A shunt current acquisition temperature compensation system and method in an energy storage system

Abstract

The present invention belongs to the technical field of battery energy storage systems, and specifically relates to a shunt current acquisition temperature compensation system and method in an energy storage system. The system includes an acquisition module, an energy storage main control module, and an AC-DC module for powering the energy storage main control module; the acquisition module is used to acquire the current value and temperature value of a high-voltage circuit inside a high-voltage box in real time; the energy storage main control module is used to read the temperature value in real time based on a preset temperature detection algorithm, and match the temperature value with a preset temperature range to control the energy storage system to enter a first response state or compensate for the current value acquisition accuracy according to a preset temperature compensation algorithm. The compensation system in the present invention is mainly used in a high-voltage box of an energy storage system, and the compensation coefficients of the temperature and current values ​​are measured for different types of shunts on the market to perform segmented compensation, thereby avoiding the deviation of the current acquisition accuracy of the shunt for the high-voltage circuit due to changes in ambient temperature, and improving the accuracy of current acquisition.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery energy storage systems, and in particular relates to a shunt current acquisition temperature compensation system and method in an energy storage system. Background Art

[0002] The main function of the high-voltage box of the energy storage system is to control the connection or disconnection of the main electrical circuit of the system. The battery management unit (BMS) installed inside it can monitor the battery voltage, current, temperature and the status of switches, contactors, fans, etc. in real time, and perform status identification, thermal management control, balancing control and other operations on the local battery pack, while sending local battery information and responding to remote control.

[0003] With the development of the energy storage battery industry and the expansion of the market scale, the improvement and optimization of system product performance have made the requirements for the accuracy of current collection in the high-voltage loop of the energy storage battery system more stringent. Temperature compensation will not only affect the accuracy of current collection in the shunt when collecting the current in the high-voltage loop, but the temperature will also affect our operational amplifier, ADC acquisition chip, isolated communication and energy storage main control MCU operation unit. Considering that the shunt itself is greatly affected by temperature and the NTC temperature sensor is installed on the shunt for easy implementation, the use of shunt current collection temperature compensation to improve accuracy is given priority.

[0004] However, high-precision shunts are generally used to collect current in high-voltage circuits, ignoring the effect of the shunt itself on the collection accuracy as the temperature changes. Usually, the high-voltage circuit current collection of the energy storage battery system is located in the high-voltage box, which is in a closed environment and contains power devices, and the temperature variation range is large. Therefore, how to compensate for the current collection accuracy according to the ambient temperature is an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a shunt current acquisition temperature compensation system and method in an energy storage system to solve the problems raised in the background technology.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] A shunt current acquisition temperature compensation system in an energy storage system, wherein the compensation system is arranged inside a high-voltage box of the energy storage system, and comprises an acquisition module, an energy storage main control module, and an AC-DC module for powering the energy storage main control module;

[0008] The acquisition module is used to collect the current value and temperature value of the high-voltage circuit inside the high-voltage box in real time;

[0009] The energy storage main control module is used to read the temperature value in real time based on a preset temperature detection algorithm, and match the temperature value with a preset temperature range to control the energy storage system to enter a first response state or compensate for the current value acquisition accuracy according to a preset temperature compensation algorithm.

[0010] As a further optimization scheme of the present invention, the temperature compensation module includes a shunt and an NTC temperature sensor. The shunt is connected in series to the high-voltage circuit, and the NTC temperature sensor is placed around the shunt for real-time collection of the ambient temperature of the shunt as the temperature value of the shunt.

[0011] As a further optimization scheme of the present invention, the high-voltage box is also provided with an on-off control module for controlling the on-off of the high-voltage circuit. The on-off control module includes a DC circuit breaker, a main positive relay, a main negative relay, a pre-charging relay and a pre-charging resistor.

[0012] As a further optimization solution of the present invention, the first response state is:

[0013] When the temperature value is not within the preset temperature range, the energy storage main control module sends a control signal to the on-off control module to cut off the high-voltage circuit.

[0014] As a further optimization scheme of the present invention, the energy storage main control module includes an ADC sampling unit, an isolated SPI communication unit and an MCU processing unit. The temperature detection algorithm is that the voltage value is sent to the MCU processing unit through the ADC sampling unit and the isolated SPI communication unit after the NTC temperature sensor and the resistor divider. The MCU processing unit determines the NTC resistance value according to the voltage value, and compares the NTC resistance value with the temperature comparison table to read the temperature value.

[0015] As a further optimization scheme of the present invention, the temperature compensation algorithm is a segmented interpolation compensation method, which determines the compensation coefficient of the current value collected in real time and the set segmented temperature, and compensates for the current value collection accuracy based on the compensation coefficient.

[0016] A method for temperature compensation of shunt current acquisition in an energy storage system, based on any of the above-mentioned systems, comprises the following steps:

[0017] S1, real-time collection of current and temperature values ​​of the high-voltage circuit inside the high-voltage box;

[0018] S2. The energy storage main control module is used to read the temperature value in real time based on a preset temperature detection algorithm, and match the temperature value with a preset temperature range to control the energy storage system to enter a first response state or compensate for the current value acquisition accuracy according to a preset temperature compensation algorithm.

[0019] The beneficial effects of the present invention are:

[0020] The compensation system in the present invention is mainly used in the high-voltage box of the energy storage system. The compensation coefficients of the temperature and current values ​​of different types of shunts on the market are measured for segmented compensation, thereby avoiding the deviation of the current collection accuracy of the shunt for the high-voltage circuit due to changes in ambient temperature and improving the accuracy of current collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the internal frame of the high-voltage box of the energy storage system in the present invention;

[0022] Figure 2 It is the shunt current temperature acquisition frame in the present invention;

[0023] Figure 3 It is an execution flow chart of the compensation method in the present invention. DETAILED DESCRIPTION

[0024] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0025] Example 1

[0026] This embodiment proposes a shunt current acquisition temperature compensation system in an energy storage system. The compensation system is arranged inside the high-voltage box of the energy storage system, and includes an acquisition module, an energy storage main control module, and an AC-DC module for powering the energy storage main control module;

[0027] The acquisition module is used to collect the current value and temperature value of the high-voltage circuit inside the high-voltage box in real time;

[0028] The energy storage main control module is used to read the temperature value in real time based on a preset temperature detection algorithm, and match the temperature value with a preset temperature range to control the energy storage system to enter the first response state or compensate for the current value acquisition accuracy according to a preset temperature compensation algorithm.

[0029] Reference Figure 1 The energy storage main control module is located in the high-voltage box and is responsible for managing the signal collection of a cluster of battery packs, the current and temperature collection of the shunt, and the implementation of the compensation algorithm (temperature detection algorithm and temperature compensation algorithm). It belongs to the secondary management unit of the energy storage system. The acquisition module is located in the high-voltage box and is responsible for real-time acquisition of the current of the high-voltage circuit and the temperature of the shunt. It consists of a shunt and an NTC temperature sensor. The energy storage main control module collects the current of the shunt in the circuit and reads the temperature of the NTC temperature sensor.

[0030] In this embodiment, the shunt is connected in series to the high-voltage circuit, and the NTC temperature sensor is placed around the shunt to collect the ambient temperature of the shunt in real time as the temperature value of the shunt.

[0031] As a further optimization solution, an on-off control module for controlling the on-off of the high-voltage circuit is also provided inside the high-voltage box. The on-off control module includes a DC circuit breaker, a main positive relay, a main negative relay, a pre-charging relay and a pre-charging resistor.

[0032] As a further optimization solution, the first response status is:

[0033] When the temperature value is not within the preset temperature range, the energy storage main control module sends a control signal to the on-off control module to cut off the high-voltage circuit.

[0034] It can be understood that by collecting the diverter temperature in real time, its operating environment temperature can be detected. When the detected temperature is not within its operating temperature (temperature range), the system can be stopped or the system can take response measures, thereby protecting the diverter itself and the entire system.

[0035] Reference Figure 2 As a further optimization solution, the energy storage main control module includes an ADC sampling unit, an isolated SPI communication unit and an MCU processing unit. The temperature detection algorithm is that the NTC temperature sensor and the resistor R1 divide the voltage and send the voltage value to the MCU processing unit through the ADC sampling unit and the isolated SPI communication unit. The MCU processing unit determines the NTC resistance value based on the voltage value. (V1 represents the voltage value collected by the MCU processing unit), and the temperature value is read by comparing the NTC resistance value with the temperature comparison table.

[0036] In this embodiment, the sampled current value of the shunt is obtained through the energy storage main control module, which includes an operational amplifier circuit, supports differential input, can detect charging and discharging currents, differential routing of the shunt input and the collected current, 5V supply voltage and 2.5V reference voltage;

[0037] In this embodiment, the ADC sampling unit supports SPI communication, and the 8-port analog signal input is compatible with high-voltage acquisition, temperature acquisition, operational amplifier 2.5V reference voltage acquisition, shunt differential input voltage amplified by the operational amplifier, 5V power supply voltage and 2.5V reference voltage;

[0038] In this embodiment, the SPI communication unit is isolated, the energy storage main control MCU and the high-voltage side communication are isolated, the 5V power supply on the high-voltage side of the dual power input is isolated and the 3.3V power supply on the matching MCU side is isolated, and the isolation voltage is 5.7KVrms.

[0039] As a further optimization scheme, the temperature compensation algorithm is a segmented interpolation compensation method, which determines the compensation coefficient of the real-time collected current value and the set segmented temperature, and compensates for the current value collection accuracy based on the compensation coefficient.

[0040] For example, the segmented interpolation compensation method is used. For example, the operating temperature is set to -25℃~+70℃ (the actual operating temperature of the energy storage device is -20℃~+65℃), and the relationship between the collected current value and the temperature change is obtained at intervals of 5℃. Considering that the temperature and current value are not linear, the compensation coefficient of the temperature and current value can be expressed in segments. The temperature of the shunt is collected in real time by NTC. According to the compensation coefficient of the collected current and segmented temperature, different temperatures correspond to different segmented compensation coefficients, which has higher accuracy.

[0041] In addition, based on the above embodiments, temperature compensation includes but is not limited to the following methods: compensating the influence of temperature on the accuracy of current collection through the inherent temperature of the shunt and the resistance characteristic curve of the shunt, and a point-slope temperature compensation algorithm.

[0042] In summary, the working mode of the above shunt current acquisition temperature compensation system is as follows:

[0043] Reference Figure 2 The NTC temperature sensor is fixed on the shunt to collect the temperature of the shunt in real time, and then goes to the ADC for sampling after passing through the voltage divider circuit, and then enters the MCU processing unit through SPI isolation communication; the shunt is fixed on the high-voltage circuit copper bus of the high-voltage box to collect the current of the circuit in real time, and the differential signal of the shunt goes to the ADC for collection and SPI isolation communication after passing through the operational amplifier to enter the MCU processing unit; the MCU processing unit of the energy storage main control module is responsible for realizing the collection and calculation of the shunt temperature and high-voltage circuit current, as well as the implementation of the temperature compensation accuracy strategy.

[0044] In order to implement the above-mentioned embodiments, based on the same inventive concept, a compensation method corresponding to the above-mentioned compensation system is also provided in this embodiment. Since the principle of solving the problem by the compensation method in the embodiment of the present disclosure is similar to the above-mentioned compensation system in the embodiment of the present disclosure, the implementation of the method can refer to the implementation of the system, and the repeated parts will not be repeated.

[0045] Reference Figure 3 This embodiment provides a method for temperature compensation of shunt current acquisition in an energy storage system, which is implemented based on the above system and includes the following steps:

[0046] S1, real-time collection of current and temperature values ​​of the high-voltage circuit inside the high-voltage box;

[0047] S2. The energy storage main control module is used to read the temperature value based on a preset temperature detection algorithm and match the temperature value with a preset temperature range to control the energy storage system to enter the first response state or compensate for the current value acquisition accuracy according to a preset temperature compensation algorithm.

[0048] In this embodiment, the NTC temperature sensor is placed around the shunt to collect the surrounding temperature in real time. The temperature value is collected by the ADC of the energy storage main control module and isolated communication is sent to the MCU of the energy storage main control module for reading. The MCU compensates for the error caused by the temperature on the shunt current collection based on the read temperature and the resistance and temperature characteristic curve of the shunt itself, thereby improving the accuracy of the shunt current collection. At the same time, the temperature of the shunt is collected to make it work within the normal operating temperature range to protect the shunt and the high-voltage box system.

[0049] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A shunt current collection temperature compensation system in an energy storage system, wherein the compensation system is arranged inside a high-voltage box of the energy storage system, and is characterized in that: It includes a collection module, an energy storage main control module, and an AC-DC module for powering the energy storage main control module; The acquisition module is used to collect the current value and temperature value of the high-voltage circuit inside the high-voltage box in real time; The energy storage main control module is used to read the temperature value in real time based on a preset temperature detection algorithm, and match the temperature value with a preset temperature range to control the energy storage system to enter a first response state or compensate for the current value acquisition accuracy according to a preset temperature compensation algorithm; The high-voltage box is also provided with an on-off control module for controlling the on-off of the high-voltage circuit, and the on-off control module includes a DC circuit breaker, a main positive relay, a main negative relay, a pre-charge relay and a pre-charge resistor; The first response status is: When the temperature value is not within the preset temperature range, the energy storage main control module sends a control signal to the on-off control module to cut off the high-voltage circuit; The energy storage main control module includes an ADC sampling unit, an isolated SPI communication unit and an MCU processing unit. The temperature detection algorithm is that the voltage value is sent to the MCU processing unit through the ADC sampling unit and the isolated SPI communication unit after the NTC temperature sensor and the resistor divider. The MCU processing unit determines the NTC resistance value according to the voltage value, and compares the NTC resistance value with the temperature comparison table to read the temperature value; The temperature compensation algorithm is a segmented interpolation compensation method, which determines the compensation coefficient of the current value collected in real time and the set segmented temperature, and compensates the current value collection accuracy based on the compensation coefficient.

2. A shunt current acquisition temperature compensation system in an energy storage system according to claim 1, characterized in that: The acquisition module includes a shunt and an NTC temperature sensor. The shunt is connected in series to the high-voltage circuit. The NTC temperature sensor is placed around the shunt to collect the ambient temperature of the shunt in real time as the temperature value of the shunt.

3. A method for temperature compensation of shunt current acquisition in an energy storage system, implemented based on the system according to any one of claims 1-2, characterized in that: The steps include: S1, real-time collection of current and temperature values ​​of the high-voltage circuit inside the high-voltage box; S2. Read the temperature value in real time based on a preset temperature detection algorithm, and match the temperature value with a preset temperature range to control the energy storage system to enter a first response state or compensate for the current value acquisition accuracy according to a preset temperature compensation algorithm.

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