Four-quadrant high-voltage variable frequency speed regulation device and control method

Abstract

The application relates to a four-quadrant high-voltage variable frequency speed regulating device and a control method, which comprises a control machine, a man-machine interface, a power unit and a unit bypass control module. The unit bypass control module comprises a unit bypass control board and a bypass contactor, and the bypass contactor is connected with the unit bypass control board and the power unit respectively. The power unit comprises a rectifying unit and an inverting unit. The rectifying unit comprises a rectifying unit driving board and a rectifying IGBT module. The inverting unit comprises an inverting unit driving board and an inverting IGBT module. The application has the advantages that: the unit bypass control is carried out on the rectifying unit fault, the continuous and reliable operation of the high-voltage variable frequency speed regulating device is ensured, whether the rectifying unit is started or not is selected according to the reverse power, the switching loss on the rectifying side is reduced, the four-quadrant rectifying unit start-stop is automatically controlled through the reverse power calculation, the rectifying unit does not work when there is no reverse power, and the rectifying unit works when there is reverse power.

Description

Technical Field

[0001] This invention relates to the field of power electronics and frequency converter control technology, and in particular to a four-quadrant high-voltage variable frequency speed control device and control method. Background Technology

[0002] With the rapid development of power electronics technology and in response to the national energy conservation policy, high-voltage frequency converters are being used more widely in the industrial field, making the performance and stability of their control systems crucial. Currently, high-voltage frequency converters widely adopt two-quadrant control, which can meet most common load conditions and field requirements. To respond to the national energy conservation policy and expand the frequency converter application market, the demand for four-quadrant frequency converters is gradually increasing. Using four-quadrant variable frequency speed control devices in loads with energy feedback not only ensures long-term stable operation of equipment but also recovers energy and saves electrical energy. Therefore, there is an urgent need to propose a new control method for a highly reliable and adaptable four-quadrant high-voltage variable frequency speed control device. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a four-quadrant high-voltage variable frequency speed control device and control method, which automatically controls the start and stop of the four-quadrant rectifier. The rectifier unit does not work when there is no reverse power, and only works when there is reverse power. At the same time, through reverse power closed-loop control, the rectifier module can also be controlled according to the magnitude of the reverse power and the opening angle range.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A four-quadrant high-voltage variable frequency speed control device includes a controller, a human-machine interface, a power unit, and a unit bypass control module. The controller and the human-machine interface are connected via ports. The unit bypass control module includes a unit bypass control board and a bypass contactor, with the bypass contactor connected to both the unit bypass control board and the power unit. The power unit includes a rectifier unit and an inverter unit. The rectifier unit includes a rectifier unit driver board and a rectifier IGBT module, and the inverter unit includes an inverter unit driver board and an inverter IGBT module.

[0006] The rectifier unit driver board, inverter unit driver board, and unit bypass control board are connected to the controller via fiber optic ports. The rectifier unit driver board receives control data from the controller to drive the rectifier IGBT module, the inverter unit driver board receives control data from the controller to drive the inverter IGBT module, and the unit bypass control board receives control data from the controller to drive the bypass contactor.

[0007] Both the rectifier unit and the inverter unit include several cascaded H-bridge power units, and the controller is connected to the H-bridge power units through ports.

[0008] The control unit includes a CPU, an optical fiber communication module, a voltage and current acquisition module, a digital quantity module, a communication module, and a power supply module. The CPU, optical fiber communication module, voltage and current acquisition module, digital quantity module, and communication module are connected through ports. The power supply module provides power to the CPU, optical fiber communication module, voltage and current acquisition module, digital quantity module, and communication module. The human-machine interface is connected to the communication module through ports.

[0009] A control method for four-quadrant high-voltage variable frequency speed regulation includes bypass control of rectifier unit fault unit, rectifier start-stop control based on reverse power, and rectifier module turn-on range control based on power magnitude.

[0010] The rectifier unit fault bypass control is performed collaboratively by the rectifier unit driver board, controller, and unit bypass control board during the bypass process when a rectifier unit fault occurs. The steps are as follows:

[0011] S11. When a rectifier unit failure occurs, the controller will detect that the rectifier unit comprehensive fault bit is set.

[0012] S12. When the rectifier unit comprehensive fault bit is detected to be set, the rectifier unit comprehensive fault word is set.

[0013] S13. When the rectifier unit fails, it will be determined whether the unit bypass is engaged. If the unit bypass is not engaged, the inverter will be shut down directly due to the fault. If the unit bypass is engaged, proceed to step S14 for judgment.

[0014] S14. When the unit bypass is engaged, perform polling on the status of all rectifier units to confirm the location of the rectifier units and specific fault information and record the number of faulty rectifier units.

[0015] S15. Determine whether the number of faulty rectifier units exceeds the limit. If it does, the inverter will shut down due to fault. Otherwise, send a bypass control command for the faulty rectifier units to the unit bypass control board.

[0016] S16. The unit bypass control board controls the bypass contactor to close according to the control command;

[0017] S17. The unit bypass control board feeds back the status of the bypass contactor to the controller.

[0018] S18. The controller judges the feedback status of the bypass contactor. If the feedback is abnormal, the inverter is shut down due to fault; otherwise, the inverter continues to run.

[0019] The rectifier start / stop control based on reverse power conditions works as follows: During inverter operation, the controller calculates the inverter's output power in real time through the voltage and current acquisition module. When the calculated output power is less than zero, reverse power occurs in the inverter, and the controller automatically sends a rectifier unit start command to the rectifier unit driver board. When the calculated power is not less than zero, the controller sends a rectifier unit stop command to the rectifier unit driver board, thus realizing the rectifier module start / stop control logic based on the presence or absence of reverse power in the inverter.

[0020] The steps to control the rectifier module's operating range based on power are as follows:

[0021] S21. The controller uses the voltage and current acquisition module to monitor the inverter input voltage U. ABC Perform PLL phase-locked loop, calculate the real-time phase of the inverter input voltage, and adjust the power unit input voltage U. abc PLL phase-locked loop is performed to calculate the real-time phase of the power unit input voltage. When the rectifier unit is not running, the rectifier voltage phase compensation value is calculated based on the real-time phase of the inverter input voltage and the real-time phase of the power unit input voltage. This value is used to perform initial phase calibration of the inverter input voltage phase when the rectifier unit is running.

[0022] S22. Perform PI closed-loop control on the power setpoint and power calculation value, and perform amplitude limiting control on the output. This is used when reverse power occurs in the frequency converter. Combined with the real-time phase of the frequency converter input voltage obtained in step S21 and the offset angle of the secondary side of the phase shift transformer, the rectification control turn-on angle range is calculated for rectification control, so as to realize the control of the rectification unit operation according to the magnitude of reverse power.

[0023] The phase-shifting transformer is installed inside the frequency converter. The primary side of the phase-shifting transformer is the input voltage of the frequency converter, and the secondary side of the phase-shifting transformer is used to supply power to the power unit of the frequency converter. The offset angle between the primary and secondary sides of the phase-shifting transformer is fixed.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. Implement unit bypass control for rectifier unit failures to ensure continuous and reliable operation of the four-quadrant variable frequency speed control device when the rectifier module fails;

[0026] 2. Select whether to start the rectifier unit based on the reverse power condition to reduce the switching loss on the rectifier side; through reverse power calculation, the start and stop of the four-quadrant rectifier unit is automatically controlled. The rectifier unit does not work when there is no reverse power, and only works when there is reverse power. At the same time, through reverse power closed-loop control, the rectifier unit can also be controlled according to the turn-on angle range based on the magnitude of reverse power. This can greatly reduce the turn-on time and switching frequency of the rectifier unit, reduce IGBT module losses and heat generation, and extend the service life of IGBT modules.

[0027] 3. The HMI (Human Machine Interface) enables parameter setting, operation monitoring, event logging, and fault recording, facilitating maintenance and debugging by on-site personnel. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the control principle of a four-quadrant high-voltage variable frequency speed control device.

[0029] Figure 2 This is the flowchart of the unit bypass control for the rectifier unit.

[0030] Figure 3 This is a schematic diagram of the principle of a four-quadrant high-voltage variable frequency speed control device and its control method.

[0031] Figure 4 This is a schematic diagram of the power unit and the unit bypass structure. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0033] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0034]

Example 1

[0035] See Figures 1-4 A four-quadrant high-voltage variable frequency speed control device includes a controller, a human-machine interface, a power unit, and a unit bypass control module. The controller and the human-machine interface are connected via ports. The unit bypass control module includes a unit bypass control board and a bypass contactor, with the bypass contactor connected to both the unit bypass control board and the power unit. The power unit includes a rectifier unit and an inverter unit. The rectifier unit includes a rectifier unit driver board and a rectifier IGBT module, and the inverter unit includes an inverter unit driver board and an inverter IGBT module. The rectifier unit driver board, inverter unit driver board, and unit bypass control board are all connected to the controller via fiber optic ports. The rectifier unit driver board receives control data from the controller and drives the rectifier IGBT module, and the inverter unit driver board receives control data from the controller and drives the inverter IGBT module. The unit bypass control board receives control data from the controller and drives the bypass contactor.

[0036] The rectifier unit driver board is located on the rectifier unit of the inverter power unit. It receives control data from the controller via fiber optic cable to drive the rectifier IGBT module, achieving frequency conversion rectification control. The inverter unit driver board is located on the inverter unit of the inverter power unit. It receives control data from the controller via fiber optic cable to drive the inverter IGBT module, achieving frequency conversion voltage inversion output. Simultaneously, it feeds back the inverter unit status data and bus voltage to the controller. The unit bypass control board receives control data from the controller via fiber optic cable to drive the bypass contactor, and simultaneously feeds back the bypass contactor status to the controller, enabling bypassing of both the rectifier and inverter units. If a rectifier or inverter unit malfunctions, the unit bypass control board will control the bypass contactor to bypass the corresponding power unit, effectively short-circuiting its output. Both the rectifier and inverter units include several cascaded H-bridge power units, and the controller connects to these H-bridge power units via ports.

[0037] The control unit is the core of the frequency converter's control system. It not only contains the frequency converter's control algorithm but also has multiple control ports, enabling expansion with analog and digital modules. The control unit includes a CPU, fiber optic communication module, voltage and current acquisition module, digital module, communication module, and power supply module. These modules are connected via ports. The power supply module provides power to the CPU, fiber optic communication module, voltage and current acquisition module, digital module, and communication module. The HMI (Human-Machine Interface) connects to the communication module via a port, enabling parameter setting, operation monitoring, event logging, and fault recording for easy on-site maintenance and debugging. The voltage and current acquisition module is used to acquire voltage and current signals from the frequency converter's input side.

[0038] See Figure 2 A control method for four-quadrant high-voltage variable frequency speed regulation includes bypass control of rectifier unit fault unit, rectifier start-stop control based on reverse power conditions, and rectifier module turn-on range control based on power magnitude.

[0039] For details on inverter unit bypass control, please refer to patent publication number CN104269998A, "A unit bypass device and control method for a unit series frequency converter".

[0040] The rectifier unit fault bypass control is performed collaboratively by the rectifier unit driver board, controller, and unit bypass control board during the bypass process when a rectifier unit fault occurs. The steps are as follows:

[0041] S11. When a rectifier unit failure occurs, the controller will detect that the rectifier unit comprehensive fault bit is set.

[0042] S12. When the rectifier unit comprehensive fault bit is detected to be set, the rectifier unit comprehensive fault word is set.

[0043] S13. When the rectifier unit fails, it will be determined whether the unit bypass is engaged. If the unit bypass is not engaged, the inverter will be shut down directly due to the fault. If the unit bypass is engaged, proceed to step S14 for judgment.

[0044] S14. When the unit bypass is engaged, perform polling on the status of all rectifier units to confirm the location of the rectifier units and specific fault information and record the number of faulty rectifier units.

[0045] S15. Determine whether the number of faulty rectifier units exceeds the limit. If it does, the inverter will shut down due to fault. Otherwise, send a bypass control command for the faulty rectifier units to the unit bypass control board.

[0046] S16. The unit bypass control board controls the bypass contactor to close according to the control command;

[0047] S17. The unit bypass control board feeds back the status of the bypass contactor to the controller.

[0048] S18. The controller judges the feedback status of the bypass contactor. If the feedback is abnormal, the inverter is shut down due to fault; otherwise, the inverter continues to run.

[0049] The rectifier start / stop control is implemented based on the reverse power condition. The process is as follows: During inverter operation, the controller calculates the inverter's output power in real time through the voltage and current acquisition module. When the calculated output power is less than zero, reverse power is generated, and the controller automatically sends a rectifier unit start command to the rectifier unit driver board. Conversely, when the calculated power is not less than zero, the controller sends a rectifier unit stop command to the rectifier unit driver board. This achieves the rectifier module start / stop control logic based on the presence or absence of reverse power in the inverter.

[0050] By using inverse power closed-loop control to control the rectifier unit according to the magnitude of the inverse power and the range of the turn-on angle, the turn-on time and switching frequency of the rectifier unit can be reduced, effectively reducing the loss and heat generation of the rectifier IGBT module. The steps are as follows:

[0051] S21. The controller uses the voltage and current acquisition module to monitor the inverter input voltage U. ABC Perform PLL phase-locked loop, calculate the real-time phase of the inverter input voltage, and adjust the power unit input voltage U. abcPLL phase-locked loop is performed to calculate the real-time phase of the power unit input voltage. When the rectifier unit is not running, the rectifier voltage phase compensation value is calculated based on the real-time phase of the inverter input voltage and the real-time phase of the power unit input voltage. This value is used to perform initial phase calibration of the inverter input voltage phase when the rectifier unit is running, thereby achieving an accurate real-time voltage phase.

[0052] S22. Perform PI closed-loop control on the power setpoint and calculated power value, and perform amplitude limiting control on the output. This is used when reverse power occurs in the frequency converter. Combined with the real-time phase of the frequency converter input voltage obtained in step S21 and the offset angle of the secondary side of the phase-shifting transformer, calculate the rectification control turn-on angle range for rectification control, so as to control the operation of the rectification unit according to the magnitude of reverse power. The phase-shifting transformer is set inside the frequency converter. The primary side of the phase-shifting transformer is the input voltage of the frequency converter, and the secondary side of the phase-shifting transformer is used to supply power to the power unit of the frequency converter. The offset angle of the primary and secondary sides of the phase-shifting transformer is fixed.

[0053] This invention provides bypass control for rectifier unit failures, ensuring continuous and reliable operation of the high-voltage variable frequency speed control device. It selects whether to start the rectifier unit based on reverse power conditions, reducing switching losses on the rectifier side. Through reverse power calculation, it automatically controls the start and stop of the four-quadrant rectifier unit; the rectifier unit does not work when there is no reverse power, and only works when there is reverse power. Furthermore, through reverse power closed-loop control, it can also control the rectifier unit according to the switching angle range based on the magnitude of the reverse power, which can greatly reduce the rectifier unit's turn-on time and switching frequency, reduce IGBT module losses and heat generation, and extend the IGBT module's service life.

Claims

1. A four-quadrant high-voltage variable frequency speed control device, characterized in that, It includes a control unit, a human-machine interface, a power unit, and a unit bypass control module. The control unit and the human-machine interface are connected via a port. The unit bypass control module includes a unit bypass control board and a bypass contactor. The bypass contactor is connected to the unit bypass control board and the power unit respectively. The power unit includes a rectifier unit and an inverter unit. The rectifier unit includes a rectifier unit driver board and a rectifier IGBT module. The inverter unit includes an inverter unit driver board and an inverter IGBT module. The rectifier unit driver board, inverter unit driver board, and unit bypass control board are connected to the controller via fiber optic ports. The rectifier unit driver board is used to receive control data from the controller to drive the rectifier IGBT module, and the inverter unit driver board is used to receive control data from the controller to drive the inverter IGBT module. The unit bypass control board is used to receive control data from the controller and drive the bypass contactor. A control method for implementing the device is a four-quadrant high-voltage variable frequency speed regulation method, the control method including rectifier unit fault unit bypass control, rectifier start-stop control based on reverse power, and rectifier module turn-on range control based on power magnitude. The aforementioned rectifier unit fault bypass control is performed collaboratively by the rectifier unit driver board, controller, and unit bypass control board during the bypass process when a rectifier unit fault occurs. The steps are as follows: S11. When a rectifier unit failure occurs, the controller will detect that the rectifier unit comprehensive fault bit is set. S12. When the rectifier unit comprehensive fault bit is detected to be set, the rectifier unit comprehensive fault word is set. S13. When the rectifier unit fails, it will be determined whether the unit bypass is engaged. If the unit bypass is not engaged, the inverter will be shut down directly due to the fault. If the unit bypass is engaged, proceed to step S14 for judgment. S14. When the unit bypass is engaged, perform polling on the status of all rectifier units to confirm the location of the rectifier units and specific fault information and record the number of faulty rectifier units. S15. Determine whether the number of faulty rectifier units exceeds the limit. If it does, the inverter will shut down due to fault. Otherwise, send a bypass control command for the faulty rectifier units to the unit bypass control board. S16. The unit bypass control board controls the bypass contactor to close according to the control command; S17. The unit bypass control board feeds back the status of the bypass contactor to the controller. S18. The controller judges the feedback status of the bypass contactor. If the feedback is abnormal, the inverter will be shut down due to a fault; otherwise, the inverter will continue to run.

2. The four-quadrant high-voltage variable frequency speed control device according to claim 1, characterized in that, Both the rectifier unit and the inverter unit include several cascaded H-bridge power units, and the controller is connected to the H-bridge power units via ports.

3. The four-quadrant high-voltage variable frequency speed control device according to claim 1, characterized in that, The control unit includes a CPU, a voltage and current acquisition module, a digital quantity module, a communication module, and a power supply module. The CPU, voltage and current acquisition module, digital quantity module, and communication module are connected through ports. The power supply module provides power to the CPU, voltage and current acquisition module, digital quantity module, and communication module. The human-machine interface is connected to the communication module through a port.

4. A four-quadrant high-voltage variable frequency speed control device according to claim 1, characterized in that, The rectification start / stop control based on reverse power conditions is as follows: During the operation of the frequency converter, the controller calculates the output power of the frequency converter in real time through the voltage and current acquisition module. When the calculated output power of the frequency converter is less than zero, the frequency converter has reverse power. The controller automatically executes the rectifier unit start command and sends it to the rectifier unit driver board. When the calculated power of the frequency converter is not less than zero, the controller sends the rectifier unit stop command to the rectifier unit driver board, thereby realizing the rectifier module start / stop control logic based on whether there is reverse power of the frequency converter.

5. A four-quadrant high-voltage variable frequency speed control device according to claim 1, characterized in that, The steps for controlling the rectifier module's operating range based on power are as follows: S21. The controller uses the voltage and current acquisition module to monitor the inverter input voltage U. ABC Perform PLL phase-locked loop, calculate the real-time phase of the inverter input voltage, and adjust the power unit input voltage U. abc PLL phase-locked loop is performed to calculate the real-time phase of the power unit input voltage. When the rectifier unit is not running, the rectifier voltage phase compensation value is calculated based on the real-time phase of the inverter input voltage and the real-time phase of the power unit input voltage. This value is used to perform initial phase calibration of the inverter input voltage phase when the rectifier unit is running. S22. Perform PI closed-loop control on the power setpoint and power calculation value, and perform amplitude limiting control on the output. This is used when reverse power occurs in the frequency converter. Combined with the real-time phase of the frequency converter input voltage obtained in step S21 and the offset angle of the secondary side of the phase shift transformer, the rectification control turn-on angle range is calculated for rectification control, so as to realize the control of the rectification unit operation according to the magnitude of reverse power.

6. A four-quadrant high-voltage variable frequency speed control device according to claim 5, characterized in that, The phase-shifting transformer is installed inside the frequency converter. The primary side of the phase-shifting transformer is the input voltage of the frequency converter, and the secondary side of the phase-shifting transformer is used to supply power to the power unit of the frequency converter. The offset angle between the primary and secondary sides of the phase-shifting transformer is fixed.

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