Lithium battery direct current side direct current and alternating current conversion output controller and control method

Abstract

The invention discloses a lithium battery direct current side direct current and alternating current conversion output controller and a control method, and the controller comprises a direct current conversion module which employs a bidirectional DC-DC converter topological structure, and is used for carrying out the voltage conversion of the direct current outputted by a lithium battery, achieving the bidirectional flow of energy, and meeting the working requirements of a subsequent circuit; and the inversion module adopts a three-phase bridge type inversion circuit, converts the direct current output by the direct current conversion module into alternating current by controlling the on and off of six switching tubes, and adjusts the frequency and amplitude of the output alternating current by utilizing a PWM (Pulse-Width Modulation) control technology. The control method is clear in logic, simple in step and easy to implement, the design difficulty and cost of the controller are reduced, and large-scale application and popularization are facilitated.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly to a lithium battery DC side DC-to-AC conversion output controller and a control method therefor. Background Art

[0002] With the rapid development of new energy technologies, lithium batteries, as an efficient and environmentally friendly energy storage device, have been widely used in many fields. In many application scenarios, it is necessary to convert the direct current output by lithium batteries into alternating current to meet the needs of different loads, or it is necessary to flexibly control and transform the direct current on the DC side.

[0003] Currently, traditional DC-to-AC conversion devices have some deficiencies. For example, the conversion efficiency is relatively low, resulting in large energy losses, which affects the usage efficiency and endurance of lithium batteries; in terms of control accuracy, it is difficult to accurately adjust parameters such as the frequency and amplitude of the output alternating current, and it cannot meet the operating requirements of some devices with high power quality requirements; moreover, the existing controllers have room for improvement in terms of stability and reliability when facing complex working conditions, are prone to failures, and affect the normal operation of the entire system. In addition, the existing control methods are often relatively complex, increasing the design difficulty and cost of the controller, which is not conducive to large-scale popularization and application. Therefore, it is necessary to design a lithium battery DC side DC-to-AC conversion output controller and a control method therefor. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a lithium battery DC side DC-to-AC conversion output controller and a control method therefor, which solve the problem of poor overall heat exchange efficiency proposed in the above background art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A lithium battery DC side DC-to-AC conversion output controller includes:

[0007] A DC conversion module, adopting a bidirectional DC-DC converter topology structure, for performing voltage conversion on the direct current output by the lithium battery, realizing bidirectional energy flow, and meeting the working requirements of subsequent circuits;

[0008] An inverter module, adopting a three-phase bridge inverter circuit, by controlling the on and off of six switching tubes, converting the direct current output by the DC conversion module into alternating current, and using PWM control technology to adjust the frequency and amplitude of the output alternating current;

[0009] The control module, based on a high-performance microprocessor, calculates and outputs control signals according to parameters such as the voltage and current of the lithium battery and the frequency and amplitude of the output alternating current fed back by the detection module, and performs real-time control on the DC conversion module and the inverter module through a preset control algorithm;

[0010] The detection module, including a voltage sensor, a current sensor, and a temperature sensor, is used to detect in real time parameters such as the voltage, current, and temperature of the lithium battery and the voltage, current, and frequency of the output alternating current, and feed the detected data back to the control module;

[0011] The communication module, using communication interfaces such as RS485 or CAN, is used to realize data interaction and remote control between the controller and external devices, receive instructions from the host computer, and send the operating status and parameters of the controller to the host computer.

[0012] Furthermore, when the lithium battery is charging, the DC conversion module converts the high voltage of the external power supply into a voltage suitable for charging the lithium battery; when the lithium battery is discharging, the DC conversion module converts the lithium battery voltage into a suitable DC bus voltage.

[0013] Furthermore, the linear current sensor in the detection module is ACS712 or its domestic substitute CH701, which is used to accurately detect the charging and discharging current of the lithium battery and output a voltage proportional to the detected current.

[0014] The present invention also discloses a control method for converting and outputting direct current and alternating current on the DC side of the lithium battery of the controller, which is characterized by including the following steps:

[0015] S1. Initialization: After the controller is powered on, the control module performs initialization settings on the DC conversion module, the inverter module, the detection module, and the communication module to make them enter the normal working state;

[0016] S2. Parameter detection: The detection module detects in real time parameters such as the voltage, current, and temperature of the lithium battery and the voltage, current, and frequency of the output alternating current, and sends these parameters to the control module;

[0017] S3. DC conversion control: The control module adjusts the conduction time of the switching tubes of the bidirectional DC-DC converter according to the detected voltage and current of the lithium battery and the working requirements of the system to achieve precise control of the DC voltage;

[0018] S4. Inverter control: The control module adopts PWM control technology according to the detected parameters such as the frequency and amplitude of the output alternating current and the working requirements of the system, and controls the on and off times of the switching tubes in the three-phase bridge inverter circuit to achieve precise adjustment of the frequency and amplitude of the output alternating current;

[0019] S5. Protection Control: The control module monitors parameters such as the voltage, current, and temperature of the lithium battery in real time. When abnormal situations are detected, such as overvoltage, overcurrent, overheating, etc. of the lithium battery, it immediately cuts off the operation of the DC conversion module and the inverter module, and sends the fault information to the host computer through the communication module.

[0020] Communication Interaction: The communication module receives the control instructions sent by the host computer in real time and transfers them to the control module. The control module adjusts the working state of the controller according to the instructions. At the same time, the communication module sends the operating state and parameters of the controller to the host computer in real time.

[0021] Furthermore, in the DC conversion control step, when the voltage of the lithium battery is low, the control module controls the DC conversion module to increase the voltage; when the voltage of the lithium battery is high, the control module controls the DC conversion module to decrease the voltage.

[0022] Furthermore, in the inverter control step, when alternating current with a specific frequency and amplitude needs to be output, the control module adjusts the duty cycle and frequency of the PWM signal to make the inverter module output alternating current that meets the requirements.

[0023] Compared with the existing technology, the advantages of the present invention are as follows:

[0024] Improve Conversion Efficiency: By adopting a DC conversion module with an advanced bidirectional DC-DC converter topology structure and an inverter module with a high-efficiency three-phase bridge inverter circuit, it can achieve efficient energy conversion, reduce energy loss, and improve the usage efficiency and endurance of the lithium battery. For example, in practical applications, compared with traditional conversion devices, the controller of the present invention can increase the conversion efficiency by 10%-15%.

[0025] Precise Control: Based on the control module of a high-performance microprocessor, combined with advanced control algorithms and a high-precision detection module, it can precisely adjust parameters such as the frequency and amplitude of the output alternating current to meet the operating requirements of equipment with high power quality requirements. For example, the frequency accuracy of the output alternating current can be controlled within ±0.1 Hz, and the amplitude accuracy can be controlled within ±1%.

[0026] Enhance Stability and Reliability: By monitoring the parameters of the lithium battery and the output alternating current in real time and taking effective protection control measures, such as overvoltage, overcurrent, overheating protection, etc., it can effectively avoid equipment failures and improve the stability and reliability of the entire system. At the same time, the modular design of the controller also facilitates maintenance and repair.

[0027] Simplify the Control Method: The control method of the present invention has clear logic, simple steps, and is easy to implement, reducing the design difficulty and cost of the controller, which is conducive to large-scale popularization and application. Description of the Drawings

[0028] Figure 1 Schematic diagram of the connection of each component of a DC - AC conversion output controller on the DC side of a lithium - battery proposed by the present invention;

[0029] Figure 2 Flowchart of the control method of the present invention. Specific embodiments

[0030] Referring to Figure 1 - Figure 2 a DC - AC conversion output controller and a control method on the DC side of a lithium - battery;

[0031] Controller structure

[0032] The DC - AC conversion output controller on the DC side of the lithium - battery of the present invention includes a DC conversion module, an inverter module, a control module, a detection module, and a communication module.

[0033] The DC conversion module is used to perform voltage conversion on the direct current output by the lithium - battery to meet the working requirements of the subsequent circuit. It adopts an advanced bidirectional DC - DC converter topology structure, which can flexibly adjust the magnitude of the DC voltage according to actual needs, realize bidirectional energy flow, and improve energy utilization efficiency. For example, when the lithium - battery is charging, it can convert the high voltage of the external power supply into a voltage suitable for charging the lithium - battery; when the lithium - battery is discharging, it can convert the voltage of the lithium - battery into a suitable DC bus voltage.

[0034] The inverter module is used to convert the direct current output by the DC conversion module into alternating current. It adopts a three - phase bridge inverter circuit. By controlling the on - off of six switching tubes (such as IGBTs or MOS tubes), the direct current is inverted into three - phase alternating current. This inverter circuit can output stable alternating current, and through PWM (pulse - width modulation) control technology, the frequency and amplitude of the output alternating current can be accurately adjusted to meet the needs of different loads.

[0035] The control module is the core of the entire controller and is used to control the DC conversion module and the inverter module. Based on a high - performance microprocessor, through a preset control algorithm, according to the information fed back by the detection module, it adjusts the working states of the DC conversion module and the inverter module in real time. For example, according to parameters such as the detected voltage and current of the lithium - battery and the frequency and amplitude of the output alternating current, it calculates appropriate control signals and sends them to the DC conversion module and the inverter module to achieve precise control of the entire system.

[0036] The detection module is used to detect parameters such as the voltage, current, temperature of the lithium battery, and the voltage, current, frequency of the output alternating current in real time, and feedback these parameters to the control module. High-precision sensors are adopted, such as voltage sensors, current sensors, and temperature sensors, etc., to ensure the accuracy and reliability of the detection data. For example, the charging and discharging current of the lithium battery is accurately detected by a linear current sensor ACS712 (or its domestic substitute CH701), which can output a voltage proportional to the detected current and has the advantages of low noise, fast response, and high sensitivity.

[0037] The communication module is used to realize the communication between the controller and external devices. Communication interfaces such as RS485 and CAN can be adopted to facilitate data interaction and remote control with the upper computer or other devices. For example, through the communication module, the upper computer can obtain the operating status and parameters of the controller in real time, and can also send control instructions to the controller to realize remote monitoring and management of the entire system.

[0038] Control Method

[0039] The control method of the present invention includes the following steps:

[0040] Initialization: After the controller is powered on, the control module performs initialization settings on each module, including the DC conversion module, the inverter module, the detection module, and the communication module, etc., to make them enter the normal working state.

[0041] Parameter Detection: The detection module detects parameters such as the voltage, current, temperature of the lithium battery, and the voltage, current, frequency of the output alternating current in real time, and sends these parameters to the control module.

[0042] DC Conversion Control: The control module calculates the control signal of the DC conversion module according to the detected lithium battery voltage and current and the working requirements of the system, and realizes the precise control of the DC voltage by adjusting the on-time of the switching tubes of the bidirectional DC-DC converter. For example, when the lithium battery voltage is low, the control module controls the DC conversion module to increase the voltage; when the lithium battery voltage is high, the control module controls the DC conversion module to decrease the voltage.

[0043] Inverter Control: The control module adopts PWM control technology according to the detected parameters such as the frequency and amplitude of the output alternating current and the working requirements of the system, calculates the control signal of the inverter module, and controls the on and off times of the switching tubes in the three-phase bridge inverter circuit to realize the precise adjustment of the frequency and amplitude of the output alternating current. For example, when it is necessary to output alternating current with a frequency of 50Hz and an amplitude of 220V, the control module adjusts the duty cycle and frequency of the PWM signal to make the inverter module output the required alternating current.

[0044] Protection control: The control module monitors parameters such as the voltage, current, and temperature of the lithium battery in real time. When abnormal situations are detected, such as overvoltage, overcurrent, and overheating of the lithium battery, protection measures are immediately taken, such as cutting off the operation of the DC conversion module and the inverter module, to prevent damage to the lithium battery or occurrence of safety accidents. At the same time, the control module sends the fault information to the host computer through the communication module for timely processing.

[0045] Communication interaction: The communication module receives the control instructions sent by the host computer in real time and transfers them to the control module. The control module adjusts the working state of the controller according to the instructions of the host computer. At the same time, the communication module sends the operating state and parameters of the controller to the host computer in real time to achieve remote monitoring and management.

[0046] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A DC and AC conversion output controller on the DC side of a lithium battery, characterized in that Including: A DC conversion module, adopting a bidirectional DC-DC converter topology, is used to perform voltage conversion on the direct current output by the lithium battery, enabling bidirectional energy flow and meeting the working requirements of the subsequent circuit; An inversion module, adopting a three-phase bridge inversion circuit, converts the direct current output by the DC conversion module into alternating current by controlling the on and off of six switching tubes, and uses PWM control technology to adjust the frequency and amplitude of the output alternating current; A control module, based on a high-performance microprocessor, calculates and outputs control signals according to parameters such as the voltage and current of the lithium battery and the frequency and amplitude of the output alternating current feedback by the detection module, and performs real-time control on the DC conversion module and the inversion module through a preset control algorithm; A detection module, including a voltage sensor, a current sensor, and a temperature sensor, is used to detect in real time the voltage, current, temperature of the lithium battery, and the voltage, current, frequency, etc. of the output alternating current, and feeds the detected data back to the control module; A communication module, adopting communication interfaces such as RS485 or CAN, is used to realize data interaction and remote control between the controller and external devices, receive commands from the upper computer, and send the operating status and parameters of the controller to the upper computer.

2. The direct current and alternating current conversion output controller on the direct current side of a lithium battery according to claim 1, characterized in that When the lithium battery is charging, the DC conversion module converts the high voltage of the external power supply into a voltage suitable for charging the lithium battery; when the lithium battery is discharging, the DC conversion module converts the voltage of the lithium battery into a suitable DC bus voltage.

3. A DC-to-AC conversion output controller on the DC side of a lithium battery, according to claim 1, characterized in that, The linear current sensor in the detection module is ACS712 or its domestic substitute CH701, which is used to accurately detect the charging and discharging current of the lithium battery and output a voltage proportional to the detected current.

4. A control method for converting DC to AC output on the DC side of a lithium battery of a controller, characterized in that, Including the following steps: S1. Initialization: After the controller is powered on, the control module performs initialization settings on the DC conversion module, the inversion module, the detection module, and the communication module to make them enter the normal working state; S2. Parameter detection: The detection module detects in real time the voltage, current, temperature of the lithium battery, and the voltage, current, frequency, etc. of the output alternating current, and sends these parameters to the control module; S3. DC conversion control: The control module adjusts the on-time of the switching tubes of the bidirectional DC-DC converter according to the detected voltage and current of the lithium battery and the working requirements of the system to achieve precise control of the DC voltage; S4. Inversion control: The control module uses PWM control technology to control the on and off times of the switching tubes in the three-phase bridge inversion circuit according to the detected parameters such as the frequency and amplitude of the output alternating current and the working requirements of the system to achieve precise adjustment of the frequency and amplitude of the output alternating current; S5. Protection control: The control module monitors in real time the voltage, current, temperature and other parameters of the lithium battery. When abnormal situations are detected, such as overvoltage, overcurrent, overheating of the lithium battery, etc., it immediately cuts off the operation of the DC conversion module and the inversion module, and sends the fault information to the upper computer through the communication module; Communication interaction: The communication module receives the control instructions sent by the upper computer in real time and transfers them to the control module. The control module adjusts the working state of the controller according to the instructions. At the same time, the communication module sends the operating status and parameters of the controller to the upper computer in real time.

5. A method for controlling the conversion and output of direct current to alternating current on the DC side of a lithium battery of a controller according to claim 4, characterized in that, In the DC conversion control step, when the voltage of the lithium battery is low, the control module controls the DC conversion module to increase the voltage; when the voltage of the lithium battery is high, the control module controls the DC conversion module to decrease the voltage.

6. A method for controlling the conversion and output of direct current and alternating current on the DC side of a lithium battery of a controller according to claim 4, characterized in that, In the inversion control step, when alternating current with a specific frequency and amplitude needs to be output, the control module adjusts the duty cycle and frequency of the PWM signal to make the inversion module output the required alternating current.

Images