A power module control method for a constant high-voltage and high-power DC power supply based on IPOS combination

Abstract

The present invention discloses a power module control method for a constant high-voltage, high-power DC power supply based on an IPOS combination. The constant high-voltage, high-power DC power supply based on an IPOS combination includes n sub-power modules and 1 system control module, wherein the n sub-power modules are connected in a parallel input and series output manner, and the constant high-voltage, high-power DC power supply based on an IPOS combination has a double-layer three-loop control loop, wherein the double-layer three-loop control loop includes a system-layer total voltage output closed loop and a module-layer voltage-sharing output closed loop, wherein the module-layer voltage-sharing output closed loop includes an output voltage-sharing control loop and an input current-sharing control loop. The present invention provides a power module control method for a constant high-voltage, high-power DC power supply based on an IPOS combination, which can effectively ensure the stability of the power module output voltage, the voltage-sharing property of the power module output, and the accuracy of the total output voltage of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of power control, and in particular to a power module control method of a constant high-voltage and high-power direct current power supply based on an IPOS combination. Background Art

[0002] In high-power and high-voltage power supplies, it is difficult to achieve an output of nearly 10,000 volts and tens of amperes through a single power circuit device due to the limitations of the power components' ability to withstand operating voltage and current. Therefore, multiple power modules are often combined in series or parallel to produce outputs. According to different connection forms, there are four main types of multi-power module series-parallel combination systems: ISOP (input series, output parallel), ISOS (input series, output series), IPOP (input parallel, output parallel), and IPOS (input parallel, output series). The key to a power supply composed of multiple power modules is to ensure equal voltage or current at the input / output of each power module. Therefore, the control method of the power module is very important and has a significant impact on the system's power loss, expansion performance, and heat dissipation characteristics. Existing power module control methods mainly include:

[0003] 1. Master-slave control method: Select one of all the power modules as the master power module (usually the first one), and the remaining power modules are used as slave power modules for output voltage equalization. The output voltage of all slave power modules changes according to the change of the output voltage of the master power module.

[0004] It has the following disadvantages:

[0005] ① This control method requires high loop control accuracy and stability of the main power module, which is difficult to achieve;

[0006] ②When the master power module outputs bias, other slave powers will follow the master power module and output bias;

[0007] ③ The master power module is a single point of failure. Once the control signal of its working loop is unstable or interfered with, it will affect the control of other slave power modules and cause the entire system to fail.

[0008] In general, the use of this control method will result in lower operating reliability of the power supply.

[0009] 2. Common duty cycle control method: All power modules share a common control loop, and the same control loop controls and adjusts all power modules simultaneously, reducing the complexity of system control and achieving rapid response.

[0010] It has the following disadvantages:

[0011] ① This control method places very high demands on the consistency of each power module. Only when the operating parameters and performance of each power module are highly consistent can the overall system achieve better results. This is a great test of the stability of component parameters and production process. It is currently difficult to achieve in actual mass production, and the application effect is not ideal.

[0012] ② Due to the parameter differences between each power module, the voltage balancing performance between modules will be poor.

[0013] 3. Single-module independent control method: Each power module is independently controlled, and a control loop is formed inside the module through a voltage closed loop or a current closed loop. There is no control connection between modules.

[0014] It has the following disadvantages:

[0015] Since the modules are independent entities, the voltage drop loss on the module output external cables, switches and other electrical components will cause a large deviation between the system's total voltage output accuracy and the required set value. The output accuracy is insufficient and it is difficult to use in situations where precise output voltage is required. Summary of the Invention

[0016] In order to address the shortcomings of existing control methods and achieve reliable operation and mass production of a constant high-voltage, high-power DC power supply based on an IPOS combination, the present invention provides a power module control method for a constant high-voltage, high-power DC power supply based on an IPOS combination. This power module control method for a constant high-voltage, high-power DC power supply based on an IPOS combination can effectively ensure the stability of the power module output voltage, the output voltage equalization of the power module, and the accuracy of the total output voltage of the system.

[0017] The present invention provides a power module control method for a constant high-voltage, high-power DC power supply based on an IPOS combination. The constant high-voltage, high-power DC power supply based on the IPOS combination includes n sub-power modules and a system control module. The n sub-power modules are connected in a parallel input and series output manner. The constant high-voltage, high-power DC power supply based on the IPOS combination has a double-layer three-loop control loop. The double-layer three-loop control loop includes a system-layer total voltage output closed loop and a module-layer voltage-sharing output closed loop. The module-layer voltage-sharing output closed loop includes an output voltage-sharing control loop and an input current-sharing control loop. The power module control method includes the following steps:

[0018] Step 1: The system control module receives the user's instruction and obtains the total output voltage target value U tgt ;

[0019] Step 2: The system control module is based on the total output voltage target value U tgt Set the total output power reference value Uref , and according to the number of sub-power modules n, it is decomposed into the sub-power module output voltage reference value U nref ;

[0020] Step 3: The system control module sets the total output voltage reference value U ref Transmitted to each sub-power module, the sub-power module opens its own output switch after receiving the instruction, and adjusts the output voltage according to the total output voltage reference value. U ref , switching frequency value f, calculate the theoretical required duty cycle and control the output;

[0021] Step 4: The system control module collects the total input current I in , and according to the number of sub-power modules n, it is decomposed into the sub-power module input current reference value I nref , then the current reference value I nref Transmitted to each sub-power module to form an input current sharing control loop and assist the output voltage sharing control loop;

[0022] Step 5: Each sub-power module collects its output voltage U nout , input current I nin And upload, all sub-power modules obtain the output voltage of other sub-power modules U nout and input current I nin , calculate the output voltage value of all sub-power modules U avg and input current sharing value I avg and the output voltage value U avg As the new output voltage reference value;

[0023] Step 6: Determine whether the output voltage of all sub-power modules meets the requirements. If so, the system control module collects the total output voltage. U out If not, the duty cycle is adjusted by PWM according to the difference and the process returns to step 5;

[0024] Step 7: Set the total output voltage U out The total output voltage reference value formed with the user command U refCompare and determine whether the total output voltage accuracy meets the requirements. If so, maintain precise and stable output until the end. If not, adjust the duty cycle through PWM according to the difference and return to step 2.

[0025] In a preferred embodiment of the power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination provided by the present invention, the system-level total voltage output closed loop is used to ensure the accuracy of the total output to meet the output requirements of the user's operating instructions; the module-level voltage-equalizing output closed loop is used to ensure the balanced working output of each sub-power module, reduce the output DC ripple, and improve the power quality.

[0026] In a preferred embodiment of the power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination provided by the present invention, the output voltage equalization control loop is used for output voltage equalization control under static conditions, and the input current equalization control loop serves as a supplement to the output voltage equalization control loop to improve the dynamic response rate of the output under dynamic change conditions. In addition, it can also serve as a redundant control loop of the sub-power module. When the output voltage equalization control loop cannot perform normal cycle control, it can work as a standby to improve the service life and reliability of the system.

[0027] In a preferred embodiment of the power module control method of the IPOS-based constant high-voltage high-power DC power supply provided by the present invention, the step seven specifically includes: the system control module collects the total voltage output after each of the sub-power modules is connected in series U out After calculation and conditioning, it becomes V Uout , and the output reference value required by the user to issue the output instruction V Uref The difference is used to update the reference value of the output voltage of each sub-power module. U nref and transmits it to each sub-power module through the communication control bus; at the same time, the system control module collects the total input current I in , formed and decomposed into the input current reference value of each sub-power module I nref and sent to each sub-power module through the communication control bus.

[0028] In a preferred embodiment of the power module control method of the IPOS combination constant high-power DC power supply provided by the present invention, each of the sub-power modules forms a new output voltage reference after receiving the updated output voltage reference value. V Unref and V InrefThe sub-power modules collect their own output voltages U nout and input current I nin , after transformation and conditioning, becomes V Unout and V Inin After comparison, the difference is adjusted by PWM duty cycle to adjust the output voltage so that the total output voltage accuracy meets the requirements; at the same time, the output voltage of the sub-power module is balanced through the communication control bus, and each sub-power module can obtain the output voltage of other sub-power modules, calculate the average output voltage value and the average input current value, and then use it as the new output voltage reference. V Unref and V Inref , again with the current acquisition output voltage U nout and input current I nin , after transformation and conditioning, becomes V Unout and V Inin After comparison, the difference is adjusted through PWM duty cycle to achieve the goal of satisfying the total output voltage accuracy requirements and ensuring the output voltage balance of each sub-power module.

[0029] Compared with the prior art, the power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination provided by the present invention has the following beneficial effects:

[0030] 1. The total output voltage of the system is highly accurate. Through the system-level output voltage feedback control loop, an isolated high-voltage Hall voltage sensor is used to sample the DC high-voltage output. The sampling accuracy is as high as ±0.1%, which can ensure that the high-voltage output accuracy of the entire machine reaches more than ±0.2%. It can be widely used in occasions that require higher performance of high-voltage DC power supplies.

[0031] 2. The output voltage equalization between the sub-power modules is high, and the input current equalization is good, which can balance the output voltage stress and input current stress differences between the sub-power modules. In the long run, it can effectively improve the working service life of the sub-power modules.

[0032] 3. The sub-power module adopts the output voltage equalization control loop and the input current equalization control loop, using the advantages of high voltage control accuracy and fast current control response, which can effectively make up for the shortcomings of slow response of single voltage control and inaccurate single current control, so that the output of the sub-power module has the advantages of fast response and precise output. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0034] Figure 1 This is a flow chart of a power module control method of a constant high-voltage and high-power DC power supply based on an IPOS combination provided by the present invention;

[0035] Figure 2 yes Figure 1 The control block diagram of the power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination is shown. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Please also refer to Figure 1 and Figure 2 ,in, Figure 1 This is a flow chart of a power module control method of a constant high-voltage and high-power DC power supply based on an IPOS combination provided by the present invention; Figure 2 yes Figure 1 The control block diagram of the power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination is shown.

[0038] The constant high-voltage high-power DC power supply based on IPOS combination includes n sub-power modules and 1 system control module, where n≥2, and the output voltage of the high-voltage DC power supply is U out ≥1 kV The system control module is responsible for feedback regulation and control of the total output voltage of the DC power supply. It uses an isolated high-voltage Hall voltage sensor to sample the DC high-voltage output. Its sampling accuracy is as high as ±0.1%, which can ensure that the high-voltage output accuracy of the entire device reaches above ±0.2%. It can be widely used in situations where higher performance requirements are required for high-voltage DC power supplies. Each sub-power module has an independent input interface, output interface, and communication control interface. The input interface of each sub-power module is connected in parallel to an external input power source (either an AC source or a DC source), and the output interface is connected in series. The total output is connected to the external load after passing through the high-voltage output switch.

[0039] The constant high-voltage, high-power DC power supply based on the IPOS combination has a double-layer three-loop control loop, which includes a system-layer total voltage output closed loop and a module-layer voltage-equalizing output closed loop. The system-layer total voltage output closed loop is used to ensure the accuracy of the total output to meet the output requirements of the user's operating instructions, and the module-layer voltage-equalizing output closed loop is used to ensure the balanced working output of each power module, reduce the output DC ripple, and improve the power quality; the module-layer voltage-equalizing output closed loop includes an output voltage-equalizing control loop and an input current-equalizing control loop. The output voltage-equalizing control loop is used for output voltage-equalizing control under static conditions, and the input current-equalizing control loop serves as a supplement to the output voltage-equalizing control loop to improve the dynamic response rate of the output under dynamic change conditions. In addition, it can also serve as a redundant control loop for the sub-power module. When the output voltage-equalizing control loop is interfered with or cannot be normally cycled for other reasons, it can work as a standby to improve the working life and reliability of the system.

[0040] The power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination includes the following steps:

[0041] Step 1: The system control module receives the user's instruction and obtains the total output voltage target value U tgt ;

[0042] Step 2: The system control module is based on the total output voltage target value U tgt Set the total output power reference value U ref , and according to the number of sub-power modules n, it is decomposed into the sub-power module output voltage reference value U nref =1 / n• U ref ;

[0043] Specifically, the user's total output voltage target value U tgt Ideally, it should be consistent with the total output voltage reference value set by the system control module. U ref However, in actual situations, due to the voltage drop loss inside the power supply, which includes the voltage drop introduced by the DC reverse voltage protection device at the total output end of the system layer and the voltage drop on the cable, the actual total output voltage of the power supply will be lower than the set total output power reference value. U ref Therefore, in order to make the actual total output voltage of the power supply as close as possible to U tgt To ensure the accuracy of the output, U ref Set to slightly larger thanU tgt , such as the user's total output voltage target value U tgt 5 kV , after receiving the actual command, the output voltage reference value will be U ref Set to 5.05 kV .

[0044] Step 3: The system control module sets the total output voltage reference value U ref Transmitted to each sub-power module, the sub-power module opens its own output switch after receiving the instruction, and adjusts the output voltage according to the total output voltage reference value. U ref , switching frequency value f, calculate the theoretical required duty cycle and control the output;

[0045] Specifically, the switching frequency value f refers to the operating frequency of the switching devices in the sub-power module, such as MOS tubes, IGBTs, etc. In the present invention, each sub-power module adopts a PWM control method, and its approximate calculation formula is output voltage = input voltage × duty cycle × conversion coefficient, where the duty cycle is the ratio of the switch conduction time to the cycle time in the switching cycle. Its value will be selected with reference to the switching frequency of the power switching device, usually based on empirical values; the conversion coefficient is mainly related to the turns ratio of the transformer in the circuit. In addition, the filter inductor also has an impact on the output voltage. In fact, there are many factors that affect the output voltage, which is relatively complicated. The calculation formula is usually only used as a directional reference; the final output voltage value of each sub-power module is controlled by PI regulation;

[0046] Step 4: The system control module collects the total input current I in , and according to the number of sub-power modules n, it is decomposed into the sub-power module input current reference value I nref =1 / n• I in , then the current reference value I nref Transmitted to each sub-power module to form an input current sharing control loop and assist the output voltage sharing control loop;

[0047] Step 5: Each sub-power module collects its output voltage U nout , input current I nin And upload, all sub-power modules obtain the output voltage of other sub-power modules U nout and input current I nin, calculate the output voltage value of all sub-power modules U avg and input current sharing value I avg and the output voltage value U avg As the new output voltage reference value;

[0048] Step 6: Determine whether the output voltage of all sub-power modules meets the requirements. If so, the system control module collects the total output voltage. U out If not, the duty cycle is adjusted by PWM according to the difference and the process returns to step 5;

[0049] Step 7: Set the total output voltage U out The total output voltage reference value formed with the user command U ref Compare and determine whether the total output voltage accuracy meets the requirements. If so, maintain precise and stable output until the end. If not, adjust the duty cycle through PWM according to the difference and return to step 2.

[0050] Specifically, the step seven includes: the system control module collects the total voltage output by connecting the sub-power modules in series. U out After calculation and conditioning, it becomes V Uout , and the output reference value required by the user to issue the output instruction V Uref The difference is used to update the reference value of the output voltage of each sub-power module. U nref and transmits it to each sub-power module through the communication control bus; at the same time, the system control module collects the total input current I in , formed and decomposed into the input current reference value of each sub-power module I nref and sent to each sub-power module through the communication control bus; with this setting, even if a sub-power module fails or is damaged during operation, the system control module can reconfirm the number n of available power modules after the abnormal power module is bypassed and exits, recalculate the output voltage target value of the sub-power module, and then send it again to continue the power supply task.

[0051] After receiving the updated output voltage reference value, each sub-power module forms a new output voltage reference value. V Unref and V InrefThe sub-power modules collect their own output voltages U nout and input current I nin , after transformation and conditioning, becomes V Unout and V Inin After comparison, the difference is adjusted by PWM duty cycle to adjust the output voltage so that the total output voltage accuracy meets the requirements;

[0052] At the same time, the output voltage of the sub-power modules is controlled by the communication bus, and each sub-power module can obtain the output voltage of other sub-power modules, calculate the average output voltage value and the average input current value and use them as the new output voltage reference. V Unref and V Inref , again with the current acquisition output voltage U nout and input current I nin , after transformation and conditioning, becomes V Unout and V Inin After comparison, the difference is adjusted through PWM duty cycle to achieve the goal of satisfying the total output voltage accuracy requirements and ensuring the output voltage balance of each sub-power module.

[0053] The output voltage-sharing control loop and the input current-sharing control loop in the sub-power module use the output voltage-sharing control loop as the main control and the input current-sharing control loop as the auxiliary control. The output voltage-sharing control loop has the characteristics of high control accuracy, but the response rate is slower than that of the input current-sharing control loop. Therefore, when the external load has instantaneous dynamic changes, the input current-sharing control loop with a faster current response rate will first be used for regulation and control, which can ensure that the power supply will not have large transient response changes and quickly recover after a transient response occurs.

[0054] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A power module control method for a constant high-voltage, high-power DC power supply based on an IPOS combination, wherein the constant high-voltage, high-power DC power supply based on an IPOS combination comprises n sub-power modules and a system control module, wherein the n sub-power modules are connected in parallel input and series output, and wherein: The IPOS-based constant-voltage, high-power DC power supply has a double-layer three-loop control loop, which includes a system-level total voltage output closed loop and a module-level voltage-sharing output closed loop. The module-level voltage-sharing output closed loop includes an output voltage-sharing control loop and an input current-sharing control loop. The power module control method includes the following steps: Step 1: The system control module receives the user's instruction and obtains the total output voltage target value U tgt ; Step 2: The system control module is based on the total output voltage target value U tgt Set the total output voltage reference value U ref , and according to the number of sub-power modules n, it is decomposed into the sub-power module output voltage reference value U nref ; Step 3: The system control module sets the total output voltage reference value U ref The instructions are transmitted to each sub-power module. After receiving the instructions, the sub-power modules open their respective output switches and adjust the output voltage according to the total output voltage reference value U ref , switching frequency value f, calculate the theoretical required duty cycle and control the output; Step 4: The system control module collects the total input current I in , and according to the number of sub-power modules n, it is decomposed into the sub-power module input current reference value I nref , then the current reference value I nref Transmitted to each sub-power module to form an input current sharing control loop and assist the output voltage sharing control loop; Step 5: Each sub-power module collects its output voltage U nout 、Input current I nin And upload, all sub-power modules obtain the output voltage U of other sub-power modules nout and input current I nin , calculate the output voltage value U of all sub-power modules avg and input current value I avg and the output voltage value U avg As the new output voltage reference value; Step 6: Determine whether the output voltage of all sub-power modules meets the requirements. If so, the system control module collects the total output voltage U out If not, the duty cycle is adjusted by PWM according to the difference and the process returns to step 5; Step 7: Set the total output voltage U out The total output voltage reference value U formed by the user instruction ref Compare and determine whether the total output voltage accuracy meets the requirements. If so, maintain precise and stable output until the end. If not, adjust the duty cycle through PWM according to the difference and return to step 2.

2. The power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination according to claim 1 is characterized in that: The system-level total voltage output closed loop is used to ensure the accuracy of the total output to meet the output requirements of user operation instructions; the module-level voltage-equalizing output closed loop is used to ensure the balanced working output of each sub-power module, reduce the output DC ripple, and improve the power quality.

3. The power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination according to claim 1, characterized in that: The output voltage balancing control loop is used for output voltage balancing control under static conditions. The input current balancing control loop serves as a supplement to the output voltage balancing control loop to improve the dynamic response rate of the output under dynamic change conditions. In addition, it can also serve as a redundant control loop of the sub-power module. When the output voltage balancing control loop cannot perform normal cycle control, it can work as a backup to improve the service life and reliability of the system.

4. The power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination according to claim 1, characterized in that: The step seven specifically includes: the system control module collects the total voltage U output by connecting the sub-power modules in series. out After calculation and conditioning, it becomes V Uout , and the output reference value V required by the user to issue the output instruction Uref The difference is used to update the output voltage reference value U of each sub-power module. nref and transmits it to each sub-power module through the communication control bus; at the same time, the system control module collects the total input current I in , formed and decomposed into the input current reference value I of each sub-power module nref and sent to each sub-power module through the communication control bus.

5. The power module control method of the constant high-voltage and high-power DC power supply based on the IPOS combination according to claim 4 is characterized in that: After receiving the updated output voltage reference value, each sub-power module forms a new output voltage reference V Unref and V Inref The sub-power modules collect their own output voltage U nout and input current I nin , after transformation and conditioning, it becomes V Unout and V Inin After comparison, the difference is adjusted by PWM duty cycle to adjust the output voltage so that the total output voltage accuracy meets the requirements; At the same time, the output voltage of the sub-power modules is balanced through the communication control bus, and each sub-power module can obtain the output voltage of other sub-power modules, calculate the average output voltage value and the average input current value and use them as the new output voltage reference V Unref and V Inref , again with the current collected output voltage U nout and input current I nin , after transformation and conditioning, it becomes V Unout and V Inin After comparison, the difference is adjusted through PWM duty cycle to achieve the goal of satisfying the total output voltage accuracy requirements and ensuring the output voltage balance of each sub-power module.

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