Current limiting circuit, DC-DC power conversion equipment, method for rapidly limiting current and related equipment

Abstract

The invention provides a current limiting circuit, DC-DC power conversion equipment, a method for quickly limiting current and related equipment. A loop output optimization device is used for receiving a first control value output by a voltage loop and a second control value output by a current loop; the difference value between the larger one of the first control value and the second control value and the smaller one of the first control value and the second control value is reduced by reducing the larger one of the first control value and the second control value, and the optimized control values are closer in numerical value, so that the regulation and control time when the DC-DC power supply conversion equipment is overloaded is shortened, the current limiting function is improved, and power supply protection is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of power supplies, and in particular, to a current limiting circuit, a DC-DC power conversion device, a method for quickly limiting current, and related devices. Background Art

[0002] As Figure 1 shown, in the existing DC-DC (direct current - direct current) power converter 10 (i.e., a power electronic device for direct current conversion), the input is a direct current voltage Vin, and through circuits such as a non-isolated BUCK (step-down chopper) or an isolated LLC (inductor - inductor - capacitor) converter provided inside, a direct current voltage Vout is output to meet the requirements of the load 20. Generally, DC-DC power converters have index requirements for limiting the output current. For example, the output current is limited to 20 A. The existing digital controller calculates respectively using two loops, namely a voltage loop and a current loop, and takes the smaller value of the calculated values output by the two loops to regulate the output of the DC-DC power converter. As Figure 2 shown, the existing digital controller 30 includes a voltage loop 310, a current loop 320, a MIN circuit (circuit for taking the smaller value) 330, and a PWM control circuit 340. The voltage loop 310 includes a comparator 311 and a PI (proportional integral) regulator 312. The comparator 311 compares the output voltage Vout of the DC-DC power converter 10 with a reference voltage Vref and outputs the comparison result to the PI regulator 312, and the PI regulator outputs a control value A. The power loop 320 includes a comparator 321 and a PI regulator 322. The comparator 321 compares the output current Iout of the DC-DC power converter 10 with a reference current Iref and outputs the comparison result to the PI regulator 322, and the PI regulator 322 outputs a control value B. The control values A and B are output to the MIN circuit 330, and the MIN circuit 330 selects the smaller value of the control values A and B and outputs it to the PWM control circuit 340. The PWM control circuit 340 outputs corresponding PWM pulses to control the output Vout and the output current Iout of the DC-DC power converter 10, so as to achieve the purpose of regulating the output of the DC-DC power converter 10.

[0003] In the prior art, when the output current exceeds the limited current point (i.e., overload), the current loop will start to decrease the output control value, while the control value output by the voltage loop continues to increase. After a long period of time, the control value output by the current loop is less than the control value output by the voltage loop, and at this time, a large current appears. Therefore, the output current cannot be quickly suppressed. Currently, for the scheme of using the voltage loop and the current loop in a double-loop to regulate the output current, in order to accelerate the suppression of the output current, generally the following several methods can be adopted:

[0004] 1. Change the PID (Proportional-Integral-Derivative) parameters of the current loop, increase the proportional and integral coefficients of the current loop to accelerate the current dynamic response. However, if the proportional and integral parameters of the current loop are too large, it is easy to generate oscillations. Under different loads, parameter changes are also required, and often the desired dynamic requirements cannot be achieved.

[0005] 2. Increase the hardware current limit, such as Figure 2 As shown, add a hardware current comparator 40. The comparator 40 compares the output current Iout of the DC-DC power converter 10 with a reference current and outputs a control signal to control the DC-DC power converter 10. However, this method will increase the cost and require a larger PCB board area. Especially for some existing models, the PCB board needs to be redesigned, resulting in a double increase in R & D time and cost.

[0006] Therefore, there is a need to provide a current limiting circuit, a DC-DC power conversion device, a method for quickly limiting current, and related devices that can quickly limit current to solve at least one of the above problems. Summary of the Invention

[0007] For the above reasons, embodiments of the present application provide a current limiting circuit, a DC-DC power conversion device, a method for quickly limiting current, and related devices.

[0008] In a first aspect, embodiments of the present application provide a current limiting circuit. The current limiting circuit is configured to be electrically connected to a DC-DC power conversion circuit to limit the current at a specific position point of the DC-DC power conversion circuit. It is characterized by including:

[0009] A voltage loop, configured to be electrically connected to the specific position point of the DC-DC power conversion circuit to output a first control value according to the voltage at the specific position point;

[0010] A current loop, configured to be electrically connected to the specific position point of the DC-DC power conversion circuit to output a second control value according to the current at the specific position point;

[0011] A loop output optimization device, electrically connected to the voltage loop and the current loop, configured to receive the first control value and the second control value, and reduce the value of the larger one of the first control value and the second control value to reduce the difference between the larger one and the smaller one of the first control value and the second control value;

[0012] A MIN circuit, configured to be electrically connected to the loop output optimization device, for receiving the processing result output by the loop output optimization device and outputting the smaller value of the processing result; and

[0013] A PWM control circuit, electrically connected to the MIN circuit, is configured to receive the smaller value in the processing result and generate a PWM pulse according to the smaller value, and the PWM pulse is configured to control the current at a specific position point of the DC-DC power conversion circuit.

[0014] In one embodiment, the loop output optimization device is configured to change the value of the larger one to the value of the smaller one plus a certain value.

[0015] In one embodiment, the certain value is 1 / n of the maximum value that the voltage loop and the current loop can output as a whole, where n is a value greater than 1.

[0016] In one embodiment, the current limiting circuit is configured to limit the output current of the DC-DC power conversion circuit.

[0017] In a second aspect, an embodiment of the present application provides a DC-DC power conversion device, including:

[0018] A DC-DC power conversion circuit; and

[0019] The above-mentioned current limiting circuit, which is electrically connected to the DC-DC power conversion circuit to limit the current at a specific position point of the DC-DC power conversion circuit.

[0020] In a third aspect, an embodiment of the present application further provides a method for quickly limiting current, which is used to quickly limit the current at a specific position point of the DC-DC power conversion circuit in a DC-DC power conversion device, and the method includes:

[0021] Receiving a first control value output by a voltage loop and a second control value output by a current loop;

[0022] Comparing the magnitudes of the first control value and the second control value;

[0023] Reducing the value of the larger one of the first control value and the second control value to reduce the difference between the larger one and the smaller one of the first control value and the second control value; and

[0024] Outputting a processing result, where the processing result includes the larger one with the reduced value and the smaller one, and the smaller one is used to control the current at the specific position point of the DC-DC power conversion circuit.

[0025] In one embodiment, the method further includes:

[0026] Sampling to obtain the voltage and current at the specific position point of the DC-DC power conversion circuit;

[0027] Input the voltage and a reference voltage into the voltage loop to generate the first control value, and input the current and a reference current into the current loop to generate the second control value.

[0028] In one embodiment, the method further includes:

[0029] Select the smaller value from the processing results;

[0030] Use the smaller value to control a PWM control circuit to generate PWM pulses; and

[0031] Output the PWM pulses to the DC-DC power conversion circuit to control the current at the specific position point.

[0032] In one embodiment, reducing the value of the larger one of the first control value and the second control value to reduce the difference between the larger one and the smaller one of the first control value and the second control value includes:

[0033] Change the value of the larger one to the value of the smaller one plus a fixed value.

[0034] In one embodiment, the fixed value is 1 / n of the maximum value that the voltage loop and the current loop can output as a whole, where n is a value greater than 1.

[0035] In one embodiment, the method is configured to limit the output current of the DC-DC power conversion circuit.

[0036] In a fourth aspect, an optimization module product is further provided in an embodiment of the present application. The optimization module product includes:

[0037] A storage unit that stores an optimization program;

[0038] A processing unit configured to call the optimization program to implement the foregoing method.

[0039] In a fifth aspect, a computer-readable storage medium is further provided in an embodiment of the present application. The computer-readable storage medium stores an optimization program, and when the optimization program is executed by a processing unit, the foregoing method is implemented.

[0040] In a sixth aspect, a computer program product is further provided in an embodiment of the present application. The computer program product includes computer program instructions, and when the computer program instructions are executed by a processing unit, the foregoing method is implemented.

[0041] Compared with the prior art, the current limiting circuit for quickly limiting current, the DC-DC power conversion device for quickly limiting current, the method for quickly limiting current and related devices provided by the embodiments of the present application utilize a loop output optimization device to optimize the control values output by the current loop and the voltage loop through a software algorithm, making the optimized control values closer numerically, thereby shortening the regulation time during overload, achieving the purpose of quickly limiting current and improving the current limiting function, which is beneficial to power supply protection. Compared with the prior art, the generation of oscillation is avoided, and for different models, only software parameters need to be adjusted, such as adjusting the magnitude of the delta value, avoiding behaviors such as redesigning the PCB board that bring R & D costs and risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings, where:

[0043] Figure 1 is a schematic diagram of the composition of a DC-DC power converter provided in the prior art;

[0044] Figure 2 is a schematic diagram of using a digital controller to control the output of a DC-DC power converter in the prior art;

[0045] Figure 3 is a schematic diagram of adding a comparator to adjust the output of a DC-DC power converter in the prior art;

[0046] Figure 4 is a schematic diagram of the composition of a DC-DC power conversion device for quickly limiting current provided by an embodiment of the present application;

[0047] Figure 5 is Figure 4 a schematic diagram of the composition of an embodiment of the loop output optimization device of the DC-DC power conversion device shown;

[0048] Figure 6 is Figure 4 a schematic diagram of the composition of another embodiment of the loop output optimization device of the DC-DC power conversion device shown;

[0049] Figure 7 is Figure 4 a schematic diagram of the composition of yet another embodiment of the loop output optimization device of the DC-DC power conversion device shown;

[0050] Figure 8 is a functional module diagram of the optimization program used by the loop output optimization device.

[0051] Figure 9 is a schematic flowchart of a method for quickly limiting the current of a DC-DC power conversion device in an embodiment of the present application;

[0052] Figure 10 is a schematic flowchart of a method for quickly limiting the current of the DC-DC power conversion device in another embodiment of the present application;

[0053] Figure 11 is a waveform diagram of the output voltage and output current of a DC-DC power conversion device under normal load and waveform diagrams of the control values output by the voltage loop and the control values output by the current loop in the prior art;

[0054] Figure 12 is a waveform diagram of the output voltage and output current of a DC-DC power conversion device during overload and waveform diagrams of the control values output by the voltage loop and the control values output by the current loop in the prior art;

[0055] Figure 13 is a waveform diagram of the output voltage and output current of a DC-DC power conversion device during overload and waveform diagrams of the control values output by the voltage loop and the current loop in an embodiment provided by the present application;

[0056] Figure 14 is a performance parameter diagram of a DC-DC power conversion device in the prior art and an embodiment provided by the present application obtained through simulation tests. Detailed implementation manners

[0057] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0058] For existing DC-DC power conversion devices, when the output current exceeds the defined current point (i.e., overload), the current loop will only start to decrease the output, while the output of the voltage loop continues to increase. After a long period of time, the output of the current loop is less than the output of the voltage loop, and at this time, a large current appears. Therefore, the output current cannot be quickly suppressed. Currently, the commonly used control schemes for limiting the output current by changing the current loop PID (Proportional-Integral-Derivative) parameters, adding hardware, etc. all bring some adverse effects, such as circuit oscillation, poor dynamic response, increased cost, etc.

[0059] Based on this, the following embodiments of the present application provide a DC-DC power conversion device for quickly limiting current and a current limiting circuit. Specifically, the following embodiments are introduced by taking the example of quickly limiting the output current of a DC-DC power conversion device.

[0060] Please refer to Figure 4 As shown, it is a schematic diagram of the composition of a DC-DC (direct current - direct current) power conversion device for quickly limiting current according to the present application. The DC-DC power conversion device 50 includes a DC-DC power conversion circuit 51 and a current limiting circuit 53 connected to the DC-DC power conversion circuit 51. The DC-DC power conversion circuit 51 is used to convert the input DC power supply into an output DC current whose voltage and current have changed relative to the input DC power supply, and the current limiting circuit 53 is used to output a control signal to control the voltage (such as the output voltage) and current (such as the output current) of the DC-DC power conversion circuit 51 so that they meet the preset requirements.

[0061] Specifically, in this embodiment, the current limiting circuit 53 includes a voltage loop 531, a current loop 532, a loop output optimization device 533, a MIN (minimum value) circuit 534, and a PWM (pulse width modulation) control circuit 535. Both the voltage loop 531 and the current loop 532 are connected to a specific position point of the DC-DC power conversion circuit 51 where the current needs to be limited and the loop output optimization device 533, so as to output corresponding control values to the loop output optimization device 533 according to the voltage and current at the specific position point of the DC-DC power conversion circuit 51. In this embodiment, the specific position point where the current needs to be limited is the output end of the DC-DC power conversion circuit 51. Therefore, the voltage loop 531 and the current loop 532 are configured to output corresponding control values to the loop output optimization device 533 according to the output voltage and output current of the DC-DC power conversion circuit 51. The loop output optimization device 533 is connected to the MIN circuit 534 to optimize the control value according to the situation and output the processing result to the MIN circuit 534. The MIN circuit 534 is connected to the PWM control circuit 535 to output the smaller value in the processing result of the loop output optimization device 533 to the PWM control circuit 535; the PWM control circuit is connected to the DC-DC power conversion circuit 51 to generate a PWM pulse according to the smaller value in the processing result of the loop output optimization device 533, and the PWM pulse is output to the DC-DC power conversion circuit 51 to control the voltage and current at the specific position point of the DC-DC power conversion circuit 51. In this embodiment, it is to control the output voltage and output current of the DC-DC power conversion circuit 51, so as to form a closed-loop control for the DC-DC power conversion circuit 51, so that the voltage and current at its specific position point (such as the output current at the output end) meet the preset requirements, and quickly limit the current at this specific position point in case of overload. For example, make the output voltage and output current at the output end of the DC-DC power conversion circuit 51 meet the preset requirements, and quickly limit the output current in case of overload.

[0062] The voltage loop 531 includes a comparison circuit 5311 and a PI (Proportional Integral) regulator 5313. The comparison circuit 5311 is connected to a specific position point of the DC-DC power conversion circuit 51, which is the output terminal in this embodiment, through a sampling circuit (not shown in the figure) to obtain the voltage at the specific position point of the DC-DC power conversion circuit 51, which is the output voltage Vout in this embodiment. Specifically, the comparison circuit 5311 has two input terminals, which are respectively used to input a preset reference voltage Vref and the output voltage Vout of the DC-DC power conversion circuit 51, to compare the output voltage Vout of the DC-DC power conversion circuit 51 with the reference voltage Vref, and output the comparison result c1 to the PI regulator 5313. In this embodiment, the comparison circuit 5311 includes a comparator, the reference voltage Vref and the output voltage Vout of the DC-DC power conversion circuit 51 are respectively input to the two input terminals of the comparator, and the comparison result c1 of the comparator is output to the PI regulator 5313. The PI regulator 5313 is used to output a control value A according to the comparison result c1 output by the comparison circuit 5311. How the PI regulator 5313 generates the control value A according to the comparison result cl output by the comparison circuit 5311 belongs to the prior art and will not be described in detail here.

[0063] The current loop 532 includes a comparison circuit 5321 and a PI (Proportional Integral) regulator 5323. The comparison circuit 5311 is connected to a specific position point of the DC-DC power conversion circuit 51, which is the output terminal in this embodiment, through a sampling circuit (not shown in the figure) to obtain the current at the specific position point of the DC-DC power conversion circuit 51, which is the output current Iout in this embodiment. Specifically, the comparison circuit 5321 has two input terminals, which are respectively used to input a preset reference current Iref and the output current Iout of the DC-DC power conversion circuit 51, to compare the output current Iout of the DC-DC power conversion circuit 51 with the reference current Iref, and output the comparison result c2 to the PI regulator 5323. In this embodiment, the comparison circuit 5321 includes a comparator, the reference current Iref and the output current Iout of the DC-DC power conversion circuit 51 are respectively input to the two input terminals of the comparator, and the comparison result c2 of the comparator is output to the PI regulator 5323. The PI regulator 5323 is used to output a control value B according to the comparison result c2 output by the comparison circuit 5321. How the PI regulator 5323 generates the control value B according to the comparison result c2 output by the comparison circuit 5321 belongs to the prior art and will not be described in detail here.

[0064] The loop output optimization device 533 is used to reduce the value of the larger one of the control values A and B to decrease the difference between the larger one and the smaller one of the control values A and B, and output the processing result to the MIN circuit. In this embodiment, the loop output optimization device 533 changes the value of the larger one of the control values A and B to the value of the smaller one plus a certain value to reduce the value of the larger one so as to narrow the difference between the larger one and the smaller one.

[0065] Specifically, please refer to Figure 5 As shown, the loop output optimization device 533 includes a processing unit 5331. The processing unit 5331 runs an optimization program 5332 to select the larger one of the control values A and B for optimization. The optimization program 5332 can be stored (for example, solidified) in the processing unit 5331; or, as Figure 6 As shown, the loop output optimization device 533 further includes a storage unit 5333. The optimization program 5332 is stored in the storage unit 5333, and the processing unit 5331 obtains the optimization program 5332 by accessing the storage unit 5333; or, it can also be as Figure 7 As shown, the processing unit 5331 can communicate with an external host to obtain an optimization program or obtain update parameters of the optimization program from the external host.

[0066] The processing unit 5331 can be a system-on-chip (SOC) or a control chip such as a microcontroller microprocessor. It receives the control values A and B output by the PI regulators 5313 and 5323 through relevant ports, and outputs the processing result to the MIN circuit 534 through relevant ports.

[0067] Please refer to Figure 8 As shown, it is a functional module diagram obtained by dividing the optimization program 5332 according to functions.

[0068] The optimization program 5332 can be divided into functional modules such as a receiving module 5332a, a comparing module 5332b, a processing module 5332c, and an output module 5332d. Among them:

[0069] The receiving module 5332a is used to receive the two control values A and B output by the voltage loop 531 and the current loop 532 respectively through relevant ports;

[0070] The comparing module 5332b is used to compare the magnitudes of the control values A and B and output a comparison result;

[0071] The processing module 5332c is used to determine whether to optimize one of the control values according to the comparison result output by the comparison module 5332b. When it is determined that one of the control values needs to be optimized, the value of the larger one is decreased to reduce the difference between the larger one and the smaller one. In this embodiment, the processing module 5332c changes the value of the larger one of the control values A and B to the value of the smaller one of A and B plus a certain value. Among them, when the comparison result shows that the control value A is less than the control value B, the value of the control value B is changed to A + delta1, where delta1 is a preset fixed value. For example, delta1 is 1 / n of the maximum value that the voltage loop 531 and the current loop 532 can output as a whole (i.e., the loop maximum value), where n is a value greater than 1. For example, delta1 is 1 / 12, 1 / 10, 1 / 8, 1 / 6, etc. of the loop maximum value, and A + delta1 is less than the loop maximum value. When the comparison result shows that the control value B is less than the control value A, the value of the control value A is changed to B + delta2, where delta2 is a preset fixed value. For example, delta2 is 1 / n of the maximum value that the voltage loop 531 and the current loop 532 can output as a whole (i.e., the loop maximum value), and n is a value greater than 1. For example, delta2 can be 1 / 12, 1 / 10, 1 / 8, 1 / 6, etc. of the loop maximum value, and B + delta2 is less than the loop maximum value. Delta1 and delta2 can be equal or not equal. When the comparison result shows that the control values A and B are equal, the optimization is abandoned.

[0072] The output module 5332d is used to output the processing result of the processing module 5332c through relevant ports. The processing result can be ① A and A + delta1, ② B + delta2 and B, or ③ A and B.

[0073] It can be understood that the optimization program is a computer program product, including computer program instructions. When the computer program instructions are executed by the processing unit, a method for quickly limiting the current at a specific position point of the DC-DC power conversion circuit is implemented.

[0074] It can be understood that the storage unit can be a computer-readable storage medium. For example, it can be a floppy disk, a USB flash drive, a magnetic disk, an optical disk, a mobile hard disk, a read-only memory, a random access memory, etc. It stores the optimization program. When the optimization program is run by the processing unit, a method for quickly limiting the current at a specific position point of the DC-DC power conversion circuit is implemented.

[0075] It can be understood that in some embodiments, the loop output optimization device 533 can be an independent optimization module product. The optimization module product includes a processing unit and a storage unit. The storage unit stores the optimization program, and the processing unit calls the optimization program to implement the method for quickly limiting the current at a specific position point of the DC-DC power conversion circuit.

[0076] The MIN circuit 534 is configured to take the smaller value from the processing result output by the processing module 5332c and output the taken smaller value to the PWM control circuit 535.

[0077] The PWM control circuit 535 is configured to generate a PWM pulse based on the smaller value sent by the MIN circuit 534 and output the generated PWM pulse to the DC-DC power conversion circuit 51 to control the voltage and current at a specific position point of the DC-DC power conversion circuit 51, which is the output voltage Vout and output current Iout of the DC-DC power conversion circuit 51 in this embodiment.

[0078] The following embodiments of the present application provide a method for quickly limiting current.

[0079] Please refer to Figure 9 As shown, it is a schematic flowchart of the method for quickly limiting current in an embodiment. The method is applied to the DC-DC power conversion circuit of the aforementioned DC-DC power conversion device for quickly limiting current, and the method includes operations 901-905.

[0080] Operation 901, receive the control value A output by the voltage loop and the control value B output by the current loop.

[0081] Operation 902, compare the magnitudes of the control value A and the control value B. When the control value A is less than the control value B, the process proceeds to operation 903. When the control value A is greater than the control value B, the process proceeds to operation 904. When the control value A is equal to the control value B, the process proceeds to operation 905.

[0082] Operation 903, reduce the value of the control value B to reduce the difference between the control value B and the control value A. Specifically, in this embodiment, change the value of the control value B to A+delta1, and the process proceeds to operation 905.

[0083] Among them, in operation 903, delta1 is a preset fixed value. For example, delta1 is 1 / n of the maximum value that the voltage loop 531 and the current loop 532 can output as a whole (i.e., the loop maximum value), where n is greater than 1. For example, delta1 can also be 1 / 12, 1 / 10, 1 / 9, 1 / 8, 1 / 6, etc. of the loop maximum value, and A+delta1 is less than the loop maximum value.

[0084] Operation 904 reduces the value of control value A to decrease the difference between control value A and control value B. Specifically, in this embodiment, the value of control value A is changed to B + delta2, and the process proceeds to operation 905.

[0085] In operation 904, delta2 is a preset fixed value. For example, delta2 is 1 / n of the maximum value that the voltage loop 531 and the current loop 532 can output as a whole (i.e., the loop maximum value), where n is greater than 1. For example, delta2 can be 1 / 12, 1 / 10, 1 / 9, 1 / 8, 1 / 6, etc. of the loop maximum value. B + delta1 is less than the loop maximum value, and delta1 and delta2 can be equal or not equal.

[0086] They can be equal or not equal.

[0087] Operation 905 outputs a processing result, which is one of ① A and A + delta1, ② B + delta2 and B, and ③ A and B. The smaller value among the processing results is used to control the current at a specific position point of the DC-DC power conversion circuit. When control value A is equal to control value B, one of control value A and control value B is output according to a preset setting.

[0088] Please refer to Figure 10 As shown, it is a flowchart of a method for quickly limiting the output current of a DC-DC power conversion device in another embodiment. The method is applied to the aforementioned DC-DC power conversion device for quickly limiting the output current, and the method includes operations 1001 - 1007.

[0089] Operation 1001 samples the voltage and current at a specific position point of the DC-DC power conversion circuit. In this embodiment, it samples the output voltage and output current of the DC-DC power conversion circuit.

[0090] Operation 1002 inputs the voltage and a reference voltage into a voltage loop to generate control value A, and inputs the current and a reference current into a current loop to generate control value B. In this embodiment, it inputs the output voltage and a reference voltage into a voltage loop to generate control value A, and inputs the output current and a reference current into a current loop to generate control value B.

[0091] Operation 1003 is the same as or similar to operation 901 in the previous embodiment.

[0092] Operation 1004 is the same as or similar to operation 902 in the previous embodiment.

[0093] Operation 1005 is the same as or similar to operation 903 in the previous embodiment.

[0094] Operation 1006 is the same as or similar to operation 904 of the previous embodiment.

[0095] Operation 1007 is the same as or similar to operation 905 of the previous embodiment.

[0096] Therefore, operations 1003 - 1007 refer to the previous embodiment and will not be elaborated here.

[0097] Operation 1008 selects the smaller value from the processing results.

[0098] Operation 1009 uses the smaller value to control the PWM control circuit to generate PWM pulses.

[0099] Operation 1010 outputs the PWM pulses to the DC - DC power conversion circuit to adjust the voltage and current at a specific position point of the DC - DC power conversion circuit. In this embodiment, it is to adjust the output voltage and output current of the DC - DC power conversion circuit.

[0100] The above introduces the DC - DC power conversion device for quickly limiting current and the method for quickly limiting the current of the DC - DC power conversion device provided by the embodiments of the present application. The following explains why the above - mentioned device and method provided by the embodiments of the present application can achieve the purpose of quickly limiting the current of the DC - DC power conversion device, such as the output current, compared with the prior art.

[0101] Please refer to Figure 11 as shown in Figure 11 Part (a) of which shows the waveform diagram of the output voltage Vout and output current Iout of the DC - DC power conversion device in the prior art when it is normally loaded. Figure 11 Part (b) of which shows the waveform diagram of the control value output by the voltage loop and the control value output by the current loop. It can be seen from Figure 11 that when normally loaded, the output voltage Vout of the DC - DC power conversion device will stabilize at its rated voltage point after continuous increase, and the output current Iout will stabilize at its rated current point after continuous increase, which is lower than the limit current point. The control value output by the voltage loop starts from the loop minimum value Loopmin and continuously increases and then stabilizes at a certain value, which is lower than the loop maximum value Loopmax; the control value output by the current loop starts from the loop minimum value Loopmin and continuously increases and then stabilizes at the loop maximum value Loopmax.

[0102] Please refer to Figure 12 as shown in Figure 12 Part (a) of which shows the waveform diagram of the output voltage Vout and output current Iout of the DC - DC power conversion device in the prior art when it is overloaded. Figure 12Part (b) shows the waveform diagrams of the control value of the voltage loop output and the control value of the current loop output. From Figure 12 It can be seen that at time t1, the output current Iout exceeds the defined current point, and the DC-DC power conversion device is overloaded. At this time, the control amount of the current loop output starts to decrease, while the control amount of the voltage loop output continues to increase. Before the control amount of the voltage loop output increases to be greater than the control amount of the current loop output, that is, at and before time t2, according to the principle of taking the smaller value by the MIN circuit, the MIN circuit outputs the control value of the voltage loop output to the PWM control circuit. That is to say, during the period from t1 to t2, the DC-DC power conversion device adjusts the output voltage Vout and the output current Iout according to the control value of the voltage loop output. Due to the overload, the output current Iout becomes larger and the output voltage Vout decreases. The control amount of the voltage loop output continues to increase, and the control amount of the current loop output continues to decrease. After a relatively long period of time, that is, after passing through time t2, the control amount of the current loop output starts to be less than the control amount of the voltage loop output, and at this time, a large current appears.

[0103] Please refer to Figure 13 as shown in Figure 13 Part (a) shows the waveform diagrams of the output voltage Vout and the output current Iout when the DC-DC power conversion device in the embodiment of the present application is overloaded. Figure 13 Part (b) shows the waveform diagrams of the control value of the voltage loop output and the control value of the current loop output of the DC-DC power conversion device in the embodiment of the present application after being optimized by the loop output optimization device. From Figure 13 It can be seen that at time t1, the output current Iout exceeds the defined current point, and the DC-DC power conversion device is overloaded. Before time t1, since the control value of the current loop output has always been greater than the control value of the voltage loop output, after the control value of the current loop output is input into the loop output optimization device, it is changed by the loop output optimization device to the control value of the voltage loop output plus the delta1 value. And the sum of the control value of the voltage loop output plus the delta1 value is less than the loop maximum value Loopmax. Therefore, when overload occurs at time t1, the control amount of the voltage loop output continues to increase, and the control amount of the current loop output continues to decrease. And because the difference between the optimized control amount of the current loop and the control amount of the voltage loop is only delta1, the optimized difference is smaller than the difference between the two before optimization in the prior art. Therefore, time t2 is reached faster, that is, the time when the control amount of the current loop output is about to start being less than the control amount of the voltage loop output is reached faster. That is to say, compared with the prior art, the value of t2 - t1 in the DC-DC power conversion device and method provided in the embodiment of the present application is smaller, and the purpose of quickly limiting the output current of the DC-DC power conversion device can be achieved.

[0104] Please refer to Figure 14 , Figure 14 Part (a) of Figure 14 is a performance parameter diagram of a DC-DC power conversion device in the prior art obtained by simulation testing using the simulation software PSIM. Figure 14 Part (b) of Figure 14 is a performance parameter diagram of the DC-DC power conversion device in the embodiment of the present application obtained by simulation testing using the simulation software PSIM. It is set that the hardware has the same parameters and the control frequency is the same in the two tests, and the parameters of the current loop and the voltage loop are consistent. From Figure 14 it can be seen that when testing the DC-DC power conversion device of the prior art, the maximum current after overload is 46.8 A, and the regulation time (t2 - t1) is 10.29 ms. While when testing the DC-DC power conversion device in the embodiment of the present application, the maximum current after overload is 44.7 A, and the regulation time (t2 - t1) is 6.63 ms. Thus, it also proves that the DC-DC power conversion device and method for quickly limiting the output current provided by the embodiment of the present application can achieve the purpose of quickly limiting the output current of the DC-DC power conversion device.

[0105] Although the above embodiment introduces quickly limiting the output current of the DC-DC power conversion device, however, the technical solution introduced in the above embodiment can also be referred to and applied to quickly limiting the current at other places of the DC-DC power conversion device. For example, quickly limiting the input current of the DC-DC power conversion device, quickly limiting the current at a certain place inside the DC-DC power conversion device.

[0106] In summary, the current limiting circuit, the DC-DC power conversion device for quickly limiting current, and the method for quickly limiting the current of the DC-DC power conversion device provided by the embodiment of the present application utilize a loop output optimization device to optimize the control values output by the current loop and the voltage loop through software algorithms, making the optimized control values closer numerically, thereby shortening the regulation time during overload, achieving the purpose of quickly limiting current and improving the current limiting function, which is beneficial to power protection. At the same time, compared with the prior art, it avoids the generation of oscillations, and only needs to adjust software parameters for different models, such as adjusting the size of the delta value, avoiding behaviors such as re-designing the PCB board that bring R & D costs and risks.

[0107] The above are only the embodiments of the present application, and do not limit the patent scope of the present application accordingly. All equivalent structural or equivalent process transformations made using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, are equally included in the patent protection scope of the present application.

Claims

1. A current limiting circuit, the current limiting circuit being configured to be electrically connected to a DC-DC power conversion circuit to limit the current at a specific position point of the DC-DC power conversion circuit, characterized in that Comprising: A voltage loop, configured to be electrically connected to the specific position point of the DC-DC power conversion circuit to output a first control value according to the voltage at the specific position point; A current loop, configured to be electrically connected to the specific position point of the DC-DC power conversion circuit to output a second control value according to the current at the specific position point; A loop output optimization device, electrically connected to the voltage loop and the current loop, configured to receive the first control value and the second control value, and reduce the value of the larger one of the first control value and the second control value to reduce the difference between the larger one and the smaller one of the first control value and the second control value; A MIN circuit, configured to be electrically connected to the loop output optimization device, for receiving the processing result output by the loop output optimization device and outputting the smaller value in the processing result; And A PWM control circuit, electrically connected to the MIN circuit, configured to receive the smaller value in the processing result and generate a PWM pulse according to the smaller value, and the PWM pulse is configured to control the current at the specific position point of the DC-DC power conversion circuit.

2. The current limiting circuit according to claim 1, wherein The loop output optimization device is configured to change the value of the larger one to the value of the smaller one plus a certain value, and the certain value is 1 / n of the maximum value that the voltage loop and the current loop can output as a whole, where n is a value greater than 1.

3. The current limiting circuit according to claim 2, wherein The current limiting circuit is configured to limit the output current of the DC-DC power conversion circuit.

4. A DC-DC power conversion device, characterized in that, Comprising: A DC-DC power conversion circuit; And The current limiting circuit according to any one of claims 1-3, the current limiting circuit being electrically connected to the DC-DC power conversion circuit to limit the current at a specific position point of the DC-DC power conversion circuit.

5. A method for quickly limiting current, which is used to quickly limit the current at a specific position point of a DC-DC power conversion circuit in a DC-DC power conversion device, characterized in that, Comprising: Receiving the first control value output by the voltage loop and the second control value output by the current loop; Comparing the magnitudes of the first control value and the second control value; Reducing the value of the larger one of the first control value and the second control value to reduce the difference between the larger one and the smaller one of the first control value and the second control value; And Outputting a processing result, the processing result including the larger one with the reduced value and the smaller one, and the smaller one is used to control the current at the specific position point of the DC-DC power conversion circuit.

6. The method according to claim 5, characterized in that, Further comprising: Sampling to obtain the voltage and current at the specific position point of the DC-DC power conversion circuit; Inputting the voltage and a reference voltage into the voltage loop to generate the first control value, and inputting the current and a reference current into the current loop to generate the second control value; And / or, Further comprising: Selecting the smaller value from the processing result; Using the smaller value to control a PWM control circuit to generate a PWM pulse; and Outputting the PWM pulse to the DC-DC power conversion circuit to control the current at the specific position point.

7. The method according to claim 6, wherein Reducing the value of the larger one of the first control value and the second control value to reduce the difference between the larger one and the smaller one of the first control value and the second control value includes: Changing the value of the larger one to the value of the smaller one plus a certain value, where the certain value is 1 / n of the maximum value that the voltage loop and the current loop can output as a whole, and n is a value greater than 1.

8. An optimized module product, characterized in that, Including: A storage unit that stores an optimization program; A processing unit configured to call the optimization program to implement the method according to claim 5 or 7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores an optimization program, and when the optimization program is executed by a processing unit, the method according to claim 5 or 7 is implemented.

10. A computer program product, characterized in that, Including computer program instructions, and when the computer program instructions are executed by a processing unit, the method according to claim 5 or 7 is implemented.

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