Power converter control method and power conversion system

Abstract

The present application discloses a control method and a power conversion system for a power converter, wherein the control method for the power converter comprises: obtaining an output voltage reference value of the power converter; obtaining an actual output voltage value of the power converter at the current moment; determining the voltage interval in which the actual output voltage value is located according to a preset voltage interval set; obtaining a control error of the current control cycle according to a preset algorithm, an output voltage reference value, and an actual output voltage value corresponding to the voltage interval; controlling the power converter using a PID control algorithm according to the control error; and returning to the step of obtaining the actual output voltage value of the power converter at the current moment until the actual output voltage value meets the preset accuracy requirement. The present application can make the output voltage of the power converter smoothly transition to its reference value when the PID controller parameter configuration is poor, which is beneficial to reducing the voltage spike of the switch tube inside the power converter and improving the robustness of the power converter control system.

Description

Technical Field

[0001] The present application relates to the technical field of power conversion, and in particular to a control method for a power converter and a power conversion system. Background Art

[0002] Currently, power converters are widely used in various power supply and power consumption equipment, and can convert DC power into a DC power with the supply voltage required by the load.

[0003] In the prior art power converter, since the output voltage reference value is a fixed value, when the power converter is "started" or the output end is suddenly overloaded, the difference between the output voltage reference value and the current output voltage actual value increases dramatically. Therefore, if the PID controller parameter configuration is poor, in the process of using the above difference to perform PID control to make the output voltage of the power converter reach the reference value, the output voltage is prone to produce excessive overshoot, which will cause the voltage spike of the internal switch tube of the power converter to be too large, directly reducing the robustness of the power converter control system. Especially for power converters with a wide input voltage range and a wide output load range, the control effect of the PID controller at different working points is different, which also makes it difficult to design the PID controller parameters. Summary of the invention

[0004] In view of this, the present application provides a control method and a power conversion system for a power converter, which are used to smoothly transition the actual value of the output voltage of the power converter to its reference value, reduce the voltage spike of the internal switch tube of the power converter, and thus improve the robustness of the power converter control system. The technical solution of the present application is as follows:

[0005] The first aspect of the present application provides a control method for a power converter, comprising: obtaining an output voltage reference value of the power converter; obtaining an actual output voltage value of the power converter at a current moment; determining, based on a preset voltage interval set, the voltage interval to which the actual output voltage value belongs; obtaining a control error of a current control cycle based on a preset algorithm corresponding to the voltage interval, the output voltage reference value and the actual output voltage value; controlling the power converter using a PID control algorithm based on the control error; and returning to the step of obtaining the actual output voltage value of the power converter at a current moment until the actual output voltage value meets a preset accuracy requirement.

[0006] In one embodiment of the present application, the control error of the current control cycle is obtained according to the preset algorithm corresponding to the voltage range, the output voltage reference value and the actual output voltage value, including: calculating the expected output voltage value according to the output voltage reference value and the actual output voltage value; calculating the difference between the expected output voltage value and the actual output voltage value as the control error.

[0007] In one embodiment of the present application, the formula for the expected output voltage value includes:

[0008] ;

[0009] ;

[0010] ;

[0011] In the formula, For the The output voltage expected value of the control cycle, For the The actual value of the output voltage during the control cycle, is the output voltage reference value, and is a preset coefficient with a value range of (0,1), .

[0012] In one embodiment of the present application, the control error formula includes;

[0013] ;

[0014] ;

[0015] ;

[0016] In the formula, For the The control error of the control cycle, For the The actual value of the output voltage during the control cycle, is the output voltage reference value, and is a preset coefficient with a value range of (0,1), .

[0017] In one embodiment of the present application, the preset coefficient Much larger than the preset coefficient .

[0018] In one embodiment of the present application, the preset coefficient , or the preset coefficient ; or the preset coefficient ; or the preset coefficient ,in, is a time value used to characterize the time taken for the actual output voltage value of the power converter to approach the output voltage reference value, is the control period of the PID controller, and The time units are the same.

[0019] The second aspect of the present application provides a power conversion system, including a power converter and a PID controller, wherein the power converter is used to access a DC voltage and convert the DC voltage into a DC voltage of another level to supply power to a load; the PID controller is connected to the power converter, and the PID controller is used to: obtain an output voltage reference value of the supply voltage of the power converter, obtain an actual output voltage value of the power converter at a current moment, determine the voltage interval to which the actual output voltage value belongs according to a preset voltage interval set, obtain a control error of a current control cycle according to a preset algorithm corresponding to the voltage interval, the output voltage reference value and the actual output voltage value, control the power converter using a PID control algorithm according to the control error, and return to the step of obtaining the actual output voltage value of the power converter at a current moment until the actual output voltage value meets the preset accuracy requirement.

[0020] In one embodiment of the present application, the power converter includes a first capacitor, a second capacitor, a third capacitor, a first resistor, a second resistor, a first diode, a second diode, a transformer and a switch tube; the first secondary terminal of the transformer is connected to the positive electrode of the first diode, the negative electrode of the first diode is connected to the second secondary terminal of the transformer through the first resistor, and the first capacitor is connected in parallel with the first resistor; the first primary terminal of the transformer is used to receive the DC voltage of the positive electrode, the second primary terminal of the transformer is connected to the first end of the switch tube, the second end of the switch tube is grounded, the first end of the second capacitor is connected to the first primary terminal, the second end of the second capacitor is connected to the negative electrode of the second diode, the positive electrode of the second diode is connected to the first end of the switch tube, the second resistor is connected to the third capacitor in parallel, the first end of the third capacitor is connected to the first primary terminal, and the second end of the third capacitor is grounded; the control end of the switch tube is connected to the PID controller.

[0021] In one embodiment of the present application, a rectifier filter is further included, wherein the rectifier filter is connected to the input end of the power converter, and the rectifier filter is used to receive an AC voltage and convert the AC voltage into the DC voltage before inputting it into the power converter.

[0022] A third aspect of the present application provides a power supply device, comprising the power conversion system.

[0023] After obtaining the actual value of the output voltage of the power converter at the current moment, the present application compares the actual value of the output voltage with the voltage interval set to determine the voltage interval to which the actual value of the output voltage belongs, so as to obtain the control error according to the preset algorithm corresponding to the voltage interval to perform PID control on the power converter. Since the control error is based on the preset algorithm corresponding to the voltage interval in the voltage interval set, that is, during PID control, the output voltage of the power converter is softened in the process of approaching its reference value in intervals, so that the actual value of the output voltage of the power converter smoothly transitions to the output voltage reference value, which is beneficial to reducing the voltage spike of the internal switching tube of the power converter, thereby improving the robustness of the PID control system of the power converter, especially for power converters with a wide input voltage range and a wide output load range. This can ensure that the PID controller has a good control effect at different operating points. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic block diagram of a power conversion system provided in an embodiment of the present application.

[0025] Figure 2 It is a flow chart of a control method of a power converter provided in an embodiment of the present application.

[0026] Figure 3 It is a flow chart of a method for obtaining a control error provided in an embodiment of the present application.

[0027] Figure 4 It is a schematic block diagram of another power conversion system provided in an embodiment of the present application.

[0028] Figure 5 It is a circuit diagram of a power conversion system provided in an embodiment of the present application.

[0029] Figure 6 It is a schematic diagram of control experimental results of the output terminal voltage of a power converter provided in an embodiment of the present application.

[0030] Figure 7 It is a schematic diagram of the comparison experimental results of the voltages across the drain and source of a switch tube of a power converter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] It should be noted that in the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0032] It should also be noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart includes one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchangeable with each other, and some of the steps can also be deleted.

[0033] Currently, power converters are widely used in various power supply and power consumption equipment, and can convert DC power into a DC power with the supply voltage required by the load.

[0034] In the power converter in the prior art, since the output voltage reference value is a fixed value, when it is "started" or the output end is suddenly overloaded, the difference between the output voltage reference value and the current output voltage actual value increases dramatically. Therefore, if the PID controller parameter configuration is poor, in the process of using the above difference to perform PID control to make the output voltage of the power converter reach the reference value, the output voltage is prone to produce excessive overshoot, which will cause the voltage spike of the internal switch tube of the power converter to be too large, directly reducing the robustness of the power converter control system. Especially for power converters with a wide input voltage range and a wide output load range, the control effect of the PID controller at different working points is different, which also causes difficulties in the design of the PID controller parameters. The present application provides a power converter control method and a power conversion system, which are used to make the output terminal voltage of the power converter, that is, the actual value of the load supply voltage, smoothly transition to the output voltage reference value, which is conducive to reducing the voltage spike of the internal switch tube of the power converter, and at the same time, it is conducive to improving the robustness of the power converter PID control system.

[0035] Please refer to Figure 1 , Figure 1 A schematic block diagram of a power conversion system provided in an embodiment of the present application, wherein the power conversion system 100 includes a power converter 110 and a PID controller 120 .

[0036] In the embodiment of the present application, the power converter 110 includes an input terminal and an output terminal. The power converter 110 is used to access a DC voltage through the input terminal and convert the DC voltage into a power supply voltage required by the load at the output terminal. The PID controller 120 is used to connect the power converter 110 and obtain a sampled value of the output voltage of the power converter 110. The PID controller 120 (PID, Proportional Integral Derivative) controls the output voltage of the power converter 110 to reach its preset expected value through a voltage negative feedback control algorithm according to the difference between the sampled value and the preset expected value.

[0037] Next, combine Figure 1 The power converter and control method thereof provided in the embodiments of the present application are described in detail. Figure 2 , the power converter control method specifically comprises the following steps:

[0038] Step S21: Obtaining an output voltage reference value of the power converter.

[0039] In the embodiment of the present application, the output voltage reference value is the voltage value to be reached at the output end of the power converter, for example, it can be a commonly used voltage such as 5V, 12V or 24V. Among them, the power supply device equipped with the above-mentioned power conversion system can be equipped with an output voltage reference value setting module, and the user of the power supply device can select the required power supply voltage value through operation, and the value is transmitted to the PID controller as the voltage reference value of the output power converter.

[0040] Step S22: Obtain the actual value of the output voltage of the power converter at the current moment.

[0041] In an embodiment of the present application, the above-mentioned power conversion system may also be equipped with a voltage sampling circuit, which is connected to the output end of the power converter. The voltage sampling circuit is used to detect the output voltage of the power converter in real time and generate a corresponding actual value of the output voltage. The PID controller is connected to the voltage sampling circuit to obtain the actual value of the output voltage.

[0042] Step S23: Determine the voltage interval to which the actual value of the output voltage belongs according to the preset voltage interval set.

[0043] In an embodiment of the present application, the above-mentioned voltage interval set includes multiple voltage intervals. For example, the output voltage range of the power converter can be divided into multiple voltage intervals according to a preset number to obtain the above-mentioned voltage interval set, so as to facilitate the interval softening processing of the output voltage reference value of the power converter when controlling the output supply voltage of the power converter.

[0044] The PID controller may be pre-set with a voltage interval set. After obtaining the actual output voltage value of the power converter at the current moment, the actual output voltage value may be compared with the voltage interval set to determine the voltage interval to which the actual output voltage value belongs.

[0045] Step S24: Obtaining the control error of the current control cycle according to the preset algorithm corresponding to the voltage interval, the output voltage reference value and the output voltage actual value.

[0046] In an embodiment of the present application, each voltage interval in the voltage interval set corresponds to a preset algorithm. The voltage interval and the corresponding preset algorithm can be associated and stored in the PID controller. After the PID controller determines the voltage interval to which the output voltage belongs based on the actual value of the output voltage, the corresponding preset algorithm can be further determined.

[0047] It can be understood that after determining the preset algorithm, the PID controller can use the current actual value of the output voltage and the reference value of the output voltage to obtain the corresponding control error of the output voltage according to the preset algorithm.

[0048] Step S25: According to the control error, the power converter is controlled by using a PID control algorithm.

[0049] In the embodiment of the present application, after obtaining the control error of the current control cycle, the PID controller performs PID control on the output voltage of the power converter according to the control error, so that the actual value of the output voltage approaches its reference value. For example, the PID controller can input the control error into a preset voltage negative feedback control loop, obtain the control parameters output by the voltage negative feedback control loop, and generate a corresponding drive signal according to the control parameters to control the switch tube in the power converter, wherein the drive signal can be a pulse width modulation signal, and the control parameters can include the duty cycle and frequency of the pulse width modulation signal.

[0050] Step S26: Return to step S22 until the actual value of the output voltage meets the preset accuracy requirement.

[0051] In the embodiment of the present application, the PID controller may return to step S22 until the steady-state error between the actual value of the output voltage and the reference value of the output voltage meets the accuracy requirement of the output voltage. That is, a preset difference may be set according to the accuracy requirement of the output voltage. After the PID controller detects that the difference between the actual value of the output voltage and the reference value of the output voltage is less than the preset difference, it will directly use the difference between the actual value of the output voltage and the reference value of the output voltage to perform PID control of the power converter, that is, it will no longer perform PID control according to the preset algorithm of the voltage interval to which the actual value of the output voltage belongs to calculate the corresponding control error of the voltage interval.

[0052] It can be understood that after obtaining the actual value of the output voltage of the power converter at the current moment, the present application compares the actual value of the output voltage with the voltage interval set to determine the voltage interval to which the actual value of the output voltage belongs, so as to obtain the control error according to the preset algorithm corresponding to the voltage interval to perform PID control on the power converter. Since the control error is based on the preset algorithm corresponding to the voltage interval in the voltage interval set, that is, during PID control, the output voltage of the power converter is softened in the process of approaching its reference value in intervals, so that the actual value of the output voltage of the power converter smoothly transitions to the output voltage reference value, which is beneficial to reducing the voltage spike of the internal switching tube of the power converter, thereby improving the robustness of the PID control system of the power converter, especially for power converters with a wide input voltage range and a wide output load range. This can ensure that the PID controller has a good control effect at different operating points.

[0053] Please refer to Figure 3 , Figure 3 A flow chart of a method for obtaining a control error provided in an embodiment of the present application specifically includes the following steps:

[0054] Step S31: Calculate and obtain the expected output voltage value according to the output voltage reference value and the actual output voltage value.

[0055] Step S32: Calculate the difference between the expected output voltage value and the actual output voltage value as the control error.

[0056] In the embodiment of the present application, the formula for calculating the expected value of the output voltage includes:

[0057] ;

[0058] ;

[0059] ;

[0060] In the formula, For the The expected output voltage value of the control cycle, For the The actual value of the output voltage during the control cycle, is the output voltage reference value, and is a preset coefficient with a value range of (0,1), .

[0061] It can be understood that the voltage interval set in the embodiment of the present application includes three voltage intervals, namely (1) 、(2) and (3) Among them, interval (1) is when the actual output voltage value is lower than A times the output voltage reference value. Interval (2) is when the actual output voltage value is higher than or equal to A times the output voltage reference value and lower than or equal to C times the output voltage reference value. Interval (3) is when the actual output voltage value is higher than C times the output voltage reference value. In some embodiments, interval (2) can be defined as a target interval. After entering the target range, in order to ensure faster dynamic response, Can be much larger than .

[0062] In some embodiments, A=0.5, B=1.5, or A=0.4, B=1.6, that is, the above voltage range can be set according to actual needs.

[0063] Among them, the above and The coefficients are all between 0 and 1 and do not take 0 or 1, so the expected output voltage Always at the output voltage reference value The actual value of the output voltage between. and The closer it is to 0, the higher the expected output voltage value. The closer to the actual output voltage value , when the power converter is PID controlled, the slower the output voltage of the power converter approaches the output voltage reference value .on the contrary, and The closer it is to 1, the higher the expected output voltage The closer the output voltage is to the expected value , when the power converter is PID controlled, the output voltage of the power converter approaches the output voltage reference value faster From this we can understand that and Determines the dynamic response speed of the power converter, so and The value can be set according to the dynamic response speed required in practice, and is not limited here.

[0064] In the embodiment of the present application, the formula for controlling the error includes:

[0065] ;

[0066] ;

[0067] ;

[0068] In the formula, For the The control error of the control cycle, For the The actual value of the output voltage during the control cycle, is the output voltage reference value, and is a preset coefficient with a value range of (0,1), In some embodiments, the preset coefficient Much larger than the preset coefficient .

[0069] In some embodiments, the preset coefficient ; or preset coefficient ; or preset coefficient , or preset coefficients ,in, is a time value used to characterize the time it takes for the actual output voltage value of the power converter to approach the output voltage reference value. is the control period of the PID controller, and The time units are the same.

[0070] Please refer to Figure 4 , Figure 4 This is a schematic block diagram of another power conversion system provided in an embodiment of the present application, wherein the power conversion system 400 includes a power converter 410 , a PID controller 420 , and a rectifier filter 430 .

[0071] In the embodiment of the present application, the power converter 410 is used to access the DC voltage and convert the DC voltage into another level of DC voltage to supply power to the load. The rectifier filter 430 is connected to the input end of the power converter 410, and the rectifier filter 430 is used to receive the AC voltage and convert the AC voltage into a DC voltage before inputting it into the power converter 410.

[0072] The PID controller 420 is connected to the power converter 410, and the PID controller 420 is used to: obtain the output voltage reference value of the power converter 410, obtain the actual output voltage value of the power converter 410 at the current moment, determine the voltage interval to which the actual output voltage value belongs according to a preset voltage interval set, obtain the control error of the current control cycle according to the preset algorithm, output voltage reference value and output voltage actual value corresponding to the voltage interval, control the power converter 410 using the PID control algorithm according to the control error, and return to the step of obtaining the actual output voltage value of the power converter 410 at the current moment, until the difference between the actual output voltage value and the output voltage reference value is less than the preset difference.

[0073] In some embodiments, the PID controller 420 is further used to calculate an expected output voltage value based on an output voltage reference value and an actual output voltage value, and calculate a difference between the expected output voltage value and the actual output voltage value as a control error.

[0074] Please refer to Figure 5 , Figure 5 A circuit diagram of a power conversion system 400 provided in an embodiment of the present application, wherein the power converter 410 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a first resistor R1, a second resistor R2, a first diode D1, a second diode D2, a transformer T1 and a switch tube Q1.

[0075] In the embodiment of the present application, the first secondary terminal of the transformer T1 is connected to the anode of the first diode D1, the cathode of the first diode D1 is connected to the second secondary terminal of the transformer T1 through the first resistor R1, and the first capacitor C1 is connected in parallel with the first resistor R1.

[0076] The first primary terminal of the transformer T1 is used to receive a positive DC voltage, that is, the first primary terminal of the transformer T1 is used to connect to the positive output terminal of the rectifier filter 430, and the negative output terminal of the rectifier filter 430 is grounded. The second primary terminal of the transformer T1 is connected to the first end of the switch tube Q1, the second end of the switch tube is grounded, the first end of the second capacitor C2 is connected to the first primary terminal, the second end of the second capacitor C2 is connected to the negative electrode of the second diode D2, the positive electrode of the second diode D2 is connected to the first end of the switch tube Q1, the second resistor R2 is connected in parallel with the third capacitor C3, the first end of the third capacitor C3 is connected to the first primary terminal, and the second end of the third capacitor C3 is grounded.

[0077] The positive input terminal and the negative input terminal of the rectifier filter 430 are respectively used to receive the AC voltage V1 through the live wire L and the neutral wire N. The control end of the switch tube Q1 is connected to the PID controller 420, which is used to drive the switch tube Q1 through the pulse width modulation signal PWM.

[0078] It can be understood that the power converter 410 of the embodiment of the present application is a flyback converter, the third capacitor C3 is a filter capacitor at the input end of the flyback converter, the transformer T1 is a high-frequency transformer, the switch tube Q1 is an N-type MOS tube, the first diode D1 is a rectifier diode, the first capacitor C1 is a filter capacitor at the input end of the flyback converter, and the first resistor R1 is a simulated load at the input end of the flyback converter. In addition, the second resistor R2, the second capacitor C2 and the second diode D2 form an RCD absorption loop, which is connected in parallel to the primary winding of the high-frequency transformer T1, which is conducive to reducing the voltage spikes at the drain and source ends of the switch tube Q1.

[0079] To further illustrate the effectiveness of the control method for the power converter provided by the present application, Figure 5 The flyback power converter 410 is used as the controlled object, and a simulation control experiment is performed on it using a common PID controller and a PID controller improved by the present application to control the output voltage of the power converter 410 to 12V, thereby forming a control experiment. The component parameters of the power converter 410 are shown in the following table:

[0080]

[0081] The common PID controller is denoted as PID, and the improved PID controller of this application is denoted as , PID and The setting parameters of the two controllers are shown in the following table (where "-" means that the parameter has no setting):

[0082]

[0083] After the simulation control experiment, the control experiment results of the output voltage curve of the power converter 410 are as follows: Figure 6 As shown, and the maximum value of the voltage between the drain and source of the switch tube Q1 in each switching cycle is obtained, and the maximum value is obtained by connecting the maximum value as shown Figure 7 FIG. 4 is a schematic diagram showing comparative experimental results of voltage curves at both ends of the drain and source of the switch tube Q1 of the power converter 410 .

[0084] from Figure 6 as well as Figure 7 It is not difficult to see that the PID controller and The controller can control the output voltage of the flyback power converter 410 to reach and stabilize at 12V. Under the action of the controller, the overshoot of the voltage at the output of the power converter 410 is smaller, the time to adjust to 12V is shorter, and the peak value of the voltage at the drain and source of the switch tube Q1 is also smaller, indicating that the improved The controller is superior to the common PID controller, which verifies that the power converter control method provided in the present application has a better effect.

[0085] In order to further illustrate the beneficial effects of the power converter control method of the present application, Figure 6 and Figure 7 The corresponding controller performance index is calculated based on the change curve, and the calculation results are shown in the following table (in the following table, the output voltage of the power converter 410 is recorded as Vout, and the voltage between the drain and source of the switch tube Q1 is Vmos):

[0086]

[0087] From the indicators in the above table, we can see that the controller The control effect is better than that of the controller PID. It can be seen that when the PID controller parameter configuration is poor, the power converter control method of the present application can make the power converter output voltage smoothly transition to its reference value, which is beneficial to reduce the voltage spike of the internal switch tube of the power converter, improve the robustness of the power converter control system, and enable the power converter to adapt to complex working conditions.

[0088] The present application also provides a power supply device, which includes the power conversion system 400 of any of the above embodiments.

[0089] It can be understood that the beneficial effects of the above-mentioned power conversion system and power supply equipment can refer to the beneficial effects of the control method of the power converter in the above-mentioned embodiment, which will not be repeated here.

[0090] An embodiment of the present application further provides a computer storage medium, which stores a computer program. When the computer program is executed by a processor, the processor executes the above-mentioned power converter control method.

[0091] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer storage medium or transmitted through a computer storage medium. The computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer storage medium can be any available medium that can be accessed by the computer or a data storage device such as a server or data center that contains one or more available media integrated. Available media may be magnetic media (eg, floppy disks, hard disks, tapes), optical media (eg, digital versatile discs (DVD)), or semiconductor media (eg, solid state disks (SSD)), etc.

[0092] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes. In the absence of conflict, the technical features in this embodiment and the implementation scheme can be combined arbitrarily.

[0093] The above embodiments are merely preferred embodiments of the present application and are not intended to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements made to the technical solutions of the present application by ordinary technicians in this field should fall within the protection scope of the claims of the present application.

Claims

1. A control method for a power converter, characterized in that: The power converter is connected to a PID controller, and the control method comprises: Obtaining an output voltage reference value of the power converter; Obtaining the actual value of the output voltage of the power converter at the current moment; Determine the voltage interval to which the actual value of the output voltage belongs according to a preset voltage interval set, wherein the voltage interval set includes a preset number of the voltage intervals; Obtaining a control error of the PID controller in a current control cycle according to a preset algorithm corresponding to the voltage interval, the output voltage reference value, and the output voltage actual value, wherein each of the voltage intervals corresponds to one of the preset algorithms; According to the control error, controlling the PID controller to use a PID control algorithm to control the power converter; Return to the step of obtaining the actual value of the output voltage of the power converter at the current moment, until the actual value of the output voltage meets the preset accuracy requirement; The control error formula includes: ； ； ； In the formula, For the The control error of the control cycle, For the The actual value of the output voltage during the control cycle, is the output voltage reference value, and is a preset coefficient with a value range of (0,1), .

2. The control method according to claim 1, characterized in that: The obtaining the control error of the current control cycle according to the preset algorithm corresponding to the voltage interval, the output voltage reference value and the output voltage actual value includes: Calculating an output voltage expected value according to the output voltage reference value and the output voltage actual value; The difference between the expected output voltage value and the actual output voltage value is calculated as the control error.

3. The control method according to claim 2, characterized in that: The formula for the expected output voltage value includes: ； ； ； In the formula, For the The output voltage expected value of the control cycle, For the The actual value of the output voltage during the control cycle, is the output voltage reference value, and is a preset coefficient with a value range of (0,1), .

4. The control method according to claim 3, characterized in that: The preset coefficient Much larger than the preset coefficient .

5. The control method according to claim 3, characterized in that: The preset coefficient ; or the preset coefficient ; or the preset coefficient ; or the preset coefficient ,in, is a time value used to characterize the time taken for the actual output voltage value of the power converter to approach the output voltage reference value, is the control period of the PID controller, and The time units are the same.

6. A power conversion system, characterized in that: It includes a power converter and a PID controller, wherein the power converter is used to receive a DC voltage and convert the DC voltage into another level of DC voltage to supply power to a load; The PID controller is connected to the power converter, and the PID controller is used to: Obtaining an output voltage reference value of the power converter, obtaining an actual output voltage value of the power converter at a current moment, determining a voltage interval to which the actual output voltage value belongs according to a preset voltage interval set, wherein the voltage interval set includes a preset number of voltage intervals, obtaining a control error of the PID controller in a current control cycle according to a preset algorithm corresponding to the voltage interval, the output voltage reference value, and the actual output voltage value, wherein each of the voltage intervals corresponds to one of the preset algorithms, and according to the control error, controlling the power converter using a PID control algorithm, and returning to the step of obtaining the actual output voltage value of the power converter at a current moment until the actual output voltage value meets a preset accuracy requirement; The control error formula includes: ； ； ； In the formula, For the The control error of the control cycle, For the The actual value of the output voltage during the control cycle, is the output voltage reference value, and is a preset coefficient with a value range of (0,1), .

7. The power conversion system according to claim 6, characterized in that: The power converter includes a first capacitor, a second capacitor, a third capacitor, a first resistor, a second resistor, a first diode, a second diode, a transformer and a switch tube; The first secondary terminal of the transformer is connected to the anode of the first diode, the cathode of the first diode is connected to the second secondary terminal of the transformer through the first resistor, and the first capacitor is connected in parallel with the first resistor; The first primary terminal of the transformer is used to receive the positive DC voltage, the second primary terminal of the transformer is connected to the first end of the switch tube, the second end of the switch tube is grounded, the first end of the second capacitor is connected to the first primary terminal, the second end of the second capacitor is connected to the cathode of the second diode, the anode of the second diode is connected to the first end of the switch tube, the second resistor is connected in parallel with the third capacitor, the first end of the third capacitor is connected to the first primary terminal, and the second end of the third capacitor is grounded; The control end of the switch tube is connected to the PID controller.

8. The power conversion system according to claim 6, characterized in that: It also includes a rectifier filter, which is connected to the input end of the power converter. The rectifier filter is used to receive an AC voltage and convert the AC voltage into the DC voltage before inputting it into the power converter.

9. A power supply device, characterized in that: The invention comprises a power conversion system as claimed in any one of claims 6 to 8.

Images