Control equipment and method of isolated power converter and related equipment

Abstract

The invention discloses a control device and method of an isolated power converter and a related device. The control device comprises a charging side controller, a starting power supply, an optical fiber signal receiver, an optical fiber signal transmitter and a voltage detection circuit. The input end of the starting power supply is used for connecting a charged side DC bus, and the output end of the starting power supply is used for supplying power to the optical fiber signal transmitter and the voltage detection circuit; the voltage detection circuit is used for detecting the voltage of the charged side direct current bus and sending a voltage detection result to the optical fiber signal transmitter; the optical fiber signal transmitter is used for transmitting the voltage detection result to the optical fiber signal receiver; the optical fiber signal receiver is used for sending the voltage detection result to the charging side controller; and the charging side controller is used for determining whether to continuously charge the charged side direct current bus according to the voltage detection result. According to the technical scheme, the charged side of the isolated power converter can be prevented from undervoltage or overvoltage, so that successful starting is ensured.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a control device, method, and related equipment for an isolated power converter. Background Technology

[0002] An isolated power converter includes a charging side and a charging side, with the charging side connected to a DC source.

[0003] When an isolated power converter starts up, the charging side typically powers on first to charge the side being charged. However, during the startup process, since the auxiliary power supply of the side being charged has not yet been powered on, the charging side cannot know the charging voltage of the side being charged, which may cause overcharging and pose an overvoltage risk, or undercharging, leading to startup failure. Summary of the Invention

[0004] In view of this, this application provides a control device, method and related equipment for an isolated power converter, which can ensure the successful startup of the isolated power converter.

[0005] This application provides a control device for an isolated power converter, comprising: a charging-side controller, a startup power supply, an optical fiber signal receiver, an optical fiber signal transmitter, and a voltage detection circuit; the input terminal of the startup power supply is used to connect to the DC bus on the charging side, and the output terminal of the startup power supply is used to supply power to the optical fiber signal transmitter and the voltage detection circuit; the voltage detection circuit is used to detect the voltage of the DC bus on the charging side and send the voltage detection result to the optical fiber signal transmitter; the optical fiber signal transmitter is used to send the voltage detection result to the optical fiber signal receiver; the optical fiber signal receiver is used to send the voltage detection result to the charging-side controller; the charging-side controller is used to determine whether to continue charging the DC bus on the charging side based on the voltage detection result.

[0006] One possible implementation further includes: an auxiliary power supply on the charging side and a controller on the charging side; the input terminal of the auxiliary power supply on the charging side is used to connect to the DC bus on the charging side; the output terminal of the auxiliary power supply on the charging side is used to supply power to the controller on the charging side; the power of the starting power supply is less than the power of the auxiliary power supply on the charging side.

[0007] One possible implementation further includes: a switching circuit; the input terminal of the startup power supply is connected to the DC bus on the charging side through the switching circuit; after the charging side controller establishes communication with the charging side controller, the charging side controller controls the switching circuit to disconnect the input terminal of the startup power supply from the DC bus on the charging side.

[0008] In one possible implementation, the controller on the charged side sends information indicating that the startup power is disconnected to the controller on the charging side; the controller on the charging side is further configured to, upon receiving the information indicating that the startup power is disconnected, control the voltage of the DC bus on the charged side to rise to the rated voltage.

[0009] In one possible implementation, the power supply terminal of the fiber optic signal transmitter is connected to the voltage output terminal of the controller on the charging side; the signal input terminal of the fiber optic signal transmitter is connected to the output terminal of the controller on the charging side and the voltage detection circuit; the controller on the charging side is further configured to, after establishing communication with the controller on the charging side, supply power to the fiber optic signal transmitter, send interactive data sent to the controller on the charging side to the fiber optic signal transmitter, and the fiber optic signal transmitter forwards the interactive data to the controller on the charging side through the fiber optic signal receiver.

[0010] In one possible implementation, the power supply terminal of the fiber optic signal transmitter is connected to the voltage output terminal of the startup power supply, the power supply terminal of the fiber optic signal transmitter is connected to the cathode of the first diode, and the anode of the first diode is connected to the voltage output terminal of the controller being charged; the signal input terminal of the fiber optic signal transmitter is connected to the voltage output terminal of the controller being charged through a pull-up resistor.

[0011] One possible implementation is that the startup power supply is a low-dropout linear regulator or a buck circuit.

[0012] In one possible implementation, the voltage detection circuit includes: a voltage divider circuit and a hysteresis comparator; the input terminal of the voltage divider circuit is connected to the charging-side DC bus, the output terminal of the voltage divider circuit is connected to the first input terminal of the hysteresis comparator, and the second input terminal of the hysteresis comparator is connected to a reference voltage; the output terminal of the hysteresis comparator is connected to the signal input terminal of the fiber optic signal transmitter; the charging-side controller is configured to stop charging the charging-side DC bus when the voltage detection result sent by the hysteresis comparator indicates that the voltage of the charging-side DC bus reaches a preset voltage, and otherwise continue charging the charging-side DC bus.

[0013] This application provides an isolated power converter, including: an isolated power conversion circuit and a control device for the isolated power converter described above; a first terminal of the isolated power conversion circuit is used to connect to a DC source; a second terminal of the isolated power conversion circuit is used to output DC or AC power; the control device is used to control the isolated power conversion circuit to transfer energy from the first terminal to the second terminal, or from the second terminal to the first terminal.

[0014] One possible implementation is that the DC source includes at least one of a photovoltaic panel or a battery.

[0015] In one possible implementation, the isolated power conversion circuit includes an isolated DC / DC circuit and an inverter circuit; the isolated DC / DC circuit includes a primary-side bridge arm circuit, a transformer, and a secondary-side bridge arm circuit; a first terminal of the primary-side bridge arm circuit is connected to the DC source, a second terminal of the primary-side bridge arm circuit is connected to the primary winding of the transformer, the secondary winding of the transformer is connected to the first terminal of the secondary-side bridge arm circuit, and the second terminal of the secondary-side bridge arm circuit is connected to the inverter circuit.

[0016] One possible implementation is that the isolated power conversion circuit includes an isolated DC / DC circuit; the isolated power conversion circuit includes an isolated DC / DC circuit; the isolated DC / DC circuit includes a primary-side bridge arm circuit, a transformer, and a secondary-side bridge arm circuit; a first end of the primary-side bridge arm circuit is used to connect to the DC source, a second end of the primary-side bridge arm circuit is connected to the primary winding of the transformer, and the secondary winding of the transformer is connected to the secondary-side bridge arm circuit.

[0017] This application also provides a control method for an isolated power converter, comprising: controlling a startup power supply to connect to the DC bus on the charging side; the output terminal of the startup power supply is used to supply power to the fiber optic signal transmitter and the voltage detection circuit; the voltage detection circuit detects the voltage of the DC bus on the charging side and sends the voltage detection result to the fiber optic signal transmitter; the fiber optic signal transmitter sends the voltage detection result to the fiber optic signal receiver; the fiber optic signal receiver sends the voltage detection result to the charging side controller; and the charging side controller determines whether to continue charging the DC bus on the charging side based on the voltage detection result.

[0018] One possible implementation further includes: after receiving information that the startup power supply is disconnected, the charging-side controller controls the voltage of the DC bus on the charging side to rise to the rated voltage.

[0019] One possible implementation further includes: after establishing communication with the charging side controller, the charging side controller supplies power to the fiber optic signal transmitter, sends the interactive data sent to the charging side controller to the fiber optic signal transmitter, and the fiber optic signal transmitter forwards the interactive data to the charging side controller through the fiber optic signal receiver.

[0020] One possible implementation involves determining whether to continue charging the DC bus on the charging side based on the voltage detection result, including: stopping charging the DC bus on the charging side when the voltage detection result indicates that the voltage of the DC bus on the charging side reaches a preset voltage, and continuing to charge the DC bus on the charging side otherwise.

[0021] This application also provides a control device, including a processor and a memory, wherein the memory is used to store programs, instructions or code, and the processor is used to execute the programs, instructions or code in the memory to complete the control method of the isolated power converter described above.

[0022] This application also provides a computer-readable storage medium storing a computer program, which is loaded by a processor to execute the control method for the isolated power converter described above.

[0023] The isolated power converter provided in this application embodiment includes a startup power supply, an optical fiber signal transmitter, and a voltage detection circuit on the charging side. When the isolated power converter starts up, as the charging voltage on the charging side gradually increases, the startup power supply can start quickly, thus providing power to the optical fiber signal transmitter and the voltage detection circuit. The voltage detection circuit sends the voltage detection result to the optical fiber signal transmitter, which then sends the result to the charging-side controller via an optical fiber signal receiver. The charging-side controller can determine whether to continue charging the charging side based on the voltage detection result, ensuring that the DC bus voltage on the charging side does not become over-voltage or under-voltage during startup. Therefore, the technical solution provided in this application enables the isolated power converter to successfully start up while meeting the isolation voltage requirements between the charging and charging sides. Attached Figure Description

[0024] Figure 1 A schematic diagram of a control device for an isolated power converter provided in an embodiment of this application;

[0025] Figure 2 A schematic diagram of a control device for another isolated power converter provided in an embodiment of this application;

[0026] Figure 3 A schematic diagram of a control device for another isolated power converter provided in an embodiment of this application;

[0027] Figure 4 A schematic diagram of a control device for another isolated power converter provided in an embodiment of this application;

[0028] Figure 5 This is a schematic diagram of an isolated power converter provided in an embodiment of this application;

[0029] Figure 6 A schematic diagram of yet another isolated power converter provided in the embodiments of this application;

[0030] Figure 7 A schematic diagram of another isolated power converter provided in the embodiments of this application;

[0031] Figure 8 A flowchart illustrating a control method for an isolated power converter provided in this application embodiment;

[0032] Figure 9 This is a schematic diagram of a control device provided in an embodiment of this application. Detailed Implementation

[0033] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0034] The isolated power converter provided in this application can be either an isolated DC / DC power converter or an isolated DC / AC power converter. For example, for ease of understanding, the following embodiments use an isolated DC / AC power converter as an example, which can be applied to medium-voltage or medium-high voltage direct-mounted photovoltaic inverters. Especially in medium-high voltage direct-mounted photovoltaic inverters, the isolation voltage requirement between the DC side and the AC side reaches several thousand volts or even tens of kilovolts. Therefore, to isolate the DC side and the AC side, separate DC-side controllers and AC-side controllers are required. To isolate the data exchanged between the two controllers, an optical fiber signal receiver and an optical fiber signal transmitter can be used. Since optical fiber communication uses optical signals for data transmission, the isolation voltage between the optical fiber signal receiver and the optical fiber signal transmitter can easily meet the requirement of tens of kilovolts of isolation voltage.

[0035] In medium- and high-voltage inverters, the DC-side controller and AC-side controller are typically powered from their respective DC buses. When the inverter is operating in inverter mode, the DC-side bus is generally energized. Therefore, once the DC-side auxiliary power supply is started, the DC-side control will operate normally. However, the AC-side DC bus energy generally comes from the DC side. When the inverter is not operating normally, there is no voltage on the AC-side DC bus, the AC-side auxiliary power supply cannot start, and the AC-side controller cannot operate. To enable the AC-side controller to operate normally and for the inverter to enter the operating state, the DC-side controller needs to control the DC-side switching transistors to charge the AC-side DC bus. Once voltage is established on the AC-side DC bus, the AC-side controller will operate normally and establish communication with the DC-side controller, enabling the inverter to enter the operating state. This process is called the startup process.

[0036] However, during the startup phase of an isolated power converter, for example, when the DC side acts as the charging side and the AC side as the charged side, the DC bus voltage on the AC side has not yet been established, and the AC auxiliary power supply has not yet been powered on. The AC side controller cannot inform the DC side controller whether the AC side voltage has been charged to the preset voltage, which may lead to overvoltage or undervoltage on the AC side DC bus, causing startup failure. It should be understood that the charging side and the charged side can interchange roles under certain operating conditions. Therefore, the technical solution provided in this application can automatically detect the DC bus voltage of the charged side and synchronously provide information to the charging side to determine whether the charging side should continue charging, enabling the isolated power converter to successfully start up while meeting the isolation voltage requirements.

[0037] See Figure 1 The figure is a schematic diagram of a control device for an isolated power converter provided in an embodiment of this application.

[0038] The control device for the isolated power converter provided in this application embodiment includes: a charging side controller 11, a startup power supply 22, an optical fiber signal receiver 12, an optical fiber signal transmitter 21, and a voltage detection circuit 23.

[0039] The input terminal of the power supply 22 is used to connect to the DC bus on the charging side, and the output terminal of the power supply 22 is used to power the fiber optic signal transmitter 21 and the voltage detection circuit 23.

[0040] This application does not specifically limit the topology of the startup power supply 22. For example, it can be implemented using a buck circuit or a low-dropout regulator (LDO), as long as the startup power supply 22 can draw power from the DC bus on the charging side and the output voltage meets the power supply voltage requirements of the fiber optic signal transmitter 21 and the voltage detection circuit 23. Generally, the power of the startup power supply 22 is less than the power of the auxiliary power supply on the charging side, and the startup voltage is also less than the voltage of the auxiliary power supply on the charging side. Therefore, the startup power supply 22 can start before the auxiliary power supply on the charging side, and thus, even before the auxiliary power supply on the charging side starts, the startup power supply 22 can supply power to the fiber optic signal transmitter 21 and the voltage detection circuit 23, so that the charging side can provide feedback on the voltage of the DC bus on the charging side to the charging side.

[0041] The voltage detection circuit 23 is used to detect the voltage of the DC bus on the charging side and send the voltage detection result to the fiber optic signal transmitter 21.

[0042] When the charging side charges the charging side, the voltage of the DC bus of the charging side rises. As the voltage of the DC bus of the charging side rises, the starting power supply can start quickly. Since the power and starting voltage of the starting power supply are both low, it can be powered on and started quickly. The starting voltage can output voltage to power the voltage detection circuit 23 and the fiber optic signal transmitter 21.

[0043] It should be understood that there is usually a DC bus capacitor on the charging side, and the voltage detection circuit 23 can detect the voltage of the DC bus capacitor.

[0044] The fiber optic signal transmitter 21 is used to send the voltage detection result to the fiber optic signal receiver 12. It should be understood that the fiber optic signal transmitter 21 converts the received electrical signal into an optical signal and transmits it.

[0045] The fiber optic signal receiver 12 is used to send the voltage detection result to the charging-side controller 11. It should be understood that the fiber optic signal transmitter 21 converts the received optical signal into an electrical signal and sends it to the charging-side controller 11.

[0046] The charging-side controller 11 is used to determine whether to continue charging the DC bus on the charging side based on the voltage detection result.

[0047] If the voltage detection result indicates that the voltage of the DC bus on the charging side has been charged to the required level, the charging side can stop charging the charging side. If the voltage detection result indicates that the voltage of the DC bus on the charging side is low and has not been charged to the required level, the charging side needs to continue charging the charging side to meet the startup requirements. Specifically, the charging condition for the DC bus on the charging side to be charged to the required level can be set according to the startup voltage of the auxiliary power supply on the charging side. When the auxiliary power supply on the charging side can start working, the charging side can stop charging the charging side.

[0048] The isolated power converter provided in this application embodiment includes a startup power supply, an optical fiber signal transmitter, and a voltage detection circuit on the charging side. When the isolated power converter starts up, as the charging voltage on the charging side gradually increases, the startup power supply can start quickly, thus providing power to the optical fiber signal transmitter and the voltage detection circuit. The voltage detection circuit sends the voltage detection result to the optical fiber signal transmitter, which then sends the result to the charging-side controller via an optical fiber signal receiver. The charging-side controller can determine whether to continue charging the charging side based on the voltage detection result, ensuring that the DC bus voltage on the charging side does not become over-voltage or under-voltage during startup. Therefore, the technical solution provided in this application enables the isolated power converter to successfully start up while meeting the isolation voltage requirements between the charging and charging sides.

[0049] For ease of understanding, the isolated power conversion circuit provided in the embodiments of this application includes an isolated DC / DC circuit and an inverter circuit; the isolated DC / DC circuit includes a primary-side bridge arm circuit, a transformer, and a secondary-side bridge arm circuit.

[0050] See Figure 2 This figure is a schematic diagram of the control device for another isolated power converter provided in an embodiment of this application.

[0051] In the isolated power conversion circuit provided in this application embodiment, the first end of the primary-side bridge arm circuit is used to connect to the DC source V1. The primary-side bridge arm circuit is described using a full-bridge circuit as an example, including four switching transistors Q1-Q4, with drive signals S1-S4 for each transistor. The secondary-side bridge arm circuit is also described using a full-bridge circuit as an example, including four switching transistors Q5-Q8, with drive signals S5-S8 for each transistor. The inverter circuit is also described using a full-bridge circuit as an example, including four switching transistors Q9-Q12, with drive signals S9-S12 for each transistor.

[0052] The second end of the primary-side bridge arm circuit is connected to the primary winding of transformer T1. The secondary winding of transformer T1 is connected to the first end of the secondary-side bridge arm circuit. The second end of the secondary-side bridge arm circuit is connected to the inverter circuit, i.e., to the DC side of the inverter circuit. The AC side of the inverter circuit outputs AC voltage V2 through the grid-connected inductor L1. It should be understood that the voltage difference between V1 and V2 is generally quite large, for example, greater than 3000V. Therefore, isolation between the charging side and the charged side is required. The highest isolation voltage using optocouplers, isolation operational amplifiers, isolation driver chips, etc., is only about 2000V, which is insufficient to meet the isolation requirements. Therefore, this embodiment utilizes optical fiber communication for data interaction and electrical isolation.

[0053] The charging side also includes a first capacitor C1 connected in parallel across the DC source, i.e., C1 is the DC bus capacitor of the charging side. The charging side also includes a second capacitor C2 connected in parallel across the DC bus of the charging side, C2 is the DC bus capacitor of the charging side.

[0054] Because the charging side and the charged side need to be electrically isolated, the charging side includes a charging auxiliary power supply, and the charged side includes a charged auxiliary power supply. The ground of the charging side is represented by GND1, and the ground of the charged side is represented by GND2.

[0055] The control device for the isolated power converter provided in this application embodiment further includes: an auxiliary power supply U5 on the charging side and a controller U6 on the charging side; the controller U6 on the charging side is used to output drive signals S5-S12 to drive the switching transistors Q5-Q12 in the isolated power converter respectively.

[0056] The input terminal of the auxiliary power supply U5 on the charging side is used to connect to the DC bus on the charging side; the output terminal of the auxiliary power supply U5 on the charging side is used to supply power to the controller U6 on the charging side.

[0057] The power and startup voltage of the starting power supply U7 are lower than those of the auxiliary power supply U6 on the charging side. Figure 2It can be seen that the voltage output terminal VCC of the power supply U7 provides power to the optical fiber signal transmitter U8.

[0058] One possible implementation is that the startup power supply U7 can be an LDO. For example, the rated input voltage of the startup power supply U7 is approximately DC 450V, the output voltage is 5V, the maximum current is 10mA, and the startup time is in the microsecond range. This LDO can quickly power the voltage detection circuit and the fiber optic signal transmitter U8, and the power requirements are met.

[0059] It should be understood that if the rated voltage of the DC bus capacitor on the charging side is greater than 450V, an LDO with a lower input voltage can be selected to reduce costs. It should be ensured that the preset voltage of the DC bus capacitor on the charging side is less than the rated operating voltage of the LDO, and the preset voltage can meet the starting voltage of the auxiliary power supply U5 on the AC side.

[0060] The control device provided in this application embodiment further includes a switching circuit; this application embodiment takes the switching circuit including S7 as an example for description.

[0061] The input terminal of the starting power supply U7 is connected to the DC bus on the side being charged through a switching circuit. That is, when S7 is closed, the input terminal of the starting power supply U7 is connected to the DC bus on the side being charged.

[0062] When the voltage of the DC bus on the charging side is high enough, the auxiliary power supply U5 on the charging side starts up and supplies power to the controller U6 on the charging side. Then, the controller U6 on the charging side can establish communication with the controller U3 on the charging side.

[0063] The control device provided in this application embodiment also includes a charging-side auxiliary power supply U2 and a charging-side controller U3.

[0064] Once the charging-side controller U6 establishes communication with the charging-side controller U3, the charging-side controller U6 can control the switching circuit, that is, control S7 to disconnect, so that the input terminal of the starting power supply U7 is disconnected from the DC bus of the charging side.

[0065] One possible implementation is the control device provided in this application embodiment, where the voltage detection circuit includes a voltage divider circuit and a hysteresis comparator.

[0066] The input terminal of the voltage divider circuit is connected to the DC bus on the charging side, and the output terminal of the voltage divider circuit is connected to the first input terminal of the hysteresis comparator. The second input terminal of the hysteresis comparator is connected to the reference voltage. The output terminal of the hysteresis comparator is connected to the signal input terminal of the fiber optic signal transmitter.

[0067] The charging-side controller is used to stop charging the DC bus when the voltage detection result sent by the hysteresis comparator indicates that the voltage of the DC bus being charged reaches a preset voltage, and to continue charging the DC bus if the voltage does not reach a preset voltage.

[0068] The voltage divider circuit includes a first resistor R1 and a second resistor R2 connected in series. The first terminal of switch S7 is connected to the DC positive bus of the charging side, and the second terminal of switch S7 is grounded to GND2 through the first resistor R1 and the second resistor R2 connected in series. The input terminal of the power supply U7 is connected to the second terminal of switch S7.

[0069] The hysteresis comparator includes comparator U1 and fifth resistor R5. The hysteresis comparator can reduce the sensitivity of comparator U1, so that the voltage of the second capacitor C2 fluctuates within an acceptable range. This can improve the anti-interference capability of the voltage detection circuit and prevent the voltage detection result output by the voltage detection circuit from frequently flipping when there are slight fluctuations in the voltage of the DC bus on the charging side, for example, frequently switching between low and high levels.

[0070] The voltage detection circuit also includes a Zener diode D1, a third resistor R3, and a fourth resistor R4.

[0071] The first terminal of Zener diode D1 is connected to power supply VCC through the third resistor R3, and the second terminal of Zener diode D1 is grounded to GND2. Zener diode D1, the third resistor R3 and power supply VCC provide a stable reference voltage for comparator U1, which is connected to the positive input pin of U1.

[0072] For example, when the voltage of the DC bus capacitor on the charging side is lower than a preset voltage, the voltage detection circuit outputs a high level. When the voltage of the DC bus capacitor on the charging side is greater than or equal to the preset voltage, the voltage detection circuit outputs a low level. When the voltage detection circuit outputs a low level, the fiber optic signal transmitter stops sending signals to the fiber optic signal receiver, instructing the charging-side controller to stop charging the charging side.

[0073] The control device provided in this application embodiment, in order to save power consumption of the startup power supply, allows the startup power supply to shut down when communication is established between the charging-side controller and the charging-side controller, and then the charging side increases the voltage of the DC bus on the charging-side. Specifically, the charging-side controller sends a startup power supply disconnection message to the charging-side controller; the charging-side controller, upon receiving the startup power supply disconnection message, also controls the voltage of the DC bus on the charging-side to rise to the rated voltage. This reduces the requirements on the startup power supply input voltage and eliminates the additional losses generated by the startup power supply when the isolated power converter is operating.

[0074] Figure 2 The starting power supply in the control equipment described is implemented using an LDO. The following section will explain... Figure 3This section introduces a startup power supply implemented using a step-down circuit, such as a Buck circuit. When the startup voltage on the charging side is high, an LDO (Low Voltage Regulator) can be used. When the startup voltage on the charging side is low, a Buck circuit can be used.

[0075] See Figure 3 The figure is a schematic diagram of the control device for another isolated power converter provided in an embodiment of this application.

[0076] Figure 3 Zhongyu Figure 2 The parts that are the same as those in the text will not be repeated here.

[0077] Figure 3 In the control device shown, the power supply U10 can be implemented using a Buck circuit chip. For example, in one possible implementation, the Buck circuit has an input voltage of approximately 370V DC, and with the help of external circuitry, it can output a voltage of 5V, a maximum current of 300mA, and a startup time in the microsecond range.

[0078] The Buck circuit can quickly power the voltage detection circuit and the fiber optic signal transmitter U8, and the power requirements are met.

[0079] When the rated voltage of the DC bus capacitor on the charging side is greater than 370V, in order to reduce costs, a Buck circuit with a lower input voltage can be selected for the starting power supply, and it should be ensured that the preset voltage of the DC bus capacitor on the charging side is less than the rated voltage of the Buck circuit.

[0080] The control device for the isolated power converter provided in this application embodiment can also be used for data communication between the charging side controller and the charged side controller after the isolated power converter is started, with the fiber optic signal transmitter and fiber optic signal receiver further reducing the overall cost of the isolated power converter. The following is a detailed description in conjunction with the accompanying drawings.

[0081] See Figure 4 This figure is a schematic diagram of the control device for another isolated power converter provided in an embodiment of this application.

[0082] The control device for the isolated power converter provided in this application embodiment has its power supply terminal VCC of the fiber optic signal transmitter U8 connected to the voltage output terminal D5V of the controller U6 on the charging side.

[0083] The signal input terminal IN of the fiber optic signal transmitter U8 is connected to the output terminal of the controller U6 on the charging side and the voltage detection circuit, i.e., the output terminal of U1.

[0084] The charged-side controller U6, after establishing communication with the charging-side controller U3, also powers the fiber optic signal transmitter U8. In this case, it is not necessary for the startup power supply U7 to power the fiber optic signal transmitter U8, as the startup power supply U7 can disconnect from the DC bus on the charged side. The charged-side controller U6 sends the interactive data sent to the charging-side controller U3 to the fiber optic signal transmitter U8, which then forwards the interactive data to the charging-side controller via the fiber optic signal receiver.

[0085] For specific circuit details, please refer to [link / reference]. Figure 4 As shown, the power supply terminal VCC of the fiber optic signal transmitter U8 is connected to the voltage output terminal OUT of the startup power supply U7. The power supply terminal VCC of the fiber optic signal transmitter U8 is also connected to the cathode of the first diode D4. The anode of the first diode D4 is connected to the voltage output terminal D5V of the controller U6 on the charging side. In addition, the anode of the first diode D4 is also connected to the signal input terminal IN of the fiber optic signal transmitter U8 through the pull-up resistor R6.

[0086] The signal input terminal of the fiber optic signal transmitter is connected to the voltage output terminal of the controller on the charging side via a pull-up resistor R6.

[0087] The specific working process is as follows: After the isolated power converter finishes startup, switch S7 is opened under the control of the charging-side controller U6, powering off the startup power supply U7 and comparator U1. The power supply to the fiber optic signal transmitter U8 is switched from VCC of the startup power supply U7 to D5V output by the charging-side controller U6. The control signal of the fiber optic signal transmitter U8 changes from the voltage detection result output by comparator U1 to the output signal of GPIO10 of the charging-side controller U6. The charging-side controller U6 can control the fiber optic signal transmitter U8 to interact with the charging-side controller U3, further reducing the cost of the isolated power converter.

[0088] Based on the control device for an isolated power converter provided in the above embodiments, this application also provides an isolated power converter, which will be described in detail below with reference to the accompanying drawings.

[0089] See Figure 5 The figure is a schematic diagram of an isolated power converter provided in an embodiment of this application.

[0090] The isolated power converter provided in this application includes: an isolated power conversion circuit 1000 and a control device 2000 for the isolated power converter described in the above embodiments.

[0091] The first terminal of the isolated power conversion circuit 1000 is used to connect to a DC source; the embodiments of this application do not specifically limit the type of DC source, for example, the DC source includes at least one of a photovoltaic panel or a battery.

[0092] The second terminal of the isolated power conversion circuit 1000 is used to output DC or AC power;

[0093] Control device 2000 is used to control the isolated power conversion circuit 1000 to transfer energy from the first end to the second end, or from the second end to the first end.

[0094] The isolated power converter provided in this application embodiment can be applied in medium-voltage and medium-high voltage direct-connected photovoltaic inverters.

[0095] Since the isolated power converter provided in this application includes the control device described above, and because a startup power supply is provided on the charging side, the DC bus voltage of the charging side can be fed back to the charging side in a timely manner. The charging side then decides whether to continue charging the charging side based on the feedback result. Therefore, undervoltage or overvoltage during startup can be avoided, thus ensuring successful startup.

[0096] The isolated power conversion circuit provided in this application embodiment can be a single-stage or a two-stage circuit, and can ultimately output DC power or AC power. It can be set according to the actual application. The following is a detailed description with reference to the accompanying drawings.

[0097] See Figure 6 This figure is a schematic diagram of another isolated power converter provided in an embodiment of this application.

[0098] The isolated power converter provided in this application embodiment finally outputs AC power. The isolated power conversion circuit includes an isolated DC / DC circuit 601 and an inverter circuit 602. The isolated DC / DC circuit 601 includes a primary side bridge arm circuit, a transformer, and a secondary side bridge arm circuit. Figure 2 The isolated power conversion circuit shown includes an isolated DC / DC circuit 601 and an inverter circuit. Specifically, the isolated DC / DC circuit 601 includes Q1-Q8 and a transformer T1, and the inverter circuit 602 includes Q9-Q12. The control device 2000 is used to control the operation of Q1-Q12 to perform energy conversion.

[0099] The first end of the primary side bridge arm circuit is used to connect to a DC source. The second end of the primary side bridge arm circuit is connected to the primary winding of the transformer. The secondary winding of the transformer is connected to the first end of the secondary side bridge arm circuit. The second end of the secondary side bridge arm circuit is connected to the inverter circuit 602.

[0100] See Figure 7 This figure is a schematic diagram of another isolated power converter provided in an embodiment of this application.

[0101] The isolated power converter provided in this application embodiment ultimately outputs DC power. The isolated power conversion circuit includes an isolated DC / DC circuit 601. The control device 2000 is used to control the operation of the switching transistors in the isolated DC / DC circuit 601 to perform energy conversion.

[0102] The isolated power conversion circuit includes an isolated DC / DC circuit 601; the isolated DC / DC circuit 601 includes a primary-side bridge arm circuit, a transformer, and a secondary-side bridge arm circuit.

[0103] The first end of the primary side bridge arm circuit is used to connect to a DC source, the second end of the primary side bridge arm circuit is connected to the primary winding of the transformer, and the secondary winding of the transformer is connected to the secondary side bridge arm circuit.

[0104] The isolated power converter provided in this application embodiment can be a DC / DC converter or an inverter, without specific limitation.

[0105] Based on the control device and isolated power converter provided in the above embodiments, this application also provides a control method for an isolated power converter, which will be described in detail below with reference to the accompanying drawings.

[0106] See Figure 8 The figure is a flowchart of a control method for an isolated power converter provided in an embodiment of this application.

[0107] The control method for the isolated power converter in this application includes:

[0108] S801: Controls the connection of the startup power supply to the DC bus on the charging side; the output of the startup power supply is used to power the fiber optic signal transmitter and voltage detection circuit.

[0109] S802: The voltage detection circuit detects the voltage of the DC bus on the charging side and sends the voltage detection result to the fiber optic signal transmitter.

[0110] S803: The fiber optic signal transmitter sends the voltage detection result to the fiber optic signal receiver;

[0111] S804: The fiber optic signal receiver sends the voltage detection results to the charging-side controller;

[0112] S805: The charging side controller determines whether to continue charging the DC bus on the charging side based on the voltage detection results.

[0113] The control method for an isolated power converter provided in this application includes a startup power supply, an optical fiber signal transmitter, and a voltage detection circuit on the charging side. When the isolated power converter starts up, as the charging voltage gradually increases on the charging side, the startup power supply can start quickly, providing power to the optical fiber signal transmitter and the voltage detection circuit. The voltage detection circuit sends the voltage detection result to the optical fiber signal transmitter, which then sends the result to the charging-side controller via an optical fiber signal receiver. The charging-side controller can determine whether to continue charging the charging side based on the voltage detection result, ensuring that the DC bus voltage on the charging side does not become over-voltage or under-voltage during startup. Therefore, the technical solution provided in this application enables the isolated power converter to successfully start up while meeting the isolation voltage requirements between the charging and charging sides.

[0114] One possible implementation, the control method provided in this application embodiment, further includes: after the charging side controller obtains the information that the starting power supply is disconnected, controlling the voltage of the DC bus on the charging side to rise to the rated voltage.

[0115] One possible implementation, the control method provided in this application embodiment, further includes: after the controller on the charged side establishes communication with the controller on the charging side, it supplies power to the fiber optic signal transmitter, sends the interactive data sent to the controller on the charging side to the fiber optic signal transmitter, and the fiber optic signal transmitter forwards the interactive data to the controller on the charging side through the fiber optic signal receiver.

[0116] One possible implementation involves determining whether to continue charging the DC bus on the charging side based on the voltage detection result, including: stopping charging the DC bus on the charging side when the voltage detection result indicates that the voltage of the DC bus on the charging side reaches a preset voltage, and continuing to charge the DC bus on the charging side otherwise.

[0117] In one possible implementation, see Figure 9 The figure is a schematic diagram of a control device provided in an embodiment of this application.

[0118] The control device may include a memory 1011 and a processor 1012. The processor 1012 may be connected to the power converter and can drive the switches in the various power conversion circuits of the power converter. For example... Figure 9 As shown, the memory can be random access memory (RAM), flash memory, read-only memory (ROM), EPROM, non-volatile read-only memory (Electronic Programmable ROM), registers, hard disks, removable disks, etc.

[0119] The memory 1011 can store computer instructions. When the computer instructions stored in the memory 1011 are executed by the processor 1012, the processor 1012 can be used to execute the control method of the isolated power converter. The memory 1011 can also store data, such as preset ranges, preset thresholds, and other information involved in the above embodiments.

[0120] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape) or a semiconductor medium (e.g., solid-state disk (SSD)).

[0121] This application also provides a readable storage medium for storing the methods provided in the above embodiments. Examples include random access memory (RAM), flash memory, read-only memory (ROM), EPROM, non-volatile read-only memory (EPROM), registers, hard disks, removable disks, or any other form of storage medium in the art.

[0122] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Regarding the methods disclosed in the embodiments, since they correspond to the product embodiments disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the description of the product embodiments.

[0123] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. 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 this application. Therefore, this application 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 control device for an isolated power converter, characterized in that, include: Charging-side controller, startup power supply, fiber optic signal receiver, fiber optic signal transmitter, and voltage detection circuit; The input terminal of the starting power supply is used to connect to the DC bus on the charging side, and the output terminal of the starting power supply is used to power the optical fiber signal transmitter and the voltage detection circuit. The voltage detection circuit is used to detect the voltage of the DC bus on the charging side and send the voltage detection result to the optical fiber signal transmitter. The fiber optic signal transmitter is used to send the voltage detection result to the fiber optic signal receiver; The fiber optic signal receiver is used to send the voltage detection result to the charging side controller; The charging-side controller is used to determine whether to continue charging the DC bus on the charging side based on the voltage detection result.

2. The control device according to claim 1, characterized in that, Also includes: Auxiliary power supply on the charging side and controller on the charging side; The input terminal of the auxiliary power supply on the charging side is used to connect to the DC bus on the charging side; The output terminal of the auxiliary power supply on the charging side is used to supply power to the controller on the charging side. The power of the starting power supply is less than the power of the auxiliary power supply on the charging side.

3. The control device according to claim 2, characterized in that, Also includes: Switching circuit; The input terminal of the starting power supply is connected to the DC bus on the charging side through the switching circuit; After the controller on the receiving side establishes communication with the controller on the charging side, the controller on the receiving side controls the switching circuit to disconnect the input terminal of the starting power supply from the DC bus on the receiving side.

4. The control device according to claim 3, characterized in that, The controller on the receiving side sends the information that the power supply is disconnected to the controller on the charging side. The charging-side controller is also configured to, upon receiving information that the startup power supply is disconnected, control the voltage of the DC bus on the charging side to rise to the rated voltage.

5. The control device according to any one of claims 2-4, characterized in that, The power supply terminal of the fiber optic signal transmitter is connected to the voltage output terminal of the controller on the charging side; The signal input terminal of the fiber optic signal transmitter is connected to the output terminal of the controller on the charging side and the voltage detection circuit. The charging-side controller is further configured to, after establishing communication with the charging-side controller, supply power to the fiber optic signal transmitter, send the interactive data sent to the charging-side controller to the fiber optic signal transmitter, and the fiber optic signal transmitter forwards the interactive data to the charging-side controller through the fiber optic signal receiver.

6. The control device according to claim 5, characterized in that, The power supply terminal of the fiber optic signal transmitter is connected to the voltage output terminal of the power supply, the power supply terminal of the fiber optic signal transmitter is connected to the cathode of the first diode, and the anode of the first diode is connected to the voltage output terminal of the controller on the charging side. The signal input terminal of the fiber optic signal transmitter is connected to the voltage output terminal of the controller on the charging side via a pull-up resistor.

7. The control device according to any one of claims 1-6, characterized in that, The startup power supply is a low-dropout linear regulator or a step-down circuit.

8. The control device according to any one of claims 1-6, characterized in that, The voltage detection circuit includes: a voltage divider circuit and a hysteresis comparator; The input terminal of the voltage divider circuit is connected to the DC bus on the charging side, the output terminal of the voltage divider circuit is connected to the first input terminal of the hysteresis comparator, and the second input terminal of the hysteresis comparator is connected to the reference voltage; the output terminal of the hysteresis comparator is connected to the signal input terminal of the fiber optic signal transmitter. The charging-side controller is configured to stop charging the DC bus when the voltage detection result sent by the hysteresis comparator indicates that the voltage of the DC bus being charged reaches a preset voltage, and otherwise continue charging the DC bus being charged.

9. An isolated power converter, characterized in that, include: An isolated power conversion circuit and a control device for the isolated power converter according to any one of claims 1-8; The first terminal of the isolated power conversion circuit is used to connect to a DC source; The second terminal of the isolated power conversion circuit is used to output DC or AC power; The control device is used to control the isolated power conversion circuit to transmit energy from the first end to the second end, or from the second end to the first end.

10. The converter according to claim 9, characterized in that, The DC source includes at least one of a photovoltaic panel or a battery.

11. The converter according to claim 9 or 10, characterized in that, The isolated power conversion circuit includes an isolated DC / DC circuit and an inverter circuit; the isolated DC / DC circuit includes a primary-side bridge arm circuit, a transformer, and a secondary-side bridge arm circuit. The first end of the primary side bridge arm circuit is used to connect to the DC source, the second end of the primary side bridge arm circuit is connected to the primary winding of the transformer, the secondary winding of the transformer is connected to the first end of the secondary side bridge arm circuit, and the second end of the secondary side bridge arm circuit is connected to the inverter circuit.

12. The converter according to claim 9 or 10, characterized in that, The isolated power conversion circuit includes an isolated DC / DC circuit; The isolated power conversion circuit includes an isolated DC / DC circuit; the isolated DC / DC circuit includes a primary-side bridge arm circuit, a transformer, and a secondary-side bridge arm circuit. The first end of the primary side bridge arm circuit is used to connect to the DC source, the second end of the primary side bridge arm circuit is connected to the primary winding of the transformer, and the secondary winding of the transformer is connected to the secondary side bridge arm circuit.

13. A control method for an isolated power converter, characterized in that, include: The starting power supply is connected to the DC bus on the charging side; the output of the starting power supply is used to power the optical fiber signal transmitter and the voltage detection circuit. The voltage detection circuit detects the voltage of the DC bus on the charging side and sends the voltage detection result to the optical fiber signal transmitter. The fiber optic signal transmitter sends the voltage detection result to the fiber optic signal receiver; The fiber optic signal receiver sends the voltage detection result to the charging-side controller; The charging-side controller determines whether to continue charging the DC bus on the charging side based on the voltage detection result.

14. The method according to claim 13, characterized in that, Also includes: After receiving information that the startup power supply is disconnected, the charging-side controller controls the voltage of the DC bus on the charging side to rise to the rated voltage.

15. The method according to claim 13, characterized in that, Also includes: After establishing communication with the charging side controller, the charging side controller supplies power to the fiber optic signal transmitter and sends the interactive data sent to the charging side controller to the fiber optic signal transmitter. The fiber optic signal transmitter then forwards the interactive data to the charging side controller through the fiber optic signal receiver.

16. The method according to any one of claims 13-15, characterized in that, Determining whether to continue charging the DC bus on the charging side based on the voltage detection result includes: When the voltage detection result indicates that the voltage of the DC bus on the charging side reaches a preset voltage, charging of the DC bus on the charging side is stopped; otherwise, charging of the DC bus on the charging side continues.

17. A control device, characterized in that, It includes a processor and a memory, the memory being used to store programs, instructions, or code, and the processor being used to execute the programs, instructions, or code in the memory to perform the control method for the isolated power converter as described in any one of claims 13-16.

18. A computer-readable storage medium, characterized in that, The device contains a computer program that is loaded by a processor to execute the control method for the isolated power converter as described in any one of claims 13-16.

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