Power conversion circuit, motor controller, inverter and charging pile

Abstract

The utility model discloses a power conversion circuit, a motor controller, an inverter and a charging pile. Any phase of the power conversion circuit comprises a first power device, a second power device, an impedance device, a voltage sampling circuit and a processor. The first power device is connected with the second power device through the impedance device; the voltage sampling circuit is used for collecting voltage at two ends of the impedance device; the output end of the voltage sampling circuit is connected with the input end of the processor, and the output end of the processor is connected with the first drive circuit of the first power device and the second drive circuit of the second power device. According to the embodiment of the invention, the mode that the voltage sampling circuit collects the voltage at the two ends of the impedance device connected with the power device is adopted, the power conversion circuit is suitable for detecting interphase short circuit type overcurrent and bridge arm direct connection type overcurrent, and the cost of the power conversion circuit is reduced.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a power conversion circuit, a motor controller, an inverter, and a charging pile. Background Technology

[0002] Power conversion circuits typically face two types of overcurrent: phase-to-phase short-circuit overcurrent and bridge arm direct current. Therefore, power conversion circuits are usually equipped with corresponding overcurrent detection circuits to provide overcurrent protection when an overcurrent is detected.

[0003] In related technologies, for phase-to-phase short-circuit overcurrent, a current sensor is used to detect the phase-to-phase current to determine whether a phase-to-phase short-circuit overcurrent has occurred in the power conversion circuit; for bridge arm direct current, the inter-electrode voltage of the power devices is detected to determine whether a bridge arm direct current has occurred. However, neither of these overcurrent detection methods can be applied to both types of overcurrent simultaneously, requiring the power conversion circuit to be configured with two different overcurrent detection circuits, thereby increasing the cost of the power conversion circuit. Utility Model Content

[0004] To address the aforementioned issues, this application provides a power conversion circuit, a motor controller, an inverter, and a charging pile, which use the same method to achieve overcurrent detection in two different scenarios, thereby reducing the cost of the power conversion circuit.

[0005] The embodiments of this application disclose the following technical solutions:

[0006] In a first aspect, embodiments of this application provide a power conversion circuit, wherein any phase power conversion circuit includes: a first power device, a second power device, an impedance device, a voltage sampling circuit, and a processor;

[0007] The first power device is connected to the second power device through an impedance device; a voltage sampling circuit is used to collect the voltage across the impedance device; the output of the voltage sampling circuit is connected to the input of the processor, and the output of the processor is connected to the first drive circuit of the first power device and the second drive circuit of the second power device.

[0008] Optionally, any phase power conversion circuit may further include: a comparator circuit;

[0009] The positive input terminal of the comparator circuit is connected to the output terminal of the voltage sampling circuit, the negative input terminal of the comparator circuit is connected to the reference voltage, and the output terminal of the comparator circuit is connected to the processor.

[0010] Optionally, the voltage sampling circuit includes a first resistor, a second resistor, and an isolation optocoupler chip;

[0011] The positive terminal of the isolation optocoupler chip is connected to the first end of the impedance device through a first resistor, and the negative terminal of the isolation optocoupler chip is connected to the second end of the impedance device through a second resistor.

[0012] The output of the isolation optocoupler chip is connected to the processor or the input of the comparator circuit.

[0013] Optionally, the voltage sampling circuit may further include: a diode;

[0014] The positive terminal of the diode is connected to the negative terminal of the isolation optocoupler chip, and the negative terminal of the diode is connected to the positive terminal of the isolation optocoupler chip.

[0015] Optionally, any phase power conversion circuit may further include: a filter circuit;

[0016] The first end of the filter circuit is connected to the output of the voltage sampling circuit or the output of the comparator circuit, and the second end of the filter circuit is connected to the processor.

[0017] Optionally, the impedance device includes at least one of a resistor and an inductor.

[0018] Optionally, the processor is configured to control the first drive circuit and the second drive circuit to stop outputting drive signals when the voltage across the impedance device is greater than a reference voltage.

[0019] Secondly, embodiments of this application provide a motor controller, including a power conversion circuit as described in any embodiment of the first aspect;

[0020] The DC side of the power conversion circuit is used to connect to a DC source, and the AC side of the power conversion circuit is used to connect to a motor.

[0021] Thirdly, embodiments of this application provide an inverter, including a power conversion circuit as described in any embodiment of the first aspect;

[0022] The DC side of the power conversion circuit is used to connect to the photovoltaic modules, while the AC side of the power conversion circuit is used to connect to the power grid.

[0023] Fourthly, embodiments of this application provide a charging pile, including a power conversion circuit as described in any embodiment of the first aspect;

[0024] The AC side of the power conversion circuit is used to connect to the power grid, and the DC side of the power conversion circuit is used to connect to the device to be charged.

[0025] The power conversion circuit in this application embodiment includes, for each phase, a first power device, a second power device, a voltage sampling circuit, and a processor. The first power device is connected to the second power device via an impedance device. The voltage sampling circuit is used to collect the voltage across the impedance device. The output of the voltage sampling circuit is connected to the input of the processor, and the output of the processor is connected to the first drive circuit of the first power device and the second drive circuit of the second power device. The method of collecting the voltage across the impedance device connected to the power device in this application embodiment is applicable to both phase-to-phase short-circuit overcurrent detection and bridge arm shoot-through overcurrent detection, reducing the cost of the power conversion circuit. Furthermore, the overcurrent detection method described in this application embodiment also helps to reduce the size of the power conversion circuit. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of a power conversion circuit provided in an embodiment of this application;

[0028] Figure 2 A schematic diagram of a voltage acquisition circuit provided in an embodiment of this application;

[0029] Figure 3 A schematic diagram of another voltage acquisition circuit provided in an embodiment of this application;

[0030] Figure 4 A schematic diagram of a comparison circuit provided in an embodiment of this application;

[0031] Figure 5 A schematic diagram of another power conversion circuit provided in an embodiment of this application;

[0032] Figure 6 A schematic diagram of a motor controller provided in an embodiment of this application;

[0033] Figure 7 A schematic diagram of an inverter provided in an embodiment of this application;

[0034] Figure 8 This is a schematic diagram of a charging pile provided in an embodiment of this application. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order of objects. For example, "first resistor" and "second resistor," etc., are used to distinguish different resistors, not to describe a specific order of resistors.

[0037] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this utility model should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0038] This application does not specifically limit the application scenarios of the power conversion circuit, such as motor controllers, charging piles, and inverters. For ease of understanding, the application scenario of motor controllers will be used as an example below.

[0039] In the motor controller, the DC side of the power conversion circuit is used to connect to a DC source, and the AC side of the power conversion circuit is used to connect to the motor. Each phase power conversion circuit includes: a first power device, a second power device, a voltage sampling circuit, and a processor. The first power device is connected to the second power device through an impedance device. The voltage sampling circuit is used to collect the voltage across the impedance device. The output of the voltage sampling circuit is connected to the input of the processor, and the output of the processor is connected to the first drive circuit of the first power device and the second drive circuit of the second power device.

[0040] Since the current of power devices changes periodically during operation, according to the formula UL=Ldi / dt, a voltage drop UL will inevitably be generated across the impedance device (such as inductor L). The voltage UL across inductor L is collected by a voltage sampling circuit to determine whether an overcurrent has occurred in the power conversion circuit. This embodiment of the application, through the above method, is suitable for detecting phase-to-phase short-circuit overcurrent and bridge arm direct current, thereby reducing the cost of the power conversion circuit.

[0041] The technical content of this application will now be described in conjunction with embodiments.

[0042] See Figure 1The figure is a schematic diagram of a power conversion circuit provided in an embodiment of this application.

[0043] like Figure 1 As shown, any phase power conversion circuit includes: a first power device Q1, a second power device Q2, an impedance device 100, a voltage sampling circuit 200, and a processor 300.

[0044] The first power device Q1 is connected to the second power device Q2 through the impedance device 100. The output of the voltage sampling circuit 200 is connected to the input of the processor 300. The output of the processor 300 is connected to the first drive circuit 400 of the first power device Q1 and the second drive circuit 500 of the second power device Q2. The output of the first drive circuit 400 is connected to both the first power device Q1 and the second drive circuit 500. The voltage sampling circuit 200 is used to collect the voltage across the impedance device 100.

[0045] The first power device Q1 and the second power device Q2 can both be either metal-oxide-semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs).

[0046] For example, when both the first power device Q1 and the second power device Q2 are IGBTs, the collector of the first power device Q1 is connected to the emitter of the second power device Q2 through the impedance device 100, the emitter of the first power device Q1 is connected to the positive terminal of the DC source, and the collector of the second power device Q2 is connected to the negative terminal of the DC source.

[0047] It should be understood that Figure 1 This is a schematic diagram of a single-phase power conversion circuit. For example, the U-phase power conversion circuit, V-phase power conversion circuit, or W-phase power conversion circuit in a UVW three-phase power conversion circuit.

[0048] Regarding the impedance device 100, the embodiments of this application do not specifically limit the relationship between the impedance device 100 and the power device. For example, the impedance device 100 can be a parasitic impedance in the power device or an independent impedance independent of the power device.

[0049] For example, when the impedance device 100 is the parasitic impedance of the first power device Q1, the parasitic impedance may be the parasitic inductance or parasitic resistance of the power terminal (the metal part through which a large current flows) of the first power device Q1.

[0050] In this embodiment, by utilizing the parasitic impedance in the first power device Q1 as the medium for voltage measurement, the cost and size of the power conversion circuit can be further reduced.

[0051] For example, when the impedance device 100 is independent of the impedance of the switching devices (first switching device Q1 and second switching device Q2), the impedance device can be at least one of inductors and resistors, that is, the impedance device can be an inductor, a resistor, or a combination of inductors and resistors.

[0052] For ease of understanding, this application uses the impedance device 100 as an inductor as an example to describe the voltage acquisition circuit 200.

[0053] Regarding the voltage acquisition circuit 200, the specific form of the voltage acquisition circuit 200 is not specifically limited in the embodiments of this application.

[0054] In one possible implementation, a voltage acquisition circuit such as Figure 2 As shown, the device includes a first resistor R1, a second resistor R2, and an isolation optocoupler chip U1. The positive terminal (ANODE) ​​of the isolation optocoupler chip U1 is connected to the first terminal of the inductor L through the first resistor R1, and the negative terminal (CATHODE) of the isolation optocoupler chip U1 is connected to the second terminal of the inductor L through the second resistor R2. The power supply terminal (VCC) of the isolation optocoupler chip U1 is connected to a 5V voltage, and the power reference terminal (VEE) of the isolation optocoupler chip U1 is connected to ground.

[0055] In one possible implementation, another voltage acquisition circuit is as follows: Figure 3 As shown, it includes a first resistor R1, a second resistor R2, a diode D1, and an isolation optocoupler chip U1. The anode of diode D1 is connected to the cathode of isolation optocoupler chip U1, and the cathode of diode D1 is connected to the anode of isolation optocoupler chip U1.

[0056] In this embodiment, a diode D1 is connected between the positive and negative terminals of the isolation optocoupler chip U1 to prevent reverse current from damaging the isolation optocoupler chip U1, thereby protecting the voltage sampling circuit.

[0057] The above embodiments describe the input terminal connection of the isolation optocoupler chip U1. The output terminal connection of the isolation optocoupler chip U1 will be described below.

[0058] In this embodiment, the connection method of the output terminal of the isolation optocoupler chip U1 is not specifically limited. For example, the output terminal (VOUT) of the isolation optocoupler chip U1 is connected to the input terminal of the processor 300 (the comparison between the voltage across the impedance device and the preset threshold is implemented in software), or the output terminal (VOUT) of the isolation optocoupler chip U1 is connected to the input terminal of the processor 300 through a comparison circuit (the comparison between the voltage across the impedance device and the preset threshold is implemented in hardware).

[0059] In one possible implementation, the comparison between the voltage across the impedance device and a preset threshold is implemented in hardware, specifically by connecting a comparison circuit between the processor and the isolation optocoupler chip U1. The comparison circuit is as follows: Figure 4 As shown, the system includes comparator U2. The positive input (+) of comparator U2 is connected to the output (VOUT) of the isolation optocoupler chip U1, and the negative input (-) is connected to the reference voltage Vref (preset threshold). The output of the comparator is connected to the input of the processor 300. The positive power supply terminal (V+) of comparator U2 is connected to a 5V voltage and grounded through capacitor C1, while the negative power supply terminal (V-) of comparator U2 is connected to ground. The processor is used to control the drive circuits of the first power device Q1 and the second power device Q2 to stop outputting drive signals when the comparator U2 outputs a high level, thereby turning off the first power device Q1 and the second power device Q2.

[0060] It should be understood that the preset threshold mentioned in the embodiments of this application is the voltage threshold corresponding to the overcurrent. The voltage threshold can be adjusted according to the magnitude of the overcurrent. That is, the larger the overcurrent, the larger the corresponding voltage threshold.

[0061] It should be understood that measuring voltage through the isolation optocoupler chip U1 is a mature technical method in this field, and will not be elaborated here.

[0062] In this embodiment of the application, the type of processor 300 is not specifically limited. For example, processor 300 can be any one of digital signal processor (DSP) and field programmable gate array (FPGA).

[0063] In another possible implementation, the comparison between the voltage across the impedance device and a preset threshold is implemented in software. Specifically, the output of the isolation optocoupler chip U1 is connected to the input of the processor. The processor 300 compares the acquired voltage UL across the inductor with the preset threshold. If the voltage UL is greater than the preset threshold, it controls the drive circuits of the first power device Q1 and the second power device Q2 to stop outputting drive signals, thereby turning off the first power device Q1 and the second power device Q2.

[0064] To facilitate understanding of the method by which the processor controls the shutdown of the first power device Q1 and the second power device Q2 in the embodiments of this application, a schematic diagram of a power conversion circuit is provided in the embodiments of this application. See [link to relevant documentation]. Figure 5 .

[0065] like Figure 5 As shown, when the processor is a digital signal processor (DSP), the first driving circuit of the first power device Q1 corresponds to the driving chip U3, and the second driving circuit of the second power device Q2 corresponds to the driving chip U4. The input terminals (ANODE and CATHODE) of the driving chip U3 are connected to the output terminals of the DSP, and the output terminal (VO) of the driving chip U3 is connected to the driving terminal of the first power device Q1. Similarly, the input terminals (ANODE and CATHODE) of the driving chip U4 are connected to the output terminals of the DSP, and the output terminal (VO) of the driving chip U4 is connected to the driving terminal of the second power device Q2.

[0066] In this embodiment, for the first power device Q1, when the comparator U2 outputs a high level or the voltage UL across the impedance device is greater than a preset threshold, the processor outputs a low level to the ANODE and CATHODE inputs of the first drive circuit U3 to control the first drive circuit U3 to stop outputting the drive signal for the first power device Q1 and turn off the first power device Q1; for the second power device Q2, when the comparator U2 outputs a high level or the voltage UL across the impedance device is greater than a preset threshold, the processor outputs a low level to the ANODE and CATHODE inputs of the second drive circuit U4 to control the second drive circuit U4 to stop outputting the drive signal for the second power device Q2 and turn off the second power device Q2.

[0067] This application embodiment acquires the voltage across the impedance device connected to the power device via a voltage sampling circuit. This method is applicable to both phase-to-phase short-circuit overcurrent detection and bridge arm shoot-through overcurrent detection, reducing the cost of the power conversion circuit. Furthermore, compared to bridge arm shoot-through overcurrent detection in related technologies, which detects the inter-collector voltage of the power device (e.g., the voltage between the collector and emitter of an IGBT), the voltage across the impedance device is less susceptible to external interference and is more stable and reliable.

[0068] In addition, in this embodiment, the input terminal of the processor 300 can also be connected to a filtering circuit, such as an RC filtering circuit. The input terminal of the processor 300 is connected to the output terminal of the voltage sampling circuit 200 (i.e., the output terminal VOUT of the isolation optocoupler U1) or the output terminal of the comparator circuit (i.e., the output terminal of the comparator U2) via resistor R3 in the RC filtering circuit, and capacitor C2 in the filtering circuit is grounded. In this embodiment, noise and interference in the input signal are removed by connecting the filtering circuit, thereby improving the signal quality and stability.

[0069] The power conversion circuit has been described in the foregoing embodiments. The following will describe the application scenarios of the power conversion circuit.

[0070] See Figure 6 The figure is a schematic diagram of a charging controller provided in an embodiment of this application.

[0071] like Figure 6 As shown, the charging controller includes the power conversion circuit 1000 and the controller (not shown in the figure) in any of the foregoing embodiments. The DC side of the power conversion circuit 1000 is used to connect to a DC source, and the AC side of the power conversion circuit is used to connect to a motor.

[0072] The embodiments of this application do not specifically limit the type of DC source. For example, the DC source can be a battery pack.

[0073] In this embodiment, the power conversion circuit used in the motor controller can simultaneously realize phase-to-phase short-circuit overcurrent and bridge arm direct current by detecting the voltage across the impedance device, thereby reducing the cost and size of the charging controller.

[0074] See Figure 7 The figure is a schematic diagram of an inverter provided in an embodiment of this application.

[0075] like Figure 7 As shown, the charging controller includes the power conversion circuit 1000 and the controller (not shown in the figure) in any of the foregoing embodiments. The DC side of the power conversion circuit 1000 is used to connect to a DC source, and the AC side of the power conversion circuit is used to connect to the power grid.

[0076] The embodiments of this application do not specifically limit the type of DC source. For example, the DC source can be a battery pack or a photovoltaic module.

[0077] In addition, the composition of the power conversion circuit is not specifically limited in the embodiments of this application. For example, the power conversion circuit can be a DC / AC power conversion circuit, or a combination of a DC / DC / DC power conversion circuit and a DC / AC power conversion circuit.

[0078] In this embodiment, the power conversion circuit used in the inverter can simultaneously achieve phase-to-phase short-circuit overcurrent and bridge arm direct current through current by detecting the voltage across the impedance device, thereby reducing the cost and size of the inverter.

[0079] See Figure 8 The figure is a schematic diagram of a charging pile provided in an embodiment of this application.

[0080] like Figure 8 As shown, the charging controller includes the power conversion circuit 1000 and the controller (not shown in the figure) in any of the foregoing embodiments. The AC side of the power conversion circuit 1000 is used to connect to the power grid, and the DC side of the power conversion circuit is used to connect to the device to be charged.

[0081] The embodiments of this application do not specifically limit the composition of the power conversion circuit. For example, the power conversion circuit can be an AC / DC power conversion circuit, or a combination of an AC / DC power conversion circuit and a DC / DC power conversion circuit.

[0082] In this embodiment, the power conversion circuit used in the charging pile can simultaneously realize phase-to-phase short-circuit overcurrent and bridge arm direct current by detecting the voltage across the impedance device, thereby reducing the cost and size of the charging pile.

[0083] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0084] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power conversion circuit, characterized in that, Each phase of the power conversion circuit includes: a first power device, a second power device, an impedance device, a voltage sampling circuit, and a processor; The first power device is connected to the second power device through the impedance device; The voltage sampling circuit is used to acquire the voltage across the impedance device; The output terminal of the voltage sampling circuit is connected to the input terminal of the processor, and the output terminal of the processor is connected to the first driving circuit of the first power device and the second driving circuit of the second power device.

2. The power conversion circuit according to claim 1, characterized in that, The power conversion circuit of any phase further includes: a comparator circuit; The positive input terminal of the comparator circuit is connected to the output terminal of the voltage sampling circuit, the negative input terminal of the comparator circuit is connected to the reference voltage, and the output terminal of the comparator circuit is connected to the processor.

3. The power conversion circuit according to claim 2, characterized in that, The voltage sampling circuit includes a first resistor, a second resistor, and an isolation optocoupler chip; The positive terminal of the isolation optocoupler chip is connected to the first terminal of the impedance device through the first resistor, and the negative terminal of the isolation optocoupler chip is connected to the second terminal of the impedance device through the second resistor. The output of the isolation optocoupler chip is connected to the processor or the input of the comparator circuit.

4. The power conversion circuit according to claim 3, characterized in that, The voltage sampling circuit further includes: a diode; The positive terminal of the diode is connected to the negative terminal of the isolation optocoupler chip, and the negative terminal of the diode is connected to the positive terminal of the isolation optocoupler chip.

5. The power conversion circuit according to claim 2, characterized in that, The power conversion circuit of any phase further includes: a filter circuit; The first end of the filter circuit is connected to the output end of the voltage sampling circuit or the output end of the comparison circuit, and the second end of the filter circuit is connected to the processor.

6. The power conversion circuit according to claim 1 or 2, characterized in that, The impedance device includes at least one of a resistor and an inductor.

7. The power conversion circuit according to claim 1 or 2, characterized in that, The processor is configured to control the first driving circuit and the second driving circuit to stop outputting driving signals when the voltage across the impedance device is greater than a reference voltage.

8. A motor controller, characterized in that, Includes the power conversion circuit as described in any one of claims 1-7; The DC side of the power conversion circuit is used to connect to a DC source, and the AC side of the power conversion circuit is used to connect to a motor.

9. An inverter, characterized in that, Includes the power conversion circuit as described in any one of claims 1-7; The DC side of the power conversion circuit is used to connect to the photovoltaic module, and the AC side of the power conversion circuit is used to connect to the power grid.

10. A charging pile, characterized in that, Includes the power conversion circuit as described in any one of claims 1-7; The AC side of the power conversion circuit is used to connect to the power grid, and the DC side of the power conversion circuit is used to connect to the device to be charged.

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