Direct current source nonlinear control method, electronic equipment and storage medium

Abstract

The invention discloses a DC source nonlinear control method, electronic equipment and a storage medium, and the method comprises the steps: setting the output voltage of a DC source and the output slope of the output voltage, judging whether the output voltage feedback value is smaller than a preset low-voltage point, if yes, enabling the DC source to work according to the set low-voltage point special slope, and if not, enabling the DC source to work according to the set low-voltage point special slope; if yes, whether the set output slope is larger than a variable slope threshold value or not is judged, if not, normal work is conducted according to the set output slope, if yes, whether the absolute value of the difference value between the set output voltage and the output voltage feedback value is larger than a set difference value or not is judged, if yes, normal work is conducted according to the set output slope, and if not, normal work is conducted according to the set output slope. If yes, the output slope of the output voltage is reduced cycle by cycle according to the set step length until the output slope is lower than the set minimum slope value, and the direct current source works according to the slope of the last change until the starting voltage is established; the circuit has the advantage that output voltage overshoot is effectively suppressed.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and particularly to a non-linear control method for a DC source, an electronic device, and a storage medium. Background Art

[0002] In the field of power electronics, DC test power supplies are widely used. In particular, feedback DC power supplies with low voltage, medium voltage, and high voltage outputs are used in many fields, such as product testing of photovoltaic inverters, charge and discharge testing of in-vehicle chargers, switching testing of power semiconductors, and testing of motor controllers. This requires that when the DC source starts up and outputs voltage after connecting to the load, in order to ensure the safety of the load and the accuracy of the load test, the output voltage should not have a large overshoot and should be able to establish the voltage in a timely manner to meet the requirements of the load test.

[0003] Currently, in the constant voltage operating mode of DC sources, the commonly used control method is the double-loop PI control as shown in Figure 1 For example, the adaptive PI regulation method based on a four-phase interleaved DC-DC circuit and the converter disclosed in Chinese Patent Publication No. CN117394690A adopt double-loop PI control. However, in such control, if a smaller output voltage overshoot and a faster recovery time are required, the Kp and Ki control parameters of the double loop often need to be adjusted faster to achieve, but this will lead to poor stability and difficulty in adapting to different characteristic loads. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to improve the overshoot of the starting voltage in the constant voltage operating mode of the DC source.

[0005] The present invention solves the above technical problem by the following technical means: A non-linear control method for a DC source, including a process of setting a variable slope of the output voltage of the DC source. The process of setting a variable slope of the output voltage of the DC source is as follows: Set the output voltage of the DC source and the output slope of the output voltage, and determine whether the output voltage feedback value is less than a preset low voltage point. If so, the DC source operates at a dedicated slope for the low voltage point set. If not, determine whether the set output slope is greater than the variable slope threshold value. If not, operate at the set output slope normally. If so, determine whether the absolute value of the difference between the set output voltage and the output voltage feedback value is greater than the set difference value. If so, operate at the set output slope normally. If not, gradually reduce the output slope of the output voltage by a set step size per cycle until it is lower than the set minimum slope value, and the DC source operates at the slope of the last change until its starting voltage is established.

[0006] The present invention simply changes the setting method of the starting voltage slope in the constant voltage mode of the DC power supply, avoiding the coupling effect of the degradation of external performance indicators in other steady-state or dynamic operating conditions caused by modifying the loop control parameters due to starting problems in only double-loop control or only non-linear control, thereby effectively suppressing the overshoot of the output voltage, achieving a good overshoot suppression effect and avoiding output instability.

[0007] Further, during the operation of the DC power supply according to the dedicated slope of the set low voltage point, it also determines whether the output voltage feedback value is less than the preset low voltage point. If so, the DC power supply operates according to the dedicated slope of the set low voltage point. If not, it determines whether the set output slope is greater than the variable slope threshold value.

[0008] Further, gradually reducing the output slope of the output voltage by a set step size per cycle until it is lower than the set minimum slope value includes:

[0009] Gradually reducing the output slope of the output voltage by a set step size per cycle, predicting whether the output slope of the output voltage in the next cycle is less than the set minimum slope value. If so, the DC power supply operates according to the slope of the last change until its starting voltage is established. If not, return to the above process and continue to gradually reduce the output slope of the output voltage by a set step size per cycle.

[0010] Further, after the variable slope setting of the output voltage of the DC power supply, it also includes a double-loop control process, and the double-loop control process includes:

[0011] The result after subtracting the result of the variable slope setting of the output voltage of the DC power supply from the output voltage feedback value, after passing through the first PI regulator and the first limiter unit, the result of subtracting the output current feedback value, after passing through the second limiter unit, is subtracted from the inductor current of the DCDC converter of the DC power supply. The difference is input to the second PI regulator and then outputs a PWM wave to control the power switch of the DCDC converter of the DC power supply.

[0012] Further, after the double-loop control, it also includes a control process for predicting the duty cycle, and the control process for predicting the duty cycle includes:

[0013] Obtain the change rule of the PWM wave based on the change amount of the PWM waves in the previous two cycles of the DCDC converter of the DC power supply, and predict the PWM wave of the DCDC converter of the DC power supply in the next cycle according to this change rule.

[0014] Further, the value range of the variable slope threshold value is 90V / ms to 110V / ms.

[0015] Further, the value range of the set difference is 40V to 60V.

[0016] Further, the value range of the set step size is 5V / ms to 15V / ms.

[0017] The present invention also provides an electronic device, including a processor and a memory. The memory stores computer program instructions that can be executed by the processor. When the processor executes the computer program instructions, the method steps described in any one of the above are implemented.

[0018] The present invention also provides a computer-readable storage medium, storing computer program instructions. When the computer program instructions are called and executed by a processor, the method steps described in any one of the above are implemented.

[0019] The advantages of the present invention are as follows:

[0020] (1) The present invention simply changes the setting method of the starting voltage slope in the constant voltage mode of the DC source, avoiding the coupling effect of the degradation of other steady-state or dynamic operating conditions' external performance indicators caused by modifying the loop control parameters due to the starting problem in only double-loop control or only non-linear control. Thus, it effectively suppresses the overshoot of the output voltage, achieves a good overshoot suppression effect, and avoids output instability.

[0021] (2) In the variable slope setting method of the present invention, before approaching the set current value, if the variable slope threshold is reached, the slope becomes smaller. A smaller efficiency means that the amplitude of each change in the output voltage set value becomes smaller and smaller. This leads to a very small change in the duty cycle of the PWM for each change. A very small change in the duty cycle means that the change in the actual output voltage for each change becomes smaller and smaller when approaching the output target voltage. This avoids the overshoot of the output voltage caused by the sudden change in the PWM duty cycle during a certain PI regulation.

[0022] (3) When the output voltage is lower than the low voltage point in the present invention, if the load has capacitive or large current, in order to prevent the voltage outer loop from calculating too slowly and being unable to enter the Limit limit of the current limiting loop, the set value of the voltage slope in the low voltage section is given a fixed relatively large value (i.e., the dedicated slope for the low voltage point), thereby avoiding output instability.

[0023] (4) The present invention can also obtain the change rule of the PWM wave based on the change amount of the PWM waves in the first two cycles of the DCDC converter of the DC source, and predict the PWM wave of the DCDC converter of the DC source in the next cycle according to this change rule. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the double-loop control architecture of the starting voltage of the DC source;

[0025] Figure 2Schematic diagram of a non - linear control architecture for setting the start - up voltage of a DC source with a variable slope by a non - linear control method for a DC source according to Embodiment 1 of the present invention;

[0026] Figure 3 Flow chart for setting the start - up voltage of a DC source with a variable slope in a non - linear control method for a DC source according to an embodiment of the present invention. Detailed implementation manners

[0027] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] Embodiment 1

[0029] Embodiment 1 of the present invention provides a non - linear control method for a DC source, which is applied to the control architecture of the last - stage DCDC converter of the DC source. The specific topology is not limited. It can be a bridge structure, or other types such as BUCK or BOOST. As Figure 2 and Figure 3 shown, the non - linear control method for a DC source includes a process of setting the variable slope of the output voltage of the DC source. The process of setting the variable slope of the output voltage of the DC source is as follows: set the output voltage of the DC source and the output slope of the output voltage, and determine whether the output voltage feedback value is less than a preset low - voltage point. If so, the DC source operates at a dedicated slope for the low - voltage point. If not, determine whether the set output slope is greater than the variable - slope threshold value. If not, operate normally according to the set output slope. If so, determine whether the absolute value of the difference between the set output voltage and the output voltage feedback value is greater than the set difference value. If so, operate normally according to the set output slope. If not, gradually reduce the output slope of the output voltage by a set step size per cycle until it is lower than the set minimum slope value, and the DC source operates at the slope of the last change until its start - up voltage is established.

[0030] Continue to refer to Figure 3 , for example, in the actual application of the present invention, the following judgment is made for the non - linear control of the output voltage slope: when the set output voltage is lower than the low - voltage point (the low - voltage point is an open control parameter that can be set by R & D personnel), if the load is capacitive or has a large current, in order to prevent the voltage outer loop calculation from being too slow to enter the Limit limit of the current - limiting loop, the set value of the voltage slope in the low - voltage section is given a fixed large value (such as Figure 3The dedicated slope for the low-voltage point) to avoid unstable output; then, it judges the initially set output slope by the customer. If it is greater than the variable slope threshold value (the variable slope threshold value in this case is set to 100V / ms), and it judges that the absolute difference between the set output voltage and the current output voltage feedback value is greater than the set difference (the set difference in this case is 50V), then the software will start to gradually change the initial voltage slope. Specifically, it will gradually reduce the voltage slope according to the set step size (the step size control parameter in this case is set to 10V / ms) until reducing further will be lower than the minimum slope value (the minimum slope value is an open control parameter that can be set by R & D personnel). If it is lower than this value, the variable slope will terminate, and the power supply will work according to the slope of the last change until the output voltage is established.

[0031] The main focus of the above control process lies in how to achieve the non-linear control of the slope of the output voltage set value. On the entire loop architecture, ordinary dual PI control can be used, or predictive algorithm control can be applied, which does not affect the control logic algorithm for adding variable slope. Specifically, continue to refer to Figure 2 When the method for setting the variable slope of the output voltage of this DC power supply is added to the dual closed-loop control, the dual closed-loop control process includes:

[0032] The result after subtracting the result of setting the variable slope of the output voltage of the DC power supply from the output voltage feedback value, after passing through the first PI regulator and the first limiting unit, is subtracted from the output current feedback value, and after passing through the second limiting unit, it is subtracted from the inductor current of the DCDC converter of the DC power supply. The difference is input to the second PI regulator and then outputs a PWM wave to control the power switch of the DCDC converter of the DC power supply.

[0033] When the method for setting the variable slope of the output voltage of this DC power supply is added to the control of the predicted duty cycle, continue to refer to Figure 2 After the dual closed-loop control, it also includes the control process of the predicted duty cycle. The control process of the predicted duty cycle includes:

[0034] Obtain the change rule of the PWM wave based on the change amount of the PWM waves in the previous two cycles of the DCDC converter of the DC power supply, and predict the PWM wave of the DCDC converter of the DC power supply in the next cycle according to this change rule.

[0035] After the actual test of the present invention, when using only double closed-loop control or only non-linear control alone, the starting voltage overshoot will basically exceed 6% under different output voltages and different load conditions (no load, capacitive load, pure resistive load, pre-bias condition). However, when applying the control architecture with variable slope setting of the present invention, the voltage overshoot is basically within 3%. Therefore, simply changing the setting method of the starting voltage slope in the constant voltage mode avoids the coupling effect of the degradation of other external performance indicators under steady-state or dynamic operating conditions caused by modifying the loop control parameters in only double closed-loop control or only non-linear control to improve the starting problem. It has a better effect on the output stability in the case of low output voltage and slow slope. It has a good inhibitory effect on the voltage overshoot under different load conditions.

[0036] Embodiment 2

[0037] Embodiment 2 of the present invention further provides an electronic device, including a processor and a memory. The memory stores computer program instructions that can be executed by the processor. When the processor executes the computer program instructions, the method steps described in Embodiment 1 are implemented.

[0038] Embodiment 3

[0039] Embodiment 3 of the present invention further provides a computer-readable storage medium, storing computer program instructions. When the computer program instructions are called and executed by a processor, the method steps described in Embodiment 1 are implemented.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A non-linear control method for a DC source, characterized in that, The output voltage variable slope setting process of a DC power supply, and the output voltage variable slope setting process of the DC power supply is as follows: Set the output voltage of the DC power supply and the output slope of the output voltage, and determine whether the output voltage feedback value is less than a preset low voltage point. If so, the DC power supply operates at the dedicated slope of the preset low voltage point. If not, determine whether the set output slope is greater than the variable slope threshold value. If not, it operates normally at the set output slope. If so, determine whether the absolute value of the difference between the set output voltage and the output voltage feedback value is greater than the set difference value. If so, it operates normally at the set output slope. If not, gradually reduce the output slope of the output voltage by a set step per cycle until it is lower than the set minimum slope value, and the DC power supply operates at the slope of the last change until its starting voltage is established.

2. The non-linear control method of a DC source according to claim 1, wherein During the process of the DC power supply operating at the dedicated slope of the preset low voltage point, it also determines whether the output voltage feedback value is less than the preset low voltage point. If so, the DC power supply operates at the dedicated slope of the preset low voltage point. If not, it determines whether the set output slope is greater than the variable slope threshold value.

3. A non-linear control method for a DC source according to claim 1, characterized in that, Gradually reducing the output slope of the output voltage by a set step per cycle until it is lower than the set minimum slope value includes: Gradually reducing the output slope of the output voltage by a set step per cycle, predicting whether the output slope of the output voltage in the next cycle is less than the set minimum slope value. If so, the DC power supply operates at the slope of the last change until its starting voltage is established. If not, return to the above process and continue to gradually reduce the output slope of the output voltage by a set step per cycle.

4. A non-linear control method for a DC source according to claim 1, characterized in that, After the output voltage variable slope setting of the DC power supply, it also includes a double closed-loop control process, and the double closed-loop control process includes: The result after subtracting the output voltage variable slope setting result of the DC power supply from the output voltage feedback value, after passing through the first PI regulator and the first limiter unit, the output result is subtracted from the output current feedback value, and after passing through the second limiter unit, it is subtracted from the inductor current of the DCDC converter of the DC power supply. The difference is input into the second PI regulator and then outputs a PWM wave to control the power switch of the DCDC converter of the DC power supply.

5. A non-linear control method for a DC source according to claim 4, characterized in that, After the double closed-loop control, it also includes a predicted duty cycle control process, and the predicted duty cycle control process includes: Obtain the change law of the PWM wave based on the change amount of the PWM waves in the previous two cycles of the DCDC converter of the DC power supply, and predict the PWM wave of the DCDC converter of the DC power supply in the next cycle according to this change law.

6. A non-linear control method for a DC source according to claim 1, characterized in that The value range of the variable slope threshold value is 90V / ms to 110V / ms.

7. A non-linear control method for a DC source according to claim 1, characterized in that The value range of the set difference value is 40V to 60V.

8. A non-linear control method for a DC source according to claim 1, characterized in that, The value range of the set step is 5V / ms to 15V / ms.

9. An electronic device, characterized in that, It includes a processor and a memory. The memory stores computer program instructions that can be executed by the processor. When the processor executes the computer program instructions, it implements the method steps described in any one of claims 1-8.

10. A computer-readable storage medium, characterized in that, Stores computer program instructions, and the computer program instructions, when called and executed by a processor, implement the method steps described in any one of claims 1-8.

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