Protection method and system for dynamically adjusting multi-section current limiting and preventing impulse current output

Abstract

The invention discloses a protection method and system for dynamically adjusting multi-section current limiting to prevent output impact current, and belongs to the technical field of power systems, and the method comprises the following steps: S1, after a power module is powered on, a microprocessor is initialized, a default current limiting value is given, and a current limiting subprogram is executed; s2, the output current sample is processed by an operational amplifier and sent to an anti-phase end of a current-limiting operational amplifier and an AD sampling port of a microprocessor; s3, the magnitude of the load current is judged, and if the load current is increased, the microprocessor gradually improves the current limiting reference until the current limiting value in the full-load state is reached; and if the load current is reduced, the microprocessor reduces the output current-limiting reference. A non-fixed current limiting value is adopted, dynamic adjustment is carried out according to the change of load current, the normal load requirement is met, the defects that the load sudden change output current impact amplitude is too large and time is too long are overcome, and the safety, reliability and stability of equipment are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply systems, and in particular to a protection method and system for dynamically adjusting multi-stage current limiting to prevent output surge current. Background Art

[0002] At present, intelligent high-power power modules usually set fixed current limiting points or power limiting points above the rated output to prevent output overcurrent, so that the response speed is related to sampling and loop parameters. The stable current limiting function often sacrifices fast responsiveness, and additional suppression measures are required for sudden impact current.

[0003] With respect to the above-mentioned related technologies, the applicant has found that a fixed current limiting point method is often used for current limiting in high-power power supply modules. However, when an impact current higher than the set value appears and the impact current value is above the rated value, the power supply module faces a large current impact and will directly enter the overcurrent protection lock state, and some may even damage the power supply module, thereby reducing the safety and stability of the power supply module. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a protection method and system for dynamically adjusting multi-stage current limiting to prevent output impact current. A non-fixed current limiting value is adopted and dynamically adjusted according to changes in load current, which can meet normal load requirements and overcome the drawbacks of excessively large output current impact amplitude and long duration due to sudden load changes, thereby effectively improving the safety, reliability and stability of the equipment.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A protection method for dynamically adjusting multiple current limiting sections to prevent output surge current comprises the following steps:

[0007] S1: After the power module is powered on, the microprocessor is initialized, a default current limiting value is given, and the current limiting subroutine is executed;

[0008] S2: The output current sampling is processed by the operational amplifier and sent to the inverting end of the current limiting operational amplifier and the AD sampling port of the microprocessor;

[0009] S3: Determine the size of the load current. If the load current increases, the microprocessor gradually increases the current limit reference until it reaches the current limit value under full load; if the load current decreases, the microprocessor reduces the output current limit reference.

[0010] Furthermore, executing the current limiting subroutine in S1 specifically includes:

[0011] S11: After DCDC is started, the current limit value is set to 55% of the rated output current value;

[0012] S12: Determine whether the current is greater than 50% of the rated output current value. If so, jump to S13; if not, continue to execute S11;

[0013] S13: Set the current limit value to 65% of the rated output current value;

[0014] S14: Determine whether the current is greater than 60% of the rated output current value. If so, jump to S15; if not, jump to S12;

[0015] S15: Set the current limit value to 75% of the rated output current value;

[0016] S16: Determine whether the current is greater than 70% of the rated output current value. If so, jump to S17; if not, jump to S14;

[0017] S17: Set the current limit value to 85% of the rated output current value;

[0018] S18: Determine whether the current is greater than 80% of the rated output current value. If so, jump to S16; if not, jump to S19;

[0019] S19: Set the current limit value to 105% of the rated output current value.

[0020] Furthermore, when executing the current limiting subroutine, the time interval between adjacent current limiting intervals is set to 100ms.

[0021] Furthermore, in a non-full load state, the current limiting value is greater than the load current value and less than or equal to the rated output current value.

[0022] Furthermore, when the current reaches the set current limit value, the output voltage is controlled by adjusting the voltage reference.

[0023] A protection system for dynamically adjusting multi-stage current limiting to prevent output surge current, comprising a microprocessor, a current sampling resistor and a current limiting circuit;

[0024] The microprocessor is used to track the load current change and automatically adjust the current limit reference upward or downward;

[0025] The current sampling resistor is used to sample the current and output an ICY signal, which is transmitted to the current limiting circuit for processing;

[0026] The first input end of the current limiting circuit is connected to the current sampling resistor for receiving the ICY signal, and the second input end of the current limiting circuit is connected to the microprocessor for receiving the PWM signal sent by the microprocessor.

[0027] Furthermore, the current limiting circuit includes two operational amplifiers D2A and D2B. The ICY signal is divided into two paths after proportional amplification and differential operation by the operational amplifier D2B. One signal I-ADC is transmitted to the microprocessor to be converted into a current value, and the other is connected to the inverting end of the operational amplifier D2A.

[0028] Furthermore, the signal PWM is connected to the second input terminal of the current limiting circuit, and is connected to the non-inverting terminal of the operational amplifier D2A after being smoothed by the resistor-capacitor integration to generate a current limiting setting reference value.

[0029] Furthermore, the current limiting circuit also includes a diode and a plurality of resistors, which are used to limit the minimum current limiting value and the maximum current limiting value after the current limiting subroutine runs out of control.

[0030] In summary, compared with the prior art, the above technical solution has the following beneficial effects:

[0031] (1) The present invention provides a protection method and system for dynamically adjusting multi-stage current limiting to prevent output impact current. The current limiting value is not fixed, but can be dynamically adjusted according to the change of load current. The current limiting value is dynamically adjusted according to the load current, which can meet the normal load demand and overcome the drawbacks of excessively large output current impact amplitude and long duration due to sudden load changes, thereby effectively improving the safety, reliability and stability of the equipment.

[0032] (2) The present invention provides a protection method and system for dynamically adjusting multiple current limiting to prevent output surge current. Through multiple current limiting, the single current limiting point setting above the rated value is changed. The surge current is blocked by multiple stages during its rise. The amplitude and time of each stage are limited, which reduces the surge energy and EMI (interference). At the same time, the software is easy to design.

[0033] (3) The present invention provides a protection method and system for dynamically adjusting multiple current limiting to prevent output impact current. The current limiting shift comparison value is set to 5% of the current limiting setting value. This can prevent the current limiting gear from constantly changing up and down due to current fluctuations when the current is close to the setting value; it can also speed up the current rising shift process; and it can also prevent the current value from being stuck at the current limiting value and the current limiting gear from not changing, resulting in the current limiting value being the same as the output current value, thereby affecting the output voltage value due to the current limiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the flow of the current limiting subroutine according to an embodiment of the present invention;

[0035] Figure 2 A block diagram of the current limiting principle of an embodiment of the present invention;

[0036] Figure 3 Schematic diagram of a current limiting circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The principles and features of the present invention are described below in conjunction with all the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0038] The embodiment of the present invention discloses a protection method and system for dynamically adjusting multi-stage current limiting to prevent output surge current.

[0039] The embodiment of the present invention provides a protection method for dynamically adjusting multi-stage current limiting to prevent output surge current, comprising the following steps:

[0040] S1: After the power module is powered on, the microprocessor is initialized, a default current limiting value is given, and the current limiting subroutine is executed;

[0041] S2: The output current sampling is processed by the operational amplifier and sent to the inverting end of the current limiting operational amplifier and the AD sampling port of the microprocessor;

[0042] S3: Determine the size of the load current. If the load current increases, the microprocessor gradually increases the current limit reference until it reaches the current limit value under full load; if the load current decreases, the microprocessor reduces the output current limit reference.

[0043] This design can realize the functions of non-fixed current limiting point and dynamic multi-stage current limiting in power supply equipment, so as to reduce the impact current amplitude and slow down the impact current rising rate. The implementation of this technical solution can reduce the instantaneous voltage and current stress of the module and enhance the safety of the module.

[0044] Reference Figure 1 , the current limiting subroutine executed in S1 specifically includes:

[0045] S11: After DCDC is started, the current limit value is set to 55% of the rated output current value;

[0046] S12: Determine whether the current is greater than 50% of the rated output current value. If so, jump to S13; if not, continue to execute S11;

[0047] S13: Set the current limit value to 65% of the rated output current value;

[0048] S14: Determine whether the current is greater than 60% of the rated output current value. If so, jump to S15; if not, jump to S12;

[0049] S15: Set the current limit value to 75% of the rated output current value;

[0050] S16: Determine whether the current is greater than 70% of the rated output current value. If so, jump to S17; if not, jump to S14;

[0051] S17: Set the current limit value to 85% of the rated output current value;

[0052] S18: Determine whether the current is greater than 80% of the rated output current value. If so, jump to S16; if not, jump to S19;

[0053] S19: Set the current limit value to 105% of the rated output current value.

[0054] The current limiting subroutine in the embodiment of the present invention can be further understood as: at the initial power-on, the program defaults to a current limiting value of 55% of the rated output current value, the current limiting setting value of each gear differs by 10% or more, the current limiting shift comparison value of each gear differs by 10%, the current limiting shift comparison value is 5% lower than the set value, and the time interval between adjacent current limiting intervals is set to 100ms. Such a design can avoid the output voltage being limited too low at the moment of power-on, and can avoid frequent switching of current limiting gears during normal operation, while reducing the amount of microprocessor calculations and enhancing the timeliness of preventing output shock current.

[0055] When the current reaches the set current limit value, the output voltage is controlled by adjusting the voltage reference. Under non-full load conditions, the current limit value is greater than the load current value and less than or equal to the rated output current value. During normal operation, the microprocessor tracks the load current changes and automatically adjusts the current limit reference upward or downward without affecting the stability of the output voltage. When the load current increases, the current limit value can be increased, and when the load current decreases, the current limit value can be adjusted back; when facing an impact, the impact current is first blocked by the gear above the load current. Because the output voltage is lowered in advance, the energy is reduced, and finally the current will not overshoot when the current reaches the maximum value of the current limit setting. The whole process is equivalent to the module being used at a reduced rate.

[0056] The current limit value is based on the rated output current value, and 5 gears are set, each gear is 10% of the rated current or other proportional difference. Too few gears will reduce the effect of suppressing the impact current; too many gears will cause frequent switching. The actual gears and number can be designed according to needs. Due to the current ripple and sampling error, the gear shift comparison value is designed to be 5% different from the current limit setting value, which is more practical in engineering.

[0057] It should be noted that: when the output has a large impact current, the module will execute the current limiting subroutine to achieve the purpose of suppressing the impact current. The default current limit value, each current limit value parameter, and the time interval between adjacent gears can be changed externally through the communication interface according to the specific load characteristics.

[0058] Reference Figure 2 An embodiment of the present invention also provides a protection system for dynamically adjusting multi-stage current limiting to prevent output impact current, including a microprocessor, a current sampling resistor and a current limiting circuit; this solution uses a microprocessor, a current sampling resistor, and two operational amplifiers to process current, and adjusts the current limiting gear and current limiting value by combining software programming with hardware.

[0059] The microprocessor is used to track the load current change and automatically adjust the current limit reference upward or downward;

[0060] The current sampling resistor is used to sample the current and output an ICY signal, which is transmitted to the current limiting circuit for processing;

[0061] Reference Figure 3 , shows a circuit diagram of a current limiting circuit, wherein a first input terminal of the current limiting circuit is connected to a current sampling resistor for receiving an ICY signal, and a second input terminal of the current limiting circuit is connected to a microprocessor for receiving a PWM signal issued by the microprocessor.

[0062] Specifically, the current limiting circuit includes two operational amplifiers D2A and D2B. The ICY signal is divided into two paths after proportional amplification and differential operation by the operational amplifier D2B. One signal I-ADC is transmitted to the microprocessor to be converted into a current value, and the other is connected to the inverting end of the operational amplifier D2A.

[0063] Furthermore, the signal PWM is connected to the second input terminal of the current limiting circuit, and is connected to the non-inverting terminal of the operational amplifier D2A after being integrated and smoothed by the resistor and capacitor R5C4 to generate a current limiting setting reference value. The non-inverting and non-inverting terminal signals are compared and processed by the operational amplifier D2A to lower the output voltage reference.

[0064] Furthermore, the current limiting circuit also includes a diode and a plurality of resistors, which are used to limit the minimum current limiting value and the maximum current limiting value after the current limiting subroutine runs out of control.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A protection method for dynamically adjusting multi-stage current limiting to prevent output surge current, characterized in that: The following steps are involved: S1: After the power module is powered on, the microprocessor is initialized, a default current limiting value is given, and the current limiting subroutine is executed; S2: The output current sampling is processed by the operational amplifier and sent to the inverting end of the current limiting operational amplifier and the AD sampling port of the microprocessor; S3: Determine the size of the load current. If the load current increases, the microprocessor gradually increases the current limit reference until it reaches the current limit value under full load; if the load current decreases, the microprocessor reduces the output current limit reference.

2. A protection method for dynamically adjusting multi-stage current limiting to prevent output surge current according to claim 1, characterized in that: The current limiting subroutine executed in S1 specifically includes: S11: After DCDC is started, the current limit value is set to 55% of the rated output current value; S12: Determine whether the current is greater than 50% of the rated output current value. If so, jump to S13; if not, continue to execute S11; S13: Set the current limit value to 65% of the rated output current value; S14: Determine whether the current is greater than 60% of the rated output current value. If so, jump to S15; if not, jump to S12; S15: Set the current limit value to 75% of the rated output current value; S16: Determine whether the current is greater than 70% of the rated output current value. If so, jump to S17; if not, jump to S14; S17: Set the current limit value to 85% of the rated output current value; S18: Determine whether the current is greater than 80% of the rated output current value. If so, jump to S16; if not, jump to S19; S19: Set the current limit value to 105% of the rated output current value.

3. A protection method for dynamically adjusting multi-stage current limiting to prevent output surge current according to claim 2, characterized in that: When executing the current limiting subroutine, the time interval between adjacent current limiting intervals is set to 100ms.

4. A protection method for dynamically adjusting multi-stage current limiting to prevent output surge current according to claim 2, characterized in that: Under non-full load condition, the current limit value is greater than the load current value and less than or equal to the rated output current value.

5. The protection method for dynamically adjusting multi-stage current limiting to prevent output surge current according to claim 2, characterized in that: When the current reaches the set current limit value, the output voltage is controlled by adjusting the voltage reference.

6. A protection system for dynamically adjusting multi-stage current limiting to prevent output surge current, characterized in that: It includes a microprocessor, a current sampling resistor and a current limiting circuit; The microprocessor is used to track the load current change and automatically adjust the current limit reference upward or downward; The current sampling resistor is used to sample the current and output an ICY signal, which is transmitted to the current limiting circuit for processing; The first input end of the current limiting circuit is connected to the current sampling resistor for receiving the ICY signal, and the second input end of the current limiting circuit is connected to the microprocessor for receiving the PWM signal sent by the microprocessor.

7. A protection system for dynamically adjusting multi-stage current limiting to prevent output surge current according to claim 6, characterized in that: The current limiting circuit includes two operational amplifiers D2A and D2B. The ICY signal is divided into two paths after proportional amplification and differential operation by the operational amplifier D2B. One path is transmitted to the microprocessor by the signal I-ADC and converted into a current value, and the other path is connected to the inverting end of the operational amplifier D2A.

8. A protection system for dynamically adjusting multi-stage current limiting to prevent output surge current according to claim 7, characterized in that: The signal PWM is connected to the second input terminal of the current limiting circuit, and is connected to the non-inverting terminal of the operational amplifier D2A after being smoothed by the resistor-capacitor integration to generate a current limiting setting reference value.

9. A protection system for dynamically adjusting multi-stage current limiting to prevent output surge current according to claim 7, characterized in that: The current limiting circuit also includes a diode and a plurality of resistors, which are used to limit the minimum current limiting value and the maximum current limiting value after the current limiting subroutine runs out of control.

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