Feedback control circuit and method for direct-current bus of generator rotor test power supply

Abstract

The invention discloses a feedback control circuit and method for a generator rotor test power supply DC bus, and relates to the technical field of power equipment measurement. The circuit comprises a direct-current power supply, a feedback signal output end, a direct-current bus voltage leading-in end, an optocoupler, a relay change-over switch, at least two switching resistors with different resistance values, a TL431 voltage-regulator tube and a divider resistor, according to the method, control is achieved through the steps of voltage introduction, resistor switching, voltage division adaptation, signal feedback, voltage regulation and the like, a 2K omega / 20K omega switching resistor is switched through a relay, a 240K omega divider resistor is matched, after 30V / 300V target voltage is divided, 2.5 V break-over voltage is provided for TL431, an independent 24V power source is combined to drive an optocoupler, the problem of driving failure of a low-voltage optocoupler is solved, and the service life of the TL431 is prolonged. A single circuit is compatible with double-voltage feedback, the test operation is simplified, the voltage stabilization precision and the electrical safety are improved, and the AC impedance and withstand voltage test requirements of the generator rotor are met.

Description

Technical Field

[0001] This invention belongs to the field of power equipment measurement technology, and relates to a feedback control circuit and method for the DC bus of a generator rotor test power supply. Background Technology

[0002] In generator rotor testing, AC withstand voltage testing and AC impedance testing are core testing items. The requirements for the DC bus voltage of the test power supply differ significantly between the two: AC withstand voltage testing requires a higher target DC voltage (high test voltage output after inversion and boosting), while AC impedance testing requires a lower target DC voltage (low test voltage output after inversion and boosting).

[0003] In existing technologies, the two types of tests typically rely on two independent instruments and boost feedback circuits: one adapted to a higher target DC voltage and the other adapted to a lower target DC voltage. This approach has significant drawbacks: first, the wiring is complex, requiring reconnection of the circuit each time the test item is switched, making the operation cumbersome; second, the equipment cost is high, with two sets of instruments increasing procurement and maintenance expenses; and third, the testing efficiency is low, with the switching process being time-consuming, making it difficult to meet the needs of batch testing.

[0004] From the perspective of feedback control principles, the core of the test power supply boost circuit is the feedback module: the rectifier and filter module converts the mains power into DC power to supply the IPM module. After receiving the target voltage signal, the MCU controller of the IPM module drives the power devices by adjusting the PWM pulse duty cycle and outputs the corresponding PWM signal, which is then rectified and filtered to obtain the target DC voltage. However, due to the inherent characteristics of switching power supplies, the output voltage is prone to fluctuations. Therefore, the feedback module needs to feed the bus voltage back to the MCU to dynamically correct the PWM parameters to stabilize the voltage.

[0005] However, the difference between the two target DC voltages is significant. If the traditional feedback circuit directly draws power from the bus to drive the optocoupler (the core feedback device), a "low-voltage drive failure" problem will occur. The higher target DC voltage can provide sufficient drive current, but the lower target DC voltage, due to insufficient voltage difference, cannot provide enough current to reach the optocoupler's operating threshold, resulting in feedback interruption and voltage instability. Therefore, a feedback control scheme that can accommodate both target voltages and solve the low-voltage drive problem is urgently needed. Summary of the Invention

[0006] The purpose of this invention is to provide a feedback control circuit and method for the DC bus of the generator rotor test power supply, which is used to address the problems that existing technologies cannot achieve accurate and stable feedback control of two target DC voltages in generator rotor testing through a single feedback circuit, and that low-voltage scenarios suffer from problems such as optocoupler drive failure and cumbersome test operations.

[0007] To solve the above problems, the technical solution of the present invention is as follows: The feedback control circuit for the DC bus of the generator rotor test power supply includes a DC power supply, a feedback signal output terminal, a DC bus voltage input terminal, an optocoupler, a relay switch, at least two switching resistors with different resistance values, a TL431 Zener diode, and voltage divider resistors. Terminal A of the TL431 Zener diode is grounded, terminal K is connected to one end of the voltage divider resistor, and terminal R is connected to any of the switching resistors via the relay switch. The other end of the voltage divider resistor is connected in parallel to one end of the DC bus voltage input terminal, and the other end of each switching resistor is connected to the DC bus voltage input terminal. The other end is connected in parallel, and the other end of the DC bus voltage input terminal is connected to the A terminal of the TL431 Zener diode; one end of the light-emitting end of the optocoupler is connected to the DC power supply, and the other end is connected to the K terminal of the TL431 Zener diode, and the output end of the light-receiving end is the feedback signal output end; the DC bus voltage input terminal is used to introduce two different target DC voltages, and the two different target DC voltages are divided by the corresponding switching resistor and voltage divider resistor respectively, and the voltage input to the R terminal of the TL431 Zener diode is equal to the preset conduction reference voltage of the TL431 Zener diode.

[0008] Furthermore, the DC power supply is set independently of the input voltage at the DC bus voltage input terminal.

[0009] Furthermore, the conduction condition of the TL431 Zener diode is that the input voltage at terminal R is greater than or equal to the preset conduction reference voltage, and the cutoff condition is that the input voltage at terminal R is less than the preset conduction reference voltage.

[0010] Furthermore, the light-receiving end of the optocoupler is connected to the IPM module. When the TL431 Zener diode is turned on, the light-receiving end outputs a low level to the feedback signal output end; when the TL431 Zener diode is turned off, the light-receiving end outputs a high level to the feedback signal output end. The IPM module adjusts the PWM pulse duty cycle according to the feedback level signal to form a closed-loop voltage regulation.

[0011] Furthermore, the IPM module is used to adjust the PWM pulse duty cycle according to the level signal at the feedback signal output terminal.

[0012] Furthermore, let the preset on-state reference voltage of the TL431 Zener diode be U. ref The first target DC voltage is U1, the second target DC voltage is U2, the voltage divider resistor has a resistance value of Rdivider, and the switching resistor that adapts to U1 has a resistance value of Radapter. 切1 The switching resistor for the U2 adapter has a resistance value of R. 切2 The R 切1 R satisfies R 切1 =R 分 ×(U ref / U1-U ref ), the R 切2 R satisfies R 切2 =R 分 ×(Uref / U2-U ref ).

[0013] A feedback control method for a DC bus of a generator rotor test power supply includes the following steps: S1. Voltage introduction: Selectively introduce a first target DC voltage or a second target DC voltage through the DC bus voltage introduction terminal. The first target DC voltage and the second target DC voltage are two different values ​​(adapted to the AC impedance test and AC withstand voltage test of the generator rotor, respectively), and the two voltages are not connected at the same time. S2. Low voltage resistor switching: If the first target DC voltage is introduced in S1, the control relay switching switch is turned on with the first switching resistor of the corresponding resistance value, so that the first target DC voltage is divided by the first switching resistor and the voltage divider resistor; S3. High voltage resistor switching: If the second target DC voltage is introduced in S1, the control relay switching switch is turned on with the second switching resistor of the corresponding resistance value, so that the second target DC voltage is divided by the second switching resistor and the voltage divider resistor; S4. Voltage Divider Adaptation: Select one of the first target DC voltage and the second target DC voltage for input. After being divided by the switching resistor and the voltage divider resistor in S2 or S3, the current input target DC voltage is equal to the preset on-state reference voltage of the TL431 Zener diode and is input to the R terminal of the TL431 Zener diode. S5. Signal Feedback and Voltage Regulation: The on or off state of the TL431 Zener diode controls the corresponding level signal output of the optocoupler, which is transmitted to the IPM module via the feedback signal output terminal. The IPM module adjusts the DC bus output voltage according to the level signal to stabilize the voltage at the target value.

[0014] Furthermore, it also includes step S6. Resistor matching: The first switching resistor and the second switching resistor have different resistance values, and the two resistors are respectively determined in advance to match the voltage divider resistors according to the corresponding target DC voltage and the preset conduction reference voltage of the TL431 Zener diode, so as to ensure that the first target DC voltage and the second target DC voltage can meet the conduction conditions of the TL431 Zener diode after being divided by the corresponding switching resistor and the voltage divider resistor.

[0015] Furthermore, it also includes step S7. Independent power supply: During the feedback control process, the optocoupler is provided with a working power supply that is independent of the input voltage of the DC bus voltage input terminal, so as to ensure that the optocoupler can be driven normally under both the first target DC voltage and the second target DC voltage scenarios.

[0016] Furthermore, S5 specifically includes: S51. Low voltage feedback: If the input voltage at the R terminal of the TL431 Zener diode is less than the preset turn-on reference voltage, the TL431 Zener diode will be turned off, the optocoupler will have no light source output, and the light receiving terminal will output a high level to the feedback signal output terminal; after the IPM module receives the high level signal, it will increase the PWM pulse duty cycle to increase the DC bus voltage and make the voltage approach the target DC voltage. S52. High Voltage Feedback Unit: If the input voltage at the R terminal of the TL431 Zener diode is greater than or equal to the preset turn-on reference voltage, the TL431 Zener diode will turn on, the optocoupler will emit light, and the light receiving terminal will output a low level to the feedback signal output terminal; after receiving the low level signal, the IPM module will limit the PWM pulse output and stabilize the DC bus voltage at the target DC voltage. S53. Cyclic regulator: Repeats S51 and S52, continuously and dynamically adjusts the DC bus voltage through closed-loop feedback loop to ensure that the voltage is always stable at the currently introduced target DC voltage value.

[0017] The beneficial effects of this invention are as follows: 1. Achieve dual-voltage compatible control and simplify the testing process: There is no need to configure two independent feedback circuits. A single circuit can adapt to the feedback requirements of two different target DC voltages in the generator rotor test, saving the equipment replacement and rewiring operations when switching test items and improving the convenience of testing.

[0018] 2. Solving the feedback failure problem in low voltage scenarios: Through the precise matching design of switching resistor and voltage divider resistor, it is ensured that the low target DC voltage can still meet the conduction conditions of TL431 Zener diode after voltage division, ensuring stable drive of optocoupler and avoiding feedback interruption in low voltage scenarios in traditional circuits.

[0019] 3. Improve voltage stability accuracy: Relying on the precise voltage reference of the TL431 Zener diode and the dynamic adjustment of the IPM module, a closed-loop feedback control is formed, which effectively suppresses DC bus voltage fluctuations, ensures stable output voltage, and meets the power supply stability requirements of generator rotor testing.

[0020] 4. Enhanced electrical safety protection: The electrical isolation design of the optocoupler blocks the transmission path of the DC bus high voltage to the feedback signal output terminal and subsequent modules, reducing the risk of equipment damage and ensuring the safety of operators and related circuits.

[0021] 5. Enhanced circuit stability: An independent power supply provides continuous and stable power to the optocoupler, unaffected by DC bus voltage fluctuations, ensuring continuous and reliable feedback signals and guaranteeing stable operation of the entire control process. Attached Figure Description

[0022] The invention will be further described below with reference to the accompanying drawings: Figure 1This is the circuit diagram of the present invention.

[0023] In the diagram: 1. DC power supply, 2. Feedback signal output terminal, 3. DC bus voltage input terminal, 4. Optocoupler, 5. Relay switch, 6. First switching resistor, 7. Second switching resistor, 8. TL431 Zener diode. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0025] like Figure 1 As shown, the feedback control circuit of the DC bus of the generator rotor test power supply includes a DC power supply 1, a feedback signal output terminal 2, a DC bus voltage input terminal 3, an optocoupler 4, a relay switch 5, at least two switching resistors with different resistance values, a TL431 Zener diode 8, and voltage divider resistors. The A terminal (input terminal) of the TL431 Zener diode 8 is grounded, the K terminal (output terminal) is connected to one end of the voltage divider resistor, and the R terminal (reference voltage input terminal) is connected to any of the switching resistors through the relay switch 5. The other end of the voltage divider resistor is connected in parallel with one end of the DC bus voltage input terminal 3, and the other end of each switching resistor is... The other end of the optocoupler 4 is connected in parallel with the DC bus voltage input terminal 3, and the other end of the DC bus voltage input terminal 3 is connected to the A terminal of the TL431 Zener diode 8; one end of the light-emitting end of the optocoupler 4 is connected to the DC power supply 1, and the other end is connected to the K terminal of the TL431 Zener diode 8. The output end of the light-receiving end is the feedback signal output terminal 2; the DC bus voltage input terminal 3 is used to introduce two different target DC voltages, and the two different target DC voltages are divided by the corresponding switching resistor and voltage divider resistor respectively, and the voltage input to the R terminal of the TL431 Zener diode 8 is equal to the preset conduction reference voltage of the TL431 Zener diode 8. This ensures that the voltage input to the R terminal of the TL431 Zener diode 8 after the two voltages are divided is equal to its preset conduction reference voltage, and then the high and low levels of the optocoupler 4 are controlled by the conduction / cutoff of the TL431; this logic not only realizes the compatible feedback of a single circuit to dual target voltages without the need for two independent devices, simplifying the test process, but also solves the feedback adaptation problem caused by the large voltage difference in traditional circuits, ensuring the stability of the feedback signal in low voltage scenarios.

[0026] Furthermore, the DC power supply 1 is set independently of the input voltage of the DC bus voltage input terminal 3. This ensures that it is unaffected by bus voltage fluctuations and continuously provides stable drive power to the optocoupler 4. This design avoids insufficient or abnormal drive current of the optocoupler due to bus voltage changes, ensuring that the optocoupler can output feedback signals normally in dual-voltage scenarios and improving the working stability of the entire feedback control process.

[0027] Furthermore, the conduction condition of the TL431 Zener diode 8 is that the input voltage at terminal R is greater than or equal to the preset conduction reference voltage, and the cutoff condition is that the input voltage at terminal R is less than the preset conduction reference voltage. This provides a clear judgment benchmark for subsequent optocoupler signal output and IPM module voltage regulation; this condition definition makes the voltage feedback logic more explicit, avoids insufficient voltage regulation accuracy caused by ambiguity in the conduction threshold, and ensures that the DC bus voltage can be accurately stabilized at the target value.

[0028] Furthermore, the light-receiving end of the optocoupler 4 is connected to the IPM module. When the TL431 Zener diode 8 is turned on, the light-emitting end emits light, and the light-receiving end outputs a low level to the feedback signal output terminal 2. When the TL431 Zener diode 8 is turned off, the light-emitting end does not emit light, and the light-receiving end outputs a high level to the feedback signal output terminal 2. This allows the IPM module to directly determine the bus voltage status through the level signal, thereby quickly adjusting the PWM pulse duty cycle to achieve dynamic voltage correction. At the same time, the isolation characteristics of the optocoupler block high voltage conduction, ensuring the safety of the IPM module.

[0029] Furthermore, the IPM module is used to adjust the PWM pulse duty cycle according to the level signal of the feedback signal output terminal 2. When a high level is received, the duty cycle is increased to boost the bus voltage, and when a low level is received, the output is limited to stabilize the voltage. This adjustment logic forms a closed-loop feedback, which can correct the voltage deviation in real time and ensure that the DC bus voltage is stable at the target value, meeting the stringent requirements of generator rotor test for power supply stability.

[0030] Furthermore, let the preset on-state reference voltage of the TL431 Zener diode 8 be U. ref The first target DC voltage is U1, the second target DC voltage is U2, the voltage divider resistor has a resistance value of Rdivider, and the switching resistor that adapts to U1 has a resistance value of Radapter. 切1 The switching resistor for the U2 adapter has a resistance value of R. 切2 The R 切1 R satisfies R 切1 =R 分 ×(U ref / U1-U ref ), the R 切2 R satisfies R 切2 =R 分 ×(U ref / U2-U refBy pre-determining the matching resistance values ​​of the three components, it is ensured that the voltage divider can provide a preset turn-on reference voltage for the 8R terminal of the TL431 Zener diode. This precise matching design avoids voltage division anomalies caused by improper resistor values. It solves the feedback failure problem of the TL431 Zener diode 8 failing to conduct in low-voltage scenarios, and ensures that the voltage after voltage division does not exceed the limit in high-voltage scenarios, thus achieving accurate triggering of the feedback signal in dual-voltage scenarios.

[0031] A feedback control method for a DC bus of a generator rotor test power supply includes the following steps: S1. Voltage Introduction: According to the requirements of the generator rotor test project (AC impedance test is adapted to 30V low voltage, AC withstand voltage test is adapted to 300V high voltage), select one of the three DC bus voltage introduction terminals to connect to the first target DC voltage of 30V or the second target DC voltage of 300V; the two voltages are different values ​​and are not connected at the same time to avoid abnormal voltage division or component damage caused by voltage conflict in the circuit, and at the same time ensure that the line connection is reliable when connected to reduce voltage detection errors caused by poor contact; S2. Low Voltage Resistance Switching: If the first target DC voltage of 30V is introduced in S1 (adapting to AC impedance testing), the IPM module or external controller sends a switching signal to the relay switch 5, controlling the relay contacts to conduct with the first switching resistor 6 with a resistance of 20KΩ; at this time, a path is formed of "DC bus voltage input terminal 3 → 20KΩ first switching resistor 6 → relay switch 5 → TL431 Zener diode 8R terminal", and the 20KΩ first switching resistor 6 and the 240KΩ voltage divider resistor form a voltage divider circuit, providing a circuit basis for the accurate voltage division of 30V; S3. High Voltage Resistor Switching: If the second target DC voltage of 300V is introduced in S1 (for AC withstand voltage testing), the controller sends a switching signal to the relay switch 5, controlling the relay contacts to conduct with the second switching resistor 7 with a resistance of 2KΩ; similarly, a path is formed of "DC bus voltage input terminal 3 → 2KΩ second switching resistor 7 → relay switch 5 → TL431 Zener diode 8R terminal", and the 2KΩ second switching resistor 7 and the 240KΩ voltage divider resistor form a voltage divider circuit to meet the voltage divider adaptation requirements of 300V high voltage; S4. Voltage Divider Adaptation: By switching the resistor in S2 or S3, the target DC voltage currently connected is divided by the corresponding switching resistor and the 240KΩ voltage divider resistor. The voltage input to the TL431 Zener diode 8R is precisely equal to its preset 2.5V turn-on reference voltage. Specifically, the 30V voltage is divided by the 20KΩ switching resistor and the 240KΩ voltage divider resistor (voltage division ratio = 240KΩ / (20KΩ+240KΩ)), and the 300V voltage is divided by the 2KΩ switching resistor and the 240KΩ voltage divider resistor (voltage division ratio = 240KΩ / (2KΩ+240KΩ)). In both scenarios, the voltage division result is 2.5V, ensuring that the TL431 Zener diode 8 can be triggered to turn on or off normally according to the bus voltage status. S5. Signal Feedback and Voltage Regulation: The on or off state of the TL431 Zener diode 8 controls the corresponding level signal output of the optocoupler 4, which is transmitted to the IPM module via the feedback signal output terminal 2. The IPM module adjusts the DC bus output voltage according to the level signal to stabilize the voltage at the target value of 30V or 300V. This step relies on the precise voltage reference of the TL431 and the signal isolation characteristics of the optocoupler to achieve reliable feedback and regulation of the voltage status.

[0032] Furthermore, before performing step S6, the resistor matching step, it is necessary to determine and verify the matching resistance values ​​of the 240KΩ voltage divider resistor, the 20KΩ first switching resistor 6, and the 2KΩ second switching resistor 7 in advance, based on the 30V first target DC voltage, the 300V second target DC voltage, and the 82.5V preset turn-on reference voltage of the TL431 Zener diode. Step S6 includes: S61. Selection of Voltage Divider Resistor: Considering the power carrying capacity of the circuit, the heat dissipation efficiency of the components, and industry-standard selection criteria, a resistor with a resistance of 240KΩ is selected as the voltage divider resistor. This resistance value must meet the power requirements of the voltage divider circuit under 30V and 300V voltage scenarios, and at the same time provide a stable reference for the subsequent calculation of the resistance value of the switching resistor, avoiding the impact of fluctuations in the voltage divider resistor parameters on the overall voltage divider accuracy.

[0033] S62. Switching Resistor Value Matching: Based on the core requirement that "after the target voltage is divided by the switching resistor and the voltage divider resistor, the voltage at the 8R terminal of the TL431 Zener diode must be equal to the 2.5V preset turn-on reference voltage," the matching resistance values ​​for the two switching resistors are determined through a combination of theoretical derivation and actual testing: For the first target DC voltage of 30V, after R... 切 =R 分 ×(U ref / UU ref After deriving the voltage divider formula and verifying multiple sets of resistance values, the resistance of the first switching resistor 6 was finally determined to be 20KΩ. This ensures that after the 30V voltage is divided by the 20KΩ first switching resistor 6 and the 240KΩ voltage divider resistor, the voltage at the 8R terminal of the TL431 Zener diode accurately reaches 2.5V. For the second target DC voltage of 300V, similarly, through derivation and testing, the resistance value of the second switching resistor 7 was determined to be 2KΩ. This ensures that after the 300V voltage is divided by the 2KΩ second switching resistor 7 and the 240KΩ voltage divider resistor, the voltage at the 8R terminal of the TL431 Zener diode is also stable at 2.5V.

[0034] S63. Resistor Assembly and Accuracy Verification: Assemble the 240KΩ voltage divider resistor, the 20KΩ first switching resistor 6, and the 2KΩ second switching resistor 7 into their respective circuits according to the circuit design requirements. Then, set up a simulated test environment: connect 30V and 300V voltages respectively, and collect the voltage value at the R terminal of the TL431 Zener diode in real time using a high-precision voltage detection instrument. If the voltage at the R terminal is stable within the allowable error range of 2.5V±0.05V under both voltage scenarios, the resistor value is considered to be qualified. If it exceeds the error range, fine-tune the switching resistor value and repeat the test until the voltage divider accuracy requirement is met, to avoid the subsequent feedback logic failing to trigger properly due to resistance deviation.

[0035] Furthermore, step S7. Independent power supply: During the feedback control process, a stable operating power supply is provided to the optocoupler 4 through a 24V DC power supply 1 that is independent of the input voltage of the DC bus voltage input terminal 3. This 24V power supply does not depend on the 30V / 300V bus voltage. Even if the bus voltage drops sharply (e.g., from 30V to 25V) or rises sharply (e.g., from 300V to 310V) due to fluctuations in the input voltage, it can still provide a constant driving current to the light-emitting terminal of the optocoupler 4, ensuring that the optocoupler can output high and low level signals normally under both voltage scenarios, avoiding feedback interruption caused by unstable power supply, and ensuring the continuity of the control process.

[0036] Furthermore, step S5 includes: S51. Low Voltage Feedback: If the DC bus voltage is lower than the current target value (30V or 300V), the voltage at the 8R terminal of the TL431 Zener diode after voltage division is <2.5V, and the TL431 Zener diode 8 is cut off; at this time, no current flows through the light-emitting terminal of the optocoupler 4, and there is no light source output. The light-receiving terminal outputs a high level to the feedback signal output terminal 2 due to the lack of light; after the IPM module receives the high-level signal, it increases the PWM pulse duty cycle (e.g., from 30% to 50%), increases the conduction time of the power devices, and increases the DC bus voltage, so that the voltage gradually approaches the target value of 30V or 300V; for example, when the bus voltage is 28V (lower than the target value of 30V), the TL431 is cut off, the optocoupler outputs a high level, and the IPM increases the duty cycle to make the voltage rise back to 30V; S52. High Voltage Feedback Unit: If the DC bus voltage reaches or exceeds the current target value (30V or 300V), the voltage at the 8R terminal of the TL431 Zener diode after voltage division is ≥2.5V, and the TL431 Zener diode 8 conducts; at this time, current flows through the light-emitting terminal of the optocoupler 4 and emits light, and the light-receiving terminal outputs a low level to the feedback signal output terminal 2 after receiving the light; after the IPM module receives the low-level signal, it reduces the PWM pulse duty cycle (e.g., from 50% to 30%) or pauses the pulse output, limiting the bus voltage from continuing to rise and stabilizing the voltage at the target value of 30V or 300V; for example, when the bus voltage is 302V (higher than the target value of 300V), the TL431 conducts, the optocoupler outputs a low level, and the IPM reduces the duty cycle to make the voltage drop back to 300V; S53. Cyclic Regulator: The IPM module collects the level signal of the feedback signal output terminal 2 every preset time interval (e.g., 10ms), repeats the judgment and adjustment actions of S51 and S52, and forms a dynamic closed-loop control; even if the bus voltage deviates due to load changes (e.g., increased test load) or input voltage fluctuations, it can quickly respond and correct within 10ms, ensuring that the 30V voltage fluctuation range is controlled within ±0.5V and the 300V voltage fluctuation range is controlled within ±1V, meeting the stringent requirements of generator rotor test for power supply stability.

[0037] The embodiments described in this specification are merely examples of implementations of the inventive concept. The scope of protection of this invention should not be considered as limited to the specific forms stated in the embodiments. The scope of protection of this invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims

1. A feedback control circuit for the DC bus of a generator rotor test power supply, characterized in that, The system includes a DC power supply, a feedback signal output terminal, a DC bus voltage input terminal, an optocoupler, a relay switch, at least two switching resistors with different resistance values, a TL431 Zener diode, and voltage divider resistors. The A terminal of the TL431 Zener diode is grounded, its K terminal is connected to one end of the voltage divider resistor, and its R terminal is connected to any of the switching resistors via the relay switch. The other end of the voltage divider resistor is connected in parallel to one end of the DC bus voltage input terminal, and the other end of each switching resistor is also connected in parallel to the other end of the DC bus voltage input terminal, which is connected to the A terminal of the TL431 Zener diode. One end of the optocoupler's light-emitting end is connected to the DC power supply, and the other end is connected to the K terminal of the TL431 Zener diode. The output terminal of the light-receiving end is the feedback signal output terminal. The DC bus voltage input terminal is used to introduce two different target DC voltages. After being divided by the corresponding switching resistors and voltage divider resistors, the voltage input to the R terminal of the TL431 Zener diode is equal to the preset on-state reference voltage of the TL431 Zener diode.

2. The feedback control circuit for the DC bus of the generator rotor test power supply according to claim 1, characterized in that, The DC power supply is set independently of the input voltage at the DC bus voltage input terminal.

3. The feedback control circuit for the DC bus of the generator rotor test power supply according to claim 1, characterized in that, The TL431 Zener diode is turned on when the input voltage at terminal R is greater than or equal to the preset turn-on reference voltage, and turned off when the input voltage at terminal R is less than the preset turn-on reference voltage.

4. The feedback control circuit for the DC bus of the generator rotor test power supply according to claim 1, characterized in that, The light-receiving end of the optocoupler is connected to the IPM module. When the TL431 Zener diode is turned on, the light-receiving end outputs a low level to the feedback signal output end; when the TL431 Zener diode is turned off, the light-receiving end outputs a high level to the feedback signal output end.

5. The feedback control circuit for the DC bus of the generator rotor test power supply according to claim 4, characterized in that, The IPM module is used to adjust the PWM pulse duty cycle according to the level signal at the feedback signal output terminal.

6. The feedback control circuit for the DC bus of the generator rotor test power supply according to claim 1, characterized in that, Let the preset on-state reference voltage of the TL431 Zener diode be U. ref The first target DC voltage is U1, the second target DC voltage is U2, the voltage divider resistor has a resistance value of Rdivider, and the switching resistor that adapts to U1 has a resistance value of Radapter. 切1 The switching resistor for the U2 adapter has a resistance value of R. 切2 The R 切1 R satisfies R 切1 =R 分 ×(U ref / U1-U ref ), the R 切2 R satisfies R 切2 =R 分 ×(U ref / U2-U ref ).

7. A method using a feedback control circuit for the DC bus of a generator rotor test power supply as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Voltage introduction: Selectively introduce a first target DC voltage or a second target DC voltage through the DC bus voltage introduction terminal. The first target DC voltage and the second target DC voltage are two different values ​​of voltage, and the two voltages are not connected at the same time. S2. Low voltage resistor switching: If the first target DC voltage is introduced in S1, the control relay switching switch is turned on with the first switching resistor of the corresponding resistance value, so that the first target DC voltage is divided by the first switching resistor and the voltage divider resistor; S3. High voltage resistor switching: If the second target DC voltage is introduced in S1, the control relay switching switch is turned on with the second switching resistor of the corresponding resistance value, so that the second target DC voltage is divided by the second switching resistor and the voltage divider resistor; S4. Voltage Divider Adaptation: Select one of the first target DC voltage and the second target DC voltage for input. After being divided by the switching resistor and the voltage divider resistor in S2 or S3, the current input target DC voltage is equal to the preset on-state reference voltage of the TL431 Zener diode and is input to the R terminal of the TL431 Zener diode. S5. Signal Feedback and Voltage Regulation: The on or off state of the TL431 Zener diode controls the corresponding level signal output of the optocoupler, which is transmitted to the IPM module via the feedback signal output terminal. The IPM module adjusts the DC bus output voltage according to the level signal to stabilize the voltage at the target value.

8. The feedback control method for the DC bus of the generator rotor test power supply according to claim 7, characterized in that, It also includes step S6. Resistor matching: The first switching resistor and the second switching resistor have different resistance values, and the two resistors are respectively determined in advance to match the voltage divider resistors according to the corresponding target DC voltage and the preset conduction reference voltage of the TL431 Zener diode, so as to ensure that the first target DC voltage and the second target DC voltage can meet the conduction conditions of the TL431 Zener diode after being divided by the corresponding switching resistor and the voltage divider resistor.

9. The feedback control method for the DC bus of the generator rotor test power supply according to claim 7, characterized in that, It also includes step S7. Independent power supply: During the feedback control process, the optocoupler is provided with working power through a DC power supply that is independent of the input voltage of the DC bus voltage input terminal, so as to ensure that the optocoupler can be driven normally under both the first target DC voltage and the second target DC voltage scenarios.

10. The feedback control method for the DC bus of the generator rotor test power supply according to claim 7, characterized in that, S5 specifically includes: S51. Low voltage feedback: If the input voltage at the R terminal of the TL431 Zener diode is less than the preset turn-on reference voltage, the TL431 Zener diode will be turned off, the optocoupler will have no light source output, and the light receiving terminal will output a high level to the feedback signal output terminal; after the IPM module receives the high level signal, it will increase the PWM pulse duty cycle to increase the DC bus voltage and make the voltage approach the target DC voltage. S52. High Voltage Feedback Unit: If the input voltage at the R terminal of the TL431 Zener diode is greater than or equal to the preset turn-on reference voltage, the TL431 Zener diode will turn on, the optocoupler will emit light, and the light receiving terminal will output a low level to the feedback signal output terminal; after receiving the low level signal, the IPM module will limit the PWM pulse output and stabilize the DC bus voltage at the target DC voltage. S53. Cyclic regulator: Repeats S51 and S52, continuously and dynamically adjusts the DC bus voltage through closed-loop feedback loop to ensure that the voltage is always stable at the currently introduced target DC voltage value.

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