JP2005045912A - Matrix converter circuit and motor drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive device, which reduces circuit loss more than a motor drive device for driving a motor, receiving DC or pulsating DC rectified by a conventional rectification circuit, and besides is smaller and less expensive than a motor drive device using a large-sized electrolytic capacitor. <P>SOLUTION: A voltage detector, which detects whether the voltage of a single-phase AC power source is positive or negative, and a control signal regenerator, which outputs twelve control signals for bidirectional switching circuits from the six output signals of a DC power controller, are added to the DC power controller which controls an inverter circuit for driving the motor, being connected to a DC power source. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a matrix converter circuit configured by using a plurality of bidirectional switches, and a motor driving device for inputting a single-phase AC power source and driving a motor using the matrix converter circuit.

  FIG. 7 shows a motor driving apparatus using an inverter circuit using a unidirectional switch according to the first prior art. 101 is a single-phase AC power source, 102 is a rectifier circuit consisting of a diode bridge consisting of four diodes 121 to 124 and a capacitor 125, 103 is an inverter circuit, 104 is a motor, and 105 is a controller for DC power source. In the rectifier circuit 102, the AC voltage generated by the single-phase AC power supply 101 is rectified by the diode bridge (121 to 124), and then smoothed by the capacitor 125 to become a DC voltage, which is input to the inverter circuit 103. .

  The inverter circuit 103 includes a plurality of unidirectional switches 103a to 103f, and each unidirectional switch includes general transistors 131 to 136 including antiparallel diodes 137 to 142. The DC voltage output from the rectifier circuit 102 is PWM driven by the unidirectional switches 103a to 103f of the inverter circuit 103, whereby an appropriate voltage is applied to the motor 104 serving as a load, and the motor 104 is driven.

  The DC power supply controller 105 outputs a PWM signal for driving the inverter circuit 103 by grasping the driving state of the motor from the motor current or the DC voltage input to the inverter circuit 103, or the motor current or DC voltage. In any case, the DC power supply control unit 105 controls the inverter circuit 103 so as to drive the motor 104. Is output. The control signal output to the inverter circuit 103 composed of each unidirectional switch requires the number of unidirectional switches, and in this case is six.

  As a second conventional technique, a matrix converter circuit using a bidirectional switch instead of a unidirectional switch has recently been proposed (for example, Patent Document 1). FIG. 8 shows this, and the basic configuration includes a DC power source 106, a high-frequency inverter circuit 107, and a matrix converter circuit 108. Further, the high-frequency inverter circuit 107 includes unidirectional switches 160 to 163, each of which includes general transistors 151 to 154 including antiparallel diodes 155 to 158. The matrix converter circuit 108 includes six bidirectional switches 140 to 145. Reference numerals 170 to 181 denote transistors, and 190 to 201 denote diodes, which are connected as shown in FIG. 8 so that current paths can be formed in both directions. The DC voltage applied by the DC power source 106 is converted into an AC voltage having a high frequency by the high frequency inverter circuit 107, and the AC voltage is input to the matrix converter circuit 108. The matrix converter circuit 108 outputs a three-phase AC voltage having a lower frequency from the high-frequency AC voltage input from the high-frequency inverter circuit 107.

As a third prior art, a motor drive device has been proposed in which the rectifier circuit 102a has only a diode bridge (121 to 124) as shown in FIG. 9 (for example, Patent Document 2). In this technique, the capacitor 125 is omitted as compared with the first conventional technique (FIG. 7). Since the rectifier circuit 102a only rectifies the AC voltage applied from the single-phase AC power supply 101 by the diode bridge (121 to 124) and does not smooth it, the input voltage Vpn to the inverter circuit 103 is the voltage applied to the single-phase AC power supply 101. In synchronization with twice the frequency, the voltage value decreases to 0 V and has a pulsating waveform as shown in FIG. According to the third prior art, even if such a pulsating DC voltage (hereinafter referred to as pulsating DC) is input to the inverter circuit 103, the motor 104 serving as a load can be driven at a frequency higher than the frequency of the pulsating DC. The pulsating direct current control unit 105a that controls the inverter circuit configured by a unidirectional switch is used.
JP-A-8-80062 (FIG. 2) JP-A-9-117183 (FIGS. 1 and 2)

  In the first prior art described above, since the DC voltage obtained by the single-phase AC power supply 101 and the rectifier circuit 102 is input to the inverter circuit 103, circuit loss due to the rectifier circuit 102 occurs. Moreover, since the capacitor | condenser which the rectifier circuit 102 has is a large capacity | capacitance electrolytic capacitor, there existed a subject that an apparatus enlarged and the price increased.

  Compared with the first prior art, the third conventional technique has the advantage that the apparatus is reduced in size and price because the electrolytic capacitor, which is a large component, is removed, but the circuit loss due to the rectifier circuit 102a is the first. There is a problem that it occurs in the same manner as the conventional technology.

  If the single-phase AC power supply 101 is used instead of the configuration of the DC power supply 106 and the high-frequency inverter circuit 107 using the second conventional technique, a rectifier circuit is not required as compared with the first and third conventional techniques. Therefore, there is an advantage that circuit loss can be reduced. However, the output frequency of the matrix converter circuit is lower than the input single-phase AC frequency. This is because the matrix converter circuit used in the past is a circuit intended for power conversion, and the output voltage is required to have a waveform with little distortion. By the way, the operation of the matrix converter circuit obtains the output voltage by straddling the input voltage waveform. Therefore, if the output frequency is increased, problems such as distortion of the output voltage occur. Therefore, the frequency of the output voltage is higher than the frequency of the input voltage. It must be lowered. Therefore, if the single-phase alternating current input is a commercial power supply of 50 Hz, the frequency of the three-phase alternating current that can be output is 50 Hz at the maximum. Therefore, when this second prior art is applied to a motor drive device, The driving frequency is only 50 Hz at the maximum, and there is a problem that the rotational speed variable range is small. That is, as a motor drive device, a device in which a single-phase AC power supply and a conventional matrix converter circuit are simply connected cannot rotate the motor at a frequency higher than the frequency of the single-phase AC power supply. Therefore, a matrix converter circuit that can output a frequency higher than the frequency of the single-phase alternating current that is input has been demanded.

  The object of the present invention is to reduce the circuit loss compared to a conventional motor driving device that drives a motor with DC or pulsating DC rectified by a rectifying circuit as an input, and to a motor driving device that uses a large electrolytic capacitor. The object is to provide a motor drive device that is smaller and less expensive. That is, in a motor drive device that uses a single-phase AC power supply as an input and drives the motor using a matrix converter circuit, a motor drive device that can increase the rotational speed of the motor beyond the frequency of the single-phase AC power supply is provided. It is. In addition, as described above, only a simple circuit is added to the DC power supply control unit or the pulsating DC control unit for controlling the inverter circuit using the unidirectional switch that drives the motor with the DC power supply as an input. An object of the present invention is to realize a matrix converter circuit capable of increasing the rotational speed of a motor higher than the frequency of a single-phase AC power supply.

  Another object of the present invention is to provide a highly efficient motor drive device that reduces circuit loss in a matrix converter circuit.

  In order to achieve the above object, the present invention provides a first bidirectional switch series circuit in which a first bidirectional switch and a second bidirectional switch are connected in series, a third bidirectional switch, and a fourth bidirectional switch. A second bidirectional switch series circuit in which two-way switches are connected in series and a third bidirectional switch series circuit in which a fifth bidirectional switch and a sixth bidirectional switch are connected in series are connected in parallel to each other. In the matrix converter circuit, each of the first to sixth bidirectional switches independently turns off conduction in either the forward direction or the reverse direction, turns on conduction in the forward direction or the reverse direction, A matrix converter circuit characterized by enabling four operating states in which conduction in either direction is on.

  In addition, the matrix converter circuit and a control unit that outputs a control signal for controlling the first to sixth bidirectional switches constituting the matrix converter circuit, the first bidirectional switch series circuit A three-phase motor is connected to an intermediate connection point of the second bidirectional switch series circuit and an intermediate connection point of the third bidirectional switch series circuit, and a power source for driving the three-phase motor As a motor driving device, a single-phase AC power source is connected to the parallel connection point of the first to third bidirectional switch series circuits.

  With such a configuration, it is possible to provide a motor drive device that can drive a three-phase motor using a matrix converter circuit that is directly connected to a single-phase AC power supply without going through a diode bridge or the like.

  In addition, the control unit determines a conduction operation of each of the first to sixth bidirectional switches based on an output voltage of the single-phase AC power supply, and outputs a control signal based on the determination. Is. As described above, by determining the switch operation of the matrix converter circuit of the motor driving device, the three-phase motor can be driven and the matrix converter circuit can be controlled.

  Further, the control unit determines each conduction operation of the first to sixth bidirectional switches based on a direction of a current flowing through the three-phase motor, and outputs a control signal based on the determination. It is a thing. As described above, the operation of the control unit can be different from the operation of the control unit described above, and the number of switches to be turned on / off can be reduced (12 to 6). It is possible to provide a more efficient motor driving device with reduced current consumption.

  In addition, the control unit determines the conduction operation of each of the first to sixth bidirectional switches so that the rotation speed of the three-phase motor continuously changes, and outputs a control signal based on the determination. To do. As described above, since the output frequency of the three-phase AC power source connected to the three-phase motor can be continuously changed from 0, the number of rotations of the three-phase motor can be continuously changed from 0 to rotate more smoothly. A motor drive device can be provided. Conventionally, if the output frequency of the three-phase AC power source is discontinuous, only the induction motor can be driven as the three-phase motor, but according to the present invention, the three-phase motor is a brushless motor or the like. It is possible to provide a motor drive device that can be driven even in the case of a synchronous machine that rotates in synchronization with the frequency of an applied voltage.

  In the present invention, if SiC (silicon carbide) is used as a material for the first to sixth bidirectional switches to form a matrix converter circuit or a motor drive circuit, a material having high withstand voltage and low loss such as SiC. By using this, it is possible to provide a motor drive device that is more efficient than conventional matrix converter circuits and inverter circuits that use Si as a material.

  ADVANTAGE OF THE INVENTION According to this invention, the motor drive device which drives a motor directly using a bidirectional | two-way switch circuit from a single phase alternating current power supply can be provided. In other words, a simple circuit is added to the DC power supply control unit of a motor driving device that drives a motor from a DC power supply using a unidirectional switch, or the control unit is a microcomputer or the like. By using a control unit to which a function program is added, a motor driving device that drives a motor from a single-phase AC power source using a bidirectional switch circuit can be provided. As a result, a motor drive device using a bidirectional switch circuit can be provided with only slight changes from a conventionally used DC power supply controller. Conventionally, in order to create a DC power supply, it was necessary to rectify the AC power supply using a diode bridge and then create a DC power supply using a large electrolytic capacitor. Since the motor drive device that can directly drive the motor can be provided, the circuit loss due to the rectifier circuit can be reduced, and a large electrolytic capacitor is not required. An inexpensive motor drive device can be provided.

  In addition, a simple circuit is added to the pulsating DC control unit in a motor drive device that does not use a large electrolytic capacitor in the rectifier circuit and pulsating DC is input, or if the control unit is a microcomputer, etc. A matrix converter circuit that can output a frequency higher than the frequency of a single-phase AC power supply can be realized by using a control unit to which is added. Therefore, the circuit loss is small, the size is low, and the rotation speed variable range is wide. A motor drive device can be provided.

  Further, the circuit loss can be further reduced by using SiC as the material of the bidirectional switch circuit and the matrix converter circuit.

  Moreover, the effect at the time of applying this invention to each product field is shown. According to the present invention, since it can be configured without using a rectifier circuit, the kinetic energy of the motor can be regenerated in the single-phase AC power supply. In a motor drive device for consumer use, especially in the case of a washing machine or a dryer, the kinetic energy is large. Therefore, since the kinetic energy can be regenerated to the single-phase AC power supply by applying it to the motor drive device for these uses, there is an effect that energy saving can be further promoted. In the case of a refrigerator, the motor drive device can be downsized, so that the internal volume can be increased, and a large-capacity refrigerator can be realized even in a space-saving manner. In addition, in the case of an air conditioner such as an air conditioner, if the motor drive device can be reduced in size, the heat exchange area in the refrigeration cycle device of the outdoor unit is increased, so that the refrigeration cycle efficiency is improved and further energy saving can be promoted. There is. In the case of an electric vehicle driven by an AC power supply, the motor is usually driven using a converter circuit, a large-capacity electrolytic capacitor, and an inverter circuit. However, according to the present invention, the converter circuit and the large-capacity electrolytic capacitor are not used. Since the motor drive device can be provided, it is possible to provide a motor drive device that can be downsized, has a long life, and has high reliability.

  Hereinafter, a matrix converter circuit and a motor drive device according to preferred embodiments of the present invention will be described with reference to FIGS.

Embodiment 1
FIG. 1 is a circuit diagram showing a configuration of a motor drive device using a bidirectional switch according to Embodiment 1 of the present invention. In FIG. 1, 1 is a single-phase AC power source, 2 is a matrix converter circuit, 3 is a motor, and 4 is a control unit. The matrix converter circuit 2 has a configuration using six bidirectional switch circuits 10 to 15. Here, each of the six bidirectional switch circuits 10 to 15 has the semiconductor switch elements 2a to 2c and 2g to 2i and the diodes 2d 'to 2f', 2j ', 2k' and 2m 'in antiparallel as shown in FIG. A switch circuit configured by connecting the semiconductor switch elements 2d to 2f, 2j, 2k, and 2m and the diodes 2a ′ to 2c ′ and 2g ′ to 2i ′ in reverse parallel to the switch circuit that is configured to be connected is connected in reverse series. Is. These bidirectional switch circuits are connected as shown in FIG. 1 with the bidirectional switch circuits 10, 12 and 14 as the upper arm and the bidirectional switch circuits 11, 13 and 15 as the lower arm. The bidirectional switch circuit 11, the bidirectional switch circuit 12 and the bidirectional switch circuit 13, and the bidirectional switch circuit 14 and the bidirectional switch circuit 15 are connected in series. A bridge circuit is configured.

  That is, the U-phase upper arm upper switch element connected to the U phase of the motor 3 and permitting conduction from the part A to the part B in the bidirectional switch circuit 10 on the upper arm side is connected to the parts 2a and 2a ′ 2d and 2d ′ are U-phase upper arm lower switch elements that allow conduction to A, and 2g are U-phase lower arm upper switch elements that allow conduction from part B to part C in the bidirectional switch circuit 11 on the lower arm side. And 2g ′ and U-phase lower arm lower switch elements that allow conduction from the part C to the part B are denoted by 2j and 2j ′. Similarly, the V-phase upper arm upper switch element that permits conduction from the portion D to the portion E in the bidirectional switch circuit 12 on the upper arm side connected to the V phase of the motor 3 is connected to the portions E from 2b and 2b ′. The V-phase upper arm lower switch element 2e and 2e 'permitting conduction to the part D, and the V-phase lower arm upper switch element permitting conduction from the part E to the part F in the bidirectional switch circuit 13 on the lower arm side. 2h and 2h ′, and the V-phase lower arm lower switch elements that allow conduction from the region F to the region E are denoted by 2k and 2k ′. Further, the W-phase upper arm upper switch element, which is connected to the W phase of the motor 3 and permits conduction from the part G to the part H in the bidirectional switch circuit 14 on the upper arm side, is provided as 2c and 2c ′, and from the part H to the part. 2f and 2f ′ are W-phase upper arm lower switch elements that allow conduction to G, and 2i are W-phase lower arm upper switch elements that allow conduction from part H to part I in the bidirectional switch circuit 15 on the lower arm side. 2i ′, and W-phase lower arm lower switch elements that allow conduction from the part I to the part H are 2m and 2m ′.

  Hereinafter, the operation of the motor drive device according to the present embodiment is compared with the operation of the motor drive device (FIG. 7) using the conventional inverter circuit using six unidirectional switch circuits 103a to 103f. explain.

  In FIG. 7, 101 is a single-phase AC power source, 102 is a rectifier circuit consisting of a diode bridge consisting of four diodes 121 to 124 and a capacitor 125, 103 is an inverter circuit, and 103a to 103f are currents from the upper side to the lower side, respectively. A unidirectional switch circuit in which current transistors 131 to 136 and diodes 137 to 142 are connected in antiparallel, 104 is a motor, and 105 is a DC power supply control unit. The DC power supply control unit 105 detects the driving state of the motor 104 by detecting the voltage input to the inverter circuit 103 or the current flowing through the motor 104, and the six unidirectional switch circuits 103a to 103f as much as possible to obtain a desired driving state. 6 control signals for PWM control are output. In these six control signals, when the phase of the motor 104 is U phase, V phase, and W phase, the switch element in the unidirectional switch circuit on the upper arm side and the lower side with respect to the terminal to which each phase is connected. Two control signals for controlling the switch elements in the unidirectional switch circuit on the arm side exist in each phase. For example, in order to control the U phase, the U phase upper arm switch element 103a and the U phase lower arm switch element 103d are controlled. In order to control the V phase, the V phase upper arm switch element 103b and the V phase lower arm switch element 103e are controlled. Similarly, the W-phase includes a W-phase upper arm switch element 103c and a W-phase lower arm switch element 103f.

  At this time, what kind of control signal is output by detecting the driving state of the motor 104 varies depending on the type of the motor 104 and how the motor 104 is to be driven. For example, if the motor 104 is an induction motor used in a compressor such as an air conditioner or a refrigerator, it is common to control the rotation speed of the compressor. Therefore, six PWM signals are output so that the rotation speed of the motor 104 becomes a desired value. At this time, the current of the motor 104 is detected and fine control is performed, so-called vector control may be performed to output the PWM signal, or according to a desired rotational speed based on a predetermined V / F pattern. The PWM signal may be output based on so-called V / F control for supplying the applied voltage to the motor 104. If the motor 104 is a brushless motor used in a compressor such as an air conditioner or a refrigerator, the rotation speed of the compressor is controlled and at the same time the motor current or the motor 104 is used without using a position detection element such as a Hall IC. Position sensorless control is also performed to detect the position from the terminal voltage. In the case of position sensorless control using the motor current, the current flowing through the motor 104 is detected, and the rotor rotation angle information of the motor 104 is estimated using a conventionally known position estimation algorithm, and according to the result. To output a PWM signal. Further, in the case of position sensorless control performed using the motor terminal voltage, the rotor rotation angle information of the motor 104 is obtained by detecting the terminal voltage of the motor 104 and detecting the rotor magnetic pole position of the motor 104 from the voltage. It estimates and outputs a PWM signal according to the result. As described above, the motor 104 is driven by PWM driving the six switch elements using DC voltage so that the motor 104 is in a desired driving state.

  On the other hand, when the bidirectional switch circuit according to the matrix converter circuit of the present invention is used, as is apparent from the configuration of the matrix converter circuit 2 in FIG. ) It is necessary to turn on and off a total of 12 switch elements. The operation of the control unit 4 for outputting the 12 on / off control signals will be described.

  Assuming that the voltage of the single-phase AC power supply 1 in FIG. 1 is Vs as shown in FIG. 1, twelve on / off control signals output from the control unit 4 when Vs takes a positive value and a negative value. Change the output. FIG. 2 is a detailed block diagram for explaining a method of generating a signal output from the control unit 4 shown in FIG. In FIG. 2, 5 is a voltage detection unit that detects the voltage value Vs supplied from the single-phase AC power supply 1, and 6 a, 6 b, and 6 c generate 12 on / off control signals based on the output from the voltage detection unit 5. 6a is for the U phase of the motor 3, 6b is for the V phase, and 6c is for the W phase.

  The DC power supply control unit 105 is the same as the DC power supply control unit shown in FIG. 7. The DC power supply control unit 105 outputs six control signals as shown in FIG. When six bidirectional switch circuits 10 to 15 are used, twelve control signals are required. Accordingly, in the present invention, the control signal regeneration unit 6a, By adding 6b and 6c, 12 control signals can be generated from 6 control signals, and a motor drive device using the matrix converter circuit 2 can be provided.

  First, the operation of the U-phase control signal regeneration unit 6a will be described. Since the operations of the V-phase control signal regeneration unit 6b and the W-phase control signal regeneration unit 6c are the same as the operations of the U-phase control signal regeneration unit 6a, description thereof will be omitted. The voltage detector 5 detects the voltage Vs of the single-phase AC power source 1 and outputs a logic signal of 1 if positive and 0 if negative. The logic signal, the control signal for the U-phase upper arm switch element 103a from the DC power supply control unit 105, and the control signal for the U-phase lower arm switch element 103d are input, and the four AND circuits 201 to 201 shown in FIG. 204 and the four output signals obtained by the four OR circuits 205 to 208 are respectively turned on / off control signal for the U-phase upper arm upper switch element 2a, on / off control signal for the U-phase lower arm lower switch element 2j, and U-phase lower arm 1 is output as an on / off control signal for the upper switch element 2g and an on / off control signal for the U-phase upper arm lower switch element 2d, and these four signals are connected to the U-phase of the motor 3 as shown in FIG. 2g and 2d), the series circuit of the U-phase bidirectional switches 10 and 11 can be controlled. The same control is applied to the V-phase and W-phase bidirectional switch series circuits, and the control from the V-phase control signal regeneration unit 6b and the W-phase control signal regeneration unit 6c, respectively. What is necessary is just to output four output signals to each two series circuit which comprises the bidirectional | two-way switches 12-15 of FIG. In this way, by configuring the control unit 4 in which the voltage detection unit 5 and the control signal regeneration units 6a, 6b, and 6c for each phase are newly provided in the DC power supply control unit 105 in the conventional motor drive device. A motor driving device using the single-phase AC power source 1 and the matrix converter circuit 2 can be provided.

  In the present embodiment, the control signal is generated and output using a logic circuit, but it goes without saying that the same function may be realized by a program using a microcomputer or the like. That is, the logic of the control signal regeneration units 6a, 6b, and 6c may be realized by a program, and 12 control signals may be generated and output by a microcomputer. When the conventional DC power supply control unit 105 is realized by a microcomputer, 12 control signals may be created by adding a logic circuit as shown in FIG.

<< Embodiment 2 >>
Next, a motor drive device according to Embodiment 2 of the present invention will be described. The present embodiment is realized by the circuit configuration shown in FIG. 1 as the overall configuration as in the first embodiment, but the control unit 4 performs a circuit configuration and operation different from those of the first embodiment. It is. FIG. 3 is a detailed block diagram of the control unit 4 for explaining the operation of the control unit 4 according to the present embodiment. In addition to the six control signals used in the first embodiment, the control unit 4 in the present embodiment determines whether the motor current is positive or negative, that is, positive when the current flows from the matrix converter circuit 2 to the motor, and from the motor to the matrix converter circuit 2. When the flow is negative, twelve control signals are output by further using positive / negative information of the motor current. The U-phase control signal regeneration unit 6d outputs a signal from the voltage detection unit 5, a signal for outputting the sign of the U-phase motor current (U-phase current), a control signal for the U-phase upper arm switch element 103a, and U Using the control signal of the lower arm switch element 103d, a control signal for driving the bidirectional switch series circuits 10 and 11 connected to the U phase is output according to the logic circuit shown in FIG. The V-phase control signal regeneration unit 6e and the W-phase control signal regeneration unit 6f can also be realized with the same logic circuit configuration as the U-phase control signal regeneration unit 6d described above. Since it is the same structure, the internal block diagram and description are abbreviate | omitted.

  As described above, the control unit 4 that outputs the 12 on / off control signals for controlling the matrix converter circuit 2 can be realized, whereby a motor driving device using the single-phase AC power source 1 and the matrix converter circuit 2 can be realized. Can be provided.

  Although the present embodiment has been described as generating and outputting a control signal using a logic circuit, a similar function can be realized by a program using a microcomputer or the like. The truth table that correlates the input signal and the output signal at that time is as shown in (Table 1) or (Table 2).

  For example, when the motor current I is positive, reference is made to (Table 1). First, it is determined whether the voltage Vs of the single-phase AC power supply 1 is positive or negative. Further, it can be realized by a microcomputer so as to determine whether the control signal of the upper arm switch element is on or off and determine the on / off state of each of the four switch elements. In Table 1, “-”, which is not written as ON or OFF, means that either ON or OFF may be used. Therefore, either output may be performed in this case. When the motor current I is negative, reference is made to (Table 2). First, it is determined whether the voltage Vs of the single-phase AC power supply 1 is positive or negative. Further, it can be realized by a microcomputer so as to determine whether the control signal of the lower arm switch element is on or off and determine the on / off state of each of the four switch elements. By preparing such a truth table, twelve necessary on / off control signals can be created. When the motor current I is positive, the U-phase lower arm (103d) command is not used. Similarly, when the motor current I is negative, the U-phase upper arm (103a) command is not used.

<< Embodiment 3 >>
Next, a motor drive device according to Embodiment 3 of the present invention will be described. As in the first embodiment, the present embodiment is realized by the circuit configuration shown in FIG. FIG. 4 is a block diagram of the control unit 4 in the motor drive apparatus according to the third embodiment of the present invention. In FIG. 4, reference numeral 105a denotes a pulsating direct current control unit, which is the same as the pulsating direct current control unit 105a of FIG. In other words, the third embodiment replaces the DC power supply control unit 105 with the pulsating DC control unit 105a in the configuration of the first embodiment (FIGS. 1 and 2) already described, and the others are the first embodiment ( By adopting the same circuit configuration or logical configuration as in FIG. 2), the motor 3 can be driven at a desired rotational speed. In FIG. 9, the pulsating direct current control unit 105 a can output a frequency higher than the pulsating direct current frequency to the motor 104 when the input voltage of the inverter circuit 103 configured by a unidirectional switch circuit is a pulsating direct current. This is a conventional technique in which the rotational speed of 104 is not limited by the frequency of the pulsating direct current. 9, the switching operation of the inverter circuit 103 controlled by the pulsating direct current control unit 105a performs a switching operation equivalent to the motor control device in FIG. 1 using the control unit 4 shown in FIG. That is, the functions of the control signal regeneration units 6a to 6c are the operations of the upper arm upper switch, the upper arm lower switch, the lower arm upper switch, and the lower arm lower switch in each phase when the AC Vs is positive and negative. Therefore, it is configured to be equivalent to the operation in the conventional inverter circuit 103 (FIG. 9). Therefore, it is obvious that the rotation speed of the motor 3 can be driven at a desired rotation speed without setting the upper limit of the frequency of the single-phase AC power supply 1 with the above-described configuration.

  4 is a circuit configuration or a logical configuration based on the first embodiment (FIG. 2), it may be a circuit configuration or a logical configuration based on the second embodiment (FIG. 3). That is, the control unit 105 may be a control unit in which the DC power supply control unit 105 in FIG. 3 is replaced with a pulsating DC control unit 105a.

<< Embodiment 4 >>
Next, a motor drive device according to Embodiment 4 of the present invention will be described. In this embodiment, SiC (silicon carbide) is used as a material in place of the conventional bidirectional switch circuits 2a to 2k and 2m using Si in the configuration shown in the first to third embodiments. This is an example of a motor drive device in which a matrix converter circuit 20 is configured using semiconductor switch elements 21 to 26. The configuration diagram is shown in FIG.

  Compared to the conventional semiconductor switch element made of Si, the semiconductor switch element made of SiC has a higher limit voltage (reverse breakdown voltage) at which the element breaks down when a reverse voltage is applied. Withstand pressure increases. In order to prevent element destruction when a reverse bias is applied to the element, a conventional semiconductor switch element made of Si is provided with diodes 41 and 42 in antiparallel with the semiconductor switch elements 31 and 32 as shown in FIG. Had to connect. However, since the semiconductor switch element made of SiC does not need to connect a diode in antiparallel, the bidirectional switch circuit 27 can be realized by the circuit shown in FIG. Therefore, by using SiC as the material of the semiconductor switch, the matrix converter circuit 20 can be realized with the configuration shown in FIG. This configuration eliminates the need for a diode, so that it is clear that the circuit loss can be reduced compared to a conventional bidirectional switch circuit made of Si.

  As mentioned above, although Embodiment 1 to Embodiment 4 were demonstrated, if this invention is applied to various product fields, a useful effect will be exhibited. Since the matrix converter circuit of the present invention and the motor drive device using the matrix converter circuit can be configured without using a rectifier circuit, the kinetic energy of the motor can be regenerated in the single-phase AC power supply. In a motor drive device for consumer use, especially in the case of a washing machine or a dryer, the kinetic energy is large. Therefore, if the present invention is applied to the motor drive device for these uses, the kinetic energy can be regenerated to the single-phase AC power supply, so that the energy saving can be further promoted. Further, when the present invention is applied to a refrigerator, the motor drive device can be downsized to increase the internal volume, and there is an effect that a large-capacity refrigerator can be realized even in a space-saving manner. In addition, when the present invention is applied to an air conditioner such as an air conditioner, if the motor drive device can be reduced in size, the heat exchange area in the refrigeration cycle device of the outdoor unit is increased, so that the refrigeration cycle efficiency is improved. There is an effect that energy saving can be promoted. In the case of an electric vehicle driven by an AC power supply, the motor is usually driven using a converter circuit, a large-capacity electrolytic capacitor, and an inverter circuit. However, by applying the present invention, the converter circuit and the large-capacity electrolytic Since a motor drive device that does not use a capacitor can be provided, it is possible to provide a motor drive device that can be downsized, has a long life, and has improved reliability.

  The present invention can provide a motor driving device capable of driving a three-phase motor using a matrix converter circuit directly connected to a single-phase AC power source without going through a diode bridge or the like, and can be reduced in size and consumed. It is suitable for use in washing machines, dryers, refrigerators, air conditioners, electric cars, and the like equipped with motor drive devices that require electric power.

1 is a circuit diagram showing a configuration of a motor drive device using a bidirectional switch circuit according to a first embodiment of the present invention. The block diagram which shows the detail of the control part of Embodiment 1 which concerns on this invention The block diagram which shows the detail of the control part of Embodiment 2 which concerns on this invention The block diagram which shows the detail of the control part of Embodiment 3 which concerns on this invention FIG. 5 is a block diagram showing a motor drive device according to a fourth embodiment of the present invention. (A) is a bidirectional switch circuit diagram according to the fourth embodiment of the present invention. (B) is a bidirectional switch circuit diagram combining conventional unidirectional switches. A block diagram showing the configuration of a first prior art motor drive device that creates a direct current by full-wave rectifying the output from a single-phase AC power supply and drives a motor using a unidirectional switch circuit Configuration diagram of second prior art three-phase cycloconverter circuit in which high-frequency inverter circuit and bidirectional switch circuit are connected A block diagram showing a configuration of a third prior art motor driving apparatus that creates a pulsating DC by full-wave rectifying the output from a single-phase AC power supply and drives a motor using a unidirectional switch circuit Waveform diagram of input voltage of inverter circuit in third prior art motor drive device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Single-phase alternating current power supply 2,20 Matrix converter circuit 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2m Unidirectional switch 3 Motor 4 Control part 5 Voltage detection part 6a, 6b, 6c, 6d, 6e, 6f Control signal regeneration unit 101 Single-phase AC power supply 102, 102a Rectifier circuit 103 Inverter circuit 103a, 103b, 103c, 103j, 103k, 103m Unidirectional switch 104 Motor 105 DC power supply control unit 105a Pulsating DC Control unit 106 DC power source 107 High frequency inverter circuit 108 Matrix converter circuit

Claims (7)

A first bidirectional switch series circuit in which a first bidirectional switch and a second bidirectional switch are connected in series;
A second bidirectional switch series circuit in which a third bidirectional switch and a fourth bidirectional switch are connected in series;
In a matrix converter circuit in which a third bidirectional switch series circuit in which a fifth bidirectional switch and a sixth bidirectional switch are connected in series is connected in parallel with each other,
Each of the first to sixth bidirectional switches independently turns off conduction in both the forward direction and the reverse direction, turns on conduction in the forward direction or the reverse direction, and switches in either the forward direction or the reverse direction. 4. A matrix converter circuit characterized by enabling four operation states in which conduction is also on. A matrix converter circuit according to claim 1;
A control unit that outputs a control signal for controlling the first to sixth bidirectional switches constituting the matrix converter circuit;
A three-phase motor is connected to an intermediate connection point of the first bidirectional switch series circuit, an intermediate connection point of the second bidirectional switch series circuit, and an intermediate connection point of the third bidirectional switch series circuit;
A motor driving apparatus comprising a single-phase AC power source connected to the parallel connection point of the first to third bidirectional switch series circuits as a power source for driving the three-phase motor. The control unit determines a conduction operation of each of the first to sixth bidirectional switches based on an output voltage of the single-phase AC power supply, and outputs a control signal based on the determination. The motor drive device according to claim 2. The control unit determines a conduction operation of each of the first to sixth bidirectional switches based on a direction of a current flowing through the three-phase motor, and outputs a control signal based on the determination. The motor drive device according to claim 2 or 3. The control unit determines the conduction operation of each of the first to sixth bidirectional switches so that the rotation speed of the three-phase motor continuously changes, and outputs a control signal based on the determination. The motor drive device according to claim 2, wherein the motor drive device is a motor drive device. 2. The matrix converter circuit according to claim 1, wherein SiC (silicon carbide) is used as a material of the first to sixth bidirectional switches. 6. The motor driving apparatus according to claim 2, wherein SiC (silicon carbide) is used as a material of the first to sixth bidirectional switches.

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