Energy storage converter and over-current protection circuit and over-current protection method thereof

Abstract

The invention discloses an energy storage converter and an overcurrent protection circuit and an overcurrent protection method thereof. The overcurrent protection method comprises the following steps: acquiring the equipment temperature and the output current and voltage of the energy storage converter; calculating a current change rate based on the acquired output current; the current real-time temperature is adjusted on the basis of the reference over-current protection threshold value, the voltage collected in real time is applied to the adjusted over-current protection threshold value according to the set proportion, and meanwhile, the current change rate obtained through real-time calculation is applied to the adjusted over-current protection threshold value according to the set proportion. Obtaining a result of a dynamic overcurrent protection threshold value; comparing the dynamic over-current protection threshold value with the output current of the energy storage converter, if the dynamic over-current protection threshold value is exceeded, triggering to execute a protection action, generating a control instruction, and tripping off a switch device for controlling the operation of the energy storage converter; and if not, continuously monitoring and comparing the output current with the dynamic overcurrent protection threshold.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage converters, and more specifically, relates to an energy storage converter and an overcurrent protection circuit and an overcurrent protection method thereof. Background Art

[0002] As the core control device of an energy storage system, the stability and reliability of the energy storage converter are directly related to the operating efficiency and safety of the entire energy storage system. In actual operation, the energy storage converter may cause overcurrent due to various factors.

[0003] Prior art document 1 (CN222735798U) discloses an output overcurrent protection circuit, but the circuit relies only on a fixed threshold and a simple overcurrent detection device, which has obvious limitations in complex and changeable actual operating environments. First, the fixed threshold cannot adapt to dynamically changing loads and working conditions, which may lead to false triggering or missed triggering. Secondly, a simple overcurrent detection device has difficulty in accurately capturing complex current waveforms, such as high-frequency noise or transient pulses, resulting in poor protection effect. In addition, the fixed threshold and simple detection device cannot meet the requirements of different working modes and may not provide effective protection in high power or low power modes.

[0004] Prior art document 2 (CN112803901B) discloses a power amplifier based on adaptive overcurrent protection, which can adaptively adjust the overcurrent protection threshold to prevent the power amplifier from burning due to overcurrent. However, its overcurrent protection threshold closely follows the adaptive changes of the power supply voltage, which has certain limitations. When the power supply voltage fluctuates frequently, the overcurrent protection threshold will also be adjusted frequently, which may lead to reduced system stability and increase the risk of malfunction. The adaptive adjustment depends on the stability of the power supply voltage. If the power supply voltage itself is unstable or the measurement is inaccurate, the adjustment of the overcurrent protection threshold will also be affected, reducing the effectiveness of the protection.

[0005] It can be seen that the areas for improvement in existing technologies include at least the following: 1. Inadequate overcurrent protection: Existing overcurrent protection methods use fixed thresholds and cannot adapt to the dynamic changes of energy storage converters under complex working conditions, resulting in failure to detect and handle overcurrent phenomena in a timely manner, which may cause equipment damage or system shutdown; 2. Limitations of single-factor adjustment: Existing adaptive overcurrent protection methods only consider changes in power supply voltage and lack comprehensive consideration of temperature, current change rate, and power fluctuations, resulting in inaccurate protection. Summary of the Invention

[0006] In order to address the deficiencies in the prior art, the present invention provides an energy storage converter, an overcurrent protection circuit thereof, and an overcurrent protection method thereof. Through a control method for dynamic threshold adjustment, the overcurrent protection performance of the energy storage converter is significantly improved.

[0007] The present invention adopts the following technical solution. A first aspect of the present invention provides an energy storage converter overcurrent protection method, comprising the following steps:

[0008] Real-time collection of equipment temperature, output current and output voltage of energy storage converter;

[0009] Calculating a current change rate based on the output current of the energy storage converter obtained by the acquisition;

[0010] Based on the reference overcurrent protection threshold, the overcurrent protection threshold is adjusted according to the difference between the current real-time device temperature and the reference temperature, and the real-time collected voltage is applied as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio. At the same time, the current change rate calculated in real time is applied as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio to obtain a dynamic overcurrent protection threshold result;

[0011] The dynamic overcurrent protection threshold result is compared with the output current of the energy storage converter. If it exceeds the dynamic overcurrent protection threshold result, the protection action is triggered and a control instruction is generated to trip the switching device that controls the operation of the energy storage converter. If it does not exceed the dynamic overcurrent protection threshold result, the output current is continuously monitored and compared with the dynamic overcurrent protection threshold.

[0012] Preferably, the dynamic overcurrent protection threshold is expressed as follows:

[0013] T total =T base ×(1+α(Tempt-Tempt base )) / I normal +m×ΔI*T / (Δt*I normal )+k×V / V normal

[0014] Where:

[0015] T total is the final overcurrent protection threshold, T base is the benchmark overcurrent protection threshold; α is the temperature influence coefficient on the threshold; Tempt is the current temperature, Tempt base is the reference temperature, I normal is the rated current; m is the coefficient of the current change rate on the threshold; ΔI / Δt is the current change rate, T is the unit time; k is the coefficient of the voltage on the threshold; V is the current voltage, V normal is the rated voltage.

[0016] A second aspect of the present invention provides an energy storage converter overcurrent protection circuit, comprising: a current detection module, a voltage detection module, a temperature detection module and a microcontroller;

[0017] The current detection module, voltage detection module, and temperature detection module are respectively used to collect the output current, voltage, and device temperature of the energy storage converter in real time; and send the current, voltage, and temperature signals to the microcontroller;

[0018] The microcontroller has a built-in dynamic overcurrent protection threshold model, which is used to adjust the overcurrent protection threshold based on the difference between the current real-time temperature and the reference temperature on the basis of the reference overcurrent protection threshold, and apply the real-time collected voltage as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio. At the same time, the real-time calculated current change rate is applied as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio to obtain a dynamic overcurrent protection threshold result; when the real-time collected current exceeds the dynamic overcurrent protection threshold, the microcontroller generates a control instruction to trip the switching device that controls the operation of the energy storage converter.

[0019] Preferably, the current detection module comprises: a current sensor, a first signal conditioning circuit and a first output interface connected in sequence;

[0020] The first signal conditioning circuit includes: an operational amplifier, a resistor connected to the inverting input terminal of the operational amplifier, a filtering subcircuit, a proportional operation subcircuit connected to the non-inverting input terminal of the operational amplifier, and a protection subcircuit connected to the output terminal of the operational amplifier.

[0021] Preferably, the voltage detection module includes: a voltage sensor, a second signal conditioning circuit and a second output interface;

[0022] The second signal conditioning circuit includes: a cascaded first-stage sub-circuit and a second-stage sub-circuit; wherein the first-stage sub-circuit includes: an operational amplifier U1, which is used to form a current parallel negative feedback circuit; the second-stage sub-circuit includes: a linear optocoupler U4, an operational amplifier U2 and an operational amplifier U3 connected in sequence, which are used to form an output current-voltage conversion circuit.

[0023] Preferably, a low-pass filter is connected between the inverting input terminal and the output terminal of the operational amplifier U2. The low-pass filter includes a capacitor C3 and a resistor R8 connected in parallel, and is used to filter out high-frequency noise generated by the linear optocoupler U4.

[0024] An op amp U3 is used to form an emitter follower; a resistor R9 and a capacitor C5 are connected between the non-inverting input terminal of the op amp U3 and the op amp U2, and a resistor R10 and a capacitor C7 are connected to the output terminal of the op amp U3 to form a filter circuit on the transmission line for filtering out high-frequency noise and interference.

[0025] Preferably, the temperature detection module includes: a temperature sensor, a third signal conditioning circuit and a third output interface;

[0026] The temperature sensor includes: an NTC resistor R112 and a resistor R111. After the NTC resistor R112 and the resistor R111 are connected in parallel, they output a voltage signal, which serves as the output end of the temperature sensor and is sent to a third signal conditioning circuit to amplify, filter, and perform analog-to-digital conversion on the temperature signal to convert it into a digital temperature signal.

[0027] Preferably, the microcontroller comprises: a current change rate calculation unit, a dynamic threshold calculation unit and a logic processing unit;

[0028] The current change rate calculation unit calculates the current change rate ΔI / Δt by the current difference between adjacent sampling points and sends it to the dynamic threshold calculation unit;

[0029] The dynamic threshold calculation unit calculates the result of the dynamic overcurrent protection threshold according to the current change rate, voltage and temperature;

[0030] The logic processing unit compares the dynamic threshold value calculated and generated by the dynamic threshold value calculation unit with the output current of the energy storage converter device collected by the current sensor of the current detection module. If the dynamic threshold value is exceeded, a protection action is triggered and a control instruction is generated to trip the switching device that controls the operation of the energy storage converter. If the dynamic threshold value is not exceeded, the output current of the comparison device is continuously monitored and compared with the dynamic threshold value.

[0031] The third aspect of the present invention provides an energy storage converter, comprising: a switching device and the overcurrent protection circuit provided in the second aspect of the present invention, wherein the overcurrent protection circuit generates a dynamic threshold for overcurrent protection and compares it with the current output by the energy storage converter device. When an overcurrent occurs, a control instruction is generated to trip the switching device that controls the operation of the energy storage converter.

[0032] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the method for overcurrent protection of an energy storage converter according to the first aspect is implemented.

[0033] Compared with the prior art, the beneficial effects of the present invention include at least:

[0034] 1. Dynamic protection threshold:

[0035] This invention utilizes a dynamic threshold adjustment mechanism, combining real-time current, voltage, and temperature to adaptively calculate protection thresholds. The dynamic threshold calculation module adjusts the protection threshold based on an adaptive algorithm. Compared to traditional fixed thresholds, dynamic thresholds better adapt to complex operating conditions, providing more timely and accurate protection actions. For example, in the event of transient overcurrent conditions caused by grid fluctuations or sudden load changes, the protection threshold can be quickly adjusted, reducing protection delays.

[0036] 2. High reliability:

[0037] This invention combines current, voltage, and temperature for comprehensive judgment, reducing the probability of false trips. By comprehensively analyzing current, voltage, and temperature variations, it avoids false trips that could be caused by single-parameter judgments. For example, high and low temperatures can cause uncontrolled changes in thresholds, leading to false triggering of overcurrent protection.

[0038] In summary, the present invention significantly improves the overcurrent protection performance of the energy storage converter through the dynamic threshold adjustment and multi-level response control method, ensuring the stable operation of the system under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic flow chart of the overcurrent protection method provided by the present invention;

[0040] Figure 2 A schematic diagram of the overcurrent protection process provided by the present invention;

[0041] Figure 3 A schematic structural diagram of the overcurrent protection circuit provided by the present invention;

[0042] Figure 4 A schematic structural diagram of a current detection circuit provided by the present invention;

[0043] Figure 5 A schematic diagram of the structure of the voltage detection circuit provided by the present invention;

[0044] Figure 6 This is a structural diagram of the temperature detection circuit provided by the present invention. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0046] like Figure 1 、 Figure 2 As shown, embodiment 1 of the present invention provides an energy storage converter overcurrent protection method based on dynamic threshold adjustment, comprising the following steps:

[0047] Step 1: Collect the device temperature, output current, and voltage of the energy storage converter. It is understood that the device temperature of the energy storage converter refers to the temperature of the power electronic device that performs the conversion.

[0048] Step 2: Calculate the current change rate based on the collected output current of the energy storage converter device; implement the adjustment based on the current real-time temperature on the basis of the benchmark overcurrent protection threshold, apply the real-time collected voltage as an influencing factor to the adjusted overcurrent protection threshold according to the set ratio, and at the same time, apply the real-time calculated current change rate as an influencing factor to the adjusted overcurrent protection threshold according to the set ratio to obtain a dynamic overcurrent protection threshold result.

[0049] For example, but not limited to, the reference overcurrent protection threshold is an overcurrent protection threshold configured based on a safety margin and a reference temperature of the device when the energy storage current device operates at rated output current and voltage.

[0050] Preferably, but not limitatively, the dynamic overcurrent protection threshold is expressed by the following formula:

[0051] T total =T base ×(1+α(Tempt-Tempt base )) / I normal +m×ΔI*T / (Δt*I normal )+k×V / V normal

[0052] Where:

[0053] T total is the final overcurrent protection threshold, T base is the benchmark overcurrent protection threshold;

[0054] α is the temperature-effect coefficient on the threshold, which is used to characterize the degree of influence of temperature on the overcurrent protection threshold. Preferably, but not limited to, it is obtained by experimentally testing the variation curve of the overcurrent protection threshold at different temperatures. For example, but not limited to, the variation of the converter output current with temperature is tested in a temperature-controlled box, and the α value is fitted.

[0055] Tempt is the current temperature, Tempt base is the reference temperature, I normal is the rated current;

[0056] m is the influence coefficient of the current change rate on the threshold, which is used to characterize the degree of influence of the current on the overcurrent protection threshold. Preferably, but not limited to, it is obtained by directly adjusting the load current and measuring the output current. For example, but not limited to, the change of the converter output current is tested under different loads to fit the m value;

[0057] ΔI / Δt is the current change rate, T is the unit time;

[0058] k is the influence coefficient of voltage on the threshold, which is used to characterize the degree of influence of voltage on the overcurrent protection threshold. It is preferably, but not limited to, obtained by changing the input voltage and measuring the output current. For example, but not limited to, the change of the converter output current is tested at different voltages to fit the k value;

[0059] V is the current voltage, V normal is the rated voltage.

[0060] One of the most significant features of this invention is the design philosophy behind the dynamic overcurrent protection threshold calculation formula, which utilizes item-by-item modeling and the superposition of influencing factors. Specifically, the dynamic threshold calculation consists of three components: the first involves temperature adjustment based on the baseline overcurrent protection threshold; the second involves the direct superposition of voltage effects; and the third involves the direct superposition of current effects. These three components form a cohesive whole, closely interconnected and interdependent, creating a synergistic effect that collectively solves the technical problem.

[0061] Specifically, the first part of the temperature adjustment based on the reference overcurrent protection threshold is intended to adjust the temperature based on the reference overcurrent protection threshold T of the device. base and the current temperature Tempt relative to the reference temperature Tempt base The beneficial technical effects of this design include at least taking into account the operating characteristics of the device at different temperatures and avoiding false triggering or missed triggering due to temperature rise.

[0062] The second part of the direct superposition of voltage effects characterizes the direct impact of voltage on the overcurrent protection threshold. Unlike the first part, the second part is not based on the reference overcurrent protection threshold T base The threshold is determined directly by the current voltage V and the influence coefficient K. The beneficial technical effects of this design include at least taking into account the impact of voltage fluctuations on the overcurrent protection threshold and avoiding false triggering or missed triggering due to voltage changes.

[0063] The third part about the direct superposition of current influence characterizes the direct influence of current on the overcurrent protection threshold, especially the direct influence of current change rate on the overcurrent protection threshold. Different from the first part, this part is not based on the reference overcurrent protection threshold T base Instead of making adjustments, the current I is directly determined by the current, specifically the current change rate ΔI / Δt and the influence coefficient m. This design has at least the following beneficial technical effects: it considers the impact of current changes on the overcurrent protection threshold, avoiding false triggering or missed triggering due to sudden current changes, that is, the impact of transient overcurrent on the overcurrent protection threshold, and avoiding false triggering or missed triggering due to transient current.

[0064] The following table shows typical methods for obtaining each influence coefficient and example values.

[0065] Table 1 Typical acquisition methods and example values ​​of each influence coefficient

[0066] parameter symbol How to obtain Example Value Temperature influence coefficient α Temperature control box test 0.005 / ℃ Voltage influence coefficient k Different voltage tests 0.01 / V Current influence coefficient m Different load tests 0.02 / A

[0067] Step 3: Compare the dynamic overcurrent protection threshold result with the output current of the energy storage converter. If the dynamic overcurrent protection threshold result is exceeded, trigger the execution of the protection action, generate a control instruction, and trip the switching device that controls the operation of the energy storage converter. If the dynamic threshold is not exceeded, continuously monitor and compare the output current with the dynamic overcurrent protection threshold.

[0068] like Figure 3 As shown, embodiment 2 of the present invention provides an energy storage converter overcurrent protection circuit based on dynamic threshold adjustment, and operates an energy storage converter overcurrent protection method based on dynamic threshold adjustment as described in embodiment 1, including: a current detection module, a voltage detection module, a temperature detection module and a microcontroller.

[0069] The current detection module collects the output current of the energy storage converter device in real time and transmits the current signal to the dynamic threshold calculation unit of the microcontroller; the current detection module includes: a current sensor, a first signal conditioning circuit and a first output interface.

[0070] The current sensor is used to collect the output current of the energy storage converter device; Figure 4 As shown, the output end of the current sensor is connected to the input end of the first signal conditioning circuit. The first signal conditioning circuit of the current detection module amplifies, filters and performs analog-to-digital conversion (ADC) on the current signal to convert it into a digital signal.

[0071] Specifically, the output end of the current sensor is connected to the inverting input end of the operational amplifier via resistors R15 and R16 to form a voltage divider circuit or bias network for adapting the output signal of the current sensor to the input range of the operational amplifier; a capacitor C9 is connected between the inverting input end and the output end of the operational amplifier to achieve a low-pass filtering function, that is, suppressing high-frequency noise and retaining low-frequency signal components; the first signal conditioning circuit also includes: a filter capacitor C15, a resistor R20, and a resistor R21, which serve as the proportional operation of the operational amplifier, and a diode that serves as the input of the protection chip.

[0072] The first output interface of the current detection module transmits the current signal processed by the first signal conditioning circuit to the dynamic threshold calculation unit of the microcontroller.

[0073] The voltage detection module collects the output voltage of the energy storage current device in real time and transmits the voltage signal to the dynamic threshold calculation unit of the microcontroller; the voltage detection module includes: a voltage sensor, a second signal conditioning circuit and a second output interface.

[0074] The voltage sensor uses a high-precision Hall effect sensor or a voltage-dividing resistor network to detect the output voltage in real time; Figure 5 As shown, the output end of the voltage sensor is connected to the input end of the second signal conditioning circuit, and the second signal conditioning circuit amplifies, filters and performs analog-to-digital conversion on the voltage signal to convert it into a digital voltage signal.

[0075] Specifically, the second signal conditioning circuit of the voltage detection module includes a first-level sub-circuit and a second-level sub-circuit. The first-level sub-circuit uses an operational amplifier U1 and its peripheral devices to form a current parallel negative feedback circuit; the second-level sub-circuit uses resistors R8~R10, operational amplifiers U2~U3, photodiode D3 in the linear optocoupler U4, and capacitors C3~C7 to form an output current-voltage conversion circuit.

[0076] More specifically, in the first-stage subcircuit, resistors R1 to R6 are used to convert the input high-voltage DC bus voltage into input current. Multiple resistors are connected in series and parallel to increase the electrical safety distance and the resistance power tolerance. Capacitor C2 can prevent the circuit from oscillating and filter out glitches in the circuit. Resistor R7 is the current-limiting resistor of the light-emitting diode D1, and C1 is the power supply filter capacitor.

[0077] In the second-stage subcircuit, a linear optocoupler U4 is employed. When its output photodiode D3 is illuminated by light from the light-emitting diode D1, the output current IPD2 changes linearly and stably. Op amp U2 and resistor R8 form a current-to-voltage converter, converting D3's current IPD2 into a voltage VU2OUT, where VU2OUT = R8 * IPD2. Capacitor C3 and resistor R8 are connected in parallel to form a low-pass filter, filtering out the high-frequency noise generated by the linear optocoupler U4. This provides a simple and effective isolation method, a key feature of the present invention. The combination of optocoupler isolation and filtering elements effectively eliminates the propagation path of ground interference, effectively suppressing spikes and various noise interference.

[0078] Furthermore, in the second-stage sub-circuit, op amp U3 is used to form an emitter follower to improve the output load capacity of the detection circuit, isolate the front-stage output circuit and the post-stage processing circuit, and ultimately achieve the purpose of improving the voltage sampling accuracy; resistor R9, capacitor C5, as well as resistor R10, capacitor C7 are filtering circuits on the transmission line, used to filter out high-frequency noise and interference; VD1 is a TVS tube, used for overvoltage protection of the back-end chip.

[0079] The second output interface of the voltage detection module transmits the voltage signal processed by the second signal conditioning circuit to the dynamic threshold calculation unit of the microcontroller.

[0080] The temperature detection module collects the device temperature of the energy storage converter in real time, including: a temperature sensor, a third signal conditioning circuit and a third output interface. A high-precision thermistor, PT100 or digital temperature sensor, such as but not limited to DS18B20, is used to detect the device temperature in real time, preferably but not limited to, Figure 6 As shown, after NTC resistor R112 is connected in parallel with resistor R111, it outputs a voltage signal, which serves as the output of the temperature sensor and is fed into a third signal conditioning circuit that amplifies, filters, and performs analog-to-digital conversion on the temperature signal, converting it into a digital temperature signal. The third output interface of the temperature detection module transmits the temperature signal processed by the third signal conditioning circuit to the dynamic threshold calculation unit of the microcontroller.

[0081] The microcontroller unit (MCU) is used to dynamically calculate the protection threshold according to the real-time current change rate and system power fluctuation, and control the switch module to disconnect to provide overcurrent protection for the device when the overcurrent protection condition is met. It includes: a current change rate calculation unit, a dynamic threshold calculation unit and a logic processing unit.

[0082] Specifically, the current change rate calculation unit calculates the current change rate ΔI / Δt by the current difference between adjacent sampling points. The dynamic threshold calculation unit calculates the dynamic protection threshold using an adaptive algorithm based on the current change rate, voltage, and temperature. More specifically, the dynamic threshold calculation unit has a built-in dynamic threshold calculation model that characterizes the adaptive algorithm, which is expressed as the following formula:

[0083] T total =T base ×(1+α(Tempt-Tempt base )) / I normal +m×ΔI*T / (Δt*I normal )+k×V / V normal

[0084] Where:

[0085] T total is the final overcurrent protection threshold, T base is the benchmark overcurrent protection threshold;

[0086] α is the temperature-effect coefficient on the threshold, which is used to characterize the degree of influence of temperature on the overcurrent protection threshold. Preferably, but not limited to, it is obtained by experimentally testing the variation curve of the overcurrent protection threshold at different temperatures. For example, but not limited to, the variation of the converter output current with temperature is tested in a temperature-controlled box, and the α value is fitted.

[0087] Tempt is the current temperature, Tempt base is the reference temperature, I normal is the rated current;

[0088] m is the influence coefficient of the current change rate on the threshold, which is used to characterize the degree of influence of the current on the overcurrent protection threshold. Preferably, but not limited to, it is obtained by directly adjusting the load current and measuring the output current. For example, but not limited to, the change of the converter output current is tested under different loads to fit the m value;

[0089] ΔI / Δt is the current change rate, T is the unit time;

[0090] k is the influence coefficient of voltage on the threshold, which is used to characterize the degree of influence of voltage on the overcurrent protection threshold. It is preferably, but not limited to, obtained by changing the input voltage and measuring the output current. For example, but not limited to, the change of the converter output current is tested at different voltages to fit the k value;

[0091] V is the current voltage, V normal is the rated voltage.

[0092] The logic processing unit compares the dynamic threshold value calculated and generated by the dynamic threshold value calculation unit with the output current of the energy storage converter device collected by the current sensor of the current detection module. If the dynamic threshold value is exceeded, the protection action is triggered, and the microcontroller generates a control instruction to trip the circuit breaker that controls the operation of the energy storage converter; if the dynamic threshold value is not exceeded, the output current of the comparison device is continuously monitored and compared with the dynamic threshold value.

[0093] Embodiment 3 of the present invention provides an energy storage converter, comprising: a circuit breaker and the overcurrent protection circuit described in Embodiment 2, wherein the overcurrent protection circuit generates a dynamic threshold for overcurrent protection and compares it with the current output by the energy storage converter device. When an overcurrent occurs, a control instruction is generated to trip the circuit breaker that controls the operation of the energy storage converter.

[0094] Embodiment 4 of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded into the processor, the method for overcurrent protection of an energy storage converter based on dynamic threshold adjustment according to embodiment 1 is implemented.

[0095] Embodiment 5 of the present invention provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the energy storage converter overcurrent protection method based on dynamic threshold adjustment according to embodiment 1.

[0096] It is worth noting that in the embodiments of the present invention, "step + number" is only a way of expressing a specific implementation method of an energy storage converter overcurrent protection method based on dynamic threshold adjustment, rather than an absolute restriction on the sequence of each step. Under the guidance of the core concept of the present invention, changing the order of implementing these steps to obtain the same or similar technical effects falls within the scope of the present invention.

[0097] Finally, it should be noted that 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 above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for overcurrent protection of an energy storage converter, characterized in that: The following steps are involved: Real-time collection of equipment temperature, output current and output voltage of energy storage converter; Calculating a current change rate based on the output current of the energy storage converter obtained by the acquisition; Based on the reference overcurrent protection threshold, the overcurrent protection threshold is adjusted according to the difference between the current real-time device temperature and the reference temperature, and the real-time collected voltage is applied as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio. At the same time, the current change rate calculated in real time is applied as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio to obtain a dynamic overcurrent protection threshold result; The dynamic overcurrent protection threshold result is compared with the output current of the energy storage converter. If it exceeds the dynamic overcurrent protection threshold result, the protection action is triggered and a control instruction is generated to trip the switching device that controls the operation of the energy storage converter. If it does not exceed the dynamic overcurrent protection threshold result, the output current is continuously monitored and compared with the dynamic overcurrent protection threshold.

2. The overcurrent protection method for an energy storage converter according to claim 1, wherein: The dynamic overcurrent protection threshold is expressed as follows: T total =T base ×(1+α(Tempt-Tempt base )) / I normal +m×ΔI*T / (Δt*I normal )+k×V / V normal Where: T total is the final overcurrent protection threshold, T base is the benchmark overcurrent protection threshold; α is the influence coefficient of temperature on the threshold; Tempt is the current temperature, Tempt base is the reference temperature, I normal is the rated current; m is the coefficient of the current change rate on the threshold; ΔI / Δt is the current change rate, T is the unit time; k is the coefficient of the voltage on the threshold; V is the current voltage, V normal is the rated voltage.

3. An energy storage converter overcurrent protection circuit, characterized in that: include: Current detection module, voltage detection module, temperature detection module and microcontroller; The current detection module, voltage detection module, and temperature detection module are respectively used to collect the output current, voltage, and device temperature of the energy storage converter in real time; and send the current, voltage, and temperature signals to the microcontroller; The microcontroller has a built-in dynamic overcurrent protection threshold model, which is used to adjust the overcurrent protection threshold based on the difference between the current real-time temperature and the reference temperature on the basis of the reference overcurrent protection threshold, and apply the real-time collected voltage as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio. At the same time, the real-time calculated current change rate is applied as an influencing factor to the adjusted overcurrent protection threshold according to a set ratio to obtain a dynamic overcurrent protection threshold result; when the real-time collected current exceeds the dynamic overcurrent protection threshold, the microcontroller generates a control instruction to trip the switching device that controls the operation of the energy storage converter.

4. The overcurrent protection circuit for an energy storage converter according to claim 3, wherein: The current detection module includes: a current sensor, a first signal conditioning circuit and a first output interface connected in sequence; The first signal conditioning circuit includes: an operational amplifier, a resistor connected to the inverting input terminal of the operational amplifier, a filtering subcircuit, a proportional operation subcircuit connected to the non-inverting input terminal of the operational amplifier, and a protection subcircuit connected to the output terminal of the operational amplifier.

5. The overcurrent protection circuit for an energy storage converter according to claim 3, wherein: The voltage detection module includes: a voltage sensor, a second signal conditioning circuit and a second output interface; The second signal conditioning circuit includes: a cascaded first-stage sub-circuit and a second-stage sub-circuit; wherein the first-stage sub-circuit includes: an operational amplifier U1, which is used to form a current parallel negative feedback circuit; the second-stage sub-circuit includes: a linear optocoupler U4, an operational amplifier U2 and an operational amplifier U3 connected in sequence, which are used to form an output current-voltage conversion circuit.

6. The overcurrent protection circuit for an energy storage converter according to claim 5, characterized in that: A low-pass filter is connected between the inverting input terminal and the output terminal of the operational amplifier U2. The low-pass filter includes a capacitor C3 and a resistor R8 connected in parallel, and is used to filter out high-frequency noise generated by the linear optocoupler U4. The operational amplifier U3 is used to form an emitter follower; a resistor R9 and a capacitor C5 are connected between the non-inverting input terminal of the operational amplifier U3 and the operational amplifier U2, and a resistor R10 and a capacitor C7 are connected to the output terminal of the operational amplifier U3 to form a filtering circuit on the transmission line for filtering out high-frequency noise and interference.

7. An energy storage converter overcurrent protection circuit according to any one of claims 3 to 6, characterized in that: The temperature detection module includes: a temperature sensor, a third signal conditioning circuit and a third output interface; The temperature sensor includes: an NTC resistor R112 and a resistor R111. After the NTC resistor R112 and the resistor R111 are connected in parallel, they output a voltage signal, which serves as the output end of the temperature sensor and is sent to a third signal conditioning circuit to amplify, filter, and perform analog-to-digital conversion on the temperature signal to convert it into a digital temperature signal.

8. An energy storage converter overcurrent protection circuit according to any one of claims 3 to 6, characterized in that: The microcontroller includes: a current change rate calculation unit, a dynamic threshold calculation unit and a logic processing unit; The current change rate calculation unit calculates the current change rate ΔI / Δt by the current difference between adjacent sampling points and sends it to the dynamic threshold calculation unit; The dynamic threshold calculation unit calculates the result of the dynamic overcurrent protection threshold according to the current change rate, voltage and temperature; The logic processing unit compares the dynamic threshold value calculated and generated by the dynamic threshold value calculation unit with the output current of the energy storage converter device collected by the current sensor of the current detection module. If the dynamic threshold value is exceeded, a protection action is triggered and a control instruction is generated to trip the switching device that controls the operation of the energy storage converter. If the dynamic threshold value is not exceeded, the output current of the comparison device is continuously monitored and compared with the dynamic threshold value.

9. An energy storage converter, characterized in that: include: A switching device and an overcurrent protection circuit as described in any one of claims 3 to 8, wherein the overcurrent protection circuit generates a dynamic threshold for overcurrent protection and compares it with the current output by the energy storage converter device, and when an overcurrent occurs, generates a control instruction to trip the switching device that controls the operation of the energy storage converter.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the energy storage converter overcurrent protection method according to claim 1 or 2 is implemented.

Images