Control circuit and three-phase power factor correction device

Abstract

To provide a control circuit that can reduce the burden on an operator when connecting a controlled device to a three-phase AC power supply, and a three-phase power factor correction device that includes the control circuit.SOLUTION: A control circuit A1 includes a two-phase conversion unit 121 that converts three-phase phase current signals Iu, Iv, and Iw detected from a controlled device (power factor correction circuit B) into a d-axis current signal Id and a q-axis current signal Iq on a rotating coordinate axis, a three-phase conversion unit 122 that converts a d-axis current control amount signal Xd and a q-axis current control amount signal Xq generated on the basis of the d-axis current signal Id and the q-axis current signal Iq, respectively, into three-phase current control amount signals Xu, Xv, and Xw on a stationary coordinate axis, and a phase rotation determination unit 15 that determines whether the phase rotation of the three-phase AC of the controlled device is forward or reverse. The two-phase conversion unit 121 and the three-phase conversion unit 122 change the transformation matrix used for conversion depending on whether the phase rotation is forward or reverse.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control circuit that converts three-phase detection signals into two-phase signals on a rotating coordinate axis for control, and to a three-phase power factor correction device that includes the control circuit. [Background technology]

[0002] In the control of various power conversion devices and the like, a control circuit is known that converts three-phase current detection signals, which detect three-phase AC current, into two-phase signals on a rotating coordinate axis and then performs control. For example, Patent Document 1 discloses an AC / DC bidirectional converter that performs such control. The control circuit of the AC / DC bidirectional converter converts three-phase current feedback signals detected by a current detector into a d-axis current feedback signal and a q-axis current feedback signal using a three-phase-two-phase current feedback calculator. The control circuit then converts a d-axis voltage command signal, which is calculated through control based on the d-axis current feedback signal, and a q-axis voltage command signal, which is calculated through control based on the q-axis current feedback signal, into three-phase voltage command signals using a two-phase-three-phase voltage command calculator. The three-phase-two-phase current feedback calculator and the two-phase-three-phase voltage command calculator perform calculations synchronized with the AC power source based on an electrical angle θ2 signal calculated from a power source voltage signal of the AC power source.

[0003] Another method is to input sine wave and cosine wave signals synchronized with the AC power supply to each calculator for coordinate transformation instead of the electrical angle θ2 signal. In this method, sine wave and cosine wave signals whose phase and frequency match the detected power supply voltage signal of the AC power supply are generated using, for example, a digital PLL (Phase-Locked Loop) circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-187082 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, portable equipment such as welding power supplies are used while being moved from one work location to another, so the power cable must be connected to a commercial power source each time. When connecting the power cable to the commercial power source, the three-phase rotation may be reversed. In this case, the power conversion device built into the equipment will not function properly because the coordinate conversion in the control circuit will not be performed correctly. Therefore, the power cable must be reconnected to the commercial power source to ensure the correct phase rotation. Both reconnecting the power cable to the commercial power source and checking the phase rotation using a phase rotation meter before connection are burdensome for the operator.

[0006] The present invention has been devised in light of the above circumstances, and has as its object to provide a control circuit that can reduce the burden on an operator when connecting a controlled device to a three-phase AC power supply, and a three-phase power factor correction device equipped with such a control circuit. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides the following technical means.

[0008] A control circuit provided by a first aspect of the present invention includes a two-phase conversion unit that converts three-phase detection signals that detect a three-phase AC of a controlled device into two-phase second detection signals on a rotating coordinate axis, a three-phase conversion unit that converts two-phase operation amount signals generated based on each of the two-phase second detection signals into three-phase second operation amount signals on a stationary coordinate axis, and a phase rotation determination unit that determines whether the phase rotation of the three-phase AC of the controlled device is forward or reverse, and the two-phase conversion unit and the three-phase conversion unit change the transformation matrix used for the conversion depending on whether the phase rotation is forward or reverse.

[0009] In a preferred embodiment of the present invention, the two-phase conversion unit includes a three-phase to two-phase conversion unit that converts the three-phase detection signals into two-phase third detection signals, and a rotational coordinate conversion unit that converts the two-phase third detection signals into the two-phase second detection signals. The three-phase conversion unit includes a stationary coordinate conversion unit that converts the two-phase operation amount signals into two-phase third operation amount signals on the stationary coordinate axes, and a two-phase to three-phase conversion unit that converts the two-phase third detection operation amount signals into the three-phase second operation amount signals. When the phase rotation is the forward rotation, the three-phase to two-phase conversion unit performs the conversion using a first conversion matrix, and the two-phase to three-phase conversion unit performs the conversion using a first inverse conversion matrix that is the inverse matrix of the first conversion matrix. When the phase rotation is the reverse rotation, the three-phase to two-phase conversion unit performs the conversion using a second conversion matrix, and the two-phase to three-phase conversion unit performs the conversion using a second inverse conversion matrix that is the inverse matrix of the second conversion matrix. The second conversion matrix is ​​a matrix obtained by exchanging the second and third columns of the first conversion matrix.

[0010] In a preferred embodiment of the present invention, the two-phase conversion unit includes a three-phase to two-phase conversion unit that converts the three-phase detection signals into two-phase third detection signals, and a rotating coordinate conversion unit that converts the two-phase third detection signals into the two-phase second detection signals, and the three-phase conversion unit includes a stationary coordinate conversion unit that converts the two-phase operation amount signals into two-phase third operation amount signals on the stationary coordinate axes, and a two-phase to three-phase conversion unit that converts the two-phase third detected operation amount signals into the three-phase second operation amount signals, and when the phase rotation is the forward rotation, the rotating coordinate conversion unit performs the conversion using a third transformation matrix, and the stationary coordinate conversion unit performs the conversion using a third inverse transformation matrix that is the inverse matrix of the third transformation matrix, and when the phase rotation is the reverse rotation, the rotating coordinate conversion unit performs the conversion using a fourth transformation matrix, and the stationary coordinate conversion unit performs the conversion using a fourth inverse transformation matrix that is the inverse matrix of the fourth transformation matrix, and the fourth transformation matrix is ​​the inverse matrix of the third transformation matrix.

[0011] In a preferred embodiment of the present invention, the phase rotation determination unit includes a first zero-cross detection unit that detects zero-cross timings at which a first-phase detection signal that detects a first phase of the three-phase AC of the controlled device switches from a negative value to a positive value, and a second zero-cross detection unit that detects zero-cross timings at which a second-phase detection signal that detects a second phase of the three-phase AC of the controlled device switches from a negative value to a positive value, and determines whether the phase rotation is forward rotation or reverse rotation based on at least a first detection result of the first zero-cross detection unit and a second detection result of the second zero-cross detection unit.

[0012] A three-phase power factor correction device provided by a second aspect of the present invention includes the control circuit provided by the first aspect of the present invention, and a power factor correction circuit controlled by the control circuit. [Effects of the Invention]

[0013] According to the present invention, the two-phase conversion unit and the three-phase conversion unit change the conversion matrix used for conversion depending on whether the phase rotation determination unit determines a forward rotation or a reverse rotation. Therefore, when a controlled device is connected to a three-phase AC power supply, the control circuit according to the present invention automatically applies a conversion matrix according to the phase rotation. This eliminates the need for an operator to worry about whether the phase rotation is forward or reverse when connecting the controlled device to a three-phase AC power supply. Furthermore, there is no need to reconnect the device. In this way, the control circuit according to the present invention can reduce the operator's burden when connecting the controlled device to a three-phase AC power supply.

[0014] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1(a) is a block diagram showing the overall configuration of a three-phase power factor correction device equipped with a control circuit according to a first embodiment, FIG. 1(b) is a block diagram showing the internal configuration of a two-phase conversion unit of the control circuit, and FIG. 1(c) is a block diagram showing the internal configuration of a three-phase conversion unit of the control circuit. [Figure 2] 1A is a block diagram showing an example of the internal configuration of a phase detection unit of a control circuit, and FIG. 1B is a block diagram showing an example of the internal configuration of a phase rotation determination unit of the control circuit. [Figure 3] 4 is a timing chart for explaining a determination method performed by a determination unit of a phase rotation determination unit. [Figure 4] (a) is a block diagram showing the internal configuration of a control circuit according to a second embodiment, (b) is a block diagram showing the internal configuration of a two-phase conversion unit of the control circuit, and (c) is a block diagram showing the internal configuration of a three-phase conversion unit of the control circuit. [Figure 5] FIG. 10(a) is a block diagram showing the overall configuration of a three-phase power factor correction device equipped with a control circuit according to a third embodiment, FIG. 10(b) is a block diagram showing the internal configuration of a two-phase conversion unit of the control circuit, and FIG. 10(c) is a block diagram showing the internal configuration of a three-phase conversion unit of the control circuit. [Figure 6] FIG. 10 is a block diagram showing the overall configuration of a three-phase power factor correction device including a control circuit according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0017] [First embodiment] Fig. 1 is a diagram for explaining a control circuit A1 according to a first embodiment. Fig. 1(a) is a block diagram showing the overall configuration of a three-phase power factor correction device C including the control circuit A1. Fig. 1(b) is a block diagram showing the internal configuration of a two-phase conversion unit 121 of the control circuit A1. Fig. 1(c) is a block diagram showing the internal configuration of a three-phase conversion unit 122 of the control circuit A1.

[0018] The three-phase power factor correction device C is a device that is placed between a three-phase AC power source and a load (such as an inverter device) and improves the power factor of the three-phase AC power input from the three-phase AC power source so that it approaches "1." The three-phase power factor correction device C includes a power factor correction circuit B and a control circuit A1. The power factor correction circuit B improves the power factor by switching a bidirectional switch (described later) in response to a drive signal input from the control circuit A1.

[0019] In this embodiment, the power factor correction circuit B is a so-called Wien rectifier. The power factor correction circuit B includes three inductors, one end of which is connected to each phase (u-phase, v-phase, and w-phase) of a three-phase AC power supply, and a full-wave rectifier circuit, the other end of which is connected to each inductor, converting the input AC voltage into a DC voltage and outputting the DC voltage to a load. The power factor correction circuit B also includes a voltage divider circuit, each of which has two series-connected capacitors, connected in parallel to the DC side of the rectifier circuit, and a bidirectional switch disposed between the midpoint of the voltage divider circuit and the other end of the inductor for each phase. Each bidirectional switch is turned on when a drive signal input from the control circuit A1 is at a high level, thereby connecting the other end of the corresponding inductor to the midpoint of the voltage divider circuit. The configuration of the power factor correction circuit B is not limited to the one described above.

[0020] The control circuit A1 is a circuit that controls the power factor correction circuit B and is realized by, for example, a microcomputer. The control circuit A1 generates a drive signal for controlling the power factor correction circuit B and outputs it to the power factor correction circuit B. The control circuit A1 feedback-controls the DC bus voltage that the power factor correction circuit B supplies to the load and the three-phase AC current that is input to the power factor correction circuit B. The control circuit A1 also performs PWM control by switching three bidirectional switches using the drive signal. The control circuit A1 has a voltage control unit 11, a current control unit 12, a drive signal generation unit 13, a phase detection unit 14, and a phase rotation determination unit 15 as its functional configuration.

[0021] The phase detector 14 receives a line voltage signal Vuv, which detects the line voltage between the u phase and the v phase of the power factor correction circuit B, and generates a sine wave signal sin θ and a cosine wave signal cos θ based on the phase θ and frequency f of the line voltage signal Vuv. The phase detector 14 outputs the signal to the two-phase converter 121 and the three-phase converter 122. The phase detector 14 may also receive another line voltage signal or a phase voltage signal of any of the phases. As shown in FIG. 2(a), the phase detector 14 includes a zero-cross detector 141, a clock output unit 142, a clock count unit 143, a count value setting unit 144, a waveform table 145, and a readout unit 146.

[0022] The zero-cross detection unit 141 detects the zero-cross timing when the input line voltage signal Vuv switches from a negative value to a positive value. For example, the zero-cross detection unit 141 converts the line voltage signal Vuv into a digital value using an AD converter, and detects the zero-cross timing when the digital value changes from a negative value to a positive value. Note that the method by which the zero-cross detection unit 141 detects the zero-cross timing is not limited. The zero-cross detection unit 141 outputs a zero-cross signal informing the detected zero-cross timing to the clock count unit 143 and the readout unit 146.

[0023] The clock output unit 142 generates a predetermined clock signal and outputs it to the clock count unit 143 and the readout unit 146. The clock frequency of the clock signal is not limited.

[0024] The clock counting unit 143 counts the clock signals input from the clock output unit 142 from when a zero-cross signal is input from the zero-cross detecting unit 141 until the next zero-cross signal is input. That is, the clock counting unit 143 counts the number of clock signals corresponding to one period of the line voltage signal Vuv. The clock counting unit 143 outputs the counted number Nc between zero crosses to the count value setting unit 144.

[0025] Waveform table 145 is a table that stores sine wave data and cosine wave data in association with count values ​​of the clock signal. Waveform table 145 stores sine wave data and cosine wave data that have been calculated in advance according to the number of data M for one cycle. Meanwhile, the count values ​​associated with the sine wave data and cosine wave data are updated and set by count value setting unit 144.

[0026] Count value setting unit 144 sets a count value in waveform table 145 based on the count number Nc between zero crosses and the number of data M for one period input from clock counting unit 143. Count value setting unit 144 calculates Nc·k / M as the kth (=0 to M) count value and sets it in waveform table 145. When zero cross detection unit 141 detects a zero cross, count value setting unit 144 sets a count value based on the count number Nc between zero crosses in the previous period counted by clock counting unit 143.

[0027] Waveform table 145 stores count values ​​associated with sine wave data and cosine wave data. The sine wave data and cosine wave data in waveform table 145 are determined by the number of data M for one cycle, and are therefore calculated and set in advance. Meanwhile, the count value in waveform table 145 is determined according to the count number Nc between zero crossings output from clock count unit 143, and is updated and set for each cycle by count value setting unit 144.

[0028] The readout unit 146 counts the clock signals input from the clock output unit 142 from the time when the zero-cross signal is input from the zero-cross detection unit 141, and when the count reaches a count value set in the waveform table 145, the readout unit 146 reads out the sine wave data and cosine wave data associated with the count value from the waveform table 145 and outputs them as a sine wave signal sin θ and a cosine wave signal cos θ. Each time a zero-cross signal is input, the readout unit 146 initializes the count number of the clock signal to "0" and starts counting the clock signal. In other words, the readout unit 146 synchronizes the sine wave signal sin θ and the cosine wave signal cos θ with the line voltage signal Vuv for each cycle of the line voltage signal Vuv.

[0029] The configuration of the phase detector 14 is not limited to the above, but may be any configuration that outputs a sine wave signal sin θ and a cosine wave signal cos θ based on the phase θ and frequency f of the voltage signal or current signal detected by the power factor correction circuit B.

[0030] The phase rotation discriminator 15 discriminates whether the phase rotation is normal or reverse based on the input line voltage signals Vuv, Vvw, and Vwu. When the power factor correction circuit B is connected to the three-phase AC power supply so that the phase rotation of the three phases is correct, the phase rotation discriminator 15 discriminates that the phase rotation is normal. On the other hand, when the power factor correction circuit B is connected to the three-phase AC power supply so that the phase rotation of the three phases is reverse, the phase rotation discriminator 15 discriminates that the phase rotation is reverse. The phase rotation discriminator 15 outputs a discrimination signal indicative of the discrimination result to the two-phase converter 121 and the three-phase converter 122. As shown in FIG. 2(b), the phase rotation discriminator 15 includes zero-cross detectors 151 to 153 and a discriminator 154.

[0031] The zero-cross detection unit 151 detects the zero-cross timing when the input line voltage signal Vuv switches from a negative value to a positive value. For example, the zero-cross detection unit 151 converts the line voltage signal Vuv into a digital value using an AD converter, and detects the zero-cross timing when the digital value changes from a negative value to a positive value. Note that the method by which the zero-cross detection unit 151 detects the zero-cross timing is not limited. The zero-cross detection unit 151 outputs a zero-cross signal Zu indicating the detected zero-cross timing to the determination unit 154.

[0032] Zero-cross detection unit 152 detects the zero-cross timing when the input line voltage signal Vvw switches from a negative value to a positive value, and outputs a zero-cross signal Zv indicative of the detected zero-cross timing to discrimination unit 154. Zero-cross detection unit 153 detects the zero-cross timing when the input line voltage signal Vwu switches from a negative value to a positive value, and outputs a zero-cross signal Zw indicative of the detected zero-cross timing to discrimination unit 154. The detection methods used by zero-cross detection units 152 and 153 are the same as those used by zero-cross detection unit 151.

[0033] The determination unit 154 determines whether the phase rotation is forward or reverse based on the zero-cross signals Zu, Zv, and Zw input from the zero-cross detection units 151 to 153.

[0034] 3 is a timing chart illustrating the discrimination method used by discriminator 154. Diagram (a) shows the case where the phase rotation is forward, and diagram (b) shows the case where the phase rotation is reverse. Diagrams (a) and (b) respectively show, from top to bottom, the time variations of line voltage signals Vuv, Vvw, and Vwu and zero-cross signals Zu, Zv, and Zw.

[0035] The zero-cross signal Zu has a pulse that rises when the line voltage signal Vuv switches from a negative value to a positive value. The zero-cross signal Zv has a pulse that rises when the line voltage signal Vvw switches from a negative value to a positive value. The zero-cross signal Zw has a pulse that rises when the line voltage signal Vwu switches from a negative value to a positive value.

[0036] As shown in Figure 3(a), when the phase rotation is forward, the pulse of zero-cross signal Zv rises before the pulse of zero-cross signal Zw after the pulse of zero-cross signal Zu. On the other hand, as shown in Figure 3(b), when the phase rotation is reverse, the pulse of zero-cross signal Zw rises before the pulse of zero-cross signal Zv after the pulse of zero-cross signal Zu. Therefore, whether the phase rotation is forward or reverse can be determined based on which pulse of zero-cross signal Zv or zero-cross signal Zw rises first after the pulse of zero-cross signal Zu.

[0037] If the pulse of the zero-cross signal Zv rises before the pulse of the zero-cross signal Zw after the pulse of the zero-cross signal Zu, the discrimination unit 154 determines that the phase rotation is forward and outputs a discrimination signal (for example, a high-level signal) indicating that. On the other hand, if the pulse of the zero-cross signal Zw rises before the pulse of the zero-cross signal Zv after the pulse of the zero-cross signal Zu, the discrimination unit 154 determines that the phase rotation is reverse and outputs a discrimination signal (for example, a low-level signal) indicating that that is the case.

[0038] The configuration of the phase rotation discriminator 15 is not limited to the above. The phase rotation discriminator 15 may be configured to discriminate between forward and reverse phase rotation. For example, the phase rotation discriminator 15 may discriminate between forward and reverse phase rotation based solely on the zero-cross signal Zu detected from the line voltage signal Vuv and the zero-cross signal Zv detected from the line voltage signal Vvw. In Japan, commercial power supplies have a frequency of 50 Hz or 60 Hz, which corresponds to one-third of the cycle, approximately 5 to 7 ms. Therefore, approximately 5 to 7 ms after the rising edge of the pulse of the zero-cross signal Zu, the pulse of either the zero-cross signal Zv or the zero-cross signal Zw rises. Therefore, if the pulse of the zero-cross signal Zv rises within a period of, for example, 4 ms to 8 ms after the rising edge of the pulse of the zero-cross signal Zu, it is determined that the phase is rotating forward. However, if the pulse of the zero-cross signal Zv does not rise within a period of, for example, 4 ms to 8 ms after the rising edge of the pulse of the zero-cross signal Zu, it is determined that the phase is rotating backward. Based on this, the phase rotation discriminator 15 may discriminate between forward and reverse phase rotation. In this case, there is no need to detect the line voltage signal Vvw.

[0039] The voltage control unit 11 calculates a DC voltage control amount for controlling the DC bus voltage to a target value. The voltage control unit 11 calculates a DC voltage control amount for controlling the DC bus voltage to a target value Vb of the DC bus voltage signal Vb detected by a voltage sensor disposed between the DC side terminals of the full-wave rectifier circuit. * The voltage control unit 11 calculates a DC voltage control amount signal by performing PI control on the deviation from the DC voltage control amount signal. The voltage control unit 11 outputs the calculated DC voltage control amount signal to the current control unit 12.

[0040] The current control unit 12 calculates a current manipulation amount for each phase to control the input three-phase AC current. The current control unit 12 receives the phase current signals Iu, Iv, and Iw detected by current sensors arranged on the power lines connecting the three-phase AC power supply and the three inductors. The current control unit 12 includes a two-phase conversion unit 121 and a three-phase conversion unit 122.

[0041] The two-phase conversion unit 121 converts the phase current signals Iu, Iv, and Iw into a d-axis current signal Id and a q-axis current signal Iq on the rotating coordinate axes. The two-phase conversion unit 121 performs different conversion processes depending on the discrimination signal input from the phase rotation discrimination unit 15. As shown in FIG. 1(b), the two-phase conversion unit 121 includes a switching unit 121a, a first conversion unit 121b, a second conversion unit 121c, and a rotating coordinate conversion unit 121d.

[0042] The switching unit 121a switches the output destination of the input phase current signals Iu, Iv, Iw based on the determination signal input from the phase rotation determination unit 15. When the determination signal input from the phase rotation determination unit 15 is a determination signal indicating forward rotation (for example, a high-level signal), the switching unit 121a outputs the phase current signals Iu, Iv, Iw to the first conversion unit 121b. On the other hand, when the determination signal input from the phase rotation determination unit 15 is a determination signal indicating reverse rotation (for example, a low-level signal), the switching unit 121a outputs the phase current signals Iu, Iv, Iw to the second conversion unit 121c.

[0043] The first conversion unit 121b and the second conversion unit 121c convert the three-phase phase current signals Iu, Iv, and Iw into a two-phase α-axis current signal Iα and a β-axis current signal Iβ. The conversion is performed using a conversion matrix, but the conversion matrix set in the first conversion unit 121b and the second conversion unit 121c is different.

[0044] The first conversion unit 121b converts the phase current signals Iu, Iv, and Iw into an α-axis current signal Iα and a β-axis current signal Iβ by the calculation shown in the following equation (1). The conversion matrix of the first conversion unit 121b is a so-called Clarke transformation matrix, and the conversion performed by the first conversion unit 121b is a so-called Clarke transformation.

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[0045] The second conversion unit 121c converts the phase current signals Iu, Iv, and Iw into an α-axis current signal Iα and a β-axis current signal Iβ by the calculation shown in the following equation (2). The conversion matrix of the second conversion unit 121c is a conversion matrix obtained by swapping the second and third columns of the conversion matrix of the first conversion unit 121b.

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[0046] The phase current signals Iu, Iv, and Iw of the power factor correction circuit B are expressed as the power frequency of the three-phase AC power supply, f s , the initial phase is θ0, and the peak value of each phase current signal is I m Then, when the phase rotation is forward, it can be expressed by the following equation (3). When the phase current signals Iu, Iv, and Iw are converted into the α-axis current signal Iα and the β-axis current signal Iβ by the calculation shown in the above equation (1), the following equation (4) is obtained.

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[0047] On the other hand, when the phase rotation is reversed, the phase current signals Iu, Iv, Iw of the power factor correction circuit B can be expressed by the following equation (5). When the phase current signals Iu, Iv, Iw are converted into the α-axis current signal Iα and the β-axis current signal Iβ by the calculation shown in the above equation (1), they are calculated as shown in the following equation (6).

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[0048] In this way, when the phase rotation is reversed, if the first conversion unit 121b performs Clarke transformation on the phase current signals Iu, Iv, and Iw, the α-axis current signal Iα and the β-axis current signal Iβ will be expressed by the above equation (6), which differs from the above equation (4) when the phase rotation is forward. Therefore, if the α-axis current signal Iα and the β-axis current signal Iβ of the above equation (6) are used when the phase rotation is reversed, normal control will not be performed. In this embodiment, when the phase rotation is reversed, the switching unit 121a outputs the phase current signals Iu, Iv, and Iw to the second conversion unit 121c, and the second conversion unit 121c performs conversion.

[0049] When the phase current signals Iu, Iv, and Iw of the above equation (5), which have reversed phase rotation, are converted into the α-axis current signal Iα and the β-axis current signal Iβ by the calculation shown in the above equation (2), the following equation (7) is obtained.

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[0050] In this way, when the phase rotation is reverse, by performing coordinate conversion on each phase current signal Iu, Iv, Iw in the second conversion unit 121c, the α-axis current signal Iα and the β-axis current signal Iβ become the above equation (7), and a result consistent with the above equation (4) when the phase rotation is forward can be calculated.

[0051] The rotating coordinate converter 121d converts the α-axis current signal Iα and β-axis current signal Iβ input from the first converter 121b or the second converter 121c into a d-axis current signal Id and a q-axis current signal Iq on the rotating coordinate axes. The rotating coordinate converter 121d converts the α-axis current signal Iα and β-axis current signal Iβ into a d-axis current signal Id and a q-axis current signal Iq by the calculation shown in the following equation (8). The transformation matrix of the rotating coordinate converter 121d is a so-called Park transformation matrix, and the transformation performed by the rotating coordinate converter 121d is a so-called Park transformation. The rotating coordinate converter 121d performs the calculation using the sine wave signal sin θ and the cosine wave signal cos θ input from the phase detector 14. From the following equation (8) and the above equation (7), it can be seen that the d-axis current signal Id and the q-axis current signal Iq are constants, as shown in the following equation (8').

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[0052] The current control unit 12 multiplies the d-axis current signal Id calculated by the two-phase conversion unit 121 by a gain to obtain a target value Id * The d-axis current control amount signal Xd is calculated by performing PI control on the deviation from the target value Id. * is set to "0." The current control unit 12 calculates the q-axis current control amount signal Xq by performing PI control on the deviation of the signal obtained by multiplying the q-axis current signal Iq calculated by the two-phase conversion unit 121 by a gain, from the DC voltage control amount signal input from the voltage control unit 11.

[0053] The three-phase conversion unit 122 converts the d-axis current control amount signal Xd and the q-axis current control amount signal Xq into three-phase current control amount signals Xu, Xv, and Xw. The three-phase conversion unit 122 performs different conversion processes depending on the determination signal input from the phase rotation determination unit 15. As shown in FIG. 1(c), the three-phase conversion unit 122 includes a stationary coordinate conversion unit 122a, a switching unit 122b, a first conversion unit 122c, and a second conversion unit 122d.

[0054] The stationary coordinate converter 122a converts the input d-axis current control amount signal Xd and q-axis current control amount signal Xq into an α-axis current control amount signal Xα and a β-axis current control amount signal Xβ on the stationary coordinate axes. The stationary coordinate converter 122a converts the d-axis current control amount signal Xd and the q-axis current control amount signal Xq into an α-axis current control amount signal Xα and a β-axis current control amount signal Xβ on the stationary coordinate axes by the calculation shown in the following equation (9). The transformation matrix of the stationary coordinate converter 122a is the inverse matrix of the Park transformation matrix, and the transformation performed by the stationary coordinate converter 122a is the so-called inverse Park transformation. The stationary coordinate converter 122a performs calculations using the sine wave signal sin θ and cosine wave signal cos θ input from the phase detector 14.

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[0055] The switching unit 122b switches the output destination of the α-axis current manipulated variable signal Xα and the β-axis current manipulated variable signal Xβ based on the determination signal input from the phase rotation determination unit 15. When the determination signal input from the phase rotation determination unit 15 indicates forward rotation (for example, a high-level signal), the switching unit 122b outputs the α-axis current manipulated variable signal Xα and the β-axis current manipulated variable signal Xβ to the first conversion unit 122c. On the other hand, when the determination signal input from the phase rotation determination unit 15 indicates reverse rotation (for example, a low-level signal), the switching unit 122b outputs the α-axis current manipulated variable signal Xα and the β-axis current manipulated variable signal Xβ to the second conversion unit 122d.

[0056] The first converter 122c and the second converter 122d convert the α-axis current control amount signal Xα and the β-axis current control amount signal Xβ into three-phase current control amount signals Xu, Xv, and Xw. The conversion is performed using a conversion matrix, but the conversion matrix set in the first converter 122c and the second converter 122d is different.

[0057] The first conversion unit 122c converts the α-axis current control amount signal Xα and the β-axis current control amount signal Xβ into current control amount signals Xu, Xv, and Xw by the calculation shown in the following equation (10). The conversion matrix of the first conversion unit 122c is the inverse matrix of the Clarke conversion matrix, which is the conversion matrix of the first conversion unit 121b (see equation (1) above), and the conversion performed by the first conversion unit 122c is what is called an inverse Clarke conversion.

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[0058] The second conversion unit 122d converts the α-axis current control amount signal Xα and the β-axis current control amount signal Xβ into current control amount signals Xu, Xv, and Xw by the calculation shown in the following equation (11). The conversion matrix of the second conversion unit 122d is the inverse matrix of the conversion matrix of the second conversion unit 121c (see the above equation (2)).

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[0059] When the α-axis current signal Iα and the β-axis current signal Iβ of the above equation (4) or (7) are transformed by the transformation matrix (inverse Clarke transformation) of the first transformation unit 122c, the following equation (12) is obtained, which shows that the phase rotation is transformed into a positive three-phase current.

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[0060] Furthermore, when the above formula (4) or (7) is transformed using the transformation matrix of the second transformation unit 122d, the following formula (13) is obtained, and it can be seen that the phases are transformed into three-phase currents with reversed phase rotation.

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[0061] In this way, when the determination result of the phase rotation determination unit 15 indicates forward rotation, the three-phase conversion unit 122 calculates the three-phase current control amount signals Xu, Xv, and Xw so that the phase rotation is forward. On the other hand, when the determination result of the phase rotation determination unit 15 indicates reverse rotation, the three-phase conversion unit 122 calculates the three-phase current control amount signals Xu, Xv, and Xw so that the phase rotation is reverse. The three-phase conversion unit 122 outputs the current control amount signals Xu, Xv, and Xw calculated by the first conversion unit 122c or the current control amount signals Xu, Xv, and Xw calculated by the second conversion unit 122d to the drive signal generation unit 13.

[0062] The drive signal generation unit 13 generates three-phase drive signals based on the three-phase current control amount signals Xu, Xv, and Xw input from the current control unit 12. The drive signal generation unit 13 receives the terminal voltage signal of the positive capacitor and the terminal voltage signal of the negative capacitor of the voltage divider circuit of the power factor correction circuit B, and amplifies the difference to obtain a voltage difference signal. The drive signal generation unit 13 adds the voltage difference signal to each of the current control amount signals Xu, Xv, and Xw, respectively, and converts the resulting voltage difference signal into an absolute value signal using an absolute value conversion unit 131 to calculate a command signal for each phase. The drive signal generation unit 13 then generates a drive signal for each phase by comparing the command signal for each phase with the triangular wave signal generated by the triangular wave generation unit 132 using a comparison unit 133. The drive signal generation unit 13 outputs the drive signal for each phase to the corresponding bidirectional switch.

[0063] Next, the effects of the control circuit A1 and the three-phase power factor correction device C will be described.

[0064] According to this embodiment, the phase rotation determination unit 15 determines whether the phase rotation is normal or reverse based on the input line voltage signals Vuv, Vvw, and Vwu. When the two-phase conversion unit 121 converts the phase current signals Iu, Iv, and Iw into the α-axis current signal Iα and the β-axis current signal Iβ, the first conversion unit 121b performs the conversion if it is determined that the phase rotation is normal, and the second conversion unit 121c performs the conversion if it is determined that the phase rotation is reverse. The first conversion unit 121b performs the conversion using a Clarke transformation matrix. The second conversion unit 121c performs the conversion using a transformation matrix in which the second and third columns of the Clarke transformation matrix are swapped. The conversion result obtained by the second conversion unit 121c when the phase rotation is reverse matches the conversion result obtained by the first conversion unit 121b when the phase rotation is normal. Furthermore, when the three-phase conversion unit 122 converts the α-axis current control amount signal Xα and the β-axis current control amount signal Xβ into three-phase current control amount signals Xu, Xv, and Xw, if it is determined that the phase rotation is normal, the conversion is performed by the first conversion unit 122c, and if it is determined that the phase rotation is reverse, the conversion is performed by the second conversion unit 122d. The first conversion unit 122c performs the conversion using the inverse matrix of the Clarke transformation matrix. The second conversion unit 122d performs the conversion using the inverse matrix of the transformation matrix of the second conversion unit 121c. If the phase rotation is normal, the three-phase current control amount signals Xu, Xv, and Xw converted by the first conversion unit 122c have normal phase rotation. On the other hand, if the phase rotation is reverse, the three-phase current control amount signals Xu, Xv, and Xw converted by the second conversion unit 122d have reverse phase rotation. Therefore, the control circuit A1 can normally control the power factor correction circuit B whether the phase rotation is forward or reverse. This means that the operator does not need to worry about whether the phase rotation is forward or reverse when connecting the power factor correction circuit B (three-phase power factor correction device C) to a three-phase AC power source. In addition, there is no need to reconnect it. In this way, the control circuit A1 can reduce the burden on the operator when connecting the power factor correction circuit B (three-phase power factor correction device C) to a three-phase AC power source.

[0065] Generally, the power factor correction circuit B is equipped with a sensor that detects a voltage signal for phase detection. The phase rotation determination unit 15 uses the voltage signal detected by this sensor to determine whether the phase rotation is forward or reverse. Therefore, the three-phase power factor correction device C according to the present invention can use a conventional power factor correction circuit B as is, and can be made into a control circuit A1 by modifying the software of the control circuit.

[0066] In this embodiment, the control circuit A1 controls the power factor correction circuit B, but this is not limiting. The control circuit A1 may also be used to control other circuits such as an inverter circuit, a converter circuit, or a power supply circuit.

[0067] 4 to 6 show other embodiments of the present invention. In these figures, elements that are the same as or similar to those in the above embodiment are given the same reference numerals as in the above embodiment, and redundant explanations will be omitted.

[0068] Second Embodiment FIG. 4 is a diagram for explaining a control circuit A2 according to a second embodiment. FIG. 4(a) is a block diagram showing the internal configuration of the control circuit A2. FIG. 4(b) is a block diagram showing the internal configuration of a two-phase conversion unit 121 of the control circuit A2. FIG. 4(c) is a block diagram showing the internal configuration of a three-phase conversion unit 122 of the control circuit A1. The control circuit A2 according to this embodiment differs from the control circuit A1 according to the first embodiment in the internal configurations of the two-phase conversion unit 121 and the three-phase conversion unit 122. The configurations and operations of other parts of this embodiment are the same as those of the first embodiment.

[0069] The control circuit A1 according to the first embodiment switches the transformation matrix used when converting between three-phase signals and two-phase signals in accordance with the discrimination signal input from the phase rotation discriminator 15. The control circuit A2 according to the present embodiment switches the transformation matrix used when converting between signals on stationary coordinate axes and signals on rotating coordinate axes in accordance with the discrimination signal input from the phase rotation discriminator 15.

[0070] 4(b), the two-phase conversion unit 121 according to this embodiment includes a first conversion unit 121b, a switching unit 121e, a first rotation conversion unit 121f, and a second rotation conversion unit 121g. The first conversion unit 121b is similar to the first conversion unit 121b according to the first embodiment, and converts the phase current signals Iu, Iv, and Iw into an α-axis current signal Iα and a β-axis current signal Iβ by the calculation shown in the above equation (1) (Clarke transformation).

[0071] The switching unit 121e switches the output destination of the α-axis current signal Iα and the β-axis current signal Iβ input from the first conversion unit 121b based on the discrimination signal input from the phase rotation discrimination unit 15. When the discrimination signal input from the phase rotation discrimination unit 15 indicates forward rotation (for example, a high-level signal), the switching unit 121e outputs the α-axis current signal Iα and the β-axis current signal Iβ to the first rotation conversion unit 121f. On the other hand, when the discrimination signal input from the phase rotation discrimination unit 15 indicates reverse rotation (for example, a low-level signal), the switching unit 121e outputs the α-axis current signal Iα and the β-axis current signal Iβ to the second rotation conversion unit 121g.

[0072] The first rotation converter 121f converts the α-axis current signal Iα and β-axis current signal Iβ input from the switcher 121e into a d-axis current signal Id and a q-axis current signal Iq by the calculation shown in the above equation (8) (Park conversion). The first rotation converter 121f performs the calculation using the sine wave signal sin θ and cosine wave signal cos θ input from the phase detector 14. In other words, when the determination signal input from the phase rotation determiner 15 indicates normal rotation, the two-phase converter 121 performs the same conversion as the two-phase converter 121 according to the first embodiment.

[0073] The second rotation converter 121g converts the α-axis current signal Iα and β-axis current signal Iβ input from the switching unit 121e into a d-axis current signal Id and a q-axis current signal Iq by the calculation shown in the following equation (14). The transformation matrix of the second rotation converter 121g is the inverse matrix of the transformation matrix of the first rotation converter 121f. The second rotation converter 121g performs the calculation using the sine wave signal sin θ and cosine wave signal cos θ input from the phase detector 14.

number

[0074] When the α-axis current signal Iα and β-axis current signal Iβ shown in the above equation (6) (which are signals obtained by converting the phase current signals Iu, Iv, and Iw whose phase rotation is reversed using the above equation (1), and which correspond to the α-axis current signal Iα and β-axis current signal Iβ input from the switching unit 121e) are converted into the d-axis current signal Id and q-axis current signal Iq by the calculation shown in the above equation (14), the following equation (14') is obtained.

number

[0075] In this way, when the phase rotation is reverse, the α-axis current signal Iα and the β-axis current signal Iβ are coordinate-converted by the second rotation conversion unit 121g, and the d-axis current signal Id and the q-axis current signal Iq become the above equation (14'), and when the phase rotation is forward, a result consistent with the above equation (8') obtained by coordinate conversion by the first rotation conversion unit 121f can be calculated.

[0076] As shown in FIG. 4(c), the three-phase conversion unit 122 according to this embodiment includes a switching unit 122e, a first static conversion unit 122f, a second static conversion unit 122g, and a first conversion unit 122c.

[0077] The switching unit 122e switches the output destination of the d-axis current manipulated variable signal Xd and the q-axis current manipulated variable signal Xq based on the determination signal input from the phase rotation determination unit 15. When the determination signal input from the phase rotation determination unit 15 indicates forward rotation, the switching unit 122e outputs the d-axis current manipulated variable signal Xd and the q-axis current manipulated variable signal Xq to the first static conversion unit 122f. On the other hand, when the determination signal input from the phase rotation determination unit 15 indicates reverse rotation, the switching unit 122e outputs the d-axis current manipulated variable signal Xd and the q-axis current manipulated variable signal Xq to the second static conversion unit 122g.

[0078] The first static conversion unit 122f converts the d-axis current control amount signal Xd and the q-axis current control amount signal Xq input from the switching unit 122e into an α-axis current control amount signal Xα and a β-axis current control amount signal Xβ by the calculation shown in the above equation (9) (inverse Park conversion). The first static conversion unit 122f performs the calculation using the sine wave signal sin θ and the cosine wave signal cos θ input from the phase detection unit 14.

[0079] The second static converter 122g converts the d-axis current manipulated variable signal Xd and the q-axis current manipulated variable signal Xq input from the switch 122e into an α-axis current manipulated variable signal Xα and a β-axis current manipulated variable signal Xβ by the calculation shown in the following equation (15). The transformation matrix of the second static converter 122g is the inverse matrix of the transformation matrix of the first static converter 122f. The second static converter 122g performs calculations using the sine wave signal sin θ and the cosine wave signal cos θ input from the phase detector 14. The transformation matrix of the second static converter 122g performs calculations that perform rotations opposite to those of the transformation matrix of the first static converter 122f, and therefore the α-axis current manipulated variable signal Xα and the β-axis current manipulated variable signal Xβ converted by the second static converter 122g have reversed phase rotations.

number

[0080] The first conversion unit 122c is similar to the first conversion unit 122c according to the first embodiment, and converts the α-axis current control amount signal Xα and the β-axis current control amount signal Xβ into current control amount signals Xu, Xv, and Xw by the calculation shown in the above equation (10) (inverse Clarke transformation). That is, when the determination signal input from the phase rotation determination unit 15 indicates normal rotation, the three-phase conversion unit 122 performs the same conversion as the three-phase conversion unit 122 according to the first embodiment.

[0081] In this embodiment, too, the phase rotation determination unit 15 determines whether the phase rotation is forward or reverse based on the input line voltage signals Vuv, Vvw, and Vwu. When the two-phase conversion unit 121 converts the α-axis current signal Iα and the β-axis current signal Iβ into the d-axis current signal Id and the q-axis current signal Iq, the first rotation conversion unit 121f performs the conversion if it is determined that the phase rotation is forward, and the second rotation conversion unit 121g performs the conversion if it is determined that the phase rotation is reverse. The first rotation conversion unit 121f performs the conversion using a Park transformation matrix. The second rotation conversion unit 121g performs the conversion using a transformation matrix that is the inverse matrix of the Park transformation matrix. The conversion result obtained by the second rotation conversion unit 121g when the phase rotation is reverse matches the conversion result obtained by the first rotation conversion unit 121f when the phase rotation is forward. Furthermore, when the three-phase converter 122 converts the d-axis current control amount signal Xd and the q-axis current control amount signal Xq into the α-axis current control amount signal Xα and the β-axis current control amount signal Xβ, the first static converter 122f performs the conversion if it is determined that the phase rotation is normal, and the second static converter 122g performs the conversion if it is determined that the phase rotation is reverse. The first static converter 122f performs the conversion using the inverse matrix of the Park transformation matrix. The second static converter 122g performs the conversion using the inverse matrix of the transformation matrix of the second rotation converter 121g. The first converter 122c converts the α-axis current control amount signal Xα and the β-axis current control amount signal Xβ into the current control amount signals Xu, Xv, and Xw using the inverse Clarke transformation. When the phase rotation is normal, the three-phase current control amount signals Xu, Xv, and Xw output from the first converter 122c have normal phase rotation. On the other hand, when the phase rotation is reversed, the three-phase current control amount signals Xu, Xv, and Xw output from the first conversion unit 122c have reversed phase rotation. Therefore, the control circuit A2 can normally control the power factor correction circuit B whether the phase rotation is forward or reverse. This means that the operator does not need to worry about whether the phase rotation is forward or reverse when connecting the power factor correction circuit B (three-phase power factor correction device C) to a three-phase AC power source. In addition, there is no need to reconnect it. In this way, the control circuit A2 can reduce the operator's burden when connecting the power factor correction circuit B (three-phase power factor correction device C) to a three-phase AC power source.Furthermore, the control circuit A2 has a common configuration with the control circuit A1, and therefore has the same effects as the control circuit A1.

[0082] Third Embodiment FIG. 5 is a diagram for explaining a control circuit A3 according to a third embodiment. FIG. 5(a) is a block diagram showing the overall configuration of a three-phase power factor correction device C including the control circuit A3. FIG. 5(b) is a block diagram showing the internal configuration of a two-phase conversion unit 123 of the control circuit A1. FIG. 5(c) is a block diagram showing the internal configuration of a three-phase conversion unit 124 of the control circuit A1. The control circuit A3 according to this embodiment differs from the control circuit A1 according to the first embodiment in that, instead of switching the transformation matrix used for signal conversion in the current control unit 12, the control circuit A3 switches the input signal to the current control unit 12 and the output signal from the drive signal generation unit 13. The configuration and operation of other parts of this embodiment are similar to those of the first embodiment. Note that the parts of the first and second embodiments described above may be combined in any desired manner.

[0083] In the control circuit A3 according to this embodiment, the current control unit 12 includes a two-phase conversion unit 123 and a three-phase conversion unit 124 instead of the two-phase conversion unit 121 and the three-phase conversion unit 122. The two-phase conversion unit 123 and the three-phase conversion unit 124 do not have a function to switch the conversion process according to the determination signal input from the phase rotation determination unit 15 for the two-phase conversion unit 121 and the three-phase conversion unit 122.

[0084] 5(b), the two-phase conversion unit 123 does not include a switching unit 121a or a second conversion unit 121c. The phase current signals Iu, Iv, and Iw are input to a first conversion unit 121b, where they are converted into an α-axis current signal Iα and a β-axis current signal Iβ by Clarke transformation. The α-axis current signal Iα and the β-axis current signal Iβ are then input to a rotating coordinate conversion unit 121d, where they are converted into a d-axis current signal Id and a q-axis current signal Iq by Park transformation. In other words, the two-phase conversion unit 123 performs a conventionally known conversion from the phase current signals Iu, Iv, and Iw to the d-axis current signal Id and the q-axis current signal Iq on the rotating coordinate axes.

[0085] 5(c), the three-phase conversion unit 124 does not include the switching unit 122b and the second conversion unit 122d. The d-axis current control amount signal Xd and the q-axis current control amount signal Xq are input to the stationary coordinate conversion unit 122a, where they are converted into an α-axis current control amount signal Xα and a β-axis current control amount signal Xβ by an inverse Park transform. The α-axis current control amount signal Xα and the β-axis current control amount signal Xβ are then input to the first conversion unit 122c, where they are converted into current control amount signals Xu, Xv, and Xw by an inverse Clarke transform. In other words, the three-phase conversion unit 124 performs a conventionally known conversion from the d-axis current control amount signal Xd and the q-axis current control amount signal Xq to three-phase current control amount signals Xu, Xv, and Xw.

[0086] 5(a), the control circuit A3 further includes a switching unit 16 and a switching unit 17. The switching unit 16 is capable of switching the output destination of the phase current signals Iu, Iv, and Iw input thereto based on the discrimination signal input thereto from the phase rotation discriminator 15. When the discrimination signal input thereto from the phase rotation discriminator 15 indicates forward rotation (e.g., a high-level signal), the switching unit 16 outputs the phase current signals Iu, Iv, and Iw directly to the current control unit 12 without switching the output destination. On the other hand, when the discrimination signal input thereto from the phase rotation discriminator 15 indicates reverse rotation (e.g., a low-level signal), the switching unit 16 switches the output destination of the phase current signal Iv with the output destination of the phase current signal Iw among the phase current signals Iu, Iv, and Iw, and outputs the switched signals to the current control unit 12. That is, when the phase rotation of the phase current signals Iu, Iv, Iw is reversed, the switching unit 16 switches the signals to make the phase rotation of the phase current signals Iu, Iv, Iw normal, and inputs them to the current control unit 12. The switching unit 16 may switch the phase current signals Iu, Iv, Iw using contacts, or may switch the phase current signals Iu, Iv, Iw that have been converted into digital signals by an AD converter.

[0087] The switching unit 17 is capable of switching the output destinations of the three-phase drive signals generated by the drive signal generator 13 based on the discrimination signal input from the phase rotation discriminator 15. When the discrimination signal input from the phase rotation discriminator 15 indicates forward rotation, the switching unit 17 outputs the three-phase drive signals as is without switching the output destinations. On the other hand, when the discrimination signal input from the phase rotation discriminator 15 indicates reverse rotation, the switching unit 17 switches the output destinations of the V-phase drive signal and the W-phase drive signal among the three-phase drive signals and outputs them. In other words, when the phase rotation of each phase current signal Iu, Iv, Iw is reversed, the switching unit 17 switches the signals so that each phase can be controlled when the drive signals are reversed. In the control circuit A3, the switching unit 17 may switch the digital drive signals and then convert them to analog signals using a DA converter and output them, or the switching unit 17 may switch the drive signals converted to analog signals using a DA converter and output them using a contact.

[0088] In this embodiment, the phase rotation discriminator 15 discriminates whether the phase rotation is forward or reverse based on the input line voltage signals Vuv, Vvw, and Vwu. When the discrimination signal input from the phase rotation discriminator 15 indicates reverse rotation, the switching unit 16 switches the output destination of the phase current signal Iv with the output destination of the phase current signal Iw, thereby changing the phase rotation to forward rotation. When the discrimination signal input from the phase rotation discriminator 15 indicates reverse rotation, the switching unit 17 switches the output destination of the V-phase drive signal with the W-phase drive signal, thereby changing the drive signals so that each phase can be controlled in reverse rotation. Therefore, the control circuit A3 can normally control the power factor correction circuit B regardless of whether the phase rotation is forward or reverse. This means that an operator does not need to worry about whether the phase rotation is forward or reverse when connecting the power factor correction circuit B (three-phase power factor correction device C) to a three-phase AC power source. Furthermore, there is no need to reconnect the power factor correction circuit B. In this way, the control circuit A3 can reduce the burden on the worker when connecting the power factor correction circuit B (three-phase power factor correction device C) to the three-phase AC power supply.

[0089] [Fourth embodiment] FIG. 6 is a diagram for explaining a control circuit A4 according to a fourth embodiment, and is a block diagram showing the overall configuration of a three-phase power factor correction device C including the control circuit A4. Note that FIG. 6 omits the illustration of a portion of the power factor correction circuit B. The control circuit A4 according to this embodiment differs from the control circuit A1 according to the first embodiment in that it switches the power lines connected to the three-phase AC power supply of the power factor correction circuit B instead of switching the transformation matrix used for signal conversion in the current control unit 12. The configuration and operation of other parts of this embodiment are the same as those of the first embodiment. Note that the parts of the first to third embodiments described above may be combined in any desired manner.

[0090] In the control circuit A4 according to this embodiment, the current control unit 12 includes a two-phase conversion unit 123 and a three-phase conversion unit 124 instead of the two-phase conversion unit 121 and the three-phase conversion unit 122, as in the third embodiment. The two-phase conversion unit 123 and the three-phase conversion unit 124 do not have a function to switch the conversion process according to the determination signal input from the phase rotation determination unit 15 for the two-phase conversion unit 121 and the three-phase conversion unit 122.

[0091] The power factor correction circuit B further includes a switching unit 2. The switching unit 2 is capable of switching the connection of two of the power lines connected to the three-phase AC power supply based on a discrimination signal input from the phase rotation discrimination unit 15. When the discrimination signal input from the phase rotation discrimination unit 15 indicates normal rotation (e.g., a high-level signal), the switching unit 2 leaves the two connections as they are without switching them. On the other hand, when the discrimination signal input from the phase rotation discrimination unit 15 indicates reverse rotation (e.g., a low-level signal), the switching unit 2 switches the connections of the two lines. In other words, when the phase rotation of the phase current signals Iu, Iv, and Iw is reverse, the switching unit 2 switches the power lines connected to the three-phase AC power supply to change the phase rotation of the phase current signals Iu, Iv, and Iw to normal rotation, and inputs the phase current signals Iu, Iv, and Iw to the current control unit 12. The switching unit 2 may switch the connection of the two lines using, for example, contacts.

[0092] In this embodiment, too, the phase rotation discriminator 15 discriminates whether the phase rotation is forward or reverse based on the input line voltage signals Vuv, Vvw, and Vwu. When the discrimination signal input from the phase rotation discriminator 15 indicates reverse rotation, the switching unit 2 changes the phase rotation to forward by switching the connection of two of the power lines connected to the three-phase AC power supply. Therefore, the control circuit A4 can normally control the power factor correction circuit B regardless of whether the phase rotation is forward or reverse. This eliminates the need for an operator to worry about whether the phase rotation is forward or reverse when connecting the power factor correction circuit B (three-phase power factor correction device C) to the three-phase AC power supply. Furthermore, there is no need to reconnect the power factor correction circuit B. In this way, the three-phase power factor correction device C according to the fourth embodiment can reduce the burden on the operator when connecting the power factor correction circuit B (three-phase power factor correction device C) to the three-phase AC power supply.

[0093] In the third and fourth embodiments, if contacts are used for the switching units 16, 17, and 2, the contact capacity will increase in accordance with the power capacity of the power factor correction circuit B, leading to an increase in size and cost of the three-phase power factor correction device C. Therefore, in order to prevent the three-phase power factor correction device C from becoming larger and more expensive, the first and second embodiments, which can be realized simply by changing the calculation method using software, are more desirable.

[0094] The control circuit and three-phase power factor correction device according to the present invention are not limited to the above-described embodiment, and the specific configurations of the components of the control circuit and three-phase power factor correction device according to the present invention can be freely designed and modified in various ways. [Explanation of symbols]

[0095] A1 to A4: control circuit, 121: two-phase conversion unit, 121a: switching unit, 121b: first conversion unit, 121c: second conversion unit, 121d: rotational coordinate conversion unit, 121e: switching unit, 121f: first rotational conversion unit, 121g: second rotational conversion unit, 122: three-phase conversion unit, 122a: static coordinate conversion unit, 122b: switching unit, 122c: first conversion unit, 122d: second conversion unit, 122e: switching unit, 122f: first static conversion unit, 122g: second static conversion unit, 15: phase rotation determination unit, 151 to 153: zero-cross detection units, B: power factor correction circuit, C: three-phase power factor correction device

Claims

1. a two-phase conversion unit that converts a three-phase detection signal obtained by detecting a three-phase AC current of the controlled device into a two-phase second detection signal on a rotation coordinate axis; a three-phase conversion unit that converts two-phase operation amount signals generated based on the two-phase second detection signals into three-phase second operation amount signals on a stationary coordinate axis; a phase rotation determination unit that determines whether a phase rotation of the three-phase AC of the controlled device is normal or reverse; Equipped with the two-phase conversion unit and the three-phase conversion unit change a conversion matrix used for conversion depending on whether the phase rotation is the forward rotation or the reverse rotation. Control circuit.

2. The two-phase conversion unit is a three-phase to two-phase conversion unit that converts the three-phase detection signals into a third two-phase detection signal; a rotational coordinate conversion unit that converts the two-phase third detection signals into the two-phase second detection signals; Equipped with The three-phase conversion unit a stationary coordinate conversion unit that converts the two-phase operation amount signals into two-phase third operation amount signals on the stationary coordinate axes; a two-phase to three-phase conversion unit that converts the two-phase third detected operation amount signals into the three-phase second operation amount signals; Equipped with When the phase rotation is the normal rotation, the three-phase to two-phase conversion unit performs conversion using a first conversion matrix, and the two-phase to three-phase conversion unit performs conversion using a first inverse conversion matrix that is an inverse matrix of the first conversion matrix; When the phase rotation is the reverse, the three-phase to two-phase conversion unit performs conversion using a second conversion matrix, and the two-phase to three-phase conversion unit performs conversion using a second inverse conversion matrix that is an inverse matrix of the second conversion matrix; The second transformation matrix is ​​a matrix obtained by swapping the second and third columns of the first transformation matrix. The control circuit of claim 1 .

3. The two-phase conversion unit is a three-phase to two-phase conversion unit that converts the three-phase detection signals into a third two-phase detection signal; a rotational coordinate conversion unit that converts the two-phase third detection signals into the two-phase second detection signals; Equipped with The three-phase conversion unit a stationary coordinate conversion unit that converts the two-phase operation amount signals into two-phase third operation amount signals on the stationary coordinate axes; a two-phase to three-phase conversion unit that converts the two-phase third detected operation amount signals into the three-phase second operation amount signals; Equipped with When the phase rotation is the forward rotation, the rotational coordinate transformation unit performs transformation using a third transformation matrix, and the stationary coordinate transformation unit performs transformation using a third inverse transformation matrix that is an inverse matrix of the third transformation matrix; When the phase rotation is the reverse, the rotational coordinate transformation unit performs transformation using a fourth transformation matrix, and the stationary coordinate transformation unit performs transformation using a fourth inverse transformation matrix that is an inverse matrix of the fourth transformation matrix; the fourth transformation matrix is ​​the inverse matrix of the third transformation matrix; The control circuit of claim 1 .

4. The phase rotation determination unit a first zero-cross detector that detects a zero-cross timing at which a first phase detection signal that detects a first phase of the three-phase AC of the control target device switches from a negative value to a positive value; a second zero-cross detection unit that detects a zero-cross timing at which a second-phase detection signal that detects a second phase of the three-phase AC of the controlled device switches from a negative value to a positive value; Equipped with determining whether the phase rotation is the forward rotation or the reverse rotation based on at least a first detection result of the first zero-cross detection unit and a second detection result of the second zero-cross detection unit; The control circuit of claim 1 .

5. a control circuit according to any one of claims 1 to 4; a power factor correction circuit controlled by the control circuit; Equipped with Three-phase power factor correction device.

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