JP5590106B2 - Matrix converter - Google Patents

Description

  The disclosed embodiments relate to a matrix converter.

  Matrix converters are attracting attention as new power converters because they can suppress harmonic currents and effectively use regenerative power. Such matrix converters include a plurality of bidirectional switches that connect each phase of the AC power source and each phase of the rotating electrical machine, and perform power conversion by controlling these bidirectional switches.

  In this type of matrix converter, a technique is known in which the power conversion operation is stopped when the AC power supply becomes a low voltage for some reason. For example, there is a technique for stopping power supply to the motor when the AC power source becomes a low voltage while the motor is driven by controlling each phase voltage of the AC power source with a bidirectional switch ( For example, see Patent Document 1).

JP-A-2005-287200

  However, in a matrix converter having a rotating electrical machine as a load, it is desirable to continue the power conversion operation without stopping even when the AC power supply becomes a low voltage.

  One aspect of the embodiments has been made in view of the above, and an object of the present invention is to provide a matrix converter capable of continuing the power conversion operation even when the AC power supply becomes a low voltage.

  A matrix converter according to an aspect of the embodiment includes a plurality of bidirectional switches and a control unit. The plurality of bidirectional switches connect each phase of the AC power source and each phase of the rotating electrical machine. The control unit controls the plurality of bidirectional switches to perform power conversion control between the AC power supply and the rotating electrical machine. Further, the control unit individually controls on / off of each of the plurality of unidirectional switching elements constituting the bidirectional switch using 120 ° energization control and PWM control individually.

  According to one aspect of the embodiment, it is possible to provide a matrix converter that can continue the power conversion operation even when the AC power supply becomes a low voltage.

FIG. 1 is a diagram illustrating a configuration example of a matrix converter according to the embodiment. FIG. 2 is a diagram illustrating a configuration example of the bidirectional switch illustrated in FIG. 1. FIG. 3 is a diagram illustrating an example of a specific configuration of the second drive control unit illustrated in FIG. 1. FIG. 4 is a diagram illustrating an example of the relationship between the grid reactive current command and the grid voltage value. FIG. 5 is a diagram showing a current source inverter model. FIG. 6 is a diagram showing the relationship between the system phase and the switch drive signal of the converter. FIG. 7 is a diagram illustrating an example of a specific configuration of the system pulse pattern generator. FIG. 8 is a diagram illustrating an example of the operation of the system pulse pattern generator. FIG. 9 is a diagram illustrating a configuration of a modulated wave signal generator according to the first modification. FIG. 10 is a diagram illustrating a configuration of an R-phase drive signal generator according to the second modification. FIG. 11 is a diagram illustrating the relationship between the generator phase and the switch drive signal of the inverter. FIG. 12 is a diagram illustrating a configuration example of the power conversion unit illustrated in FIG. 1.

  Hereinafter, embodiments of a matrix converter disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

  FIG. 1 is a diagram illustrating a configuration example of a matrix converter according to the embodiment. In the following embodiments, a matrix converter that converts the generated electric power of a rotating electrical machine that is an AC generator (ACG) and supplies it to an AC power source will be described as an example. However, the rotating electrical machine is not limited to an AC generator, An AC motor may be used. Moreover, although an electric power system | strain (Grid) is mentioned as an example and demonstrated as an alternating current power supply, an alternating current power supply is not restricted to this.

  As shown in FIG. 1, a matrix converter 1 according to the embodiment is provided between a three-phase AC power system 2 and a rotating electrical machine 3, and performs power conversion between the power system 2 and the rotating electrical machine 3. In the following, an example in which a synchronous generator is used as an example of the rotating electrical machine 3 will be described.

A position detector 4 for detecting the rotational position of the rotating electrical machine 3 is provided on the rotating shaft of the rotating electrical machine 3, and the rotational position θ _G of the rotating electrical machine 3 detected by the position detector 4 is sent to the matrix converter 1. Entered.

  The matrix converter 1 includes a power conversion unit 10, an LC filter 11, a current detection unit 12, a voltage detection unit 13, a power failure detection unit 14, and a control unit 15. The matrix converter 1 includes system side terminals Tr, Ts, Tt and generator side terminals Tu, Tv, Tw. The power system 2 is connected to the system side terminals Tr, Ts, Tt, and the generator side terminals Tu, The rotating electrical machine 3 is connected to Tv and Tw.

  The power conversion unit 10 includes a plurality of bidirectional switches Sw1 to Sw9 that connect the R phase, S phase, and T phase of the power system 2 to the U phase, V phase, and W phase of the rotating electrical machine 3. Prepare. The bidirectional switches Sw <b> 1 to Sw <b> 3 are bidirectional switches that connect the R phase, S phase, and T phase of the power system 2 and the U phase of the rotating electrical machine 3, respectively. The bidirectional switches Sw4 to Sw6 are bidirectional switches that connect the R phase, the S phase, and the T phase of the power system 2 and the V phase of the rotating electrical machine 3, respectively. The bidirectional switches Sw7 to Sw9 are bidirectional switches that connect the R phase, the S phase, and the T phase of the power system 2 and the W phase of the rotating electrical machine 3, respectively.

  The bidirectional switches Sw1 to Sw9 have a configuration as shown in FIG. 2, for example. FIG. 2 is a diagram illustrating a configuration example of each of the bidirectional switches Sw1 to Sw9. As shown in FIG. 2, each of the bidirectional switches Sw <b> 1 to Sw <b> 9 includes a series connection body composed of a unidirectional switching element 31 and a diode 33, and a series connection body composed of a unidirectional switching element 32 and a diode 34. It is configured to be connected in parallel.

  As the unidirectional switching elements 31 and 32, for example, a semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) is used. The energization direction can be controlled by individually turning on / off the unidirectional switching elements 31 and 32 constituting the bidirectional switches Sw1 to Sw9.

  Note that the bidirectional switches Sw1 to Sw9 are not limited to the configuration shown in FIG. For example, the bidirectional switches Sw1 to Sw9 may be configured such that the unidirectional switching elements 31, 32 are respectively reverse blocking type switching elements, and these switching elements are connected in parallel in opposite directions. The structure shown may be sufficient.

  The LC filter 11 is provided between the R phase, S phase, and T phase of the power system 2 and the power conversion unit 10, and suppresses the influence of noise from the power conversion unit 10 to the power system 2. Specifically, the LC filter 11 includes three reactors and three capacitors, and removes high-frequency components (PWM components) caused by switching of the bidirectional switches Sw1 to Sw9 that constitute the power conversion unit 10. Thereby, the output to the electric power grid | system 2 of the high frequency component which the electric power conversion part 10 generate | occur | produces can be suppressed. Note that the LC filter 11 is not limited to the configuration illustrated in FIG. 1, and may have a configuration in which no reactor is provided, for example.

  Note that one end of each of the three reactors is connected to the power system 2 side between the R phase, S phase, and T phase sides of the power system 2 and the power conversion unit 10, and the other end of the three reactors is a power conversion unit. 10 side connected. The three capacitors are connected between the other ends of two different reactors.

  The current detection unit 12 is provided between the power system 2 and the LC filter 11, and the current value Ir of the current flowing between the R phase, S phase, and T phase of the power system 2 and the LC filter 11, Is and It (hereinafter referred to as “system phase current values Ir, Is, It”) are detected. The current detection unit 12 is a current sensor that detects a current by using, for example, a Hall element that is a magnetoelectric conversion element.

  The voltage detection unit 13 is provided between the power system 2 and the power conversion unit 10, and voltage values Vr, Vs, Vt (hereinafter, “system phase”) of the R phase, S phase, and T phase of the power system 2. Voltage values Vr, Vs, Vt ”).

  The power failure detection unit 14 detects whether or not the voltage value Va of the system voltage (hereinafter referred to as the system voltage value Va) is equal to or less than the voltage value V1. When the system voltage value Va is equal to or lower than the voltage value V1, the power failure detection unit 14 determines that the power system 2 has failed and outputs a high level power failure detection signal Sd. On the other hand, when the system voltage value Va exceeds the voltage value V1, the power failure detection unit 14 determines that the power system 2 has not failed and outputs a low level power failure detection signal Sd.

The power failure detection unit 14 converts the system phase voltage values Vr, Vs, and Vt into orthogonal two-axis αβ components on fixed coordinates, and the system voltage value V _{α in the} α-axis direction and the system voltage value V in the β-axis direction. _{Find β} . Then, the power failure detection unit 14 calculates a square sum square root (= √ (V _α ² + V _β ² )) of the system voltage values V _α and V _{β and} sets the calculation result as the system voltage value Va.

  The control unit 15 includes a first drive control unit 20, a second drive control unit 21, and a switching unit 22. The first drive control unit 20 generates a voltage command based on a torque command that indicates the amount of torque generated by the rotating electrical machine 3, and generates a voltage corresponding to the voltage command by a known matrix converter PWM control method. Switch drive signals S <b> 1 to S <b> 18 to be output to the power converter 10 and output to the power converter 10.

  The voltage command is generated based on a known vector control law of a synchronous generator based on the torque command. In addition, the power conversion unit 10 uses the switch drive signals S1 to S18 to turn on the plurality of unidirectional switching elements 31 and 32 that respectively configure the plurality of bidirectional switches Sw1 to Sw9, and outputs a voltage according to the voltage command. Power conversion is performed by PWM control, and power conversion is performed in which the magnitude of the flowing current and the energization direction are determined by the relationship between the output voltage and the generated voltage.

  The second drive control unit 21 includes a plurality of unidirectional switching elements that respectively configure the plurality of bidirectional switches Sw1 to Sw9 based on the system phase voltage values Vr, Vs, Vt and the system phase current values Ir, Is, It. A part of 31 and 32 is turned on to perform power conversion control.

  The energization direction can be controlled by turning on some of the plurality of unidirectional switching elements 31 and 32 that respectively configure the plurality of bidirectional switches Sw1 to Sw9. Thereby, even in the case of a power failure in which the voltage of the power system 2 is extremely lower than the voltage of the rotating electrical machine 3, it is possible to avoid a large current continuously flowing between the rotating electrical machine 3 and the power system 2, and to control the current. The power conversion operation can be performed while performing.

  For example, the second drive control unit 21 has a unidirectional flow of current between any two phases on the power system 2 side among the unidirectional switching elements 31 and 32 constituting the plurality of bidirectional switches Sw1 to Sw9. The switching element is always turned on. In addition, the second drive control unit 21 has a unidirectional flow of current between any two phases on the rotating electrical machine 3 side among the unidirectional switching elements 31 and 32 constituting the plurality of bidirectional switches Sw1 to Sw9. The switching element is always turned on. By such control, current can continue to flow between any two phases of the power system 2 and between any two phases of the rotating electrical machine 3.

  In such control, the second drive control unit 21 turns on / off each of the plurality of unidirectional switching elements 31 and 32 constituting the bidirectional switches Sw1 to Sw9 by using 120 ° energization control and PWM control individually. By controlling, the occurrence of resonance phenomenon is suppressed. Details of this point will be described later with reference to FIGS.

  Based on the power failure detection signal Sd output from the power failure detection unit 14, the switching unit 22 selects and outputs the switch drive signals S1 to S18 to be output to the power conversion unit 10. Specifically, when the power failure detection signal Sd output from the power failure detection unit 14 is at a low level, the switching unit 22 uses the switch drive signals Sa1 to Sa18 generated by the first drive control unit 20 as switch drive signals. Output as S1 to S18.

  On the other hand, when the power failure detection signal Sd output from the power failure detection unit 14 is at a high level, the switching unit 22 switches the switch drive signals Sb1 to Sb18 generated by the second drive control unit 21 to the switch drive signals S1 to S18. Output as.

  Therefore, when the power system 2 becomes low voltage, the plurality of unidirectional switching elements 31 that configure the bidirectional switches Sw1 to Sw9 by the switch drive signals Sb1 to Sb18 generated by the second drive control unit 21, respectively. , 32 to turn on a part of the power conversion control. Thereby, even when the electric power grid | system 2 becomes a low voltage, power conversion operation | movement can be continued.

  As described above, the control unit 15 controls the plurality of unidirectional switching elements 31 and 32 constituting the bidirectional switches Sw1 to Sw9 together to perform power conversion control, and the bidirectional switches Sw1 to Sw9. The second control mode in which the power conversion control is performed by individually controlling a part of the plurality of unidirectional switching elements 31 and 32 constituting the power supply is executed.

  Specifically, in the control unit 15, the first drive control unit 20 executes the first control mode when the system voltage value Va that is the voltage of the AC power supply exceeds the voltage value V <b> 1 that is a predetermined value. On the other hand, when the system voltage value Va is equal to or lower than the voltage value V1, the second drive control unit 21 executes the second control mode.

  Hereinafter, an example of a specific configuration of the second drive control unit 21 will be specifically described. FIG. 3 is a diagram illustrating an example of a specific configuration of the second drive control unit 21. As shown in FIG. 3, the second drive control unit 21 includes an active current compensation unit 41, a reactive current compensation unit 42, and a pulse pattern generation unit 43.

  First, the active current compensator 41 will be described. The active current compensator 41 includes a PQ converter 51, a low-pass filter (LPF) 52, a system active current command unit 53, a subtractor 54, and a system effective current controller 55. The active current compensation unit 41 generates a system phase compensation value dθrst so that the system active current value matches the system active current command IPref, and outputs the generated system phase compensation value dθrst to the pulse pattern generation unit 43.

The PQ converter 51 converts the system phase current values Ir, Is, and It into two orthogonal αβ components orthogonal to each other on fixed coordinates, and the system current value I _{α in the} α-axis direction and the system current value I in the β-axis direction. _{Find β} . Further, the PQ converter 51 converts the components of the αβ axis coordinate system into components of a rotating coordinate system that rotates in accordance with the voltage phase θrst of the power system 2 (hereinafter referred to as “system phase θrst”). The system active current IP and the system reactive current IQ are obtained.

For example, the PQ converter 51 calculates the system active current IP and the system reactive current IQ by performing the calculation of the following formula (1).

  The LPF 52 removes the high frequency component from the system effective current IP and outputs the result to the subtractor 54. Thereby, the influence by the high frequency component is removed from the system effective current IP.

  The subtractor 54 subtracts the output of the LPF 52 from the system active current command IPref output from the system active current command unit 53, thereby obtaining a system active current deviation that is a deviation between the system active current command IPref and the system effective current IP. Calculate and output to the grid active current controller 55.

  The grid active current controller 55 is composed of, for example, a PI (proportional integral) controller, and generates a grid phase compensation value dθrst by performing a proportional integral calculation so that the grid active current deviation becomes zero. Here, the grid active current command IPref is set to zero, and the grid active current controller 55 generates the grid phase compensation value dθrst so that the grid active current IP becomes zero.

  Next, the reactive current compensation unit 42 will be described. The reactive current compensation unit 42 includes a low pass filter (LPF) 61, a system reactive current command device 62, a subtractor 63, and a system reactive current controller 64. The reactive current compensation unit 42 generates the generator phase correction value dθuvw so that the system reactive current value matches the system reactive current command IQref, and outputs the generated generator phase correction value dθuvw to the pulse pattern generation unit 43. To do.

  The subtractor 63 subtracts the output of the LPF 61 from the system reactive current command IQref output from the system reactive current command unit 62, thereby obtaining a system reactive current deviation that is a deviation between the system reactive current command IQref and the system reactive current IQ. Calculate and output to the system reactive current controller 64.

  The grid reactive current controller 64 is constituted by, for example, a PI controller, and generates a generator phase correction value dθuvw by performing a proportional-integral calculation so that the grid reactive current deviation becomes zero. The system reactive current command IQref can be set to a value corresponding to the system voltage value Va, for example.

  FIG. 4 is a diagram illustrating an example of the relationship between the grid reactive current command IQref and the grid voltage value Va. As shown in FIG. 4, the grid reactive current command device 62 has a grid voltage value Va of the grid voltage value Va in a region where the grid voltage value Va exceeds the voltage value V2 that is the second threshold and is equal to or less than the voltage value V1 that is the first threshold. A system reactive current command IQref that decreases linearly with increase is generated.

  In addition, the system reactive current command device 62 has a maximum value when the system voltage value Va is equal to or less than the voltage value V2 that is the second threshold value, and a system that has a zero value in a region that exceeds the voltage value V1 that is the first threshold value. A reactive current command IQref is generated. Note that the relationship between the grid reactive current command IQref and the grid voltage value Va is not limited to the example shown in FIG. 4, and may be a different relationship.

Next, the pulse pattern generation unit 43 shown in FIG. 3 will be described. The pulse pattern generation unit 43 drives the bidirectional switches Sw1 to Sw9 based on the system phase voltage values Vr, Vs, Vt, the rotational position θ _G , the system phase compensation value dθrst, the generator phase correction value dθuvw, and the power failure detection signal Sd. Switch drive signals S1 to S18 to be generated are generated.

  The pulse pattern generation unit 43 includes a system frequency detector 70, a holder 71, an integrator 72, an adder 73, a generator phase generator 74, and an adder 75. The pulse pattern generation unit 43 includes a system pulse pattern generator 76, a generator pulse pattern generator 77, a GeGr switch drive signal generator 78, and a GrGe switch drive signal generator 79.

  The system frequency detector 70 is, for example, a PLL (Phase Locked Loop), and outputs a system frequency frst synchronized with the voltage frequency of the power system 2 based on the system phase voltage values Vr, Vs, and Vt.

  The holder 71 holds the system frequency frst output from the system frequency detector 70 at the timing when the power failure detection signal Sd changes from the Low level to the High level, and at the timing when the system frequency changes from the High level to the Low level. Release the holding of frst.

  The integrator 72 integrates the system frequency frst output from the holder 71 to generate the system phase θrst, and outputs the system phase θrst to the active current compensator 41 and the adder 73. The adder 73 adds the system phase compensation value dθrst to the system phase θrst to generate the system correction phase θrst ′, and outputs the generated system correction phase θrst ′ to the system pulse pattern generator 76.

Generator phase generator 74, by multiplying the number of pole pairs of the rotary electric machine 3 to the rotational position theta _G, generates a generator phase Shitauvw, and outputs it to the adder 75. The adder 75 adds the generator phase correction value dθuvw to the generator phase θuvw to generate the generator correction phase θuvw ′, and outputs the generated generator correction phase θuvw ′ to the generator pulse pattern generator 77.

  The pulse pattern generation unit 43 generates the switch drive signals S1 to S18 using the current source inverter model shown in FIG. FIG. 5 is a diagram showing a current source inverter model.

  A current source inverter model 80 shown in FIG. 5 is a model including a converter 81 and an inverter 82. Converter 81 is composed of a plurality of switching elements that are full-bridge connected to the R phase, S phase, and T phase of power system 2. Each switching element of the converter 81 is driven by switch drive signals Srp, Ssp, Stp, Srn, Ssn, Stn (hereinafter referred to as “switch drive signals Srp to Stn”).

  The inverter 82 is composed of a plurality of switching elements connected in full bridge to the U phase, V phase, and W phase of the rotating electrical machine 3. Each switching element of the inverter 82 is driven by a switch drive signal Sup, Svp, Swp, Sun, Svn, Swn (hereinafter referred to as “switch drive signals Sup to Swn”).

  The system pulse pattern generator 76 has a pattern of switch drive signals Srp to Stn of the converter 81 that supplies a current of 120 ° with respect to the system phase θrst, and the switch drive signal Srp according to the system correction phase θrst ′. ~ Stn is generated. FIG. 6 is a diagram showing the relationship between the system phase θrst and the switch drive signals Srp to Stn, and shows the relationship between the two for flowing a 120 ° energization current advanced by 90 ° with respect to the system phase θrst. .

  The system correction phase θrst ′ is generated by adding the system phase compensation value dθrst obtained so that the system active current IP becomes zero to the system phase θrst. Therefore, the system pulse pattern generator 76 generates the switch drive signals Srp to Stn based on the system correction phase θrst ′ as shown in FIG. It is possible to pass a reactive current with zero.

  The system pulse pattern generator 76 generates the switch drive signals Srp to Stn so as to always turn on the switching element that allows current to flow between any two phases on the power system 2 side. For example, when 0 ° ≦ θrst <30 ° and 330 ° ≦ θrst <360 °, the switch drive signals Stn and Ssp are at the high level, and the others are at the low level. Thereby, a current flows between the T phase and the S phase.

  Similarly, when it is in a range of 30 ° ≦ θrst <90 °, the switch drive signals Srn and Ssp are at a high level, and a current flows between the R phase and the S phase. In the case of 90 ° ≦ θrst <150 °, the switch drive signals Srn and Stp are at a high level, and a current flows between the R phase and the T phase. When it is in the range of 150 ° ≦ θrst <210 °, the switch drive signals Ssn and Stp are at the high level, and a current flows between the S phase and the T phase.

  When in the range of 210 ° ≦ θrst <270 °, the switch drive signals Ssn and Srp are at a high level, and a current flows between the S phase and the R phase. In the case of 270 ° ≦ θrst <330 °, the switch drive signals Stn and Srp are at a high level, and a current flows between the T phase and the R phase. Thus, the system pulse pattern generator 76 generates a pulse pattern so that a current having a phase advanced by 90 ° with respect to the system phase θrst flows.

  In the case where 120 ° energization control is performed on the converter 81 such that a current whose phase is advanced by 90 ° from the voltage waveform flows between any two phases on the power system 2 side, the resonance of the LC filter 11 is applied to the flowing current. A frequency component that matches the frequency may be included, which causes a resonance phenomenon. When such a resonance phenomenon occurs, distortion occurs in the waveform of the current or voltage that flows between any two phases on the power system 2 side.

  The pulse pattern generation unit 43 suppresses the occurrence of a resonance phenomenon by performing on / off control using 120 ° energization control and PWM control for each switching element driven by the switch drive signals Srp to Stn. .

  For example, as shown in FIG. 6, the system pulse pattern generator 76 of the pulse pattern generation unit 43 uses a pulse pattern for 120 ° energization control in which the switch drive signal Srn is at a high level in a range of 30 ° ≦ θrst <150 °. Is generated.

  In such a case, the system pulse pattern generator 76, for example, in the range of 0 ° ≦ θrst <30 °, the pulse width at which the switch drive signal Srn becomes a high level gradually increases as θrst approaches 30 °. A pulse pattern for control is generated. Further, the system pulse pattern generator 76 is used for PWM control in a range of 150 ° ≦ θrst <180 °, and the width of the pulse at which the switch drive signal Srn becomes a high level gradually decreases as θrst approaches 180 °. The pulse pattern is generated.

  The system pulse pattern generator 76 generates a 120 ° energization pulse pattern and a PWM control pulse pattern for the other switch drive signals Ssn, Stn, Srp, Ssp, Stp as shown in FIG. Generate in the same way.

  The pulse pattern generation unit 43 generates the switch drive signals S1 to S18 based on the switch drive signals Srp to Stn and the switch drive signals Sup to Swn generated by the generator pulse pattern generator 77 described in detail later. Generate. Thereby, since the waveform of the electric current sent between any two phases by the side of the electric power grid | system 2 can be brought close to a sine waveform, generation | occurrence | production of a resonance phenomenon can be suppressed.

  Here, an example of a specific configuration of the system pulse pattern generator 76 that generates the switch drive signals Srp to Stn will be described with reference to FIGS. 7 and 8. FIG. 7 is a diagram illustrating an example of a specific configuration of the system pulse pattern generator 76, and FIG. 8 is a diagram illustrating an example of the operation of the system pulse pattern generator 76.

  As shown in FIG. 7, the system pulse pattern generator 76 includes a timer 91, phase shifters 761, 762, an R-phase drive signal generator 90a, an S-phase drive signal generator 90b, and a T-phase drive signal generator. And a drive signal generator 90c.

  The timer 91 measures the time from when the power failure detection signal Sd becomes High level. The timer 91 measures time based on an operation clock of a processor (not shown), and uses the measured time for the R-phase drive signal generator 90a, the S-phase drive signal generator 90b, and the T-phase drive signal generation. Output to the device 90c.

  The phase shifter 761 adds a phase of 120 ° to the system correction phase θrst ′ input from the adder 73 (see FIG. 3), and outputs the result to the S-phase drive signal generator 90b. Further, the phase shifter 762 adds a phase of 240 ° to the system correction phase θrst ′ input from the adder 73 (see FIG. 3), and outputs the result to the T-phase drive signal generator 90c. The system correction phase θrst ′ is input from the adder 73 (see FIG. 3) to the R-phase drive signal generator 90a.

  The R-phase drive signal generator 90a generates switch drive signals Srp and Srn for controlling the current flowing to the R-phase of the electric power system 2 to generate a GeGr switch drive signal generator 78 and a GrGe switch drive signal generator 79 ( (See FIG. 3).

  The S-phase drive signal generator 90b generates switch drive signals Ssp and Ssn for controlling the current flowing to the S-phase of the power system 2 to generate a GeGr switch drive signal generator 78 and a GrGe switch drive signal generator 79 ( (See FIG. 3).

  The T-phase drive signal generator 90c generates switch drive signals Stp and Stn for controlling the current flowing to the T-phase of the electric power system 2 to generate a GeGr switch drive signal generator 78 and a GrGe switch drive signal generator 79 ( (See FIG. 3).

  Here, the S-phase drive signal generator 90b outputs a switch drive signal Ssn whose phase is delayed by 120 ° from the switch drive signal Srn and a switch drive signal Ssp whose phase is delayed by 120 ° from the switch drive signal Srp. The configuration is the same as that of the R-phase drive signal generator 90a.

  The T-phase drive signal generator 90c outputs a switch drive signal Stn that is 240 degrees behind the switch drive signal Srn and a switch drive signal Stp that is 240 degrees behind the switch drive signal Srp. The configuration is the same as that of the R-phase drive signal generator 90a.

  Therefore, here, the configuration and operation of the R-phase drive signal generator 90a will be described, and the components included in the S-phase drive signal generator 90b and the T-phase drive signal generator 90c will be described. The same reference numerals as those of the signal generator 90a are attached, and the description thereof is omitted.

  The R-phase drive signal generator 90 a includes a modulated wave signal generator 92, a carrier signal generator 93, and a comparator 94. The modulated wave signal generator 92 includes a sine wave generator 95 and an amplifier 96. The sine wave generator 95 generates a sine wave signal having a phase difference of 180 ° from the system correction phase θrst ′ input from the adder 73 (see FIG. 3), and outputs it to the amplifier 96. At this time, the sine wave generator 95 generates a sine wave signal whose amplitude varies between “−1” and “1” and outputs it to the amplifier 96.

  The amplifier 96 generates a modulated wave signal (see FIG. 8) by amplifying the amplitude of the modulated wave signal input from the sine wave generator 95, and outputs the modulated wave signal to the comparator 94.

  The carrier signal generator 93 includes a triangular wave generator 97 and an amplifier 98. The triangular wave generator 97 is a first triangular wave whose amplitude varies between “0” and “1” based on the time input from the timer 91 and the predetermined carrier frequency, as shown in FIG. Are output to the comparator 94 and the amplifier 98. As shown in FIG. 8, the amplifier 98 amplifies the first carrier signal by −1 to obtain a second carrier signal that is a triangular wave whose amplitude varies between “0” and “−1”. Generated and output to the comparator 94.

  The comparator 94 includes a first comparator 99 and a second comparator 100. The modulated wave signal is input from the modulated wave signal generator 92 to the non-inverting input of the first comparator 99, and the first carrier signal is input from the carrier signal generator 93 to the inverting input. The first comparator 99 sequentially compares the modulated wave signal with the first carrier signal, and the signal level of the modulated wave signal becomes a high level within a phase range larger than the signal level of the first carrier signal. A switch drive signal Srp is generated.

  Then, the first comparator 99 outputs the generated switch drive signal Srp to the GeGr switch drive signal generator 78 and the GrGe switch drive signal generator 79 (see FIG. 3). Here, the waveform of the modulated wave signal compared with the first carrier signal whose amplitude varies between “0” and “1” is a sine whose amplitude varies between “−1” and “1”. It is a sine wave waveform obtained by amplifying the amplitude of the wave signal by a factor of two. Therefore, the switch drive signal Srp is always at a high level in the range of 210 ° ≦ θrst <330 °, and becomes a pulse pattern for 120 ° energization control.

  In addition, in the range of 180 ° ≦ θrst <210 ° and the range of 330 ° ≦ θrst <360 °, the switch drive signal Srp is intermittently high in the range of the phase of the modulated wave signal larger than that of the first carrier signal. The level becomes a pulse pattern for PWM control.

  On the other hand, the second carrier signal is input from the carrier signal generator 93 to the non-inverting input of the second comparator 100, and the modulation wave signal is input from the modulation wave signal generator 92 to the inverting input. The second comparator 100 sequentially compares the second carrier signal and the modulated wave signal, and the signal level of the second carrier signal becomes a high level within a phase range larger than the signal level of the modulated wave signal. A switch drive signal Srn is generated.

  Then, the second comparator 100 outputs the generated switch drive signal Srn to the GeGr switch drive signal generator 78 and the GrGe switch drive signal generator 79 (see FIG. 3). Thus, the switch drive signal Srn is always at a high level in the range of 30 ° ≦ θrst <150 °, and becomes a pulse pattern for 120 ° energization control.

  In addition, in the range of 0 ° ≦ θrst <30 ° and 150 ° ≦ θrst <180 °, the switch drive signal Srn is intermittently high in the range where the second carrier signal is larger in phase than the modulation wave signal. The level becomes a pulse pattern for PWM control.

  As described above, the R-phase drive signal generator 90a includes the switch drive signals Srp and Srn for performing the 120 ° energization control, and the switch drive signals Srp and Srn for performing the PWM control before and after performing the 120 ° energization control. And generate

  The carrier signal generator 93 shown in FIG. 7 may be provided in any one of the R-phase drive signal generator 90a, the S-phase drive signal generator 90b, and the T-phase drive signal generator 90c. . For example, the carrier signal generator 93 may be selectively provided in the R-phase drive signal generator 90a. In this case, the carrier signal generator 93 provided in the R-phase drive signal generator 90a causes the first carrier signal and the first carrier signal to be supplied to the comparator 94 of the S-phase drive signal generator 90b and the T-phase drive signal generator 90c. 2 carrier signals.

  Also, an S-phase drive signal generator generates a signal obtained by shifting the phase of the modulated wave signal output from the modulated wave signal generator 92 of the R-phase drive signal generator 90a by 120 ° and a signal shifted by 240 °. 90b and the T-phase drive signal generator 90c may be supplied to the comparator 94, respectively. With this configuration, the phase shifters 761 and 762 can be omitted, and the modulation wave signal generator 92 can be omitted from the S-phase drive signal generator 90b and the T-phase drive signal generator 90c. .

  The configuration of the system pulse pattern generator 76 shown in FIG. 7 is an example, and the configuration of the modulated wave signal generator 92, the R-phase drive signal generator 90a, the S-phase drive signal generator 90b, and the T-phase Various modifications can be further made to the configuration of the driving signal generator 90c. FIG. 9 is a diagram illustrating a configuration of a modulated wave signal generator 92a according to Modification 1. FIG. 10 is a diagram illustrating a configuration of an R-phase drive signal generator 90d according to Modification 2.

  As shown in FIG. 9, the modulated wave signal generator 92a according to the first modification includes a trapezoidal wave table 95a instead of the sine wave generator 95 (see FIG. 7). The trapezoidal wave table 95a is a table in which the amplitude is fixed to “1” or “−1” in the phase range in which 120 ° energization control is performed, and the trapezoidal wave that is linear in the phase range before and after performing 120 ° energization control is stored. It is. Then, the trapezoidal wave table 95a outputs a trapezoidal wave to the comparator 94 with a phase corresponding to the system correction phase θrst ′ input from the adder 73 (see FIG. 3).

  Similarly to the R-phase drive signal generator 90a shown in FIG. 7, the R-phase drive signal generator 90a performs switch drive signals Srp and Srn for performing 120 ° energization control and 120 ° energization control. Switch drive signals Srp and Srn for performing PWM control before and after can be generated.

  Thereby, since the waveform of the current flowing through the R phase can be made closer to a sine waveform, the occurrence of a resonance phenomenon can be suppressed. Therefore, distortion caused by a resonance phenomenon that occurs in the current and voltage waveforms can be reduced.

  Note that the trapezoidal wave stored by the trapezoidal wave table 95a has a fixed amplitude of “1” or “−1” in the phase range in which 120 ° energization control is performed, and in the phase range before and after the 120 ° energization control. 8 may be a curve approximating the slope of the corresponding portion in the modulated wave signal shown in FIG.

  As shown in FIG. 10, the R-phase drive signal generator 90d according to the second modification includes an Srp pulse table 101 and an Srn pulse table 102. The Srp pulse table 101 is a table that stores the switch drive signal Srp output from the first comparator 99 shown in FIG. The Srn pulse table 102 is a table that stores the switch drive signal Srn output from the second comparator 100 shown in FIG.

  The Srp pulse table 101 outputs the switch drive signal Srp with a phase corresponding to the input system correction phase θrst ′. The Srn pulse table 102 outputs the switch drive signal Srn with a phase corresponding to the input system correction phase θrst ′.

  As described above, the system pulse pattern generator 76 performs switch driving that performs on / off control using 120 ° energization control and PWM control for the switching element that controls the current flowing to each phase of the power system 2. A pulse pattern of the signals Srp to Stn is generated. As a result, the waveform of the current flowing through each phase of the power system 2 can be brought close to a sinusoidal waveform, so that the occurrence of the resonance phenomenon can be suppressed, and the distortion caused by the resonance phenomenon generated in the current and voltage waveforms. Can be reduced.

  Further, the system pulse pattern generator 76 generates a pulse pattern of switch drive signals Srp to Stn that performs PWM control before and after the switching element that controls the current flowing to each phase of the power system 2 is turned on by 120 ° control. . As a result, the waveform of the current flowing through each phase of the power system 2 can be made closer to the waveform of the sine wave more accurately.

  Further, the system pulse pattern generator 76 compares the first and second carrier signals shown in FIG. 8 with the modulated wave signal, so that the switch drive signals Srp to Stn for 120 ° energization control and PWM control are compared. Generate a pulse pattern.

  For this reason, the system pulse pattern generator 76 does not need to separately provide a processing unit that generates switch drive signals Srp to Stn for 120 ° energization control and switch drive signals Srp to Stn for PWM control. Therefore, according to the system pulse pattern generator 76, it is possible to reduce the distortion caused by the resonance phenomenon occurring in the current and voltage waveforms while suppressing an increase in circuit scale.

  Here, the case where PWM control is performed before and after performing 120 ° energization control has been described, but PWM control may be performed either before or after performing 120 ° energization control. By performing such control, it is possible to suppress the occurrence of a resonance phenomenon and to reduce the distortion caused by the resonance phenomenon that occurs in the current and voltage waveforms as compared with the case where PWM control is not performed.

  Returning to FIG. 3, the generator pulse pattern generator 77 generates switch drive signals Sup to Swn corresponding to the generator correction phase θuvw ′. Here, the relationship between the generator phase θuvw and the switch drive signals Sup to Swn will be described with reference to FIG. FIG. 11 is a diagram illustrating the relationship between the generator phase θuvw and the switch drive signals Sup to Swn.

  The generator pulse pattern generator 77 has a pattern of switch drive signals Sup to Swn of the inverter 82 that flows a current of 120 ° with respect to the generator phase θuvw, and the switch drive signal according to the generator correction phase θuvw ′. Sup to Swn are output.

  The generator correction phase θuvw ′ is obtained by adding the generator phase correction value dθuvw obtained so that the system reactive current deviation as a deviation becomes zero to the generator phase θuvw. Therefore, the generator pulse pattern generator 77 uses the generator correction phase θuvw ′ as a reference so that a current delayed by 90 ° −dθuvw flows with respect to the generator phase θuvw as shown in FIG. The switch drive signals Sup to Swn are output. As a result, a reactive current having a magnitude equal to the grid reactive current command IQref can be passed to the power grid 2 side.

  The generator pulse pattern generator 77 outputs switch drive signals Sup to Swn so as to always turn on a switching element that allows current to flow between any two phases on the rotating electrical machine 3 side. For example, when the ranges are 0 ° ≦ θuvw−dθuvw <30 ° and 330 ° ≦ θuvw−dθuvw <360 °, the switch drive signals Swp and Svn are at the high level, and the others are at the low level. Thereby, a current flows between the W phase and the V phase.

  Similarly, when it is in the range of 30 ° ≦ θuvw−dθuvw <90 °, the switch drive signals Sup and Svn are at a high level, and a current flows between the U phase and the V phase. When it is in the range of 90 ° ≦ θuvw−dθuvw <150 °, the switch drive signals Sup and Swn are at a high level, and a current flows between the U phase and the W phase. When in the range of 150 ° ≦ θuvw−dθuvw <210 °, the switch drive signals Svp and Swn are at a high level, and a current flows between the V phase and the W phase.

  When in the range of 210 ° ≦ θuvw−dθuvw <270 °, the switch drive signals Svp and Sun are at the high level, and a current flows between the V phase and the U phase. When 270 ° ≦ θuvw−dθuvw <330 °, the switch drive signals Swp and Sun are at a high level, and a current flows between the W phase and the U phase. In this way, the generator pulse pattern generator 77 generates a pulse pattern so that a current delayed by 90 ° −dθuvw flows with respect to the generator phase θuvw.

Based on the switch drive signals Srn, Ssn, Stn, Sup, Svp, and Swp, the GeGr switch drive signal generator 78 uses the following equation (2) to switch drive signals Sur, Sus, Sut, Svr, Svs, Svt, Swr, Sws, and Swt are generated.

  In the above formula (2), the switch drive signals Sur, Sus, Sut, Svr, Svs, Svt, Swr, Sws, Swt are from the rotary electric machine 3 side of the bidirectional switches Sw1 to Sw9 as shown in FIG. This is a signal for driving the unidirectional switching elements 31 and 32 for passing a current to the power system 2. FIG. 12 is a diagram illustrating a configuration example of the power conversion unit 10. In the configuration example of the power conversion unit 10 illustrated in FIG. 12, the configurations of the bidirectional switches Sw1 to Sw9 are different from the example illustrated in FIG. That is, the bidirectional switches Sw1 to Sw9 shown in FIG. 12 have a configuration in which the collectors of the unidirectional switching elements 31 and 32 and the diodes 33 and 34 in the bidirectional switches Sw1 to Sw9 shown in FIG. Even with such a connection configuration, the operations of the bidirectional switches Sw1 to Sw9 shown in FIG. 12 are the same as the operations of the bidirectional switches Sw1 to Sw9 shown in FIG.

The GrGe switch drive signal generator 79 uses the following formula (3) based on the switch drive signals Sun, Svn, Swn, Srp, Ssp, Stp, and uses the switch drive signals Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw are generated.

  In the above equation (3), the switch drive signals Sru, Ssu, Stu, Srv, Ssv, Stv, Srw, Ssw, and Stw rotate from the power system 2 side of the bidirectional switches Sw1 to Sw9 as shown in FIG. This is a signal for driving the unidirectional switching elements 31 and 32 for supplying a current to the electric machine 3 side.

  The switch drive signals Sur, Sru, Sus, Ssu, Sut, Stu, Svr, Srv, Svs, Ssv, Svt, Stv, Swr, Srw, Sws, Ssw, Swt, and Stw generated in this way are the switch drive signal S1. Are output from the pulse pattern generation unit 43 to the power conversion unit 10 in correspondence relationships shown in FIG.

  As a result, among the unidirectional switching elements 31 and 32 constituting the plurality of bidirectional switches Sw1 to Sw9, a current is passed between any two phases on the power system 2 side, and any one of the rotating electrical machine 3 side is provided. The unidirectional switching element that conducts current between the two phases is always turned on.

  In addition, 120 ° energization control and PWM control are individually used in combination with each of the unidirectional switching elements 31 and 32 constituting the plurality of bidirectional switches Sw1 to Sw9 by the switch drive signals S1 to S18. Control is performed. Thereby, since the waveform of the current flowing on the power system 2 side is brought close to a sine waveform, the occurrence of a resonance phenomenon is suppressed, and distortion of the current waveform and voltage waveform on the power system 2 side can be suppressed.

  Note that any one of the switch drive signals Srn, Ssn, and Stn is always at a high level, and any one of the switch drive signals Sup, Svp, and Swp is always at a high level. Therefore, any one of the unidirectional switching elements 31 and 32 constituting the plurality of bidirectional switches Sw1 to Sw9 is always turned on to flow a current from the power system 2 side to the rotating electrical machine 3 side.

  In addition, any one of the switch drive signals Sun, Svn, and Swn is always at a high level, and any one of the switch drive signals Srp, Ssp, and Stp is always at a high level. Therefore, any one of the unidirectional switching elements 31 and 32 configuring the plurality of bidirectional switches Sw1 to Sw9 is always turned on, and the unidirectional switching element that allows current to flow from the rotating electrical machine 3 side to the power system 2 side is always turned on.

  As described above, the control unit 15 of the matrix converter 1 according to the present embodiment includes the first drive control unit 20 and the second drive control unit 21. The first drive control unit 20 performs power conversion by voltage control performed by turning on both of the plurality of unidirectional switching elements 31 and 32 that respectively configure the plurality of bidirectional switches Sw1 to Sw9. On the other hand, the second drive control unit 21 performs power conversion by current control performed by turning on some of the plurality of unidirectional switching elements 31 and 32 that respectively configure the plurality of bidirectional switches Sw1 to Sw9.

  The matrix converter 1 performs power conversion control by the first drive control unit 20 when the voltage of the power system 2 exceeds a predetermined value. When the voltage of the power system 2 is equal to or lower than the predetermined value, the matrix converter 1 The drive control unit 21 performs power conversion control. Thereby, the matrix converter 1 can continue the power conversion operation while flowing the reactive current to the power system 2 side even when the power system 2 becomes a low voltage.

  Further, the second drive control unit 21 performs on / off control of each of the plurality of unidirectional switching elements 31 and 32 constituting the bidirectional switches Sw1 to Sw9 by using 120 ° energization control and PWM control individually. . As a result, the matrix converter 1 brings the current waveform of the current flowing to the power system 2 side closer to a sine waveform, so that the voltage waveform and the current waveform are changed by the resonance phenomenon with the LC filter 11 caused by the current flowing to the power system 2 side. It is possible to prevent distortion from occurring.

  In the power generation system, when the power system 2 becomes a low voltage due to a power failure or the like, there is a case where it is required to supply reactive power to the power system 2, and the matrix converter 1 according to the present embodiment meets this request. It becomes possible to respond appropriately.

  When a system reactive current command IQref that defines the magnitude of reactive power is transmitted from the manager of the power system 2, the system reactive current command IQref is output from the system reactive current command device 62 to the subtractor. May be. By doing in this way, the magnitude | size of the reactive current by the side of the electric power grid | system 2 can be set from the outside.

  Further, the second drive control unit 21 employs a current source inverter model 80 as a switching model. The converter 81 is provided with a 120 ° energization switching pattern for supplying a current advanced by 90 ° from the voltage waveform, and the inverter 82 has a phase 120 for supplying a reactive current having a magnitude corresponding to the system reactive current command IQref. ° Energized switching pattern is given. The switching pattern applied to the converter 81 and the switching pattern applied to the inverter 82 are combined and output as a switch drive signal for the unidirectional switching elements 31 and 32 constituting the bidirectional switches Sw1 to Sw9.

  As a result of such processing, the switch driving signal is output to the unidirectional switching elements 31 and 32 constituting the bidirectional switches Sw1 to Sw9, so that a reactive current having a magnitude corresponding to the system reactive current command IQref can be easily supplied to the power system 2. And it can be flowed with high accuracy.

  In the above-described embodiment, the power conversion unit 10 is driven using the 120 ° energization switching pattern, but the control method is not limited to the 120 ° energization switching pattern. That is, it is sufficient that the power conversion operation is continued while flowing the reactive current to the power system 2 side by performing the current control for individually controlling the unidirectional switching elements 31 and 32, and various modifications are possible.

  In the above-described embodiment, the rotary electric machine 3 is described as a synchronous generator, but the rotary electric machine 3 may be an induction generator. When the rotating electrical machine 3 is an induction generator, the matrix converter 1 is configured as follows, for example.

  After the power failure, the induction generator generates a generated voltage due to residual magnetic flux, and the position detector 4 detects the rotation speed of the induction generator. The control unit 15 sets the torque command for the induction generator to substantially zero in accordance with a known induction machine vector control law, generates a slip frequency command based on the torque command, and detects the rotational speed detected by the position detector 4. To generate an output frequency command.

  Then, the control unit 15 generates the generator phase θuvw by integrating the output frequency command, and generates the generator correction phase θuvw ′ by adding the generated generator phase θuvw to the generator phase correction value dθuvw. To do. By doing in this way, even if the electric power grid | system 2 becomes a low voltage, electric power conversion operation | movement can be continued, supplying a reactive current to the electric power grid | system 2 side.

  In the above-described embodiment, an example in which a generator is applied as the rotating electrical machine 3 has been described. However, an electric motor can also be applied as the rotating electrical machine 3, and even when the voltage of the power system 2 becomes a low voltage. The operation can be continued by the speed electromotive force of the electric motor.

  That is, when the voltage of the power system 2 becomes a low voltage, it is difficult to supply power from the power system 2 to the motor, but the rotor of the motor is in a rotating state while decelerating. Therefore, the operation can be continued by supplying the electromotive force generated by the rotation to the power system 2 as, for example, reactive power.

In the above-described embodiment, the configuration illustrated in FIG. 3 has been described as an example of the active current compensation unit 41. However, the active current compensation unit 41 may be configured using a table. That is, the active current compensator 41 is provided with a storage unit that stores a two-dimensional table indicating the relationship between the system active current IP and system reactive current IQ and the system phase compensation value dθrst, and the system phase current values Ir and Is are obtained from the table. , It may output the system phase compensation value dθrst. Alternatively, the system phase compensation value dθrst may be obtained and output by calculating dθrst = −tan ⁻¹ (IQ / IP).

  In the above-described embodiment, the configuration illustrated in FIG. 3 has been described as an example of the reactive current compensation unit 42. However, the reactive current compensation unit 42 may be configured using a table. That is, the reactive current compensation unit 42 is provided with a storage unit that stores a table indicating the relationship between the system reactive current command IQref and the generator phase correction value dθuvw, and the generator phase is determined based on the system reactive current command IQref from the table. The correction value dθuvw may be output.

  In the above-described embodiment, the system pulse pattern generator 76 can also generate the switch drive signals Srp to Stn that flow a 120 ° energization current delayed by 90 ° with respect to the system phase θrst. As a result, a reactive current having a delay of 90 ° and a system active current IP of zero can flow to the power system 2 side. Whether the reactive current caused by the 90 ° delay or the reactive current caused by the 90 ° advance is allowed to flow to the power system 2 side can be selected, for example, by setting to the system pulse pattern generator 76 from the outside.

  Further effects and modifications can be easily derived by those skilled in the art. Accordingly, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1 Matrix converter 2 Power system (AC power supply)
DESCRIPTION OF SYMBOLS 3 Rotating electrical machinery 10 Power conversion part 11 LC filter 12 Current detection part 13 Voltage detection part 14 Power failure detection part 15 Control part 20 1st drive control part 21 2nd drive control part 22 Switching part 90a, 90d Drive signal for R phase Generator 90b S-phase drive signal generator 90c T-phase drive signal generator 92 Modulated wave signal generator 93 Carrier signal generator 94 Comparator 95a Trapezoidal wave table 99 First comparator 100 Second comparator 101 Srp Pulse table 102 Srn pulse table

Claims (6)

A plurality of bidirectional switches for connecting each phase of the AC power source and each phase of the rotating electrical machine;
A control unit that controls the plurality of bidirectional switches to perform power conversion control between the AC power supply and the rotating electrical machine,
The controller is
Matrix converter and controlling the on / off by the PWM control of the plurality of pieces directional switching device before and after on the individual 120 ° conduction control each of the plurality of unidirectional switching elements constituting the bidirectional switch . A modulated wave signal that is larger than the magnitude of the carrier signal is generated during the 120 ° energization control period, and a switch drive signal that controls the one-way switching element is generated by comparing the modulated wave signal with the carrier signal. The matrix converter according to claim 1 , further comprising a drive signal generator. The matrix converter according to claim 2 , wherein the modulated wave signal is a sine wave signal or a trapezoidal wave signal. The drive signal generator is
A carrier signal generator for generating a first carrier signal and a second carrier signal having different polarities as the carrier signal;
A modulated wave signal generator for generating the modulated wave signal;
A first comparator that compares the first carrier signal and the modulated wave signal to generate a first switch drive signal;
A second comparator that compares the second carrier signal and the modulated wave signal to generate a second switch drive signal;
Matrix converter according to claim 2 or 3, characterized in that to control different said unidirectional switching element by the first switch drive signal and the second switch drive signal. The controller is
A first control mode for controlling the power conversion control by controlling a plurality of unidirectional switching elements constituting the bidirectional switch, and individually controlling a plurality of unidirectional switching elements constituting the bidirectional switch. matrix converter according to any one of claims 1-4, characterized in that performing by switching a second control mode in which the power conversion control. A voltage detector for detecting the voltage of the AC power supply;
The controller is
When the voltage of the AC power source exceeds a predetermined value, the power conversion control is performed in the first control mode, and when the voltage of the AC power source is equal to or lower than the predetermined value, the power is controlled according to the second control mode. 6. The matrix converter according to claim 5 , wherein conversion control is performed.

Images