Control method of AC output power and bidirectional power supply system

Abstract

The invention provides an AC output power control method and a bidirectional power supply system, the system comprises a battery and a DC-AC inversion module connected with the battery, and the control method comprises the following steps: obtaining the battery discharge depth and the battery temperature in real time; when the battery temperature is higher than the third temperature and not higher than the fourth temperature, if the battery discharge depth is smaller than or equal to the second preset value and larger than the first preset value, the output power of the direct-current and alternating-current inversion module is reduced, and if the battery discharge depth is smaller than or equal to the first preset value, the output power of the direct-current and alternating-current inversion module is kept at the expected power; when the battery temperature is smaller than or equal to the third temperature or larger than the fourth temperature, the output power is reduced to zero. According to the invention, the capability of reversely outputting alternating current can be provided for the battery, the output power can be adjusted according to the battery discharge depth and the battery temperature, and the effects of protecting the battery and prolonging the service life of the battery are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery charging and discharging, and in particular to a method for controlling AC output power and a bidirectional power supply system. Background Art

[0002] Aerial vehicles refer to vehicles that are over 3 meters high and have multiple hydraulic cylinders controlled by a hydraulic or electric system. They can lift workers and objects to a certain height through a lifting mechanism to perform aerial operations. Manned aerial vehicles with hydraulic transmission are advanced special machinery and equipment in contemporary times. Construction workers can use aerial vehicles to work in the air, and safety can be guaranteed as long as they are used correctly. Aerial vehicles are widely used in the construction, electricity, gardening and other industries for equipment installation, maintenance, cleaning and other operations. The application scenarios of aerial vehicles include convenient maintenance of urban transportation, power communications, street lights, traffic police roads, highways, cable TV, high-altitude installation and cleaning of telephone poles, as well as the construction of large equipment, shipbuilding, construction, gardening, advertising photography, etc.

[0003] In recent years, with the continuous improvement of people's quality of life, vehicles can be seen everywhere in life and work, but also bring more and more exhaust emissions to pollute the environment. Under the background of environmental protection departments advocating green environmental protection, new energy electric vehicles for various purposes have emerged, and aerial vehicles are no exception to the use of new energy technology.

[0004] The current new energy aerial vehicles can charge the on-board battery unidirectionally through the charger, but in actual work, there are still many power supply needs, which require the on-board battery to have the ability to reverse output AC power, which is a function that the current new energy aerial vehicles do not have. Summary of the invention

[0005] The purpose of the present invention is to provide a control method for AC output power and a bidirectional power supply system, which can provide the ability of a battery to reversely output AC power, and can adjust the output power according to the battery discharge depth and battery temperature, thereby protecting the battery and extending the battery life.

[0006] In order to achieve the above object, the present invention provides a method for controlling AC output power, which is applied to a bidirectional power supply system, wherein the system includes a battery and a DC-AC inverter module connected to the battery, and the control method includes:

[0007] Obtain battery discharge depth and battery temperature in real time;

[0008] When the battery temperature is higher than the third temperature and not higher than the fourth temperature, if the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, the output power of the DC-AC inverter module is reduced; if the battery discharge depth is less than or equal to the first preset value, the output power of the DC-AC inverter module is maintained at the expected power;

[0009] When the battery temperature is less than or equal to the third temperature or greater than the fourth temperature, the output power is reduced to zero.

[0010] Optionally, if the battery discharge depth is greater than the second preset value, the output power is reduced to zero.

[0011] Optionally, the step of obtaining the battery discharge depth includes:

[0012] Discharging the battery and establishing a two-dimensional relationship curve between the battery voltage and the battery discharge depth at different battery temperatures;

[0013] The real-time battery discharge depth is obtained according to the real-time acquired battery temperature, battery voltage and the two-dimensional relationship curve.

[0014] Optionally, when establishing the two-dimensional relationship curve, the first temperature is increased to the second temperature based on a fixed value, so as to obtain different battery temperatures.

[0015] Optionally, let the battery temperature be C and the output power be P out , the preset power is P ref If the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, the output power of the DC-AC inverter module is reduced in the following manner:

[0016] When the battery temperature C is greater than or equal to the fifth temperature and less than or equal to the fourth temperature, P out =P ref ; When the battery temperature C is greater than the third temperature and less than the fifth temperature,

[0017] Let the battery discharge depth be DOD and the expected power be P max , then P ref =2*(1-DOD)*P max .

[0018] Optionally, the resistance of the external load is detected, and if the resistance of the external load is greater than or equal to a preset resistance, it is determined that the external load is not connected to the DC-AC inverter module, and the output power of the DC-AC inverter module is controlled to be zero.

[0019] Optionally, if it is detected that the resistance of the external load is less than the preset resistance, the DC-AC inverter module is controlled to output a first preset voltage and maintain it for a preset time. If the output current of the DC-AC inverter module is greater than the preset current, the first preset voltage is increased to a second preset voltage. If the output current of the DC-AC inverter module is not greater than the preset current, the output power of the DC-AC inverter module is controlled to be zero.

[0020] Based on another aspect of the present invention, the present invention also provides a bidirectional power supply system, comprising:

[0021] Battery;

[0022] A DC-AC inverter module connected to the battery, the DC-AC inverter module is used to obtain the battery discharge depth in real time and convert the DC power output by the battery into AC power;

[0023] A temperature detection module, which is used to obtain the battery temperature in real time;

[0024] An output control module, wherein the output control module is configured as follows: when the battery temperature is higher than a third temperature and not higher than a fourth temperature, if the battery discharge depth is less than or equal to a second preset value and greater than a first preset value, then the DC-AC inverter module is controlled to reduce the output power; if the battery discharge depth is less than or equal to the first preset value, then the DC-AC inverter module is controlled to maintain the output power at a desired power; when the battery temperature is less than or equal to the third temperature or greater than the fourth temperature, then the DC-AC inverter module is controlled to reduce the output power to zero.

[0025] Optionally, the output control module is used to detect the resistance of an external load, and the output control module is further configured as follows: if the resistance of the external load is greater than or equal to a preset resistance, it is determined that the external load is not connected to the DC-AC inverter module, and the output control module turns off the AC output; if the resistance of the external load is less than the preset resistance, the DC-AC inverter module is controlled to output a first preset voltage and maintain it for a preset time, and if the output current is greater than the preset current, the first preset voltage is increased to a second preset voltage, and if the output current is not greater than the preset current, the output control module turns off the AC output.

[0026] Optionally, the system includes a charging module, the charging module includes an AC-DC conversion unit and a charging control unit, the AC-DC conversion unit is used to access an external AC power source, and the AC-DC conversion unit is connected to the battery through the charging control unit.

[0027] As configured above, the present invention can convert the direct current output by the battery into alternating current through the DC-AC inverter module, and provides the ability of the battery to reversely output alternating current, thereby meeting the demand for powering an external load; the DC-AC inverter module of the present invention can adjust the output power according to the battery discharge depth and battery temperature, so that the battery can be discharged at an appropriate temperature, and prevent the battery from deep discharge, thereby protecting the battery and extending the battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Those skilled in the art should understand that the drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0029] Figure 1 is a schematic diagram of a bidirectional power supply system according to an embodiment of the present invention;

[0030] Figure 2 FIG. 4 is a schematic diagram of a method for controlling AC output power according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In this document, unless otherwise specified, the terms "upper", "lower", "left", "right", "inside", "outside", "front", "back", "top", "bottom", etc. are used to indicate directions or positional relationships based on the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction and operation. Therefore, they cannot be understood as limiting the present invention.

[0032] The specific implementation of the present invention will be described in more detail below in conjunction with the schematic diagram. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0033] Figure 1 is a schematic diagram of a bidirectional power supply system according to an embodiment of the present invention, Figure 2 FIG. 1 is a schematic diagram of a method for controlling AC output power according to an embodiment of the present invention. Figure 1 and Figure 2 An embodiment of the present invention provides a method for controlling AC output power, which is applied to a bidirectional power supply system. The system includes a battery and a DC-AC inverter module connected to the battery. The control method includes step S1, step S2 and step S3. Step S1, step S2 and step S3 are described in detail below.

[0034] Step S1: Obtain the battery discharge depth and battery temperature in real time.

[0035] Exemplarily, the battery temperature may be acquired in real time through a temperature detection module of the bidirectional power supply system.

[0036] The step of obtaining the battery discharge depth includes: discharging the battery and establishing a two-dimensional relationship curve between the battery voltage and the battery discharge depth at different battery temperatures; obtaining the real-time battery discharge depth according to the battery temperature, battery voltage and two-dimensional relationship curve obtained in real time. Furthermore, when establishing the two-dimensional relationship curve, the first temperature can be incremented to the second temperature based on a fixed value, thereby obtaining different battery temperatures, and each different battery temperature corresponds to a two-dimensional relationship curve. For example, the first temperature can be a temperature of -25°C or below, the second temperature can be a temperature of 65°C or above, the fixed value can be 3°C to 6°C, for example, the fixed value can be 5°C, that is, a two-dimensional relationship curve is established every 5°C.

[0037] Step S2: When the battery temperature is higher than the third temperature and not higher than the fourth temperature, if the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, the output power of the DC-AC inverter module is reduced, thereby reducing the rating; if the battery discharge depth is less than or equal to the first preset value, the output power of the DC-AC inverter module is maintained at the expected power. Further, the third temperature may be -25°C, the fourth temperature may be 40°C, the second preset value may be 80%, the first preset value may be 50%, and the expected power may refer to the maximum power or rated power of the aerial vehicle.

[0038] For example, the battery temperature can be C and the output power can be P out , the preset power is P ref If the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, that is, 50%<battery discharge depth≤80%, the output power of the DC-AC inverter module is reduced in the following manner:

[0039] When the battery temperature C is greater than or equal to the fifth temperature and less than or equal to the fourth temperature, the fifth temperature may be, for example, 0°C, that is, when 0°C≤C≤40°C, P out =P ref ; When the battery temperature C is greater than the third temperature and less than the fifth temperature, that is, when -25℃<C<0℃, Among them, let the battery discharge depth be DOD and the expected power be P max , then P ref =2*(1-DOD)*P max , it is understandable that P ref is the intermediate value of the calculation, P ref and Both are less than P max That is, when the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, the battery has discharged a lot of electricity, so the output power is reduced to extend the discharge time and prevent the battery power from dropping too low quickly, preventing the battery from deep discharge and thus protecting the battery.

[0040] Preferably, if the battery discharge depth is greater than the second preset value, the output power is reduced to zero. It is understandable that when the battery discharge depth is greater than the second preset value, it means that the battery power is about to run out, so the discharge should be stopped to protect the battery and prevent the battery from deep discharge. Deep discharge will reduce the battery life and capacity, and will also accelerate the aging of the battery, causing the battery to lose its performance and capacity faster.

[0041] Step S3: When the battery temperature is less than or equal to the third temperature or greater than the fourth temperature, the output power is reduced to zero. That is, when C ≤ -25 ° C or C > 40 ° C, the output power is reduced to zero to protect the battery. It is understandable that a battery temperature that is too high or too low may cause performance degradation, damage the battery life, and may even cause an explosion. Therefore, when the battery temperature is too high or too low, the output power needs to be reduced to zero to protect the battery.

[0042] Further, the control method of AC output power also includes detecting the resistance of the external load. If the resistance of the external load is greater than or equal to the preset resistance, it is determined that the external load is not connected to the DC-AC inverter module, and the output power of the DC-AC inverter module is controlled to be zero, that is, the output control module turns off the AC output. Exemplarily, the output control module includes an external load detection unit, which is used to detect the resistance of the external load. The preset resistance can be 10MΩ, that is, when the resistance of the external load is ≥10MΩ, the output control module determines that the DC-AC inverter module is not connected to the external load and does not need to discharge the battery, so the output control module turns off the AC output. If it is detected that the resistance of the external load is less than the preset resistance, that is, the resistance of the external load is <10MΩ, then the DC-AC inverter module is controlled to output a first preset voltage, and after maintaining the preset time, if the output current of the DC-AC inverter module is greater than the preset current, it means that an external load is connected to the DC-AC inverter module and needs battery power supply, then the first preset voltage is increased to a second preset voltage, and if the output current is not greater than the preset current, the output control module turns off the AC output. For example, the first preset voltage can be set according to the lowest operating voltage of the commonly used electrical appliances surveyed, such as 85VAC / 50Hz, the second preset voltage can be the domestic standard voltage 220VAC / 50Hz, the preset time can range from a few seconds to tens of seconds, for example, the preset time can be six seconds or seven seconds, and the preset current can be 0.1A, for example. It can be understood that if the output current is not greater than the preset current, it means that the DC-AC inverter module is not connected to an external load and does not require battery power, so the output control module turns off the AC output.

[0043] Based on another aspect of the present invention, the present invention also provides a bidirectional power supply system, comprising:

[0044] Battery;

[0045] The DC-AC inverter module is connected to the battery and is used to obtain the battery discharge depth in real time and convert the DC power output by the battery into AC power. It is understandable that the DC-AC inverter module also includes a controllable switch component, a controllable inverter component and a protection component, and the protection component can be used for overvoltage protection, overcurrent protection or overtemperature protection.

[0046] The temperature detection module is used to obtain the battery temperature in real time. For example, the temperature detection module may include a temperature sensor. The temperature sensor may be arranged on a battery pole, for example.

[0047] The output control module is configured as follows: when the battery temperature is higher than the third temperature and not higher than the fourth temperature, if the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, the DC-AC inverter module is controlled to reduce the output power; if the battery discharge depth is less than or equal to the first preset value, the DC-AC inverter module is controlled to maintain the output power at the expected power; when the battery temperature is less than or equal to the third temperature or greater than the fourth temperature, the DC-AC inverter module is controlled to reduce the output power to zero.

[0048] Further, the output control module is used to detect the resistance of the external load. It can be understood that the output control module includes an external load detection unit, and the external load detection unit is used to detect the resistance of the external load. The output control module is also configured as follows: if the resistance of the external load is greater than or equal to the preset resistance, it is determined that the external load is not connected to the DC-AC inverter module, and the output control module turns off the AC output; if the external load detection unit detects that the resistance of the external load is less than the preset resistance, the DC-AC inverter module is controlled to output the first preset voltage and maintain it for a preset time. If the output current is greater than the preset current, the first preset voltage is increased to the second preset voltage. If the output current is not greater than the preset current, the output control module turns off the AC output, that is, the output control module controls the DC-AC inverter module to reduce the output power to zero. The DC-AC inverter module and the output control module make battery discharge more intelligent, safe and automatic.

[0049] The system also includes a charging module for charging the battery, the charging module includes an AC-DC conversion unit and a charging control unit, the AC-DC conversion unit is used to access an external AC power source, and the AC-DC conversion unit is connected to the battery through the charging control unit. It can be understood that the AC-DC conversion unit is used to convert the input AC power into DC power, and the charging control unit is used to control the DC output to the battery.

[0050] Exemplarily, the DC-AC inverter module, the temperature detection module, the output control module and the charging module are all arranged in the charger of the aerial vehicle.

[0051] As configured above, the present invention can convert the direct current output by the battery into alternating current through the DC-AC inverter module, and provides the ability of the battery to reversely output alternating current, thereby meeting the demand for powering an external load; the DC-AC inverter module of the present invention can adjust the output power according to the battery discharge depth and battery temperature, so that the battery can be discharged at an appropriate temperature, and prevent the battery from deep discharge, thereby protecting the battery and extending the battery life.

[0052] It should be noted that references to "one embodiment", "an embodiment", "a specific embodiment", "some embodiments", etc. in the specification only indicate that the described embodiment may include a particular feature, structure or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure or characteristic is described in conjunction with an embodiment, whether or not explicitly described, it is within the knowledge of a person skilled in the relevant art to implement such feature, structure or characteristic in conjunction with other embodiments.

[0053] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0054] It should also be noted that, although the present invention has been disclosed as a preferred embodiment, the above embodiment is not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

[0055] It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are merely used to distinguish between the various components, elements, steps, etc. in the specification, and are not used to indicate the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0056] It should also be recognized that the terms described herein are only used to describe specific embodiments and are not intended to limit the scope of the invention. It should be noted that the singular forms "a" and "an" used herein and in the appended claims include plural references unless the context clearly indicates otherwise. For example, a reference to "a step" or "a device" means a reference to one or more steps or devices, and may include secondary steps and secondary devices. All conjunctions used should be understood in the broadest sense. And, the word "or" should be understood to have the definition of a logical "or", rather than a logical "exclusive or", unless the context clearly indicates otherwise. In addition, the implementation of the method and / or device in the embodiments of the present invention may include performing the selected task manually, automatically, or in combination.

Claims

1. A method for controlling AC output power, applied to a bidirectional power supply system, the system comprising a battery and a DC-AC inverter module connected to the battery, characterized in that: The method comprises: Obtain battery discharge depth and battery temperature in real time; When the battery temperature is higher than the third temperature and not higher than the fourth temperature, if the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, the output power of the DC-AC inverter module is reduced; if the battery discharge depth is less than or equal to the first preset value, the output power of the DC-AC inverter module is maintained at the expected power; When the battery temperature is less than or equal to the third temperature or greater than the fourth temperature, the output power is reduced to zero.

2. The method for controlling AC output power according to claim 1, characterized in that: If the battery discharge depth is greater than the second preset value, the output power is reduced to zero.

3. The method for controlling AC output power according to claim 1, characterized in that: The step of obtaining the battery discharge depth comprises: Discharging the battery and establishing a two-dimensional relationship curve between the battery voltage and the battery discharge depth at different battery temperatures; The real-time battery discharge depth is obtained according to the real-time acquired battery temperature, battery voltage and the two-dimensional relationship curve.

4. The method for controlling AC output power according to claim 3, characterized in that: When establishing the two-dimensional relationship curve, the first temperature is increased to the second temperature based on a fixed value, thereby obtaining different battery temperatures.

5. The method for controlling AC output power according to claim 1, characterized in that: Let the battery temperature be C and the output power be P out , the preset power is P ref If the battery discharge depth is less than or equal to the second preset value and greater than the first preset value, the output power of the DC-AC inverter module is reduced in the following manner: When the battery temperature C is greater than or equal to the fifth temperature and less than or equal to the fourth temperature, P out =P ref ; When the battery temperature C is greater than the third temperature and less than the fifth temperature, Let the battery discharge depth be DOD and the expected power be P max , then P ref =2*(1-DOD)*P max .

6. The method for controlling AC output power according to claim 1, characterized in that: The resistance of the external load is detected. If the resistance of the external load is greater than or equal to a preset resistance, it is determined that the external load is not connected to the DC-AC inverter module, and the output power of the DC-AC inverter module is controlled to be zero.

7. The method for controlling AC output power according to claim 6, characterized in that: If it is detected that the resistance of the external load is less than the preset resistance, the DC-AC inverter module is controlled to output a first preset voltage and maintain it for a preset time. If the output current of the DC-AC inverter module is greater than the preset current, the first preset voltage is increased to a second preset voltage. If the output current of the DC-AC inverter module is not greater than the preset current, the output power of the DC-AC inverter module is controlled to be zero.

8. A bidirectional power supply system, characterized in that: include: Battery; A DC-AC inverter module connected to the battery, the DC-AC inverter module is used to obtain the battery discharge depth in real time and convert the DC power output by the battery into AC power; A temperature detection module, which is used to obtain the battery temperature in real time; An output control module, wherein the output control module is configured as follows: when the battery temperature is higher than a third temperature and not higher than a fourth temperature, if the battery discharge depth is less than or equal to a second preset value and greater than a first preset value, then the DC-AC inverter module is controlled to reduce the output power; if the battery discharge depth is less than or equal to the first preset value, then the DC-AC inverter module is controlled to maintain the output power at a desired power; when the battery temperature is less than or equal to the third temperature or greater than the fourth temperature, then the DC-AC inverter module is controlled to reduce the output power to zero.

9. The bidirectional power supply system according to claim 8, characterized in that: The output control module is used to detect the resistance of the external load. The output control module is also configured as follows: if the resistance of the external load is greater than or equal to a preset resistance, it is determined that the external load is not connected to the DC-AC inverter module, and the output control module turns off the AC output; if the resistance of the external load is less than the preset resistance, the DC-AC inverter module is controlled to output a first preset voltage and maintain it for a preset time. If the output current is greater than the preset current, the first preset voltage is increased to a second preset voltage. If the output current is not greater than the preset current, the output control module turns off the AC output.

10. The bidirectional power supply system according to claim 8, characterized in that: The system comprises a charging module, which comprises an AC-DC conversion unit and a charging control unit. The AC-DC conversion unit is used to access an external AC power source, and the AC-DC conversion unit is connected to the battery through the charging control unit.

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