Charger, charger internal device temperature protection method and charger internal device temperature protection device

Abstract

The invention belongs to the technical field of charging temperature protection, and particularly relates to a charger and a temperature protection method and device for internal devices of the charger. The method comprises the following steps: acquiring sampling point temperatures of internal devices of the charger except a charging module and a charging gun, setting sampling point weights based on importance degrees and heating values of the internal devices at the sampling points, and calculating weighted temperatures of the sampling points, and when the weighted temperature exceeds the set temperature threshold value and the charging module and the charging gun do not trigger the temperature protection strategy of the corresponding module, the output power of the charger is reduced, and meanwhile, a heat dissipation unit in the charger is started for auxiliary heat dissipation to perform temperature protection, so that the service life of the device is greatly prolonged, and the aging of the device is slowed down.

Description

Technical Field

[0001] The present invention belongs to the technical field of charging temperature protection, and particularly relates to a charger, a method and a device for temperature protection of internal devices of the charger. Background Art

[0002] In recent years, the new energy vehicle industry in China has entered a stage of rapid development with large scale and high quality. The charging technology of new energy vehicles has been continuously innovated, and the power rating of chargers for charging new energy vehicles has been continuously improved. Chargers with power ratings of 240kW, 480kWh, 600kW and even higher have emerged on the market, and their output current can reach 250A - 600A. However, a higher power rating means that the heat generation will increase exponentially, resulting in an increasing demand for the heat dissipation performance of the charger.

[0003] Currently, the temperature protection strategy of chargers is generally to set temperature sampling points at the air inlet of the charging module and at the charging gun head. When the temperature at the sampling point is too high, the charger is cooled by sampling and air-cooling. When the detected temperature at the air inlet of the charging module exceeds the corresponding temperature protection value, the charging controller adopts a temperature protection strategy of over-temperature derating of the charging module; when the detected temperature at the charging gun head exceeds the corresponding temperature protection value, the charging controller adopts a temperature protection strategy of over-temperature shutdown of the charging gun head. However, due to the different internal structural layouts of chargers, the distances between other internal devices of the charger (such as weak electrical devices like charging controllers, billing control units, and electricity meters, as well as switching devices like contactors) and the charging module and the charging gun head may be relatively far. During charging, it may occur that the temperatures at the air inlet of the charging module and at the charging gun head of the charger are below the temperature protection value and the temperature protection is not triggered, but these weak electrical devices and switching devices continue to work at a temperature of 70°C, 80°C or even higher. These weak electrical devices and switching devices cannot be effectively protected. According to the theory that the device life is reduced by half for every 10-degree increase in temperature, the service life of the internal devices of the charger will be greatly reduced, and even potential safety hazards may be brought to the equipment and users. Summary of the Invention

[0004] The purpose of the present invention is to provide a charger, a method and a device for temperature protection of internal devices of the charger, so as to solve the problem that the existing temperature protection strategy of the charger cannot effectively protect the internal devices of the charger when the temperature of the internal devices of the charger is too high but the temperatures of the charging module and the charging gun do not exceed the temperature protection threshold.

[0005] The present invention provides a method for temperature protection of internal devices of a charger to solve the above technical problems, including:

[0006] Obtain the sampled temperature of the internal devices of the charger, where the internal devices of the charger refer to the internal devices of the charger other than the charging module and the charging gun;

[0007] Calculate the weighted temperature based on the temperatures of each sampling point of the internal components of the charger and the weights of the sampling points. When the weighted temperature exceeds the set temperature threshold and the temperature protection strategies of the corresponding modules are not triggered by the charging module and the charging gun, reduce the output power of the charger, and at the same time start the heat dissipation unit in the charger for auxiliary heat dissipation; the higher the weighted temperature, the lower the output power of the charger; the weights of the sampling points are set based on the importance and heat generation of the internal components at the sampling points, the higher the importance, the greater the weight, and the higher the heat generation, the smaller the weight.

[0008] When the weighted temperature drops after exceeding the set temperature threshold, control the output power of the charger to gradually increase until the weighted temperature drops below the set temperature threshold, and then output power according to the output power of the charger corresponding to when it does not exceed the set temperature threshold.

[0009] Further, the process of controlling the reduction of the output power of the charger after the weighted temperature exceeds the set temperature threshold is: after the weighted temperature exceeds the set temperature threshold, for every 1°C increase, the output power of the charger is reduced by η% of the output power of the charger corresponding to when it does not exceed the set temperature threshold.

[0010] Further, the η is a fixed value.

[0011] Further, the η is a variable value, which increases as the weighted temperature rises.

[0012] Further, the method further includes: if the temperature continues to rise until it exceeds the maximum allowable value, control the output power of the charger to be 0 and stop this charging; the maximum allowable value is the minimum of the maximum allowable temperature rise values of each internal component and the maximum allowable temperature rise value required by the national standard.

[0013] The beneficial effects of the above technical solutions are as follows: This invention is an improved invention. Multiple temperature sampling points are set for the internal components of the charger outside the charging module and the charging gun, and the weights of the sampling points are set according to the importance and heat generation of each internal component at the corresponding temperature sampling points. Calculate the weighted temperature based on the temperatures of each sampling point of the internal components of the charger and the weights of the sampling points, and comprehensively judge whether the temperature is too high according to the weighted temperature. When the temperature is too high, limit the power output of the charger and start the heat dissipation unit for auxiliary heat dissipation at the same time, which can enable temperature protection when the temperature of the internal components is too high but the temperature protection of the sampling points of the charging module and the charging gun head is not triggered, limit the power and start the heat dissipation in time, thereby greatly improving the service life of the components and slowing down the aging of the components.

[0014] To solve the above technical problems, the present invention also provides a temperature protection device for internal components of a charger, which includes a charging controller and a temperature sampling unit. The temperature sampling unit is used to collect the temperatures of each sampling point of the internal components of the charger. The charging controller is used to obtain the temperatures of each sampling point, calculate the weighted temperature according to the temperatures of each sampling point and the sampling point weights, and reduce the output power of the charger when the weighted temperature exceeds the set temperature threshold and the temperature protection strategies of the corresponding modules are not triggered by the charging module and the charging gun. At the same time, the heat dissipation unit of the charger is started for auxiliary heat dissipation. The higher the weighted temperature, the lower the output power of the charger. When the weighted temperature exceeds the set temperature threshold and then decreases, the output power of the charger is controlled to gradually increase until the weighted temperature drops below the set temperature threshold, and the power output is carried out according to the output power of the charger corresponding to when it does not exceed the set temperature threshold. Among them, the internal components of the charger refer to the internal components of the charger except for the charging module and the charging gun. The sampling point weights are set based on the importance and heat generation of the internal components at the sampling points. The higher the importance, the greater the weight, and the higher the heat generation, the smaller the weight.

[0015] Further, after the weighted temperature exceeds the set temperature threshold, the process of the charging controller controlling the reduction of the output power of the charger is as follows: after the weighted temperature exceeds the set temperature threshold, for every 1°C increase, the output power of the charger is reduced by η% of the output power of the charger corresponding to when it does not exceed the set temperature threshold.

[0016] Further, the η is a fixed value.

[0017] Further, if the temperature continues to rise until it exceeds the maximum allowable value, the charging controller controls the output power of the charger to be 0 and stops this charging. The maximum allowable value is the minimum of the maximum allowable temperature rise values of each internal component and the maximum allowable temperature rise value required by the national standard.

[0018] To solve the above technical problems, the present invention also provides a charger, and the charger uses the temperature protection method for internal components of the charger introduced above to protect the temperature of the internal components of the charger.

[0019] The beneficial effects of the above technical solutions are as follows: The present invention is an improved invention. Multiple temperature sampling points are set for the internal components of the charger outside the charging module and the charging gun, and the sampling point weights are set according to the importance and heat generation of each internal component at the corresponding temperature sampling points. The weighted temperature is calculated based on the temperatures of each sampling point of the internal components of the charger and the sampling point weights. Whether the temperature is too high is comprehensively judged according to the weighted temperature. When the temperature is too high, the power output of the charger is limited and the heat dissipation unit is started for auxiliary heat dissipation. It can enable temperature protection when the temperature of the internal components is too high but the temperature protection is not triggered by the sampling points of the charging module and the charging gun head, limit the power and start the heat dissipation in time, thereby greatly improving the service life of the charger components and slowing down the aging of the components. Description of the Drawings

[0020] Figure 1 is a schematic diagram of the temperature protection principle of the internal components of the charger in the embodiment of the charger of the present invention;

[0021] Figure 2 is a characteristic curve graph of the output power and weighted temperature of the charger in the embodiment of the charger of the present invention;

[0022] Figure 3 is a graph of temperature rise data without adding the temperature control protection strategy for the internal components of the present invention in the embodiment of the charger of the present invention;

[0023] Figure 4 is a graph of temperature rise data with adding the temperature control protection strategy for the internal components of the present invention in the embodiment of the charger of the present invention. Detailed Description of the Invention

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further describes the specific implementation manners of the present invention with reference to the drawings.

[0025] The inventive concept of the present invention is: multiple temperature sampling points are set in the internal components of the charger other than the charging module and the charging gun, and weights corresponding to the sampling points are set according to the importance and heat generation of each internal component, so as to calculate the comprehensive temperature of the internal components of the charger based on the temperature of the sampling points detected in real time and the weights, and perform temperature protection when the temperature is too high.

[0026] Embodiment of the Charger

[0027] In a charging pile, the charger is used to convert alternating current in the AC power grid into direct current for charging electric vehicles and the like. The internal components of the charger include, in addition to the charging module and the charging gun, also internal components such as AC terminals, contactors (including AC contactors and DC contactors), monitoring units (such as shunt resistors), charging controllers, billing controllers, and electricity meters. The present invention sets temperature sampling units (temperature sensing devices) at key internal components that cannot be protected by the existing temperature protection strategy. Each temperature sampling unit is connected to the sampling port of the charging controller to perform multi-point temperature sampling simultaneously. The charging controller processes and judges the multi-point temperatures sampled, and controls the power output and heat dissipation unit of the charging module, thereby realizing a temperature protection method for the internal components of the charger, protecting the internal components of the charger in a high-temperature environment, reducing the failure rate of the charging pile components, and further reducing the material cost, maintenance cost, and safety risk during use. The implementation principle of the temperature protection method for the internal components of the charger is as Figure 1 shown, and the following is a detailed description.

[0028] 1. Each temperature sampling unit collects the temperatures of each sampling point of the internal components of the charger, and the charger controller obtains the temperatures of each sampling point of the internal components of the charger.

[0029] The internal components of the charger in the present invention refer to the internal components of the charger except for the charging module and the charging gun. The charging module and the charging gun are temperature-protected according to the existing temperature protection strategy, and the internal components of the charger except for the charging module and the charging gun are temperature-protected according to the temperature protection method of the present invention. The temperature sampling unit can be set on the surfaces, chips, connection points, etc. of the internal components of the charger. For example, the temperature sampling points are set on the control board chips of the charging controller, the control board chips of the billing controller, the surface of the electricity meter, the surface of the AC contactor housing, the connection points of the AC contactor (i.e., the AC contactor poles), the surface of the DC contactor housing, the connection points of the DC contactor, the surface of the shunt, the surface of the AC terminal, etc. Corresponding temperature sampling units are set at these sampling points. The temperature sampling points are set according to the charger model and specific requirements, and are not limited here.

[0030] 2. Calculate the weighted temperature according to the temperatures of each sampling point of the internal components of the charger and the sampling point weights. When the weighted temperature exceeds the set temperature threshold K and the charging module and the charging gun do not trigger the temperature protection strategy of the corresponding module, the charging controller reduces the output power of the charger and simultaneously starts the heat dissipation unit for auxiliary heat dissipation.

[0031] Since the temperatures of the sampling points of the internal components of the charger in the charging pile are different at the same time and there are sampling deviations, in order to make the sampling data more accurate and reliable, the present invention sets according to the importance and heat generation of the internal components at the sampling points of the charger. The higher the importance, the greater the weight. At the same time, the weight of the device with higher heat generation characteristics can be appropriately reduced, that is, the higher the heat generation, the smaller the weight. In actual use, the weight can be adaptively set according to the user's own needs. Suppose four devices are sampled: the electricity meter, the controller chip, the current-carrying copper bar, and the DC contactor. Since the electricity meter is a precision sampling device and high temperature may affect its accuracy, the weight can be appropriately increased to 0.3; the controller chip is the core device of the charger and high temperature will affect its performance, so the weight is set to the highest 0.4; the current-carrying copper bar usually has a large heat generation, high heat resistance and is a non-precision device, so the weight is appropriately reduced to 0.1, and the DC contactor is a switching device, has a certain heat resistance and is also a non-precision device, so the weight is reduced to 0.2. If the temperature of the electricity meter is sampled as 50°C, the temperature of the controller chip is 48°C, the temperature of the current-carrying copper bar is 55°C, and the temperature of the DC contactor is 53°C, then the current weighted temperature T is 50.3°C after weighted calculation. The charging controller performs weighted processing on the temperature values of each sampling point collected at the same time to obtain the weighted temperature. The calculation formula is as follows:

[0032]

[0033] Among them, T is the weighted temperature, n is the total number of sampling points, T i is the temperature of the i-th sampling point, and f i is the weight of the i-th sampling point.

[0034] When the weighted temperature does not exceed the set temperature threshold K, the charger works normally. If the charger power meets the vehicle-end requested power at this time, the charger output power corresponding to when the set temperature threshold is not exceeded is the vehicle-end demand power; if the charger power does not meet the vehicle-end requested power at this time, the charger output power corresponding to when the set temperature threshold is not exceeded is the maximum charger power.

[0035] After the weighted temperature exceeds the temperature threshold K, the temperature control strategy takes effect, the charger limits the power output, the output power decreases, and the higher the weighted temperature, the lower the charger output power. After the weighted temperature exceeds the temperature threshold K, for every 1°C increase, the charger output power decreases by η% of the current vehicle-end demand power. As an implementation method, temperature control can be carried out in an equal-proportion manner, and at this time, η is a fixed value. In another implementation method, η is a variable value, which increases as the weighted temperature rises. The higher the weighted temperature, the higher the η by which the charger output power decreases for every 1°C increase.

[0036] If the temperature continues to rise until it exceeds the maximum allowable value, the charging controller issues a stop charging command to control the charger output power to be 0 and stop this charging. The maximum allowable value is the minimum of the maximum allowable temperature rise of each internal device and the maximum allowable temperature rise required by the national standard. The national standard can adopt the limit temperature rise of each component inside the charger specified in Section 5.17 of NB / T33008.1-2018. When the weighted temperature exceeds the set temperature threshold K and then the weighted temperature drops, the charger output power is controlled to gradually increase until the weighted temperature drops below the set temperature threshold, and the power output is carried out according to the charger output power corresponding to when the set temperature threshold is not exceeded, and the temperature protection limit is lifted. At this time, the cooling device can be controlled to stop working, or the cooling device can be controlled to stop working after a set time after the temperature drops below the set temperature threshold. The entire temperature protection is a dynamically changing process, and its purpose is to minimize the impact on the charging vehicle as much as possible.

[0037] Furthermore, for the convenience of temperature control, the present invention formulates a characteristic curve of the charger output power and the weighted temperature. The charging controller stores the characteristic curve of the charger output power and the weighted temperature, and according to the calculated weighted temperature, the charging module is power-controlled according to this characteristic curve. The characteristic curve of the charger output power and the weighted temperature is as Figure 2 shown. In this figure, η is a fixed value. If the charger power meets the vehicle-end requested power, the relationship between the charger output power and the weighted temperature is:

[0038]

[0039] Among them, P0 is the output power of the charger, P n is the current required power at the vehicle end, and η is the percentage of power limit increase per degree Celsius. The corresponding relationship between the weighted temperature and the output power of the charger can also be stored, and the charging controller controls the charging module according to the look-up table method.

[0040] Taking a 40kW low-power charger as an example, the protection temperature at the air inlet of the charging module is 55°C, and the protection temperature at the charging gun head is 90°C. Simulating the outdoor conditions of summer exposure, the temperature effect of the temperature protection method for the internal components of the charger of the present invention is verified.

[0041] Scenario 1: Since the temperature on the surface of the charger housing under direct sunlight reaches 48°C. Therefore, set the ambient temperature to 48°C, set the required voltage to 300V, the required current to 130A, start charging, and charge for 2 hours without adding the internal component temperature control protection strategy. Use thermocouples to measure different positions and components, and the temperature rise data of each component sampling point recorded during the test are as Figure 3 shown. It can be seen that the highest temperature at the air inlet of the charging module is 54.5°C, the highest temperature at the charging gun head is 55°C, the temperature at the air inlet of the charging module at the end of charging is 52.1°C, and the temperature at the charging gun head is 50°C. During the entire charging process, the temperature sampling values at the charging module and the charging gun do not reach the corresponding temperature protection values. Therefore, the charger does not perform temperature control and outputs almost at full power for 2 hours. Finally, the temperature of the AC contactor reaches 87.1°C, the AC terminal reaches 76.2°C, and some other components are around 70°C, which is already at a relatively high value.

[0042] Scenario 2: The variables such as the test object, ambient temperature, voltage, current, and charging time are the same as those in Scenario 1. According to the temperature protection method for the internal components of the charger of the present invention, formulate a protection strategy: the temperature threshold is 70°C, and the charging power decreases by 2% for every 1°C increase in the weighted temperature. Use a small fan to blow directly on the components for auxiliary heat dissipation. The temperature rise data of each component sampling point recorded during the test are as Figure 4 shown. It can be seen that temperature protection is entered 20 minutes after the start of charging, and the temperature is significantly suppressed compared with before. Finally, the temperature of the AC contactor stabilizes at 75.5°C, the surface of the AC terminal stabilizes at 69.2°C, and the remaining components are basically stable at about 60°C, which is about 10°C lower than before. The temperature control effect is obvious. The voltage finally drops to 289V, the current drops to 122.6A, and the total power drops to 35.5kW, restricting by about 9%. It has little impact on the charging speed of the vehicle, but effectively protects the internal components and improves safety.

[0043] Therefore, the method for protecting the temperature of internal components of the charger of the present invention can protect the internal components of the charger outside the charging module and the charging gun in a high-temperature environment. For the harsh climate of intense outdoor sunlight and high temperature in summer, as an insurance measure, it can greatly increase the service life of the components, slow down the aging of the components, and can reduce the failure rate of the components of the charging pile to a certain extent, thereby reducing the material cost, maintenance cost and safety risk of use.

[0044] Embodiment of the method for protecting the temperature of internal components of the charger

[0045] A method for protecting the temperature of internal components of the charger of the present invention is used to achieve the temperature protection of the internal components of the charger outside the charging module and the charging gun under high temperature, and includes the following steps:

[0046] S1: Obtain the sampled-point temperature of the internal components of the charger. The internal components of the charger refer to the internal components of the charger except for the charging module and the charging gun.

[0047] S2: Calculate the weighted temperature according to the sampled-point temperature and the sampled-point weight of the internal components of the charger. When the weighted temperature exceeds the set temperature threshold and the charging module and the charging gun do not trigger the temperature protection strategy of the corresponding module, reduce the output power of the charger, and at the same time start the heat dissipation unit in the charger for auxiliary heat dissipation; the higher the weighted temperature, the lower the output power of the charger; if the temperature continues to rise until it exceeds the maximum allowable value, stop the current charging; the maximum allowable value is the minimum of the maximum allowable temperature rise of each internal component and the maximum allowable temperature rise required by the national standard.

[0048] Among them, the sampled-point weight is set based on the importance and heat generation of the internal components at the sampled point. The higher the importance and the higher the heat generation, the greater the weight. After the weighted temperature exceeds the temperature threshold, for every 1°C increase, the output power of the charger is reduced by η% of the current vehicle-end demand power. η can be a fixed value or a variable value that increases with the increase of the weighted temperature.

[0049] S3: When the weighted temperature drops after exceeding the set temperature threshold, control the output power of the charger to gradually increase until the weighted temperature drops below the set temperature threshold, and perform power output according to the output power of the charger corresponding to when it does not exceed the set temperature threshold.

[0050] Embodiment of the device for protecting the temperature of internal components of the charger

[0051] A temperature protection device for internal components of a charger according to the present invention includes a charging controller and a temperature sampling unit. The temperature sampling unit is used to collect the temperatures of various sampling points of the internal components of the charger, and the charging controller is used to obtain the temperatures of various sampling points to implement a temperature protection method for the internal components of the charger. This method is the temperature protection method for the internal components of the charger described in the above charger embodiment and will not be elaborated here.

Claims

1. A method for protecting the temperature of internal components of a charger, characterized in that: include: Get the sampling point temperature of the charger's internal components. The charger's internal components refer to the charger's internal components excluding the charging module and charging gun. The weighted temperature is calculated based on the temperature of each sampling point of the internal components of the charger and the weight of the sampling point. When the weighted temperature exceeds the set temperature threshold and the charging module and the charging gun do not trigger the temperature protection strategy of the corresponding module, the output power of the charger is reduced, and the heat dissipation unit in the charger is started for auxiliary heat dissipation. The higher the weighted temperature, the lower the output power of the charger; The sampling point weight is set based on the importance and heat generation of the internal device at the sampling point. The higher the importance, the greater the weight, and the higher the heat generation, the smaller the weight; When the weighted temperature exceeds the set temperature threshold and then drops, the output power of the charger is controlled to gradually increase until the weighted temperature drops below the set temperature threshold, at which time the power output is performed according to the charger output power corresponding to the setting temperature threshold.

2. The charger internal device temperature protection method according to claim 1, characterized in that: After the weighted temperature exceeds the set temperature threshold, the process of controlling the output power of the charger to decrease is as follows: after the weighted temperature exceeds the set temperature threshold, for every 1°C increase, the output power of the charger decreases by η% of the output power of the charger corresponding to the setting temperature threshold.

3. The charger internal device temperature protection method according to claim 2, characterized in that: The η is a fixed value.

4. The charger internal device temperature protection method according to claim 2, characterized in that: The η is a variable value, which increases as the weighted temperature increases.

5. The charger internal device temperature protection method according to claim 1 or 2, characterized in that: The method also includes: if the temperature continues to rise until it exceeds the maximum allowable value, controlling the output power of the charger to 0 and stopping the current charging; the maximum allowable value is the minimum value between the maximum allowable temperature rise value of each internal component and the maximum allowable temperature rise value required by the national standard.

6. A temperature protection device for internal components of a charger, comprising a charging controller and a temperature sampling unit, characterized in that: The temperature sampling unit is used to collect the temperature of each sampling point of the internal components of the charger, and the charging controller is used to obtain the temperature of each sampling point, calculate the weighted temperature according to the temperature of each sampling point and the weight of the sampling point, and reduce the output power of the charger when the weighted temperature exceeds the set temperature threshold and the charging module and the charging gun do not trigger the temperature protection strategy of the corresponding module, and start the heat dissipation unit of the charger for auxiliary heat dissipation, wherein the higher the weighted temperature, the lower the output power of the charger; when the weighted temperature drops after exceeding the set temperature threshold, the output power of the charger is controlled to gradually increase until the weighted temperature drops below the set temperature threshold, and the power is output according to the corresponding output power of the charger when the set temperature threshold is not exceeded; wherein, the internal components of the charger refer to the internal components of the charger except the charging module and the charging gun; the sampling point weight is set based on the importance and heat generation of the internal components at the sampling point, and the higher the importance, the greater the weight, and the higher the heat generation, the smaller the weight.

7. The charger internal component temperature protection device according to claim 6, characterized in that: After the weighted temperature exceeds the set temperature threshold, the charging controller controls the charger output power to reduce the process as follows: after the weighted temperature exceeds the set temperature threshold, for every 1°C increase, the charger output power is reduced by η% of the charger output power corresponding to the setting temperature threshold.

8. The charger internal component temperature protection device according to claim 6, characterized in that: The η is a fixed value.

9. The charger internal component temperature protection device according to claim 6 or 7, characterized in that: If the temperature continues to rise until it exceeds the maximum allowable value, the charging controller controls the output power of the charger to 0 and stops charging; the maximum allowable value is the minimum value between the maximum allowable temperature rise value of each internal component and the maximum allowable temperature rise value required by the national standard.

10. A charger, characterized in that: The charger uses the charger internal component temperature protection method as described in any one of claims 1 to 5 to perform temperature protection on the internal components of the charger.

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