Power conversion device and power conversion system

Abstract

To provide a power conversion device capable of increasing detection accuracy.SOLUTION: A power conversion device according to an embodiment comprises an input power terminal, an output power terminal, a power conversion circuit including a sensor which can covert power supplied via the input power terminal, output the converted power via the output power terminal, and generate a first detection signal according to an output voltage or an output current, a signal generation circuit which can generate a second detection signal according to the first detection signal, and a control circuit. The signal generation circuit comprises a correction unit which can perform correction processing for the first detection signal, a photocoupler including a light-emitting element which can emit light with luminance according to the first detection signal having been subjected to correction processing and a light-receiving element which can receive light emitted from the light-emitting element and generate a light-receiving signal according the amount of light received, and an output unit which can output a second detection signal according to the light-receiving signal. The correction unit can perform correction processing according to a current transmission rate of the photocoupler.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power conversion device and a power conversion system for converting power.

Background Art

[0002] In a power conversion device, output voltage and output current are often detected. For example, Patent Document 1 discloses a technique having a plurality of power conversion devices connected in parallel and controlling the output currents in each of the plurality of power conversion devices to be substantially equal to each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is desired that the output voltage and output current be detected with high accuracy, and further improvement in detection accuracy is expected.

[0005] It is desirable to provide a power conversion device and a power conversion system capable of enhancing detection accuracy.

Means for Solving the Problems

[0006] According to an embodiment of the present invention FirstThe power conversion device comprises an input power terminal, an output power terminal, a power conversion circuit, a signal generation circuit, and a control circuit. The power conversion circuit is capable of converting power supplied via the input power terminal and outputting the converted power via the output power terminal. This power conversion circuit has a sensor capable of generating a first detection signal corresponding to the output voltage or output current. The signal generation circuit is capable of generating a second detection signal corresponding to the first detection signal. The control circuit is capable of controlling the operation of the power conversion circuit. The signal generation circuit has a correction unit, a photocoupler, and an output unit. The correction unit is capable of performing correction processing on the first detection signal. The photocoupler has a light-emitting element capable of emitting light with a brightness corresponding to the first detection signal after correction processing, and a light-receiving element capable of receiving light emitted by the light-emitting element and generating a light-receiving signal corresponding to the amount of light received. The output unit is capable of outputting a second detection signal corresponding to the light-receiving signal. The correction unit is capable of performing correction processing according to the current transmission rate of the photocoupler. The signal generation circuit includes a first AD conversion circuit capable of generating a first digital value by performing AD conversion on a first detection signal, a digital isolator, a second AD conversion circuit capable of generating a second digital value by performing AD conversion on a second detection signal, and a processing circuit capable of estimating the current transfer rate based on the first digital value and the second digital value supplied via the digital isolator, and generating parameters corresponding to the estimated current transfer rate. The correction unit is capable of performing correction processing according to the current transfer rate based on the parameters. A second power conversion device according to one embodiment of the present invention comprises an input power terminal, an output power terminal, a power conversion circuit, a signal generation circuit, a control circuit, and a signal terminal. The power conversion circuit is capable of converting power supplied via the input power terminal and outputting the converted power via the output power terminal. This power conversion circuit has a sensor capable of generating a first detection signal corresponding to the output voltage or output current. The signal generation circuit is capable of generating a second detection signal corresponding to the first detection signal. The control circuit is capable of controlling the operation of the power conversion circuit. The signal terminal is led to a terminal that outputs the second detection signal of the signal generation circuit. The signal generation circuit has a correction unit, a photocoupler, and an output unit. The correction unit is capable of performing correction processing on the first detection signal. The photocoupler has a light-emitting element capable of emitting light with a brightness corresponding to the first detection signal after correction processing, and a light-receiving element capable of receiving light emitted by the light-emitting element and generating a light-receiving signal corresponding to the amount of light received. The output unit is capable of outputting a second detection signal corresponding to the light-receiving signal. The correction unit can perform correction processing according to the current transmission rate of the photocoupler. The control circuit can control the operation of the power conversion circuit based on the voltage of the signal terminal and the voltage of the second detection signal.

[0007] A power conversion system according to one embodiment of the present invention comprises a plurality of power conversion devices. Each of the plurality of power conversion devices comprises an input power terminal, an output power terminal, a power conversion circuit, a signal generation circuit, a signal terminal, and a control circuit. The power conversion circuit is capable of converting power supplied via the input power terminal and outputting the converted power via the output power terminal. This power conversion circuit has a sensor capable of generating a first detection signal corresponding to the output voltage or output current. The signal generation circuit is capable of generating a second detection signal corresponding to the first detection signal. The signal terminal is led to the terminal that outputs the second detection signal of the signal generation circuit. The control circuit is capable of controlling the operation of the power conversion circuit based on the voltage of the signal terminal and the voltage of the second detection signal. The signal terminals of each of the plurality of power conversion devices are connected to each other. The signal generation circuit comprises a correction unit, a photocoupler, and an output unit. The correction unit is capable of performing correction processing on the first detection signal. The photocoupler comprises a light-emitting element capable of emitting light at a brightness corresponding to a first detection signal that has undergone correction processing, and a light-receiving element capable of receiving light emitted by the light-emitting element and generating a light-receiving signal corresponding to the amount of light received. The output unit is capable of outputting a second detection signal corresponding to the light-receiving signal. The correction unit is capable of performing correction processing according to the current transmission rate of the photocoupler. [Effects of the Invention]

[0008] According to one embodiment of the present invention, the power conversion device and power conversion system can improve detection accuracy. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing one example configuration of a power conversion system according to one embodiment of the present invention. [Figure 2] Figure 1 is an explanatory diagram illustrating one example of a power conversion device connection. [Figure 3] Figure 1 is a block diagram showing one example configuration of a power conversion device. [Figure 4]It is a circuit diagram showing a configuration example of an insulated power conversion circuit shown in FIG. 3. [Figure 5] It is a circuit diagram showing a configuration example of a correction unit and an output unit shown in FIG. 3. [Figure 6] It is a circuit diagram showing a configuration example of another correction unit and another output unit shown in FIG. 3. [Figure 7] It is a waveform diagram showing a characteristic example of the signal generation circuit shown in FIG. 5. [Figure 8] It is a waveform diagram showing a characteristic example of the signal generation circuit according to the comparative example. [Figure 9] It is a block diagram showing a configuration example of a power conversion system according to a modification example. [Figure 10] It is a block diagram showing a configuration example of the power conversion device shown in FIG. 9. [Figure 11] It is a circuit diagram showing a configuration example of a non-insulated power conversion circuit shown in FIG. 10. [Figure 12] It is a block diagram showing a configuration example of a power conversion system according to another modification example. [Figure 13] It is an explanatory diagram showing a connection example of the power conversion device shown in FIG. 12.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] <Embodiment> [Configuration Example] FIG. 1 shows a configuration example of a power conversion system (power conversion system 1) according to an embodiment of the present invention. This power conversion system 1 is configured to convert DC power supplied from a DC power source PDC and supply the converted DC power to a load LD.

[0012] The power conversion system 1 has power terminals T11, T12, a plurality of power conversion devices 10 (in this example, four power conversion devices 10A, 10B, 10C, 10D), and power terminals T21, T22.

[0013] Power terminals T11 and T12 are power input terminals for the power conversion system 1. Power terminal T11 is connected to one end of the DC power source PDC, and power terminal T12 is connected to the other end of the DC power source PDC. The DC power source PDC may be, for example, a power supply circuit that generates DC power or a battery.

[0014] Each of the four power conversion devices 10 is an isolated DC / DC conversion circuit and has input power terminals Vip and Vin, output power terminals Vop and Von, balance terminals Vbi and Vbv, and a reference terminal GNDb.

[0015] Input power terminals Vip and Vin are power input terminals for the power conversion device 10. The input power terminals Vip of the power conversion devices 10A to 10D are connected to each other and to the power terminal T11. The input power terminals Vin of the power conversion devices 10A to 10D are connected to each other and to the power terminal T12.

[0016] Output power terminals Vop and Von are output terminals for the power converted by the power conversion device 10. The output power terminals Vop of the power conversion devices 10A and 10B are connected to each other and to the power terminal T21. The output power terminals Von of the power conversion devices 10A and 10B are connected to each other and to the output power terminals Vop of the power conversion devices 10C and 10D. The output power terminals Vop of the power conversion devices 10C and 10D are connected to each other and to the output power terminals Von of the power conversion devices 10A and 10B. The output power terminals Von of the power conversion devices 10C and 10D are connected to each other and to the power terminal T22.

[0017] Balance terminal Vbi is a terminal for inputting and outputting a signal for making the output currents (output current Iout described later) in each of the four power conversion devices 10 approximately equal to each other. The balance terminals Vbi of the power conversion devices 10A to 10D are connected to each other.

[0018] The balance terminal Vbv is a terminal that inputs and outputs signals to make the output voltages (output voltage Vout, described later) of each of the four power converters 10 approximately equal to each other. The balance terminals Vbv of power converters 10A to 10D are connected to each other.

[0019] The reference terminal GNDb is the terminal in the four power converters 10 that inputs and outputs the reference voltage of the tertiary circuit described later. The reference terminals GNDb of power converters 10A to 10D are connected to each other.

[0020] Power terminals T21 and T22 are output terminals for the power converted by the power conversion system 1. Power terminal T21 is connected to one end of the load LD, and power terminal T22 is connected to the other end of the load LD.

[0021] Figure 2 shows the connections of the output power terminals Vop and Von in the four power converters 10. The output power terminal Vop of power converters 10A and 10B is connected to power node N1, which is led to power terminal T21, and the output power terminal Von of power converters 10A and 10B is connected to power node N2. The output power terminal Vop of power converters 10C and 10D is connected to power node N2, and the output power terminal Von of power converters 10C and 10D is connected to power node N3, which is led to power terminal T22. In other words, in power conversion system 1, power converters 10A and 10B are connected in parallel, and power converters 10C and 10D are connected in parallel. Power converters 10A and 10B are connected in series with power converters 10C and 10D.

[0022] (Power converter 10) Figure 3 shows an example configuration of the power converter 10. The power converter 10 includes an isolated power conversion circuit 11, correction circuits 12A and 12B, photocouplers 13A and 13B, correction circuits 14A and 14B, resistors 15A and 15B, amplifiers 16A and 16B, an MCU (Micro Controller Unit) 30, a digital isolator 17, an MCU 20, and an isolated drive circuit 18.

[0023] The isolated power conversion circuit 11 is configured to convert DC power supplied via input power terminals Vip and Vin, and to output the converted DC power via output power terminals Vop and Von.

[0024] Figure 4 shows an example configuration of an isolated power conversion circuit 11. The isolated power conversion circuit 11 includes a capacitor C1, transistors SW1 and SW2, a transformer TR, a rectifier circuit 43, a current sensor 44, a smoothing circuit 45, and a voltage sensor 46. Capacitor C1 and transistors SW1 and SW2 constitute the primary circuit. The rectifier circuit 43, current sensor 44, smoothing circuit 45, and voltage sensor 46 constitute the secondary circuit.

[0025] One end of capacitor C1 is connected to voltage line L11, which is led to the input power terminal Vip, and the other end is connected to reference voltage line L12, which is led to the input power terminal Vin. Transistors SW1 and SW2 are N-type field-effect transistors (FETs) in this example. The gate signal SG is supplied to the gate of transistor SW1, its drain is connected to the primary winding 41 (described later) of transformer TR, and its source is connected to reference voltage line L12. The gate signal SG is supplied to the gate of transistor SW2, its drain is connected to the primary winding 41 (described later) of transformer TR, and its source is connected to reference voltage line L12.

[0026] The transformer TR is configured to DC-isolate the primary and secondary circuits while AC-connecting them. The transformer TR has a primary winding 41 and a secondary winding 42. One end of the primary winding 41 is connected to voltage line L11, and the other end is connected to the drains of transistors SW1 and SW2. One end of the secondary winding 42 is connected to voltage line L21 led to the output power terminal Vop, and the other end is connected to reference voltage line L22 led to the output power terminal Von.

[0027] The rectifier circuit 43 is configured to rectify the AC voltage output from the secondary winding 42 of the transformer TR. The rectifier circuit 43 has diodes D1 and D2. Diode D1 is located on the voltage line L21, its anode is connected to one end of the secondary winding 42, and its cathode is connected to the cathode of diode D2 and also to the smoothing circuit 45. The anode of diode D2 is connected to the reference voltage line L22, and its cathode is connected to the cathode of diode D1 on the voltage line L21.

[0028] The current sensor 44 is configured to detect the output current Iout of the power converter 10. The current sensor 44 is mounted on the reference voltage line L22, with one end connected to the other end of the secondary winding 42 and the anode of the diode D2, and the other end connected to the smoothing circuit 45. The current sensor 44 detects the current flowing from the smoothing circuit 45 toward the rectifier circuit 43 in the reference voltage line L22 as the output current Iout. The polarity of the output current Iout is positive when the current flows from the smoothing circuit 45 toward the rectifier circuit 43. The current sensor 44 is configured to generate a detection signal SI having a voltage corresponding to this output current Iout. The current sensor 44 can be configured, for example, using a resistive element provided on the reference voltage line L22 and an amplifying circuit that amplifies the voltage difference across the resistive element. In this case, the current sensor 44 can generate the detection signal SI by amplifying the voltage difference across the resistive element. In this example, the current sensor 44 is placed on the reference voltage line L22, but it is not limited to this and may also be placed on the voltage line L21.

[0029] The smoothing circuit 45 is configured to smooth the voltage rectified by the rectifier circuit 43. The smoothing circuit 45 includes an inductor L1 and a capacitor C2. The inductor L1 is provided on the voltage line L21, with one end connected to the cathodes of diodes D1 and D2, and the other end connected to the capacitor C2. One end of the capacitor C2 is connected to the other end of the inductor L1 on the voltage line L21, and the other end is connected to the other end of the current sensor 44 on the reference voltage line L22.

[0030] The voltage sensor 46 is configured to detect the output voltage Vout of the power converter 10. One end of the voltage sensor 46 is connected to the other end of the inductor L1 on the voltage line L21, and the other end is connected to the other end of the current sensor 44 on the reference voltage line L22. The voltage sensor 46 detects the voltage of the voltage line L21, with the voltage of the reference voltage line L22 as the reference voltage, as the output voltage Vout. The voltage sensor 46 is configured to generate a detection signal SV having a voltage value corresponding to this voltage. The voltage sensor 46 can be configured, for example, using a resistor network in which multiple resistors are connected in series. In this case, the voltage sensor 46 can generate the detection signal SV by dividing the output voltage Vout by the multiple resistors.

[0031] As shown in Figure 1, the four power converters 10A to 10D are supplied with DC power from the DC power supply PDC. Therefore, the operating voltages of the primary circuits of power converters 10A to 10D are equal to each other.

[0032] On the other hand, as shown in Figure 2, power converters 10A and 10B are connected in series with power converters 10C and 10D. Therefore, the operating voltage of the secondary circuit of power converters 10A and 10B, with respect to the power terminal T22, is higher than the operating voltage of the secondary circuit of power converters 10C and 10D, with respect to the power terminal T22.

[0033] In Figure 3, the correction circuits 12A, 12B and MCU 20, together with the rectifier circuit 43, current sensor 44, smoothing circuit 45, and voltage sensor 46 shown in Figure 4, constitute the secondary circuit. The correction circuits 14A, 14B, resistors 15A, 15B, amplifiers 16A, 16B, and MCU 30 constitute the tertiary circuit.

[0034] As shown in Figure 1, the reference terminal GNDb of the four power converters 10 are connected to each other. Therefore, the reference voltage of the tertiary circuit of the four power converters 10 is the same, and thus the operating voltage of the tertiary circuit of the four power converters 10 is equal to each other.

[0035] As shown in Figure 3, MCU20 includes correction calculation circuits 21A and 21B, error amplifiers 22A and 22B, and a switching control circuit 23. MCU30 includes correction calculation circuits 31A and 31B, adjustment calculation circuits 32A and 32B, a command value generation circuit 33, and adder circuits 34A and 34B. MCU20 and 30 have an AD conversion circuit that converts the supplied analog signal into a digital value and performs processing based on the converted digital value.

[0036] The correction circuit 12A and the correction calculation circuit 21A of the MCU 20 constitute the correction unit 101A.

[0037] The correction circuit 12A is configured to correct the detection signal SI supplied from the current sensor 44. Based on the correction signal SCI supplied from the correction calculation circuit 21A, the correction circuit 12A corrects the detection signal SI according to the characteristics of the photocoupler 13A. Then, the correction circuit 12A drives the light-emitting element of the photocoupler 13A based on the corrected detection signal SI.

[0038] The correction calculation circuit 21A is configured to understand the characteristics of the photocoupler 13A by exchanging data with the correction calculation circuit 31A via the digital isolator 17, and to generate a correction signal SCI according to the characteristics of the photocoupler 13A. The correction calculation circuit 21A then supplies the generated correction signal SCI to the correction circuit 12A.

[0039] The photocoupler 13A is configured to transmit and receive signals while being electrically isolated. The light-emitting element of the photocoupler 13A is connected to the correction circuit 12A, and the light-receiving element is connected to the correction circuit 14A. The light-emitting element emits light with a brightness corresponding to the signal supplied from the correction circuit 12A. The light-receiving element receives the light emitted by the light-emitting element and supplies a light-receiving signal corresponding to the amount of light received to the correction circuit 14A.

[0040] The correction circuit 14A and the correction calculation circuit 31A of the MCU 30 constitute the output section 102A.

[0041] The correction circuit 14A generates a detection signal SI2 in accordance with the light received signal supplied from the photocoupler 13A, and is configured to correct this detection signal SI2 based on the correction signal SCI2 supplied from the correction calculation circuit 31A. The correction circuit 14A is configured to perform correction according to the characteristics of the photocoupler 13A.

[0042] The correction calculation circuit 31A is configured to estimate the characteristics of the photocoupler 13A by exchanging data with the correction calculation circuit 21A via the digital isolator 17, and to generate a correction signal SCI2 corresponding to the characteristics of the photocoupler 13A. The correction calculation circuit 31A then supplies the generated correction signal SCI2 to the correction circuit 14A.

[0043] With this configuration, the power converter 10 can generate a detection signal SI2 corresponding to the detection signal SI supplied from the current sensor 44, while reducing the influence of the characteristics of the photocoupler 13A. That is, the current transfer ratio (CTR) of the photocoupler 13A can change depending on environmental conditions such as temperature. This current transfer ratio is the ratio of the light-emitting current flowing through the light-emitting element of the photocoupler 13A to the light-receiving current flowing through the light-receiving element. Furthermore, this current transfer ratio can decrease over time, for example. Thus, since the current transfer ratio of the photocoupler 13A changes, the detection signal SI2 can change even if the detection signal SI is the same. The power converter 10 generates the detection signal SI2 by performing a correction according to the characteristics of the photocoupler 13A. As a result, the power converter 10 can suppress the influence of the characteristics of the photocoupler 13A on the detection signal SI2.

[0044] The correction circuit 12B and the correction calculation circuit 21B of the MCU 20 constitute the correction unit 101B.

[0045] The correction circuit 12B is configured to correct the detection signal SV supplied from the voltage sensor 46, similar to the correction circuit 12A. Based on the correction signal SCV supplied from the correction calculation circuit 21B, the correction circuit 12B corrects the detection signal SV according to the characteristics of the photocoupler 13B. The correction circuit 12B then drives the light-emitting element of the photocoupler 13B based on the corrected detection signal SV.

[0046] Similar to the correction calculation circuit 21A, the correction calculation circuit 21B is configured to understand the characteristics of the photocoupler 13B by exchanging data with the correction calculation circuit 31B via the digital isolator 17, and to generate a correction signal SCV according to the characteristics of the photocoupler 13B. The correction calculation circuit 21B then supplies the generated correction signal SCV to the correction circuit 12B.

[0047] Photocoupler 13B, like photocoupler 13A, is configured to transmit and receive signals while being electrically isolated. The light-emitting element of photocoupler 13B is connected to correction circuit 12B, and the light-receiving element is connected to correction circuit 14B.

[0048] The correction circuit 14B and the correction calculation circuit 31B of the MCU 30 constitute the output section 102B.

[0049] Similar to the correction circuit 14A, the correction circuit 14B generates a detection signal SV2 in response to the light received signal supplied from the photocoupler 13B, and is configured to correct this detection signal SV2 based on the correction signal SCV2 supplied from the correction calculation circuit 31B. The correction circuit 14B is configured to perform correction according to the characteristics of the photocoupler 13B.

[0050] Similar to the correction calculation circuit 31A, the correction calculation circuit 31B is configured to estimate the characteristics of the photocoupler 13B by exchanging data with the correction calculation circuit 21B via the digital isolator 17, and to generate a correction signal SCV2 corresponding to the characteristics of the photocoupler 13B. The correction calculation circuit 31B then supplies the generated correction signal SCV2 to the correction circuit 14B.

[0051] With this configuration, the power converter 10 can generate a detection signal SV2 corresponding to the detection signal SV supplied from the voltage sensor 46, while reducing the influence of the characteristics of the photocoupler 13B, similar to the case of the detection signal SI.

[0052] One end of the resistor 15A is connected to the output terminal of the correction circuit 14A and the negative input terminal of the amplifier 16A, while the other end is connected to the positive input terminal of the amplifier 16A and the balance terminal Vbi. As shown in Figure 1, the balance terminals Vbi of the four power converters 10 are connected to each other. As a result, the voltage at the balance terminal Vbi becomes the average voltage of the detection signal SI2 of the four power converters 10.

[0053] The positive input terminal of amplifier 16A is connected to the other end of resistor element 15A and the balance terminal Vbi, while the negative input terminal is connected to one end of resistor element 15A and the output terminal of correction circuit 14A. Amplifier 16A generates a differential signal Sdfi by amplifying the voltage difference across the ends of resistor element 15A.

[0054] One end of the resistor element 15B is connected to the output terminal of the correction circuit 14B and the negative input terminal of the amplifier 16B, while the other end is connected to the positive input terminal of the amplifier 16B and the balance terminal Vbv. As shown in Figure 1, the balance terminals Vbv of the four power converters 10 are connected to each other. As a result, the voltage at the balance terminal Vbv becomes the average voltage of the detection signal SV2 of the four power converters 10.

[0055] The positive input terminal of amplifier 16B is connected to the other end of resistor element 15B and the balance terminal Vbv, while the negative input terminal is connected to one end of resistor element 15B and the output terminal of correction circuit 14B. Amplifier 16B generates a differential signal Sdfv by amplifying the voltage difference across the ends of resistor element 15B.

[0056] The adjustment calculation circuit 32A is configured to generate a difference value Cdfi that changes according to the difference signal Sdfi by performing a predetermined adjustment calculation process based on the digital value of the difference signal Sdfi. The adjustment calculation circuit 32B is configured to generate a difference value Cdfv that changes according to the difference signal Sdfv by performing a predetermined adjustment calculation process based on the digital value of the difference signal Sdfv.

[0057] The command value generation circuit 33 is configured to generate a voltage command value CMV for the output voltage Vout of the power converter 10, and a current command value CMI for the output current Iout.

[0058] The adder circuit 34A is configured to generate a voltage command value CMV2 by adding the difference value Cdfi and the voltage command value CMV. The adder circuit 34B is configured to generate a current command value CMI2 by adding the difference value Cdfv and the current command value CMI.

[0059] The digital isolator 17 is configured to supply digital signals from the MCU 20 to the MCU 30 and to supply digital signals from the MCU 30 to the MCU 20. The digital isolator 17 is configured to electrically isolate the MCU 20 and the MCU 30 while facilitating the exchange of digital signals.

[0060] The positive input terminal of the error amplifier 22A is supplied with the voltage command value CMV2, which is provided from the MCU 30 via the digital isolator 17, and the negative input terminal is supplied with the digital value of the detection signal SV, which is provided from the voltage sensor 46. The digital value of the detection signal SV corresponds to the digital value of the output voltage Vout of the power converter 10. The error amplifier 22A generates the error value Cerv by amplifying the difference between the voltage command value CMV2 and the digital value of the detection signal SV.

[0061] The positive input terminal of the error amplifier 22B is supplied with the current command value CMI2, which is supplied from the MCU 30 via the digital isolator 17, and the negative input terminal is supplied with the digital value indicated by the detection signal SI supplied from the current sensor 44. The digital value of the detection signal SI corresponds to the digital value of the output current Iout of the power converter 10. The error amplifier 22B generates the error value Ceri by amplifying the difference between the current command value CMI2 and the digital value of the detection signal SI.

[0062] The switching control circuit 23 is configured to generate a gate signal SG1 based on error values ​​Cerv and Ceri, and to use this gate signal SG1 to control the operation of the isolated power conversion circuit 11.

[0063] The isolated drive circuit 18 is configured to generate a gate signal SG based on the gate signal SG1 and to use this gate signal SG to drive the transistors SW1 and SW2 (Figure 4) of the isolated power conversion circuit 11. The MCU 20 that generates the gate signal SG1 is a secondary circuit, and the transistors SW1 and SW2 to which the gate signal SG is supplied are primary circuits. Therefore, the isolated drive circuit 18 drives the transistors SW1 and SW2 while electrically isolating the MCU 20 from the transistors SW1 and SW2 based on the gate signal SG1.

[0064] In this configuration, the power converter 10 performs negative feedback control so that the output voltage Vout detected by the voltage sensor 46 (Figure 4) becomes equal to the voltage indicated by the voltage command value CMV2, and also performs negative feedback control so that the output current Iout detected by the current sensor 44 becomes equal to the current indicated by the current command value CMI2. This negative feedback control may be P (Proportional) control or PI (Proportional and Integral) control.

[0065] Furthermore, the power conversion system 1 can maintain the balance of the output currents Iout in power converters 10A to 10D. For example, if the output current Iout of power converter 10A is greater than the output currents Iout of power converters 10B to 10D, then in power converter 10A, the voltage of the detection signal SI2 is higher than the voltage at the balance terminal Vbi, so the difference signal Sdfi becomes smaller, the difference value Cdfi becomes smaller, and the voltage command value CMV2 becomes smaller. As a result, the output voltage Vout of power converter 10A is controlled to be lower, so the output current Iout of power converter 10A becomes smaller. On the other hand, if the output current Iout of power converter 10A is less than the output currents Iout of power converters 10B to 10D, then in power converter 10A, the voltage of the detection signal SI2 is lower than the voltage at the balance terminal Vbi, so the difference signal Sdfi becomes larger, the difference value Cdfi becomes larger, and the voltage command value CMV2 becomes larger. As a result, the output voltage Vout of power converter 10A is controlled to be higher, and therefore the output current Iout of power converter 10A becomes larger. The same applies to power converters 10B to 10D. In this way, in power conversion system 1, the output currents Iout of power converters 10A to 10D are controlled to be approximately equal to each other.

[0066] Furthermore, the power conversion system 1 can maintain the balance of the output voltage Vout in power converters 10A to 10D. For example, if the output voltage Vout of power converter 10A is higher than the output voltage Vout of power converters 10B to 10D, then in power converter 10A, the voltage of the detection signal SV2 is higher than the voltage at the balance terminal Vbv, so the difference signal Sdfv becomes smaller, the difference value Cdfv becomes smaller, and the current command value CMI2 becomes smaller. As a result, the output current Iout of power converter 10A is controlled to become smaller, so the output voltage Vout of power converter 10A becomes lower. On the other hand, if the output voltage Vout of power converter 10A is lower than the output voltage Vout of power converters 10B to 10D, then in power converter 10A, the voltage of the detection signal SV2 is lower than the voltage at the balance terminal Vbv, so the difference signal Sdfv becomes larger, the difference value Cdfv becomes larger, and the current command value CMI2 becomes larger. As a result, the output current Iout of power converter 10A is controlled to increase, so the output voltage Vout of power converter 10A increases. The same applies to power converters 10B to 10D. In this way, in power conversion system 1, the output voltages Vout of power converters 10A to 10D are controlled to be approximately equal to each other.

[0067] Figure 5 shows a more specific configuration example of the correction unit 101A and the output unit 102A. The correction unit 101A, the photocoupler 13A, and the output unit 102A constitute the signal generation circuit 100A. Based on the detection signal SI in the secondary circuit supplied from the current sensor 44, the signal generation circuit 100A generates a detection signal SI2 in the tertiary circuit that corresponds to the detection signal SI, while reducing the influence of the characteristics of the photocoupler 13A.

[0068] (Correction unit 101A) The correction calculation circuit 21A of the correction unit 101A includes an AD conversion circuit 121A, a CTR correction circuit 122A, a DA conversion circuit 123A, a transmission circuit 124A, and a reception circuit 125A.

[0069] The AD conversion circuit 121A is configured to generate a detected value CI, which is the digital value of the detected signal SI, by performing AD conversion at a predetermined sampling frequency based on the detected signal SI supplied from the current sensor 44.

[0070] The CTR correction circuit 122A is configured to generate a correction value CCI based on the detected value CI, using a parameter PARA, which is supplied from the receiving circuit 125A and indicates an estimated value of the current transfer rate of the photocoupler 13A. The CTR correction circuit 122A may, for example, generate a correction function based on the parameter PARA, in which the detected value CI is input and the correction value CCI is output, and use this correction function to generate the correction value CCI based on the detected value CI. Alternatively, the CTR correction circuit 122A may, for example, generate a lookup table based on the parameter PARA, in which the detected value CI is input and the correction value CCI is output, and use this lookup table to generate the correction value CCI based on the detected value CI. The correction value CCI is, for example, proportional to the detected value CI and changes according to the detected value CI. The CTR correction circuit 122A is configured to, for example, increase the correction value CCI when the estimated value of the current transfer rate is small, and decrease the correction value CCI when the estimated value of the current transfer rate is large.

[0071] The DA conversion circuit 123A is configured to generate a correction signal SCI by performing DA conversion at a predetermined sampling frequency based on the correction value CCI generated by the CTR correction circuit 122A. The DA conversion circuit 123A then supplies the generated correction signal SCI to the correction circuit 12A.

[0072] The transmitting circuit 124A is configured to transmit the detected value CI generated by the AD conversion circuit 121A to the correction calculation circuit 31A via the digital isolator 17.

[0073] The receiving circuit 125A is configured to receive the parameter PARA transmitted from the correction calculation circuit 31A via the digital isolator 17 and to supply the received parameter PARA to the CTR correction circuit 122A.

[0074] The correction circuit 12A of the correction unit 101A includes resistors R1 and R2, an operational amplifier OPA1, and resistors R3 to R5. A detection signal SI is supplied to one end of resistor R1, and the other end is connected to the positive input terminal of resistor R2 and operational amplifier OPA1. A correction signal SCI is supplied to one end of resistor R2, and the other end is connected to the other end of resistor R1 and the positive input terminal of operational amplifier OPA1. The positive input terminal of operational amplifier OPA1 is connected to the other ends of resistors R1 and R2, the negative input terminal is connected to resistors R3 and R5, and the output terminal is connected to the anode of the light-emitting element (e.g., light-emitting diode) of photocoupler 13A. One end of resistor R3 is connected to the negative input terminal of operational amplifier OPA1 and resistor R5, and the other end is connected to the reference power supply node of the power supply voltage VGND2. This reference power supply node is the reference power supply node of the secondary circuit. One end of resistor R4 is connected to the cathode of the light-emitting element of photocoupler 13A and resistor R5, and the other end is connected to the reference power supply node of power supply voltage VGND2. One end of resistor R5 is connected to the negative input terminal of operational amplifier OPA1 and one end of resistor R3, and the other end is connected to the cathode of the light-emitting element of photocoupler 13A and one end of resistor R4.

[0075] In the correction circuit 12A, the detection signal SI and the correction signal SCI are combined by the resistors R1 and R2, thereby correcting the detection signal SI, and the corrected detection signal SI is supplied to the positive input terminal of the operational amplifier OPA1. The correction circuit 12A then supplies a current to the light-emitting element of the photocoupler 13A, corresponding to the voltage at the positive input terminal of the operational amplifier OPA1.

[0076] For example, if the current transfer coefficient of the photocoupler 13A is small, the photocurrent received at the photodetector of the photocoupler 13A may become small. Therefore, the correction calculation circuit 21A increases the voltage at the positive input terminal of the operational amplifier OPA1 by increasing the correction signal SCI. This prevents the photocurrent received at the photodetector of the photocoupler 13A from becoming small. Also, the current of the photocoupler 13A CommunicationWhen the ratio is large, the photocurrent at the photodetector of the photocoupler 13A may become large, so the correction calculation circuit 21A reduces the correction signal SCI, thereby lowering the voltage at the positive input terminal of the operational amplifier OPA1. This prevents the photocurrent at the photodetector of the photocoupler 13A from becoming large. In this way, the correction unit 101A corrects the detection signal SI so that the photocurrent at the photodetector of the photocoupler 13A is less affected by the current transfer rate of the photocoupler 13A.

[0077] (Output section 102A) The correction circuit 14A of the output section 102A includes resistors R6 to R9 and an operational amplifier OPA2. The correction circuit 14A connects the collector of the photodetector (e.g., phototransistor) of the photocoupler 13A to the power supply node of power supply voltage VDD3. One end of resistor R6 is connected to the emitter of the photodetector of the photocoupler 13A and resistor R7, and the other end is connected to the reference power supply node of power supply voltage VGND3. This reference power supply node is the reference power supply node of the tertiary circuit and is connected to the reference terminal GNDb (Figure 1). One end of resistor R7 is connected to the emitter of the photodetector of the photocoupler 13A and one end of resistor R6, and the other end is connected to resistors R8, R9 and the positive input terminal of the operational amplifier OPA2. One end of resistor R8 is connected to the other end of resistor R7, resistor R9, and the positive input terminal of the operational amplifier OPA2, and the other end is connected to the reference power supply node of power supply voltage VGND3. A correction signal SCI2 is supplied to one end of resistor R9, and the other end is connected to the other end of resistor R7, one end of resistor R8, and the positive input terminal of operational amplifier OPA2. The positive input terminal of operational amplifier OPA2 is connected to the other ends of resistors R7 and R9 and one end of resistor R8, the negative input terminal is connected to the output terminal of operational amplifier OPA2, and the output terminal is connected to the negative input terminal of operational amplifier OPA2. Operational amplifier OPA2 constitutes a so-called voltage follower circuit and generates a detection signal SI2. The correction circuit 14A supplies this detection signal SI2 to resistor 15A.

[0078] The correction calculation circuit 31A of the output unit 102A includes an AD conversion circuit 131A, a receiving circuit 132A, an output correction circuit 133A, a DA conversion circuit 134A, a CTR estimation circuit 135A, and a transmitting circuit 136A. The output correction circuit 133A and the CTR estimation circuit 135A constitute the processing circuit 139A.

[0079] The AD conversion circuit 131A is configured to generate a detected value CI2, which is the digital value of the detected signal SI2, by performing AD conversion at a predetermined sampling frequency based on the detected signal SI2.

[0080] The receiving circuit 132A is configured to receive the detected value CI transmitted from the correction calculation circuit 21A via the digital isolator 17 and to supply the received detected value CI to the output correction circuit 133A.

[0081] The output correction circuit 133A is configured to calculate the expected value of the detected value CI2 based on the detected value CI supplied from the receiving circuit 132A, and to generate a correction value CCI2 such that the detected value CI2 supplied from the AD conversion circuit 131A is equal to this expected value. In other words, it is desirable that the detected value CI2 is equal to the expected value obtained based on the detected value CI. However, even if the correction unit 101A performs correction processing, the detected value CI2 may deviate from the expected value. Therefore, the output correction circuit 133A is configured to generate a correction value CCI2 such that the detected value CI2 is equal to the expected value.

[0082] The DA conversion circuit 134A is configured to generate a correction signal SCI2 by performing DA conversion at a predetermined sampling frequency based on the correction value CCI2 generated by the output correction circuit 133A. The DA conversion circuit 134A then supplies the generated correction signal SCI2 to the correction circuit 14A.

[0083] The CTR estimation circuit 135A is configured to estimate the current transfer rate of the photocoupler 13A based on the correction value CCI2 generated by the output correction circuit 133A. The CTR estimation circuit 135A then supplies a parameter PARA, which indicates the estimated value of the current transfer rate, to the transmission circuit 136A. In this example, the CTR estimation circuit 135A estimates the current transfer rate based on the correction value CCI2, but is not limited to this. For example, the CTR estimation circuit 135A may estimate the current transfer rate based on processing data inside the output correction circuit 133A, or it may estimate the current transfer rate based on the detected values ​​CI and CI2.

[0084] The transmission circuit 136A is configured to transmit the parameter PARA generated by the CTR estimation circuit 135A to the correction calculation circuit 21A via the digital isolator 17.

[0085] In the correction circuit 14A, the light-receiving signal from the photo-receiving element of the photocoupler 13A and the correction signal SCI2 are combined by the resistors R7 to R9. The output correction circuit 133A generates a correction value CCI2 so that the detected value CI2 is equal to the expected value of the detected value CI2. Therefore, the output unit 102A corrects the detected signal SI2 so that it becomes the expected detected signal SI2 corresponding to the detected signal SI.

[0086] Figure 6 shows a more specific configuration example of the correction unit 101B and the output unit 102B. The correction unit 101B, the photocoupler 13B, and the output unit 102B constitute the signal generation circuit 100B. Based on the detection signal SV in the secondary circuit supplied from the voltage sensor 46, the signal generation circuit 100B generates a detection signal SV2 in the tertiary circuit corresponding to this detection signal SV, while reducing the influence of the characteristics of the photocoupler 13B.

[0087] (Correction unit 101B) The correction calculation circuit 21B of the correction unit 101B, like the correction calculation circuit 21A of the correction unit 101A (Figure 5), includes an AD conversion circuit 121B, a CTR correction circuit 122B, a DA conversion circuit 123B, a transmission circuit 124B, and a reception circuit 125B. The AD conversion circuit 121B is configured to generate a detected value CV, which is the digital value of the detected signal SV, by performing AD conversion at a predetermined sampling frequency based on the detected signal SV supplied from the voltage sensor 46. The CTR correction circuit 122B is configured to generate a correction value CCV based on the detected value CV, using a parameter PARB, which indicates an estimated value of the current transfer rate of the photocoupler 13B, supplied from the reception circuit 125B. The DA conversion circuit 123B is configured to generate a correction signal SCV by performing DA conversion at a predetermined sampling frequency based on the correction value CCV generated by the CTR correction circuit 122B. The transmitting circuit 124B is configured to transmit the detected value CV generated by the AD conversion circuit 121B to the correction calculation circuit 31B via the digital isolator 17. The receiving circuit 125B is configured to receive the parameter PARB transmitted from the correction calculation circuit 31B via the digital isolator 17 and to supply the received parameter PARB to the CTR correction circuit 122B.

[0088] The correction circuit 12B of the correction unit 101B has the same circuit configuration as the correction circuit 12A of the correction unit 101A (Figure 5). A detection signal SV is supplied to one end of the resistor element R1.

[0089] (Output section 102B) The correction circuit 14B of output unit 102B is the same as the correction circuit 14A of output unit 102A (Figure 5). A correction signal SCV2 is supplied to one end of the resistor R9. The operational amplifier OPA2 generates a detection signal SV2.

[0090] The correction calculation circuit 31B of the output unit 102B, like the correction calculation circuit 31A of the output unit 102A (Figure 5), includes an AD conversion circuit 131B, a receiving circuit 132B, an output correction circuit 133B, a DA conversion circuit 134B, a CTR estimation circuit 135B, and a transmitting circuit 136B. The output correction circuit 133B and the CTR estimation circuit 135B constitute the processing circuit 139B. The AD conversion circuit 131B is configured to generate a detected value CV2, which is the digital value of the detected signal SV2, by performing AD conversion at a predetermined sampling frequency based on the detected signal SV2. The receiving circuit 132B is configured to receive the detected value CV transmitted from the correction calculation circuit 21B via the digital isolator 17 and to supply the received detected value CV to the output correction circuit 133B. The output correction circuit 133B is configured to calculate the expected value of the detected value CV2 based on the detected value CV supplied from the receiving circuit 132B, and to generate a correction value CCV2 such that the detected value CV2 supplied from the AD conversion circuit 131B is equal to this expected value. The DA conversion circuit 134B is configured to generate a correction signal SCV2 by performing DA conversion at a predetermined sampling frequency based on the correction value CCV2 generated by the output correction circuit 133B. The CTR estimation circuit 135B is configured to estimate the current transfer rate of the photocoupler 13B based on the correction value CCV2. The CTR estimation circuit 135B is configured to supply a parameter PARB indicating the estimated value of the current transfer rate to the transmission circuit 136B. The transmission circuit 136B is configured to transmit the parameter PARB generated by the CTR estimation circuit 135B to the correction calculation circuit 21B via the digital isolator 17.

[0091] Here, the input power terminals Vip and Vin correspond to one specific example of the "input power terminals" in this disclosure. The output power terminals Vop and Von correspond to one specific example of the "output power terminals" in this disclosure. The current sensor 44 or voltage sensor 46 corresponds to one specific example of the "sensor" in this disclosure. The isolated power conversion circuit 11 corresponds to one specific example of the "power conversion circuit" in this disclosure.Switching control circuit 23 corresponds to one specific example of the “control circuit” in this disclosure. Signal generation circuit 100A or signal generation circuit 100B corresponds to one specific example of the “signal generation circuit” in this disclosure. Detection signal SI or detection signal SV corresponds to one specific example of the “first detection signal” in this disclosure. Detection signal SI2 or detection signal SV2 corresponds to one specific example of the “second detection signal” in this disclosure. Correction unit 101A or correction unit 101B corresponds to one specific example of the “correction unit” in this disclosure. Photocoupler 13A or photocoupler 13B corresponds to one specific example of the “photocoupler” in this disclosure. Output unit 102A or output unit 102B corresponds to one specific example of the “output unit” in this disclosure. AD conversion circuit 121A or AD conversion circuit 121B corresponds to one specific example of the “first AD conversion circuit” in this disclosure. Detection value CI or detection value CV corresponds to one specific example of the “first digital value” in this disclosure. The digital isolator 17 corresponds to one specific example of a “digital isolator” in this disclosure. The AD conversion circuit 131A or AD conversion circuit 131B corresponds to one specific example of a “second AD conversion circuit” in this disclosure. The detected value CI2 or detected value CV2 corresponds to one specific example of a “second digital value” in this disclosure. The processing circuit 139A or processing circuit 139B corresponds to one specific example of a “processing circuit” in this disclosure. The parameter PARA or parameter PARB corresponds to one specific example of a “parameter” in this disclosure. The balance terminals Vbi and Vbv correspond to one specific example of a “signal terminal” in this disclosure.

[0092] [Action and function] Next, the operation and function of the power conversion system 1 of this embodiment will be described.

[0093] (Overview of overall operation) First, the overall operation of the power conversion system 1 will be explained with reference to Figures 1 and 3. In each of the four power conversion devices 10, the isolated power conversion circuit 11 converts the DC power supplied via the input power terminals Vip and Vin, and outputs the converted DC power via the output power terminals Vop and Von.

[0094] The signal generation circuit 100A (correction unit 101A, photocoupler 13A, and output unit 102A) generates a detection signal SI2 corresponding to the detection signal SI supplied from the current sensor 44, while reducing the influence of the characteristics of the photocoupler 13A. The signal generation circuit 100A then supplies the generated detection signal SI2 to one end of the resistor element 15A. The voltage at the balance terminal Vbi becomes the average voltage of the detection signals SI2 of the four power converters 10.

[0095] The signal generation circuit 100B (correction unit 101B, photocoupler 13B, and output unit 102B) generates a detection signal SV2 corresponding to the detection signal SV supplied from the voltage sensor 46, while reducing the influence of the characteristics of the photocoupler 13B. The signal generation circuit 100B then supplies the generated detection signal SV2 to one end of the resistor element 15B. The voltage at the balance terminal Vbv becomes the average voltage of the detection signals SV2 of the four power converters 10.

[0096] Amplifier 16A generates a differential signal Sdfi by amplifying the voltage difference across resistor element 15A. Amplifier 16B generates a differential signal Sdfv by amplifying the voltage difference across resistor element 15B. Adjustment calculation circuit 32A generates a differential value Cdfi that changes according to the differential signal Sdfi, based on the digital value of the differential signal Sdfi. Adjustment calculation circuit 32B generates a differential value Cdfv that changes according to the differential signal Sdfv, based on the digital value of the differential signal Sdfv. Command value generation circuit 33 generates a voltage command value CMV for the output voltage Vout of the power converter 10, and a current command value CMI for the output current Iout. Adder circuit 34A generates a voltage command value CMV2 by adding the differential value Cdfi and the voltage command value CMV. Adder circuit 34B generates a current command value CMI2 by adding the differential value Cdfv and the current command value CMI. Error amplifier 22A generates an error value Cerv by amplifying the difference between the voltage command value CMV2 and the digital value of the detection signal SV. Error amplifier 22B generates an error value Ceri by amplifying the difference between the current command value CMI2 and the digital value of the detection signal SI. Switching control circuit 23 generates a gate signal SG1 based on the error values ​​Cerv and Ceri, and uses this gate signal SG1 to control the operation of the isolated power conversion circuit 11. Isolated drive circuit 18 generates a gate signal SG based on the gate signal SG1, and uses this gate signal SG to drive the transistors SW1 and SW2 of the isolated power conversion circuit 11.

[0097] (Detailed operation) The signal generation circuit 100A (correction unit 101A, photocoupler 13A, and output unit 102A) generates a detection signal SI2 corresponding to the detection signal SI supplied from the current sensor 44, while reducing the influence of the characteristics of the photocoupler 13A. This operation will be described in detail below.

[0098] In the secondary circuit, as shown in Figure 5, the AD conversion circuit 121A generates a detected value CI, which is the digital value of the detected signal SI, by performing AD conversion at a predetermined sampling frequency based on the detected signal SI supplied from the current sensor 44. The transmitting circuit 124A transmits this detected value CI to the tertiary circuit via the digital isolator 17. The receiving circuit 125A receives the parameter PARA transmitted from the tertiary circuit via the digital isolator 17. The CTR correction circuit 122A generates a correction value CCI based on the detected value CI, using the parameter PARA, which is supplied from the receiving circuit 125A and represents the estimated value of the current transfer rate of the photocoupler 13A. The correction value CCI is, for example, proportional to the detected value CI and changes according to the detected value CI. For example, the CTR correction circuit 122A increases the correction value CCI when the estimated value of the current transfer rate is small, and decreases the correction value CCI when the estimated value of the current transfer rate is large. Then, the DA conversion circuit 123A generates a correction signal SCI by performing DA conversion at a predetermined sampling frequency based on the correction value CCI generated by the CTR correction circuit 122A.

[0099] The correction circuit 12A corrects the detection signal SI based on the correction signal SCI generated by the DA conversion circuit 123A, and drives the photocoupler 13A based on the corrected detection signal SI.

[0100] The light-emitting element of the photocoupler 13A emits light with a brightness corresponding to the signal supplied from the correction circuit 12A. The light-receiving element receives the light emitted by the light-emitting element and supplies a light-receiving signal corresponding to the amount of light received to the correction circuit 14A.

[0101] In the tertiary circuit, the correction circuit 14A generates a detection signal SI2 corresponding to the light received signal supplied from the photocoupler 13A, and corrects this detection signal SI2 based on the correction signal SCI2 supplied from the correction calculation circuit 31A.

[0102] The AD conversion circuit 131A generates a detected value CI2, which is the digital value of the detected signal SI2, by performing AD conversion at a predetermined sampling frequency based on the detected signal SI2 generated by the correction circuit 14A. The receiving circuit 132A receives the detected value CI transmitted from the secondary circuit via the digital isolator 17. The output correction circuit 133A calculates the expected value of the detected value CI2 based on the detected value CI supplied from the receiving circuit 132A, and generates a correction value CCI2 so that the detected value CI2 supplied from the AD conversion circuit 131A is equal to this expected value. Then, the DA conversion circuit 134A generates a correction signal SCI2 by performing DA conversion at a predetermined sampling frequency based on the correction value CCI2 generated by the output correction circuit 133A. The correction circuit 14A corrects the detected signal SI2 based on this correction signal SCI2.

[0103] The CTR estimation circuit 135A estimates the current transfer rate of the photocoupler 13A based on the correction value CCI2 generated by the output correction circuit 133A, and generates a parameter PARA that indicates the estimated current transfer rate. The transmission circuit 124A transmits this parameter PARA to the secondary circuit via the digital isolator 17.

[0104] Figure 7 shows an example of operation of the signal generation circuit 100A, where (A) shows an example of the waveform of the detection signal SI, (B) shows an example of the waveform of the current (light emission current If) flowing through the light-emitting element of the photocoupler 13A, (C) shows an example of the waveform of the current (photodetection current Ic) flowing through the photodetector of the photocoupler 13A, (D) shows an example of the current transfer rate of the photocoupler 13A, (E) shows an example of the estimated value of the current transfer rate of the photocoupler 13A estimated by the CTR estimation circuit 135A, and (F) shows an example of the waveform of the detection signal SI2. This figure shows the characteristics when the current transfer rate of the photocoupler 13A is "100", "200", and "300", respectively. Note that the current transfer rate of the photocoupler 13A also changes depending on the operating point of the photocoupler 13A, as shown in Figure 7(D).

[0105] In the output section 102A, the CTR estimation circuit 135A of the correction calculation circuit 31A estimates the current transfer rate of the photocoupler 13A (Figure 7(E)).

[0106] In the correction unit 101A, the correction calculation circuit 21A uses an estimated value of the current transfer rate of the photocoupler 13A to generate a correction signal SCI based on a detection signal SI (Figure 7(A)) which has a sinusoidal shape in this example. The correction circuit 12A corrects the detection signal SI based on the correction signal SCI generated by the DA conversion circuit 123A, and drives the photocoupler 13A based on the corrected detection signal SI. As a result, as shown in Figure 7(B), the light-emitting current If flowing through the light-emitting element of the photocoupler 13A differs depending on the current transfer rate. Specifically, the light-emitting current If is a large current when the current transfer rate is "100" and a small current when the current transfer rate is "300".

[0107] The light-emitting element of the photocoupler 13A emits light with a brightness corresponding to the signal supplied from the correction circuit 12A. The light-receiving element receives the light emitted by the light-emitting element and supplies a light-receiving signal corresponding to the amount of light received to the correction circuit 14A.

[0108] As shown in Figure 7(C), the photodetector current Ic flowing through the photodetector of the photocoupler 13B is approximately the same regardless of the current transfer coefficient. In other words, the signal generation circuit 100A is designed to minimize the influence of the current transfer coefficient on the photodetector current Ic by increasing the light-emitting current If when the current transfer coefficient is "100" and decreasing the light-emitting current If when the current transfer coefficient is "300".

[0109] Then, in the output unit 102A, the correction circuit 14A generates a detection signal SI2 corresponding to the photoreceiving current Ic, and corrects this detection signal SI2 based on the correction signal SCI2 supplied from the correction calculation circuit 31A. In this way, the output unit 102A generates the detection signal SI2 (Figure 7(F)).

[0110] In the signal generation circuit 100A, the correction unit 101A performs correction processing on the detection signal SI, and drives the light-emitting element of the photocoupler 13A based on the corrected detection signal SI. As a result, in the signal generation circuit 100A, the current of the photocoupler 13A in relation to the detection signal SI2 is different from that of the comparative example shown below. Communication The impact of the rate can be mitigated.

[0111] (Comparative example) Next, a signal generation circuit 100R relating to a comparative example will be described. This signal generation circuit 100R does not perform any correction to the detected signal SI before the photocoupler 13A.

[0112] Figure 8 shows an example of operation of the signal generation circuit 100R, where (A) shows an example of the waveform of the current (light emission current If) flowing through the light-emitting element of the photocoupler 13A, (B) shows an example of the waveform of the current (photodetection current Ic) flowing through the photodetector of the photocoupler 13A, and (C) shows an example of the current transfer rate of the photocoupler 13A.

[0113] In this signal generation circuit 100R, no correction is made to the detection signal SI before the photocoupler 13A, so a light-emitting current If corresponding to the detection signal SI flows through the light-emitting element of the photocoupler 13A (Figure 8(A)). The light-emitting current If is approximately the same regardless of the current transfer coefficient.

[0114] On the other hand, the photodetector current Ic of the photodetector element of the photocoupler 13A differs depending on the current transfer coefficient (Figure 8(B)). That is, the photodetector current Ic is small when the current transfer coefficient is "100" and large when the current transfer coefficient is "300".

[0115] For example, if the current transfer coefficient is "300", the received photocurrent Ic is large, so the correction signal SCI2 downstream of the photocoupler 13A is relatively small. In other words, the photo received signal from the photocoupler 13A is dominant over the correction signal SCI2. In this case, the detection signal SI2 is generated based on the photo received signal from the photocoupler 13A.

[0116] For example, if the current transfer coefficient is "100", the photodetection current Ic is small, so the correction signal SCI2 may become dominant downstream of the photocoupler 13A. In this case, the detection signal SI2 is generated based on the correction signal SCI2. The correction signal SCI2 is generated by the correction calculation circuit 21A and the correction calculation circuit 31A communicating via the digital isolator 17. Therefore, delays may occur due to this communication and calculation processing, so the detection signal SI2 may be a signal with a delayed timing compared to the detection signal SI.

[0117] Thus, in the signal generation circuit 100R of the comparative example, the characteristics of the detected signal SI2 may differ depending on the current transfer rate. Since the detected signal SI2 is a signal corresponding to the output current Iout of the power converter 10, the detection accuracy of the output current Iout may decrease in the signal generation circuit 100R depending on the current transfer rate.

[0118] On the other hand, in the signal generation circuit 100A according to the embodiment, the correction unit 101A performs correction processing on the detection signal SI and drives the light-emitting element of the photocoupler 13A based on the corrected detection signal SI. As a result, as shown in Figure 7, the photoreceiving current Ic can be maintained so as not to become small, regardless of the current transfer rate of the photocoupler 13A. Therefore, for example, in the correction circuit 14A downstream of the photocoupler 13A, the photoreceiving signal of the photocoupler 13A can be made sufficiently larger than the correction signal SCI2. Thus, the detection signal SI2 can be a signal corresponding to the detection signal SI, regardless of the current transfer rate of the photocoupler 13A. As a result, the detection accuracy of the output current Iout can be improved in the signal generation circuit 100A.

[0119] The above explanation used signal generation circuit 100A as an example, but the same applies to signal generation circuit 100B. This allows signal generation circuit 100B to improve the detection accuracy of the output voltage Vout.

[0120] Thus, the power conversion device 10 includes an isolated power conversion circuit 11 having input power terminals Vip, Vin, output power terminals Vop, Von, a current sensor 44 that converts the power supplied via the input power terminals Vip, Vin and outputs the converted power via the output power terminals Vop, Von, and generates a detection signal SI corresponding to the output current, a signal generation circuit 100A that generates a detection signal SI2 corresponding to the detection signal SI, and a switching control circuit 23 that controls the operation of the isolated power conversion circuit 11. The signal generation circuit 100A includes a correction unit 101A that performs correction processing on the detection signal SI, a photocoupler 13A having a light-emitting element that emits light with a brightness corresponding to the corrected detection signal SI, a light-receiving element that receives the light emitted by the light-emitting element and generates a light-receiving signal according to the amount of light received, and an output unit 102A that outputs a detection signal SI2 corresponding to the light-receiving signal. The correction unit 101A performs correction processing according to the current transmission rate of the photocoupler 13A. As a result, the power converter 10 can maintain the photoreceiving current Ic so that it does not become small, regardless of the current transfer rate of the photocoupler 13A, as shown in Figure 7, thereby improving the detection accuracy of the output current Iout.

[0121] In the power converter 10, the signal generation circuit 100A includes an AD conversion circuit 121A that generates a detected value CI by AD conversion of the detected signal SI, a digital isolator 17, an AD conversion circuit 131A that generates a detected value CI2 by AD conversion of the detected signal SI2, and a processing circuit 139A that estimates the current transfer rate based on the detected value CI and detected value CI2 supplied via the digital isolator 17, and generates a parameter PARA corresponding to the estimated current transfer rate. The correction unit 101A performs correction processing according to the current transfer rate based on the parameter PARA. As a result, the signal generation circuit 100A can perform correction processing on the detected signal SI using the estimated current transfer rate. Therefore, even if the current transfer rate changes due to temperature or changes over time, for example, the correction unit 101A can effectively perform correction processing on the detected signal SI according to the change. As a result, the power converter 10 can improve the detection accuracy of the output current Iout.

[0122] The power converter 10 is further equipped with a balance terminal Vbi connected to the terminal that outputs the detection signal SI2 of the signal generation circuit 100A. The switching control circuit 23 controls the operation of the isolated power converter circuit 11 based on the voltage of the balance terminal Vbi and the voltage of the detection signal SI2. This makes it possible, for example, to make the output current Iout of multiple power converters 10 approximately equal to each other when multiple power converters 10 are provided.

[0123] These multiple power converters 10 include, for example, a power converter 10A having an output power terminal Vop connected to power node N1 guided to power terminal T21 and an output power terminal Von connected to power node N2, and a power converter 10B having an output power terminal Vop connected to power node N1 and an output power terminal Von connected to power node N2. That is, power converters 10A and 10B are connected in parallel to each other. In this case, the output current Iout in power converter 10A and the output current Iout in power converter 10B can be made approximately equal to each other.

[0124] In the power converter 10, the isolated power conversion circuit 11 has a voltage sensor 46 that generates a detection signal SV according to the output voltage. The power converter 10 is also provided with a signal generation circuit 100B that generates a detection signal SV2 according to the detection signal SV. The signal generation circuit 100B has a correction unit 101B that performs correction processing on the detection signal SV, a photocoupler 13B having a light-emitting element that emits light with a brightness corresponding to the corrected detection signal SV, a light-receiving element that receives the light emitted by the light-emitting element and generates a light-receiving signal according to the amount of light received, and an output unit 102B that outputs a detection signal SV2 according to the light-receiving signal. The correction unit 101B performs correction processing according to the current transmission rate of the photocoupler 13B. As a result, the power converter 10 can maintain the photo-receiving current Ic so that it does not become small regardless of the current transmission rate of the photocoupler 13B, thereby improving the detection accuracy of the output voltage Vout.

[0125] In the power converter 10, the signal generation circuit 100B includes an AD conversion circuit 121B that generates a detected value CV by performing AD conversion on the detected signal SV, a digital isolator 17, and an AD conversion circuit that generates a detected value CV2 by performing AD conversion on the detected signal SV2. 131B The power converter 10 includes a processing circuit 139B that estimates the current transfer rate based on the detected value CV and detected value CV2 supplied via the digital isolator 17, and generates a parameter PARB corresponding to the estimated current transfer rate. The correction unit 101B performs correction processing according to the current transfer rate based on the parameter PARB. As a result, the signal generation circuit 100B can perform correction processing on the detected signal SV using the estimated current transfer rate. Therefore, even if the current transfer rate changes due to temperature or changes over time, for example, the correction unit 101B can effectively perform correction processing on the detected signal SV according to the change. As a result, the power converter 10 can improve the detection accuracy of the output voltage Vout.

[0126] The power converter 10 is further equipped with a balance terminal Vbv connected to the terminal that outputs the detection signal SV2 of the signal generation circuit 100B. The switching control circuit 23 controls the operation of the isolated power converter circuit 11 based on the voltage of the balance terminal Vbv and the voltage of the detection signal SV2. This makes it possible, for example, to make the output voltage Vout of multiple power converters 10 approximately equal to each other when multiple power converters 10 are provided.

[0127] These multiple power converters 10 include, for example, a power converter 10A having an output power terminal Vop connected to a power node N1 led to a power terminal T21 and an output power terminal Von connected to a power node N2, and an output power terminal Vop connected to a power node N2 and a power node led to a power terminal T22. N3 The system includes a power converter 10C having an output power terminal Von connected to a power converter 10A. In other words, power converters 10A and 10C are connected in series with each other. In this case, the output voltage Vout of power converter 10A and the output voltage Vout of power converter 10C can be made approximately equal to each other.

[0128] [effect] As described above, this embodiment provides an isolated power conversion circuit having an input power terminal, an output power terminal, a current sensor that converts the power supplied through the input power terminal, outputs the converted power through the output power terminal, and generates a detection signal SI corresponding to the output current, a signal generation circuit that generates a detection signal SI2 corresponding to the detection signal SI, and a switching control circuit that controls the operation of the isolated power conversion circuit. The signal generation circuit has a correction unit that performs correction processing on the detection signal SI, a photocoupler having a light-emitting element that emits light with a brightness corresponding to the corrected detection signal SI, a light-receiving element that receives the light emitted by the light-emitting element and generates a light-receiving signal according to the amount of light received, and an output unit that outputs a detection signal SI2 corresponding to the light-receiving signal. The correction unit performs correction processing according to the current transmission rate of the photocoupler. This makes it possible to improve the detection accuracy of the output current.

[0129] In this embodiment, the signal generation circuit includes an AD conversion circuit 121A that generates a detected value CI by performing AD conversion on a detected signal SI, a digital isolator, an AD conversion circuit 131A that generates a detected value CI2 by performing AD conversion on a detected signal SI2, and a processing circuit that estimates the current transfer rate based on the detected value CI and detected value CI2 supplied via the digital isolator, and generates parameters corresponding to the estimated current transfer rate. The correction unit performs correction processing according to the current transfer rate based on the parameters. This makes it possible to improve the detection accuracy of the output current.

[0130] In this embodiment, the isolated power conversion circuit has a voltage sensor that generates a detection signal SV according to the output voltage. A signal generation circuit is provided that generates a detection signal SV2 according to the detection signal SV. The signal generation circuit has a correction unit that performs correction processing on the detection signal SV, a photocoupler having a light-emitting element that emits light with a brightness corresponding to the corrected detection signal SV, a light-receiving element that receives the light emitted by the light-emitting element and generates a light-receiving signal according to the amount of light received, and an output unit that outputs a detection signal SV2 according to the light-receiving signal. The correction unit performs correction processing according to the current transmission rate of the photocoupler. As a result, This can improve the accuracy of output voltage detection.

[0131] In this embodiment, the signal generation circuit includes an AD conversion circuit 121B that generates a detected value CV by performing an AD conversion on the detected signal SV, a digital isolator, and an AD conversion circuit that generates a detected value CV2 by performing an AD conversion on the detected signal SV2. 131B The system includes a processing circuit that estimates the current transfer rate based on the detected values ​​CV and CV2 supplied via a digital isolator, and generates parameters corresponding to the estimated current transfer rate. The correction unit performs correction processing according to the current transfer rate based on the parameters. This improves the detection accuracy of the output voltage.

[0132] [Example 1] In the above embodiment, the power converter 10 has an isolated power conversion circuit 11, but it is not limited to this. Alternatively, for example, the power converter may have a non-isolated power conversion circuit. Below, the power conversion system 2 according to this modified example will be described in detail.

[0133] Figure 9 shows an example configuration of the power conversion system 2. The power conversion system 2 has a plurality of power conversion devices 50 (in this example, four power conversion devices 50A, 50B, 50C, and 50D) and a plurality of power conversion devices 60 (in this example, four power conversion devices 60A, 60B, 60C, and 60D). The four power conversion devices 50 and the four power conversion devices 60 are arranged in a corresponding manner to each other.

[0134] Each of the four power converters 50 is an isolated DC / DC converter circuit and has input power terminals Vip and Vin, and output power terminals Vop and Von. The input power terminal Vip of power converters 50A to 50D is connected to each other and is also connected to power terminal T11. The input power terminal Vin of power converters 50A to 50D is connected to each other and is also connected to power terminal T12. The output power terminal Vop of power converter 50 is connected to the input power terminal Vip of the corresponding power converter 60, and the output power terminal Von of power converter 50 is connected to the input power terminal Vin of the corresponding power converter 60. Since power converters 50 are isolated circuits, they have a primary circuit, a transformer, and a secondary circuit, as shown in the isolated power converter circuit in Figure 4, for example.

[0135] Each of the four power converters 60 is a non-isolated DC / DC converter circuit and has input power terminals Vip, Vin, output power terminals Vop, Von, balance terminals Vbi, Vbv, and reference terminal GNDb.

[0136] The input power terminal Vip of the power converter 60 is connected to the output power terminal Vop of the corresponding power converter 50, and the input power terminal Vin of the power converter 60 is connected to the output power terminal Von of the corresponding power converter 50.

[0137] The connection of the output power terminals Vop and Von of the power converter 60 is the same as in the power conversion system 1 according to the above embodiment (Figure 1). Specifically, the output power terminals Vop of power converters 60A and 60B are connected to each other and also to power terminal T21. The output power terminals Von of power converters 60A and 60B are connected to each other and also to the output power terminals Vop of power converters 60C and 60D. The output power terminals Vop of power converters 60C and 60D are connected to each other and also to the output power terminals Von of power converters 60A and 60B. The output power terminals Von of power converters 60C and 60D are connected to each other and also to power terminal T22. In power conversion system 2, similar to the power conversion system 1 according to the above embodiment (Figure 2), power converters 60A and 60B are connected in parallel, and power converters 60C and 60D are connected in parallel. Then, power converters 60A and 60B and power converters 60C and 60D are connected in series.

[0138] The balance terminals Vbi of power converters 60A to 60D are connected to each other. The balance terminals Vbv of power converters 60A to 60D are connected to each other. The reference terminal GNDb of power converters 60A to 60D are connected to each other.

[0139] Figure 10 shows an example configuration of the power converter 60. The power converter 60 includes a non-isolated power conversion circuit 61 and a drive circuit 68.

[0140] Figure 11 shows an example configuration of a non-isolated power conversion circuit 61. The non-isolated power conversion circuit 61 includes a capacitor C3, a transistor SW3, a rectifier circuit 73, a current sensor 74, a smoothing circuit 75, and a voltage sensor 76.

[0141] One end of capacitor C3 is connected to a voltage line L31 led to the input power terminal Vip and the output power terminal Vop, and the other end is connected to a reference voltage line L32 led to the input power terminal Vin and the output power terminal Von. Transistor SW3 is an N-type field-effect transistor in this example. Transistor SW3 is located on the voltage line L31, and a gate signal SG is supplied to the gate of transistor SW3. The drain is connected to one end of capacitor C3, and the source is connected to rectifier circuit 73. Rectifier circuit 73 has a diode D3. The anode of diode D3 is connected to the reference voltage line L32, and the cathode is connected to the source of transistor SW3 on the voltage line L31. A current sensor 74 is configured to detect the output current Iout of the power converter 60. The current sensor 74 is located on the reference voltage line L32, one end is connected to the anode of diode D3 and the other end of capacitor C3, and the other end is connected to smoothing circuit 75. Smoothing circuit 75 has an inductor L2 and a capacitor C4. Inductor L2 is located on the voltage line L31, and one end is a diode. D3 The cathode of the transistor SW3 and the source of the transistor SW3 are connected, and the other end is connected to the capacitor C4. One end of the capacitor C4 is connected to the other end of the inductor L2 on the voltage line L31, and the other end is connected to the other end of the current sensor 74 on the reference voltage line L32. The voltage sensor 76 is configured to detect the output voltage Vout of the power converter 60. One end of the voltage sensor 76 is connected to the other end of the inductor L2 on the voltage line L31, and the other end is connected to the other end of the current sensor 74 on the reference voltage line L32.

[0142] As shown in Figure 9, the four power converters 50A to 50D are supplied with DC power from the DC power supply PDC. Therefore, the operating voltages of the primary circuits of power converters 50A to 50D are equal to each other.

[0143] In Figure 10, the non-isolated power conversion circuit 61, correction circuits 12A and 12B, MCU 20, and drive circuit 68 constitute the secondary circuit. The correction circuits 14A and 14B, resistors 15A and 15B, amplifiers 16A and 16B, and MCU 30 constitute the tertiary circuit.

[0144] Similar to the power conversion system 1 described above (Figure 2), power converters 60A and 60B and power converters 60C and 60D are connected in series. Therefore, the operating voltage of power converters 60A and 60B, with respect to the power terminal T22 of the secondary circuit, is higher than the operating voltage of power converters 60C and 60D, with respect to the power terminal T22 of the secondary circuit.

[0145] As shown in Figure 9, the reference terminal GNDb of the four power converters 60 are connected to each other. Therefore, the reference voltage of the tertiary circuit in the four power converters 60 is the same, and thus the operating voltage of the tertiary circuit in the four power converters 60 is equal to each other.

[0146] The drive circuit 68 (Figure 10) is configured to generate a gate signal SG based on the gate signal SG1 and to drive the transistor SW3 (Figure 11) of the non-isolated power conversion circuit 61 using this gate signal SG. The MCU 20 that generates the gate signal SG1 and the transistor SW3 to which the gate signal SG is supplied are both secondary side circuits. Therefore, the drive circuit 68 drives the transistor SW3 based on the gate signal SG1 without electrically isolating the MCU 20 and the transistor SW3.

[0147] In this configuration, the power converter 60 performs negative feedback control so that the output voltage Vout detected by the voltage sensor 76 becomes equal to the voltage indicated by the voltage command value CMV2, similar to the power converter 10 according to the above embodiment. Furthermore, negative feedback control is performed so that the output current Iout detected by the current sensor 74 becomes equal to the current indicated by the current command value CMI2.

[0148] Furthermore, in the power conversion system 2, similar to the power conversion system 1 according to the above embodiment, the balance of the output current Iout in the power conversion devices 60A to 60D can be maintained, and the balance of the output voltage Vout in the power conversion devices 60A to 60D can be maintained.

[0149] [Differentiation 2] In the above embodiment, the estimated value of the current transfer rate of the photocoupler 13A was used as the parameter PARA, but it is not limited to this, and various parameters corresponding to the estimated value of the current transfer rate of the photocoupler 13A can be used as the parameter PARA. Specifically, for example, if the CTR correction circuit 122A generates a corrected value CCI using a correction function in which a detected value CI is input and a corrected value CCI is output, the parameter representing this correction function may be used as the parameter PARA. Also, for example, if the CTR correction circuit 122A generates a corrected value CCI using a lookup table in which a detected value CI is input and a corrected value CCI is output, the parameter representing this lookup table may be used as the parameter PARA. Similarly, although the estimated value of the current transfer rate of the photocoupler 13B was used as the parameter PARB, it is not limited to this, and various parameters corresponding to the estimated value of the current transfer rate of the photocoupler 13B can be used as the parameter PARB.

[0150] [Difference 3] In the above embodiment, as shown in Figures 1 and 2, the power conversion system 1 is configured by connecting power converters 10A and 10B in parallel, connecting power converters 10C and 10D in parallel, and connecting power converters 10A and 10B in series with power converters 10C and 10D. However, the system is not limited to this configuration. Alternatively, for example, as shown in Figures 12 and 13, the power conversion system 10A and 10C may be connected in series, power converters 10B and 10D may be connected in series, and power converters 10A and 10C may be connected in parallel with power converters 10B and 10D. In this example, the modified configuration was applied to the power conversion system 1 shown in Figures 1 and 2, but it may also be applied to the power conversion system 2 shown in Figure 9.

[0151] [Other variations] Furthermore, these variations may be combined.

[0152] Although the present invention has been described above with reference to embodiments and modifications, the present invention is not limited to these embodiments and various modifications are possible.

[0153] For example, in the embodiments described above, the present technology was applied to a power conversion device having a power conversion circuit with the circuit configuration shown in Figure 4, 11, for example. However, the present technology is not limited to this and can be applied to power conversion devices having various circuit configurations to which it can be applied.

[0154] For example, in the above embodiment, both signal generation circuits 100A and 100B are provided, but the invention is not limited to this, and instead, for example, only one of the signal generation circuits 100A and 100B may be provided.

[0155] For example, in the above embodiment, as shown in Figures 1 and 2, four power converters 10 are provided, but the invention is not limited to this, and for example, one or more power converters 10 can be provided. When multiple power converters 10 are provided, they may be connected in series or in parallel. Also, as shown in Figure 2, a device consisting of multiple power converters 10 connected in parallel may be connected in series. Similarly, in this example, as shown in Figure 9, four power converters 60 are provided, but the invention is not limited to this, and for example, one or more power converters 60 can be provided. [Explanation of Symbols]

[0156] 1,1A,2...Power conversion system, 11...Isolated power conversion circuit, 12A,12B...Correction circuit, 13A,13B...Photocoupler, 14A,14B...Correction circuit, 15A,15B...Resistor element, 16A,16B...Amplifier, 17...Digital isolator, 18...Isolated drive circuit, 20...MCU, 21A,21B...Correction calculation circuit, 22A,22B...Error amplifier, 23...Switching control circuit, 30...MCU, 31A,31B...Correction calculation circuit, 32A,32B...Adjustment calculation circuit, 33...Command value generation circuit, 34A,34B...Adding circuit, 41...Primary winding, 42...Secondary winding 43,73…Rectifier circuit, 44,74…Current sensor, 45,75…Smoothing circuit, 46,76…Voltage sensor, 50,50A~50D…Power converter, 61…Non-isolated power converter circuit, 68…Drive circuit, 10,10A~10D,60,60A~60D…Power converter, 100A,100B…Signal generation circuit, 101A,101B…Correction unit, 102A,102B…Output unit, 121A,121B…AD conversion circuit, 122A,122B…CTR correction circuit, 123A,123B…DA conversion circuit, 124A,124B…Transmitting circuit, 125A,125B…Receiver circuit, 131A,1 31B…AD conversion circuit, 132A,132B…Receiver circuit, 133A,133B…Output correction circuit, 134A,134B…DA conversion circuit, 135A,135B…CTR estimation circuit, 136A,136B…Transmitter circuit, 139A,139B…Processing circuit, Cdfi,Cdfv…Difference value, Ceri,Cerv…Error value, CCI,CCI2,CCV,CCV2…Correction value, CI,CI2,CV,CV2…Detection value, CMI,CMI2…Current command value, CMV,CMV2…Voltage command value, C1~C4…Capacitor, D1~D3…Diode, GNDb…Reference terminal, Iout…Output power Current, L1...Inductor, L11, L21, L31...Voltage lines, L12, L22, L32...Reference voltage lines, N1~N3...Power nodes, OPA1, OPA2...Operational amplifiers, PARA, PARB...Parameters, R1~R9...Resistor elements, SCI, SCI2, SCV, SCV2...Correction signals, Sdfi, Sdfv...Difference signals, SG, SG1...Gate signals, SI, SI2, SV, SV2...Detection signals, SW1~SW3...Transistors, T11, T12, T21, T22...Power terminals, TR...Transformers, Vbi, Vbv...Balance terminals, Vip, Vin...Input power terminals, Vop,Von…Output power terminal, Vout…Output voltage.

Claims

1. Input power terminals, Output power terminal and A power conversion circuit having a sensor capable of converting power supplied via the input power terminal, outputting the converted power via the output power terminal, and generating a first detection signal corresponding to the output voltage or output current, A signal generation circuit capable of generating a second detection signal corresponding to the first detection signal, A control circuit capable of controlling the operation of the power conversion circuit and Equipped with, The aforementioned signal generation circuit is A correction unit capable of performing correction processing on the first detection signal, A photocoupler having a light-emitting element capable of emitting light with a brightness corresponding to the first detection signal after the correction process described above, and a light-receiving element capable of receiving light emitted by the light-emitting element and generating a light-receiving signal corresponding to the amount of light received, An output unit capable of outputting the second detection signal corresponding to the light received signal, It has, The correction unit is capable of performing the correction process according to the current transmission rate of the photocoupler. The aforementioned signal generation circuit is A first AD conversion circuit capable of generating a first digital value by performing AD conversion on the first detection signal, Digital isolators and, A second AD conversion circuit capable of generating a second digital value by performing AD conversion on the second detection signal, A processing circuit capable of estimating the current transfer rate based on the first digital value and the second digital value supplied via the digital isolator, and generating parameters corresponding to the estimated current transfer rate. It has, The correction unit can perform the correction process according to the current transfer rate based on the parameters. Power converter.

2. The processing circuit is capable of correcting the second detection signal based on the first digital value and the second digital value supplied via the digital isolator. The power conversion device according to claim 1.

3. The signal generation circuit further comprises a signal terminal connected to the terminal that outputs the second detection signal, The control circuit can control the operation of the power conversion circuit based on the voltage of the signal terminal and the voltage of the second detection signal. A power conversion device according to claim 1 or claim 2.

4. Input power terminal and Output power terminal and A power conversion circuit having a sensor capable of converting power supplied via the input power terminal, outputting the converted power via the output power terminal, and generating a first detection signal corresponding to the output voltage or output current, A signal generation circuit capable of generating a second detection signal corresponding to the first detection signal, A control circuit capable of controlling the operation of the power conversion circuit, The signal terminal connected to the terminal of the signal generation circuit that outputs the second detection signal and Equipped with, The aforementioned signal generation circuit is A correction unit capable of performing correction processing on the first detection signal, A photocoupler having a light-emitting element capable of emitting light with a brightness corresponding to the first detection signal after the correction process described above, and a light-receiving element capable of receiving light emitted by the light-emitting element and generating a light-receiving signal corresponding to the amount of light received, An output unit capable of outputting the second detection signal corresponding to the light received signal, It has, The correction unit is capable of performing the correction process according to the current transmission rate of the photocoupler. The control circuit can control the operation of the power conversion circuit based on the voltage of the signal terminal and the voltage of the second detection signal. Power converter.

5. Equipped with multiple power conversion devices, Each of the aforementioned multiple power converters is Input power terminals, Output power terminal and A power conversion circuit having a sensor capable of converting power supplied via the input power terminal, outputting the converted power via the output power terminal, and generating a first detection signal corresponding to the output voltage or output current, A signal generation circuit capable of generating a second detection signal corresponding to the first detection signal, A signal terminal connected to the terminal of the signal generation circuit that outputs the second detection signal, A control circuit capable of controlling the operation of the power conversion circuit based on the voltage of the signal terminal and the voltage of the second detection signal, Equipped with, The signal terminals of each of the aforementioned power converters are connected to one another. The aforementioned signal generation circuit is A correction unit capable of performing correction processing on the first detection signal, A photocoupler having a light-emitting element capable of emitting light with a brightness corresponding to the first detection signal after the correction process described above, and a light-receiving element capable of receiving light emitted by the light-emitting element and generating a light-receiving signal corresponding to the amount of light received, An output unit capable of outputting the second detection signal corresponding to the light received signal, It has, The correction unit is capable of performing the correction process according to the current transmission rate of the photocoupler. Power conversion system.

6. Each of the output power terminals of the plurality of power converters includes a power terminal and a reference power terminal. The plurality of power converters, A first power converter having a power terminal connected to a first power node and a reference power terminal connected to a second power node, A second power converter having the power terminal connected to the first power node and the reference power terminal connected to the second power node. including The power conversion system according to claim 5.

7. Each of the output power terminals of the plurality of power converters includes a power terminal and a reference power terminal. The plurality of power converters, A first power converter having a power terminal connected to a first power node and a reference power terminal connected to a second power node, A third power converter having the power terminal connected to the second power node and the reference power terminal connected to the third power node. including The power conversion system according to claim 5 or claim 6.

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