heat radiation fin, 34 pattern wiring, 41 module Module, 42a to 42c diode, 43a to 43c switching element, 44 heat radiation fin, 45 metal wiring, 101 air conditioner, 102 outdoor unit, 103 compressor, 104 blower, 105 indoor unit, 111 refrigerator, 112 compressor, 113 cooling Chamber, 114 cooler, 115 blower.

Claims (22)

A rectifier for rectifying the AC voltage;
It is constituted by a series circuit of at least one set of diodes and a switching element having one end connected to the anode side of the diodes, and the cathode sides of the diodes are connected to each other (hereinafter, the connection line is referred to as “connection line A”). A multiphase bridge circuit in which the other ends of the switching elements are connected to each other (hereinafter, the connection line is referred to as a “connection line B”), and connections between the diodes and the switching elements in the multiphase bridge circuit A chopper circuit composed of a reactor having one end connected to the wire;
A smoothing capacitor having one end connected to the connection line A and the other end connected to the connection line B;
Switching control means for controlling ON / OFF operation of the switching element;
With
The output positive side of the rectifier is connected to the other end of the reactor, the output negative side is connected to the connection line B,
The switching control means boosts the output voltage of the chopper circuit by controlling the ON / OFF operation of the switching element. A rectifier for rectifying the AC voltage;
It is constituted by a series circuit of at least one set of switching elements and a diode having a cathode connected to one end of the switching elements, and the other ends of the switching elements are connected to each other (hereinafter, the connection lines are referred to as “connection lines C”). A multiphase bridge circuit in which the anode sides of the respective diodes are connected to each other (hereinafter, the connection line is referred to as “connection line D”), and each connection between the switching element and the diode in the multiphase bridge circuit. A chopper circuit composed of a reactor having one end connected to the wire;
A smoothing capacitor having one end connected to the other end of the reactor and the other end connected to the connecting line D;
Switching control means for controlling ON / OFF operation of the switching element;
With
The output positive side of the rectifier is connected to the connection line C, the output negative side is connected to the connection line D,
The switching control means steps down the output voltage of the chopper circuit by controlling the ON / OFF operation of the switching element. A rectifier for rectifying the AC voltage;
A series circuit of at least one set of switching elements and a diode having one end of the switching element connected to the cathode side is connected, and the other ends of the switching elements are connected to each other (hereinafter, the connection lines are referred to as “connection lines E”). A multi-phase bridge circuit in which the anode sides of the diodes are connected to each other (hereinafter, the connection line is referred to as “connection line F”), and each connection between the switching element and the diode in the multi-phase bridge circuit. A chopper circuit composed of a reactor having one end connected to the wire;
A smoothing capacitor having one end connected to the connecting line F and the other end connected to the other end of the reactor;
Switching control means for controlling ON / OFF operation of the switching element;
With
The output positive side of the rectifier is connected to the connection line E, the output negative side is connected to the other end of the reactor,
The switching control means increases or decreases the output voltage of the chopper circuit by controlling ON / OFF operation of the switching element. The number of reactors is the same as the series circuit,
4. The power converter according to claim 1, wherein one end of the one reactor is connected to a connection line between the diode and the switching element for each series circuit. 5. The power converter according to any one of claims 1 to 4, wherein the switching control unit controls the ON / OFF operation of the switching element in the polyphase bridge circuit at the same timing. The power conversion device according to claim 4, wherein the switching control unit controls the timing of ON / OFF operation of the switching element in the multiphase bridge circuit by shifting in each phase. The power conversion device according to claim 6, wherein the switching control unit controls the frequency of the ON operation of the switching element in the multiphase bridge circuit to be the same in each phase. The switching control means can switch the operation of the current flowing through the reactor to any one of a continuous mode, a discontinuous mode, and a critical mode. The power converter described. The power converter according to any one of claims 1 to 8, wherein the polyphase bridge circuit is configured by one module. A bus current detector connected to the output side of the rectifier and detecting the output current;
An output voltage detector connected to both ends of the smoothing capacitor and detecting a voltage across the both ends;
With
The switching control means controls the ON / OFF operation of the switching element based on the output current detected by the bus current detector and the both-end voltage detected by the output voltage detector. The power conversion device according to any one of claims 1 to 9, wherein the power conversion device is characterized. The power conversion device according to any one of claims 1 to 10, further comprising a backflow prevention element connected between an output positive electrode side of the rectifier and an output positive electrode side of the chopper circuit. The power conversion device according to any one of claims 1 to 10, further comprising a switching element connected between an output positive electrode side of the rectifier and an output positive electrode side of the chopper circuit. Instead of the diode in the multi-phase bridge circuit, a switching element in which a reflux diode is connected in reverse parallel is connected, the direction of connection of the diode and the direction of connection of the reflux diode are the same,
The power conversion device according to any one of claims 1 to 12, wherein the switching control unit controls the switching element in which the freewheeling diode is connected in antiparallel to an OFF operation. The power converter according to any one of claims 1 to 13, wherein the switching element has a super junction structure. The power conversion device according to any one of claims 1 to 14,
An inverter circuit for driving a motor by converting a DC voltage, which is an output of the power converter, into an AC voltage;
Inverter driving means for driving the inverter circuit;
A motor drive control device comprising: The motor drive control device according to claim 15, wherein the inverter circuit is configured by one module. The power conversion device according to claim 13,
An inverter circuit for driving a motor by converting a DC voltage, which is an output of the power converter, into an AC voltage;
Inverter driving means for driving the inverter circuit;
With
The motor drive control device, wherein the multi-phase bridge circuit and the inverter circuit are configured by a common module. A motor drive control device according to any one of claims 15 to 17,
A motor driven by the motor drive control device;
The compressor characterized by having. A motor drive control device according to any one of claims 15 to 17,
A motor driven by the motor drive control device;
A blower characterized by comprising: An air conditioner comprising at least one of the compressor according to claim 18 or the blower according to claim 19. A refrigerator comprising at least one of the compressor according to claim 18 or the blower according to claim 19. A freezer comprising at least one of the compressor according to claim 18 or the blower according to claim 19.

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