High-voltage load and control method

Abstract

The invention relates to a control method of a high-voltage load. According to the method, the number n of resistive loads working with constant parameters is determined according to a target working parameter pg, n is equal to floor (pg / pu), n is larger than or equal to 1 and is a natural number, pu is the constant parameter of a single resistive load, and floor is an integer function. Then, an operation parameter pi needing to be modulated is obtained, pi = mod (pg / pu), and mod is a complementation function; n resistive loads are input into the system to operate at a constant parameter pu, a resistive loads are input at the same time, the actual operation parameter pm of the system is controlled in a closed-loop mode, the actual operation parameter pm of the a resistive loads is made to approach to the parameter pi, and therefore the overall operation parameter of the n + a resistive loads approaches to the target working parameter pg. Wherein a > = 1 and a is a natural number. According to the invention, accurate control and adjustment of the load can be realized, and the stability and efficiency of system operation are improved.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, in particular to high voltage power supply testing and load control technology. Background Art

[0002] High voltage load is a tool used to test high voltage power supply equipment. It can simulate the working state of actual load and can withstand higher voltage. It is mainly used for R&D, debugging and production testing of power electronic equipment, inverter, high voltage power supply and other systems. Its core functions include current control, constant resistance load simulation, constant current, constant voltage and constant power control.

[0003] Currently, most electronic loads are used for power supply development below 1kV, and high-voltage power supply testing above 3kV is relatively rare. When a few high-voltage power supply developments require the use of electronic load testing, it is usually achieved by connecting multiple MOS tubes in series to work in the linear region. This method drives the MOS tube with a DC voltage to make it work in the linear region, and adjusts the gate voltage of each MOS to the same level through resistor voltage division to form an adjustable linear load. However, this design faces many challenges.

[0004] 1. Voltage balancing problem: Multiple MOS tubes connected in series have uneven voltage distribution due to differences in manufacturing parameters. If the voltage on some MOS tubes is too high and exceeds their safe operating area (SOA), the device may fail. This uneven voltage distribution makes it difficult to accurately control and affects system stability.

[0005] 2. Poor stability: MOS tubes need to work in the linear region under high voltage environment. However, it is very difficult to keep multiple MOS tubes working stably in this state. When the load changes dynamically, it is easy to cause instability, resulting in instantaneous fluctuations and system instability. At the same time, traditional high-voltage loads are still difficult to meet the requirements of high dynamic performance and bandwidth, and the system stability is poor. Especially in the early debugging stage when the high-voltage power supply is unstable, the resistive load is easily damaged due to stability problems. At the same time, since traditional loads mostly use fixed resistors, stepless load adjustment, dynamic loading and unloading cannot be achieved, which limits the effectiveness of high-voltage power supply testing.

[0006] 3. Slow response: MOS tubes in series respond slowly when adjusting the load, especially when the load needs to change quickly. This is due to the delay of the MOS tube control circuit and the complexity of driving multiple MOS tubes, making it difficult for the system to respond quickly when dealing with disturbances or load changes, affecting performance.

[0007] 4. Switching characteristic consistency problem: Multiple MOS tubes may have differences in switching speed, on-time, off-time, etc. These differences will lead to inconsistent system response and reduced control accuracy in the series circuit. For example, when controlling voltage or current, the difference in response time of different MOS tubes will cause instantaneous load fluctuations, making it difficult to ensure consistency.

[0008] 5. Long-term operation consistency problem: MOS tubes and their control circuits will produce parameter drift due to aging or temperature stress during long-term operation. In high-voltage applications, this consistency problem is more obvious, because high voltage accelerates device aging, and the aging speed of different MOS tubes is inconsistent, which may cause some MOS tubes to fail prematurely, affecting the overall reliability of the system.

[0009] 6. High cost: Due to the above problems, designers often need to add more MOS tubes and complex voltage equalization circuits. This not only increases the complexity of the system, but also significantly increases the cost. In addition, MOS tubes are usually designed for switching applications, and their performance under DC conditions is poor, and their safe operating area (SOA) is small, which increases the redundancy requirements during design, further increasing the redundancy requirements and costs of the system.

[0010] In summary, current high-voltage load technology faces multiple challenges, mainly because it relies on a large number of MOS tubes in series. The stability and voltage balancing of the series circuit are difficult to guarantee, resulting in the accuracy of constant current, constant voltage and constant power control being limited by the MOS tube parameters and the voltage balancing circuit, and being unable to respond quickly to system disturbances and difficult to adapt to different high-voltage power supply requirements. In addition, the system's difficulties in voltage balancing, stability, response speed and cost further hinder the standardization and promotion of high-voltage loads, especially in high-voltage power supply testing above 3kV, where the consistency and reliability of the system become the main bottlenecks.

[0011] Therefore, in order to improve the performance of high-voltage loads, it is urgent to improve the design and solve these problems so that it can better meet the needs of high-voltage environments. Summary of the invention

[0012] The present invention aims to solve the above problems in the prior art and provide a control method and corresponding device for high-voltage loads, which can dynamically adjust the number and operating parameters of resistive loads according to target operating parameters to ensure that the entire system can operate efficiently and stably in different operating modes.

[0013] The present invention provides a control method for a high-voltage load, comprising the following steps: determining the number n of resistance loads operating with constant parameters according to a target operating parameter pg, wherein n=floor(pg / pu), n≥1, pu is a constant operating parameter of a single resistance load, and floor is a rounding function; obtaining an operating parameter pi that needs to be modulated, pi=mod(pg / pu), mod is a remainder function; putting n resistance loads into operation with a constant parameter pu; putting a resistance load into operation, and controlling the actual operating parameter pm thereof in a closed loop, so that the actual operating parameter pm of the a resistance loads approaches the parameter pi, and the operating parameter of the n+a resistance loads approaches the target operating parameter pg; wherein a≥1 and a is a natural number.

[0014] In one embodiment of the present invention, the closed-loop control includes: outputting control parameters according to actual operating parameters and target operating parameters, the actual operating parameters pm=pd*k, where k is a proportional factor, k=des(pg / pu), and des is the decimal place.

[0015] In one embodiment of the present invention, the closed-loop control includes a pid control algorithm, the closed-loop control includes a pid control algorithm, the pid control algorithm outputs a pwm signal that controls a resistive load, and the error parameter of the pid algorithm is e(t)=pi-pm.

[0016] In one embodiment of the present invention, the pid algorithm further includes a feedforward term f, where the feedforward term f=k, for improving control accuracy and response speed.

[0017] In one embodiment of the present invention, the target operating parameter pg is determined according to the working mode of the resistor load, the working mode of the resistor includes a constant parameter mode and a pulse working mode, and the target operating parameter in the pulse working mode is determined by the pulse curve; a≥floor(△pg / pu)+1; △pg is the difference between the maximum value and the minimum value on the pulse curve.

[0018] In one embodiment of the present invention, the constant parameter mode includes a constant power parameter mode, a constant voltage parameter mode, and a constant current parameter mode.

[0019] In one embodiment of the present invention, the constant parameter mode includes a constant power parameter wg, and the actual power parameter of a resistive load is Wherein Vmi represents the measured voltage of the resistive load, Imi represents the measured current of n+1 resistive loads; k=des(wg / wu), where wu represents the rated operating power of a single resistive load; error parameter e(t)=wi-wm, where wi=mod(wg / wu).

[0020] In one embodiment of the present invention, the pulse curve may be defined as:

[0021]

[0022] Among them, b represents the coefficient, and c1, c2, E1, and E2 represent constants.

[0023] In addition, the present invention also provides a high-voltage load device for executing the above method, including: a load circuit having a load resistor and a switching circuit for controlling the operation of the load resistor; a detection circuit for detecting the operating parameters of the load circuit during operation; a control circuit electrically connected to the detection circuit and the switching circuit; the control circuit outputs a PWM signal for controlling the switching circuit based on the detected operating parameters of the load circuit and the target parameters in a specific operating mode, so that the operating parameters of the load circuit approach the target parameters.

[0024] In one embodiment of the present invention, the load circuit includes at least one resistive load; the resistive load includes: a first switch tube and a second switch tube connected in series, the drain of the first switch tube is connected to the source of the second switch tube, the source of the first switch tube is grounded, the drain of the second switch tube is connected to the load resistor, and the load resistor is connected to the positive electrode of the high-voltage power supply; the gate of the second switch tube is connected to the positive electrode of the high-voltage power supply through a bias resistor, a Zener diode is connected between the gate of the second switch tube and the source of the second switch tube, and the breakdown voltage of the Zener diode is greater than the conduction voltage of the second switch tube.

[0025] Beneficial technical effects:

[0026] Compared with the prior art, the present invention has the following improvements:

[0027] 1. Solve the voltage balancing problem and improve system stability: By using high-power high-voltage resistors to bear the main power loss, the problem of uneven voltage distribution caused by differences in manufacturing parameters of multiple series MOS tubes in traditional high-voltage loads is avoided. The dependence on MOS tube voltage balancing control is reduced, the system is easier to maintain a balanced voltage distribution, and the failure risk caused by MOS tube voltage exceeding the safe operating area (SOA) is reduced, which significantly improves the stability and reliability of the system.

[0028] 2. Enhance system adaptability: The design of the present invention makes the high-voltage load not need to rely on the linear working state of the MOS tube under high-voltage environment, solving the problem of instability when multiple MOS tubes work stably in the high-voltage linear area. The system dynamically adjusts the load to effectively cope with the dynamic changes of the load, realizes stepless load adjustment and dynamic loading and unloading, especially in the high-voltage power supply debugging stage, significantly improves the reliability of the equipment, reduces the risk of damage, enhances the robustness of the system, and further improves the overall stability.

[0029] 3. Improve response speed: Using resistors instead of MOS tubes as loads has a faster response speed. The present invention can quickly respond to disturbances and load adjustment requirements in the system.

[0030] 4. Improve the consistency of switching characteristics and enhance control accuracy: Compared with the problem of inconsistent switching characteristics that may be caused by the traditional series connection of multiple MOS tubes, the present invention reduces the number of MOS tubes used and only uses them as switching elements, thereby improving the consistency and control accuracy of the switch. At the same time, there is no consistency problem when the resistor is used as a load. The response consistency of each component in the overall system is higher, which greatly reduces the complexity of the control circuit.

[0031] 5. Extend the service life of the system: The present invention reduces the dependence on MOS tubes, avoids the parameter drift problem caused by MOS tube aging or temperature stress, and extends the service life of the system. By dynamically adjusting the heat loss temperature distribution of the high-voltage load, the system maintains consistency in long-term operation, reduces the impact of high-voltage accelerated device aging, and ensures the long-term reliability of the system.

[0032] 6. Adapt to a wide range of high voltage demands. Since the switch tube works in a switching state rather than a linear state, and a high-power high-voltage resistor is used to bear the power loss, the present invention can adapt to a wider range of high voltage usage needs, making high-voltage loads easier to standardize and promote, and adapt to different high-voltage application scenarios.

[0033] 7. Reduce costs and improve economic benefits. The present invention uses power resistors to bear the main power loss, reduces the dependence on expensive devices such as MOS transistors, significantly reduces the overall cost of electronic loads, and avoids the need to use a large number of MOS tubes and complex voltage-equalizing circuits. Since there is no need to install a large number of MOS tubes, the present invention significantly saves man-hours, simplifies the production process, and improves production efficiency, thereby further reducing system design and production costs and improving the economic benefits of high-voltage loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the high-voltage load frame structure of the present invention.

[0035] Figure 2 Schematic diagram of the resistance load of the present invention.

[0036] Figure 3 FIG. 2 is another schematic diagram of a resistive load according to the present invention.

[0037] Figure 4 It is a schematic diagram of the topological structure of multiple resistive loads of the present invention.

[0038] Figure 5 This is the operating status diagram of the system of the present invention.

[0039] Figure 6 This is the first step of the schematic diagram of the operation flow of the system of the present invention.

[0040] Figure 7This is the second step of the schematic diagram of the operation flow of the system of the present invention.

[0041] Figure 8 It is a schematic diagram of the pulse working mode curve of the present invention. DETAILED DESCRIPTION

[0042] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. This description is only used as a basis for those skilled in the art to understand the technical solution of the present application.

[0043] System Structure

[0044] Please refer to Figure 1 The high voltage load system shown in FIG. 1 includes a load circuit ETL_LOAD which includes at least one resistive load (eg Figure 2 and Figure 3 As shown in FIG. 1 , the resistive load includes a load resistor and a switch circuit for controlling the operation of the load resistor; a detection circuit V / I_DETECTION for detecting the working parameters of the load circuit ETL_LOAD in a set working mode; and a control circuit ETL_CTRL electrically connected to the detection circuit and the switch circuit. The control circuit ETL_CTRL outputs a PWM signal for controlling the switch circuit according to the detected working parameters of the load circuit and the target parameters in the set mode, so that the working parameters of the load circuit gradually approach the target parameters.

[0045] The load circuit ETL_LOAD is connected to the detection circuit V / I_DETECTION for monitoring parameters such as internal temperature (Temperature_DET), voltage, current, power, etc. The module adjusts the load to simulate different working conditions by connecting to the control circuit ETL_CTRL. Common working modes of high-voltage power supplies include constant parameter working mode and pulse parameter working mode, wherein the constant parameter working mode includes but is not limited to constant power working mode, constant voltage working mode and constant current working mode. The pulse parameter working mode includes but is not limited to pulse power working mode, pulse voltage working mode and pulse current working mode. In the pulse working mode, the working parameters are determined by the time-pulse parameter curve.

[0046] In addition, the control circuit ETL_CTRL supports multi-channel control (Multi_Channel_Drl) or single-channel control. This allows the high-voltage load to support multiple resistance loads connected to one controller, or multiple loads connected to one detection circuit. Those skilled in the art can envision a many-to-one or one-to-many connection mode, and control the operation of the load or detection circuit by a time-division multiplexing method.

[0047] In the load circuit ETL_LOAD, terminals TL+ and TL- are the positive and negative terminals of the high voltage test circuit, which are used to input the voltage and current signals of the power supply under test (usually a high voltage power supply).

[0048] The detection circuit V / I_DETECTION is used to measure the voltage and current (TL+ and TL-) in the test line and feed back the detection results to the control system through optical fiber signal transmission (OpticalFiber). The detection circuit also monitors temperature data (through the Temperature_DET port)

[0049] The control circuit ETL_CTRL receives the signal from the detection module and controls the operation of the load circuit ETL_LOAD. It communicates with the detection circuit V / I_DETECTION through an optical fiber signal (OpticalFiber). The control circuit has a built-in closed-loop control algorithm, which receives the signal from the detection module and outputs a PWM signal for controlling the switch circuit according to the detected working parameters of the load circuit ETL_LOAD and the set working mode target parameters, so that the working parameters of the high-voltage power supply gradually approach the target parameters.

[0050] The control circuit ETL_CTRL is also electrically connected to other peripheral devices to form a human-computer interaction interface. The interface is used to receive user input and display system working status, parameters and other information to the user. At the same time, fault information is fed back to the user through the interface during the working process. The peripheral devices include: a keyboard (KeyBoard), as one of the input devices of the control system, connected to the control circuit through a 5V signal line; a touch panel (TouchPanel), providing a user input interface, connected to the control circuit through an I2C communication protocol; a liquid crystal display (LCD), used to display system status and parameter information, and communicate with the control circuit through an RS485 protocol.

[0051] Resistive load

[0052] like Figure 2 As shown, the structure of the load resistor and the switch circuit in the electronic load includes: a first switch tube Q1 and a second switch tube Q2 connected in series. The drain of the first switch tube Q1 is connected to the source of the second switch tube Q2, the source of the first switch tube Q1 is grounded, and the drain of the second switch tube Q2 is connected to the load resistors R1 and R3, and the load resistors R1 and R3 are connected to the positive electrode of the high-voltage power supply.

[0053] The gate of the second switch tube Q2 is connected to the positive electrode of the high voltage power supply through the bias resistor R2. At the same time, a Zener diode D1 is connected between the gate and the source of the second switch tube Q2, and the breakdown voltage of the Zener diode D1 is greater than the conduction voltage of the second switch tube Q2. In addition, the second end of the resistor is connected to the first end of the resistor R4, and the first end of the resistor R4 is connected to the Zener diodes D2-D5 connected in series. These Zener diodes (D2-D5) are used to protect the first switch tube and the second switch tube from being damaged by surge impact.

[0054] The gate of the first switch tube Q1 is connected to the driving signal through the resistor R5, connected to the ground through the resistor R6, and connected to the Zener diode D6. The resistor R6 is used to pull the gate down to the ground, the Zener diode D6 is used for voltage stabilization, and the resistor R5 is used to provide the driving signal Driver_K.

[0055] The input signal of the driving signal Driver_K is a PWM control signal, which is derived from a control circuit or a dedicated driving module connected to the control circuit. The PWM control signal is used to control the resistive load so that the whole load behaves as a constant parameter device or a pulse parameter device. Constant parameter devices include constant power devices, constant voltage devices, and constant current devices; while pulse parameter devices include pulse power devices, pulse voltage devices, and pulse current devices.

[0056] Further references Figure 3 ,exist Figure 2 A detection resistor R13 is added to the circuit shown, and the current of the load resistors R7 and R9 and the voltage of the load resistors R7 and R9 can be detected by the voltage division of the detection resistor R13. The detected voltage or current signal is connected to the current detection terminals TL+ and TL_I+ of the detection circuit. Obviously, there are many other voltage or current detection methods, which the applicant does not list one by one, but those skilled in the art can select an appropriate voltage or current detection method according to actual needs.

[0057] In one embodiment, each resistive load includes a driving terminal connected to a driving signal terminal of a controller, and the positive terminals of the plurality of resistive loads are connected to the positive electrode of a high voltage power supply, and the negative terminals are connected to the negative electrode of the high voltage power supply. The driving signal of the resistive load is connected to the control module through a multi-channel terminal, and it can be known that the terminal of each control channel is respectively connected to a resistive load, so as to independently control the working mode of each resistive load.

[0058] Figure 3 The diodes D8-D12 in Figure 2D2-D5 have the same function, resistor R10 has the same function as resistor R4, diode D7 has the same function as diode D1, resistors R7 and R9 have the same function as resistors R1 and R3, resistor R8 has the same function as resistor R2, and switches Q3 and Q4 have the same function as switches Q1 and Q2.

[0059] like Figure 4 As shown, all N, N≥2, resistance loads ETL_LOAD are arranged in an array and connected in parallel at both ends of the positive and negative electrodes (TL+ / TL-) of the high voltage power supply. However, the connection method of the resistance loads in the present application is not limited to this, and those skilled in the art can also choose different connection methods according to actual needs, such as: connecting the resistance loads ETL_LOAD in parallel; connecting the resistance loads ETL_LOAD in parallel after connecting them in groups in series; or connecting all the resistance loads in series, and then connecting the resistance loads in parallel after connecting them in groups in series.

[0060] System operating status

[0061] like Figure 5 The high-voltage load system shown starts initialization from the "start" state. During the system initialization process, the current system configuration and status information will be scanned and recorded first, and then the key historical data will be read to understand the previous operation. Subsequently, the system is ready to respond to the operation input of the human-machine interface, including setting the target parameters and operation mode of the operation. The system highlights the icon and lights up the "ready" indicator through the human-machine interface, indicating that it is ready and can operate normally. When the system receives the operation instruction, it will automatically enter the operation state; if an error occurs during the startup process, the system will enter the error handling state. In addition, the human-machine interface can also choose to perform a soft shutdown or a hard shutdown operation to put the system into the end state.

[0062] In the "Run" state, various operations are performed according to the actual operating conditions. The system processes tasks according to the preset logic and continuously monitors key operating parameters such as temperature and voltage to ensure safe operation. If the task is successfully completed, the system will return to the "Standby" state and wait for the start of the next task; if an abnormality or error is detected during operation, the system will enter the "Error Handling" state. Operation errors may include parameters exceeding the system's receiving range, system over-temperature, over-voltage, over-current, protection triggering, and component damage. At the same time, the system can accept instructions from the human-machine interface in the running state. For example, when a shutdown command is received, the system will back up the current operating state and enter the "End" state.

[0063] In the "error handling" state, the system will try to automatically repair the problem, such as reinitializing the module or retrying the operation. During the system error handling process, the human-machine interface will feedback the problems and error handling operations that occurred. The repair includes restarting the mainboard to re-enter the start state, or accepting the human-machine interface input command to softly shut down or hard shut down to enter the end state.

[0064] In the standby state, the system continuously detects whether there are new instructions from the human-machine interface, and switches from the "standby" state to the "running" state according to the instructions. In the "running" state, or in the standby state, it accepts the shutdown instruction from the human-machine interface to perform a soft shutdown. If an error occurs in the standby state, it enters the error handling state.

[0065] System operation steps

[0066] like Figure 6 and Figure 7 As shown, the system startup is initiated by the human-machine interface. First, the controller enters the initialization step 601 and performs a system self-check. Subsequently, the system establishes communication with the detection module and completes step 602. In this state, the system enters step 603 to accept the input of the human-machine interface, including parameter instructions and the setting of the load working mode, to ensure the normal operation of subsequent operations. At the same time, the operation of the detection circuit also includes the initialization step 651, and establishes communication with the detection circuit through step 652, and in step 653 of determining whether the connection is successful, repeating the attempt to establish the connection after the connection fails.

[0067] Then, the system enters the running state, and the system detects whether the human-machine interface has timed out, as shown in step 605. If there is no input within 10 minutes, the system will enter the standby state and continue to monitor the input of the human-machine interface, and then enter step 621 to prepare to accept new instructions.

[0068] After the setting of the mode and parameters is completed, the system enters the operating state. In step 606, the system first determines whether the working mode has been selected, and then obtains the set mode and parameters in step 607. In this state, step 609 detects whether the set parameter and mode combination is within the rated operating range of the system. If it exceeds the rated range, the system will feedback the setting error information through the human-machine interface. Subsequently, the system further confirms the timeout information of step 604 through the human-machine interface.

[0069] If the system operating range is not exceeded, the system will confirm the parameters in step 610, and enter the operating state of the resistive load after writing the system parameter values ​​in step 611. In step 612, the detection circuit monitors the operating parameters of the load, such as voltage, current, and temperature. In step 613, the system determines whether these operating parameters are abnormal. If an error is detected, the abnormality is prompted through the human-machine interface in step 614.

[0070] Next, the system determines the type of exception in step 631, and determines the priority of the error by querying the database in step 633. In step 632, the processing method is determined according to the priority of the exception. In step 636, the system determines whether shutdown processing is required. If shutdown is not required, a processing plan is generated in step 635, and then the error processing plan is sent to the human-machine interface through step 615. Step 615 prompts the user to handle the exception, and the system returns to the running state. If shutdown is required, the system enters the end state.

[0071] During the error handling process, the system will record the operation status in step 634, including the system operation parameters and the system status when the error occurred. If shutdown processing is required, the system enters the end state in step 641, saves the field data, and records the system parameters (such as load parameters, control module and detection module, etc.) when the error occurs, so as to facilitate subsequent problem analysis.

[0072] If the module does not detect an abnormality in step 613, or after the abnormality handling step 615, the control circuit will output a control signal according to a specific closed-loop control algorithm in step 616. In the present application, the control signal is a PWM signal, and the PWM signal is output in step 617, and the PWM signal includes a duty cycle.

[0073] The PWM signal controls the switch of the resistive load in step 621. In step 622, the detection circuit detects whether the operating parameters of the resistive load are abnormal. If an abnormality is detected, the process proceeds to step 623 for soft restart processing; if no abnormality is detected, the process proceeds to step 624 to continuously monitor the operating parameters and feed back the results to step 612.

[0074] The closed-loop control algorithm provides multiple working modes according to the setting of the human-machine interface, mainly including constant parameter working mode and pulse parameter working mode. In the constant parameter working mode, the working parameters remain unchanged during the operation of the system until the operation ends. In the pulse parameter working mode, the system dynamically adjusts the working parameters over time according to the changes in the pulse curve until the operation ends. The constant parameter working mode includes but is not limited to the constant power working mode, the constant voltage working mode and the constant current working mode.

[0075] Closed-loop control algorithm

[0076] Reference Figure 4 , the closed-loop control algorithm determines the number of resistive loads n that need to operate at rated parameters based on the target operating parameter pg of the resistive load, where n = floor(pg / pu), and n ≥ 1. Among them, pu is a constant parameter of a single resistive load, and floor represents a rounding function. Through this calculation step, the number of electronic loads n that need to operate at rated parameters can be determined.

[0077] Furthermore, the constant parameter may refer to the resistance load operating under constant parameters, such as constant voltage or constant current. Preferably, the constant parameter includes rated voltage, current or power, etc., to reduce the number of resistance loads put into operation. This approach can achieve a more efficient working state by optimizing the load operating parameters.

[0078] At the same time, when the calculated n value > N, the system will enter the error handling state and feedback signals that exceed the operating parameter range, such as over-power signals, over-voltage signals, over-current signals, etc., to the human-machine interface so that the user can process and adjust them in time.

[0079] Obtain the operating parameter pi that needs to be modulated, where pi=mod(pg / pu), mod is the modulo function; the operating parameter pi is the target operating parameter of the n+1th to n+ath resistance loads. The target operating parameter pg can be expressed as pg=n*pu+pi. Therefore, by adjusting the operating parameters of the n+1th to n+ath resistance loads separately, the operating parameters of the entire high-voltage load can be gradually approached to the target operating parameter pg.

[0080] After obtaining the parameter n and the parameter a, it is necessary to perform operation control with different parameters for the n resistance loads and the n+1th to n+ath resistance loads respectively. Among them, the n resistance loads operate with the parameter pu, and the n+1th to n+ath resistance loads are controlled by the control circuit through a closed loop to control the actual operation parameter pm so that it gradually approaches the parameter pi. According to different application scenarios, the parameter a satisfies a≥0 and a≤N-(n+1).

[0081] The closed-loop control includes measuring the actual working parameter pm of the resistive load according to the detection circuit, and calculating the error between the actual working parameter and the target parameter pi. The control algorithm calculates the output signal according to the error. The output signal is a PWM signal. The duty cycle of the PWM signal is input into the resistance control circuit.

[0082] Among them, the closed-loop control algorithms include proportional control (P control), integral control (I control), differential control (D control), PID control, fuzzy control, sliding mode control, optimal control, model predictive control, adaptive control, feedback linearization control, incremental control, H∞ control, Q learning, Lyapunov stability control and other control algorithms.

[0083] The above closed-loop control algorithm uses the difference between the target parameter pi and the actual working parameter pm as an input parameter. The actual working parameter pm is expressed as pm=pd*k, where k is a proportional factor, defined as k=des(pg / pu), des is a decimal point operation; pd is the detected value of the actual operating parameter.

[0084] The role of the proportional factor k is to achieve linearization. Through this proportional factor, the detection signal is adjusted to a uniform range, thereby eliminating the influence of the magnitude difference or nonlinear characteristics of different parameters. In this way, the output response of the control algorithm is more consistent and accurate, and is not affected by load changes or external interference, thereby enhancing the robustness and adaptability of the system.

[0085] The following uses the PID algorithm in constant power mode as an example to explain the control algorithm process in detail. During the system startup phase, the human-machine interface selects the constant power test mode, and the target operating power parameter is set to Wg. The constant power of a single resistive load is Wu, which can be the operating power of a single resistive load under constant PWM parameter modulation, or the rated power of a single resistive load. Using the rated power can reduce the number of resistive loads required.

[0086] According to the power parameter Wg, the number n of resistive loads operating at constant power is determined, where n=floor(Wg / Wu), and the obtained n is a natural number greater than or equal to 1. n resistive loads operate at constant power or rated power, providing a total power n*Wu.

[0087] Obtain the operating power parameter Wi that needs to be modulated, and the calculation formula is Wi = mod(Wg / Wu), that is, Wi = Wg-n*Wu. Due to disturbances in the system operation, it is impossible to automatically maintain the target power Wg, so Wi needs to be modulated to offset the impact of fluctuations on constant power, so that the total power remains at Wg.

[0088] By putting in a resistor load, the actual operating parameter pm is controlled in a closed loop, so that the actual operating parameter pm of these resistor loads approaches the parameter Wi. The overall operating parameter of n+a loads will approach the target operating parameter Wg. The number of resistor loads a is determined according to the fluctuation degree △Wg. The greater the fluctuation, the more resistor loads are required. Usually when operating in constant power mode, the fluctuation is less than Wu, so a = 1. Obviously, a ≥ 1 and a is a natural number.

[0089] The detection circuit detects the actual voltage Vm and actual current Im of the closed-loop control load, and calculates the actual power Wm based on the actual voltage and current. The calculation formula is: Wm = (Vm × k) × (Im × k) × a, where a = 1, that is, Wm = Vm × Im × k 2 .

[0090] Where Im_T is the total current, Vm is the voltage, and Ru is the load resistance. The error parameter of the pid algorithm is e(t) = Wi-Wm = Wi-Vm×Im×k 2 , then the parameter e(t) is substituted into the pid algorithm equation, The output value u(t) is the duty cycle of the PWM control signal, which is used to adjust the power of the resistive load in real time so that the actual power Wm approaches the total power Wg.

[0091] Furthermore, by introducing the feedforward term f into the PID control formula, it can be expressed as a function of time F(t),

[0092] The feedforward term F(t) = Wi / Wu. By introducing the feedforward term, the PID output is not only adjusted based on the error, but also compensates the input requirements of the system in advance through feedforward control, thereby improving the response speed and accuracy of the system. Feedforward control can pre-adjust the system before the error occurs, reduce the response time, and ensure that the system is more stable and accurate.

[0093] In order to further improve the system's operational stability and extend the life of the device, the system implements temperature management during operation. The system algorithm selects the appropriate execution unit to switch the load based on the monitored temperature information, thereby balancing the device temperature. For example, by monitoring the temperature difference, when the temperature difference between the highest temperature and the resistive load in the closed-loop control state reaches a certain level, the system will automatically switch the execution unit with the highest temperature to the execution unit with the lowest temperature. In order to avoid instantaneous fluctuations in the load, the system ensures that the two execution units are shut down and turned on synchronously when switching.

[0094] In addition, when there are multiple resistor loads in closed-loop control (for example, a=3), the system will select the three resistor loads with the highest temperature to enter the closed-loop control mode, and the remaining three resistor loads will enter the constant power working mode. In this way, the N resistor loads in the system can reasonably dissipate heat in turn as the temperature rises, ensuring the overall stable operation of the system and avoiding the burning of the resistor loads due to overload.

[0095] Taking the constant voltage mode as an example, another control method is explained. In the constant voltage mode, both the voltage and current need to be adjusted by the proportional factor before participating in the closed-loop control of the voltage or current. After PID adjustment, the PWM duty cycle D is calculated, and the integer and decimal parts of D*N are further calculated: n=floor(D*N), k=des(D*N). When n is an integer greater than 0, the system sets the n execution units to the full cut-in state and adjusts the duty cycle of the n+1th execution unit to k. The remaining execution units are temperature-monitored together with the n execution units that are cut in. When the temperature difference exceeds the set threshold, the execution unit with the highest temperature is cut out and the unit with the lowest temperature is cut in.

[0096] The above control method not only improves the accuracy of load execution, but also effectively prolongs the service life of high-voltage loads. In constant voltage mode, resistive loads can be connected in a variety of ways, including series, parallel, first parallel then series, or first series then parallel, to meet the requirements of different loads for withstand voltage, current, power, and heat dissipation.

[0097] The pulse working mode is explained below, and the process of the control algorithm is described in detail.

[0098] Figure 8 The figure shows how the load working parameters change over time in the pulse parameter mode. The pulse parameters include power, resistance, voltage and current. The following takes pulse power as an example to illustrate how the power of the load circuit changes over time in the pulse mode. The control methods in other modes are the same as those in the power mode, and the working parameters are adjusted according to similar principles.

[0099] The pulse working mode divides the power into a high pulse period and a low pulse period. The high pulse period is shown as marked T1 and T2, and the low pulse period is shown as T3. The arrangement of the pulse periods can be pre-set according to the parameters of the human-machine interface, and the duration of the pulse period can also be pre-adjusted. Different high pulse and low pulse periods can be set with different time lengths. The high pulse period includes a constant power stage t1 to t2, a rising power stage t0 to t1, and a falling power stage t1 to t2. The power parameter of the constant power stage is between t2 and t3. The power of the low pulse period T3 is a constant value C1, and the power of the high pulse periods T1 and T2 is a constant value C1. Further, the time-pulse working parameter curve is defined as:

[0100]

[0101] Among them, b represents the coefficient, and c1, c2, E1, and E2 represent constants.

[0102] The target power changes periodically according to the power curve as the power demand of the load circuit to simulate a load with periodic power shocks. In a high pulse cycle (such as T1, T2), there are four stages, and the pulse power of each stage is different. In the t0-t1 stage, the pulse power gradually increases until it reaches t1. The power design of the load continues to increase through the closed-loop control algorithm, linearly following the change of the target power. In the t1-t2 stage, the target power remains constant at C2.

[0103] In the closed-loop control algorithm, the power of a resistive load approaches the modulation power wi, where a

[0104] ≥floor(△Wg / Wu)+1, △Wg represents the power change amplitude, that is, △Wg=C2-C1. In the t2-t3 stage, the power gradually decreases, showing a linear downward trend, and the closed-loop control algorithm continues to maintain control to ensure that the power change meets the target requirements.

[0105] In addition to the pulse power working mode, technical personnel in this field can also implement pulse voltage mode, pulse current mode, pulse resistance mode and other working modes that the high-voltage power supply needs to be tested based on the same technical principles to adapt to different test conditions of the high-voltage power supply.

[0106] Through the technical solution of the present application, the present application can solve the voltage balancing problem in the prior art, improve the stability and reliability of the system, increase the response speed of the load, improve the consistency problem of the switch, extend the service life of the test equipment, and improve the economy of the equipment.

[0107] Although the present invention has been described in detail with reference to specific embodiments, it should be understood by those skilled in the art that various modifications and changes may be made to its form and details without departing from the spirit and scope of the present invention, such as modifying operating parameters, modifying closed-loop control algorithms, modifying the number of components, etc. Therefore, the scope of the present invention shall be defined by the appended claims and their equivalents.

Claims

1. A method for controlling a high voltage load, comprising: According to the target working parameter pg, the number n of the resistance loads working with constant parameters is determined, where n=floor(pg / pu), n≥1 and n is a natural number, pu is the constant parameter of a single resistance load, and floor is a rounding function; Get the operating parameter pi that needs to be modulated, pi = mod(pg / pu), mod is the modulo function; Put n resistance loads into operation with constant parameter pu; A resistive load is put into use, and its actual operating parameter pm is controlled in a closed loop, so that the actual operating parameter pm of the a resistive load approaches the parameter pi, and the operating parameter of n+a resistive load approaches the target operating parameter pg; wherein a≥1 and a is a natural number.

2. The control method of the high voltage electronic load according to claim 1, characterized in that: The closed-loop control includes: outputting control parameters according to actual operating parameters and target operating parameters, the actual operating parameter pm=pd*k; the k is a proportional factor, the k=des(pg / pu), des is the decimal place; the pd is a parameter detection value.

3. The control method of high voltage load according to claim 2, characterized in that: The closed-loop control includes a pid control algorithm, which outputs a pwm signal for controlling a resistive load, and an error parameter of the pid algorithm is e(t)=pi-pm.

4. The control method of high voltage load according to claim 3, characterized in that: The pid algorithm includes a feedforward term f, wherein the feedforward term f=k.

5. The control method of high voltage load according to claim 2, characterized in that: The target operating parameter pg is determined according to the working mode of the resistor load. The working modes of the resistor include a constant parameter mode and a pulse working mode. In the pulse working mode, the target operating parameter is determined by a pulse curve; a≥floor(△pg / pu)+1; △pg is the difference between the maximum value and the minimum value on the pulse curve.

6. The method for controlling a high voltage load according to claim 5, characterized in that: The constant parameter mode includes a constant power target parameter wg, and the actual power parameter of the a resistance load is Wherein Vmi represents the measured voltage of the resistive load, Imi represents the measured current of the resistive load; k=des(wg / wu), where wu represents the rated operating power of a single resistive load; the error parameter e(t)=wi-wm, where wi=mod(wg / wu).

7. The method for controlling a high voltage load according to claim 5, characterized in that: The working modes include a constant voltage mode, a constant current mode, a constant power mode, a pulse mode and a gradient load programmable mode.

8. The method for controlling a high voltage load according to claim 1, characterized in that: Monitoring the temperatures of the n electronic high-voltage loads and selecting a resistance load with the highest temperature; Perform steps 1 and 2 simultaneously: Step 1: the a resistance load under closed-loop control operates with a constant parameter pu; Step 2: Closely control the actual operating parameter pm of a said highest temperature resistance load so that the actual operating parameter pm approaches the parameter pi; Step 3 repeats steps 1 and 2.

9. A high voltage load, characterized in that: include: A load circuit, comprising a load resistor and a switch circuit for controlling the operation of the load resistor; A detection circuit, used to detect the working parameters of the load circuit during operation; A control circuit, electrically connected to the detection circuit and the switch circuit; The control circuit outputs a PWM signal for controlling the switch circuit according to the detected operating parameters of the load circuit and the target parameters in a specific operating mode, so that the operating parameters of the load circuit approach the target parameters.

10. The high voltage load according to claim 9, characterized in that: The load circuit includes at least one resistive load; The resistance load comprises: a first switch tube and a second switch tube connected in series, the drain of the first switch tube is connected to the source of the second switch tube, the source of the first switch tube is grounded, the drain of the second switch tube is connected to the load resistor, and the load resistor is connected to the positive electrode of the high voltage power supply; The gate of the second switch tube is connected to the positive electrode of the high voltage power supply through a bias resistor, a Zener diode is connected between the gate of the second switch tube and the source of the second switch tube, and the breakdown voltage of the Zener diode is greater than the turn-on voltage of the second switch tube.

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