An electric vehicle charging circuit logic control system

Abstract

The application discloses an electric vehicle charging circuit logic control system, and relates to the technical field of electric vehicle charging, which comprises an EMI circuit, a rectification module, a filtering module, a PFC switch tube and an LLC switch tube adopting GaN material, a high-frequency transformer, a synchronous rectification module and the like. When the system is working, the EMI circuit filters out AC interference first, and then corrects the power factor through the PFC circuit after rectification and filtering, and then transforms the electric energy through the LLC circuit, adjusts the voltage through the high-frequency transformer, and outputs DC power after synchronous rectification. The system has anti-reverse connection protection, the charging MCU communicates with the BMS to dynamically adjust the charging parameters, and has an electric quantity display and an auxiliary power supply module. The system is high in efficiency and energy saving, can realize fast charging, reduce the equipment size, reduce the heat generation, reduce the harmonic pollution, improve the charging efficiency and safety, reduce the use cost, and expand the use scene.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric vehicle charging, in particular to a logic control system of an electric vehicle charging circuit. BACKGROUND

[0002] In recent years, with the deepening of environmental protection concept and the aggravation of urban traffic congestion, electric bicycles have rapidly become an important means of transportation for short trips due to their advantages of portability, green environmental protection and low use cost, and the market demand has shown explosive growth. However, the charging link of electric bicycles has exposed many problems to be solved, for example:

[0003] 1. The traditional electric bicycle charging circuit technology is relatively backward, and the power factor is generally low. During the charging process, a large amount of reactive power flows in the power grid, not only causing a significant decrease in power utilization and energy waste, but also increasing the burden on the power grid and affecting the stable operation of the power grid. Moreover, the performance of the switching tube and other components used in the traditional charging circuit is limited, and the loss is large during the power conversion process, making it difficult to improve the charging efficiency and prolonging the charging time, which brings many inconveniences to the users.

[0004] 2. The traditional charging equipment is large in size and heavy in weight, and is not convenient to carry and install. For some users living in high-rise buildings or limited space, the placement of the charging equipment becomes a problem, limiting the use of electric bicycles. At the same time, the traditional charging circuit also has shortcomings in heat dissipation, and long-time charging can easily cause the equipment to overheat, affecting the charging efficiency and possibly causing safety hazards and shortening the service life of the equipment. SUMMARY

[0005] To solve the technical problems in the background art, the present application provides a logic control system of an electric vehicle charging circuit.

[0006] The logic control system of the electric vehicle charging circuit provided by the present application comprises an EMI circuit, a rectifier module, a filter module, a PFC switching tube (GaN), an LLC switching tube (GaN), a high-frequency transformer, a synchronous rectification module connected in sequence, and further comprises a PFC controller connected with the PFC switching tube (GaN), an LLC controller connected with the LLC switching tube (GaN), and a charging DC controller, an anti-reverse connection relay and a DC auxiliary current module connected with the synchronous rectification module. The charging DC controller is connected with a charging MCU CAN protocol management control module and a charging DC output end respectively, the charging MCU CAN protocol management control module is connected with a battery power display module and an electric vehicle BMS, and the electric vehicle BMS is connected with a battery.

[0007] Further, the EMI circuit is used for electromagnetic interference filtering processing of 220V AC input to remove the noise interference in the input AC power.

[0008] Further, the rectifier module converts the alternating current processed by the EMI circuit into direct current, and the filter module filters the rectified direct current to obtain smooth direct current voltage.

[0009] Further, the PFC controller controls the PFC switch tube (GaN) to work, realizes power factor correction, improves power utilization rate, and makes the input current and voltage phase consistent.

[0010] Further, the LLC controller controls the LLC switch tube (GaN), and through the high-frequency transformer and the synchronous rectifier module, the power processed by the PFC is converted into direct current power suitable for charging the electric vehicle battery.

[0011] Further, the anti-reverse connection relay is used to prevent the charging circuit from being damaged when the battery is reversed, and automatically disconnects the charging circuit when the battery reverse connection condition is detected.

[0012] Further, the charging MCU CAN protocol management control module communicates with the electric vehicle BMS through the CAN protocol to obtain battery state information including battery capacity, voltage, temperature, etc., and controls the charging DC controller to output appropriate charging parameters according to the information.

[0013] Further, the battery capacity display module displays the remaining capacity of the electric vehicle battery according to the battery capacity information obtained by the charging MCU CAN protocol management control module, so that the user can check it.

[0014] Further, the DC auxiliary current module provides auxiliary DC power for the control circuit, communication circuit, etc. in the charging circuit to ensure stable work of each control and communication module.

[0015] The control method of the above electric vehicle charging circuit logic control system includes the following steps:

[0016] S1, after the 220V alternating current is filtered by the EMI circuit to remove electromagnetic interference, it is converted into pulsating direct current by the rectifier module, and then smoothed into stable direct current voltage by the filter module;

[0017] S2, the PFC controller drives the PFC switch tube (GaN) to high-frequency chopping, adjusts the input current phase, makes the current and voltage in phase, and completes the power factor correction;

[0018] S3, the LLC controller drives the LLC switch tube (GaN) to work, inverts the PFC output direct current into high-frequency alternating current, isolates and adjusts the voltage through the high-frequency transformer, and then converts it into direct current power suitable for battery charging by the synchronous rectifier module;

[0019] S4, the reverse connection relay detects the battery connection polarity in real time, and disconnects the charging circuit if reverse connection is detected;

[0020] S5, the charging MCU communicates with the electric vehicle BMS through the CAN protocol, obtains state information such as battery capacity, voltage, temperature, and dynamically adjusts the output current / voltage parameters of the charging DC controller;

[0021] S6, the battery capacity display module displays the remaining battery capacity in real time according to the capacity information obtained by the charging MCU;

[0022] S7, the DC auxiliary current module converts the main circuit electric energy into low-voltage direct current to provide stable working power for the PFC controller, LLC controller, charging MCU and communication module.

[0023] The beneficial effects of the present application are:

[0024] 1, the PFC switch tube and LLC switch tube using GaN material have extremely low on-resistance and switching loss, greatly improving the electric energy conversion efficiency of the charging circuit. When charging the electric bicycle battery, it can input electric energy at a higher power, significantly shortening the charging time. The battery that needs several hours to be fully charged in the past can be charged in a shorter time using the present charging circuit, greatly saving the user's time cost, improving the use efficiency of the electric bicycle, and is especially suitable for time-stressed groups such as office workers and delivery riders.

[0025] 2, the high-frequency characteristics of GaN switch tube greatly reduce the size of high-frequency transformer, and further make the whole charging circuit logic control system more compact and portable. Users can easily carry it with them, whether in the office, school or travel, and can easily charge the electric bicycle. At the same time, the small size also facilitates installation in various space environments, such as home balconies, staircases, etc., solving the problem of difficult placement of traditional charging equipment due to large size, and expanding the use scenarios of electric bicycles.

[0026] 3, due to the improvement of electric energy conversion efficiency, a large amount of unnecessary electric energy loss is reduced during charging. For users, this means that less electric energy is consumed each time, thereby reducing the use cost of the electric bicycle. In the long run, it can save users a considerable amount of expenses, and improve the economy of the electric bicycle.

[0027] 4, the lower switching loss and on-resistance greatly reduce the heat generated by the charging circuit during operation, effectively reducing the heat dissipation of the device. This not only reduces the burden of the heat dissipation system and the cost of heat dissipation, but also avoids the performance degradation and damage of components caused by overheating, improving the safety and stability of the charging device. Users do not need to worry about safety problems caused by overheating of the device during charging, and can use it more confidently.

[0028] 5、The charging circuit effectively reduces the harmonic pollution of the power grid during the charging process through power factor correction technology, improving the power quality. This helps to reduce the loss of the power grid and reduce the negative impact on the environment, meeting the requirements of modern society for green and environmentally friendly products. At the same time, the efficient charging process also reduces energy waste, making a positive contribution to sustainable development. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The logic diagram of the present application. DETAILED DESCRIPTION

[0030] Referring to Figure 1 The electric vehicle charging circuit logic control system proposed by the present application realizes efficient conversion and accurate control of 220V alternating current through circuit modules and intelligent control strategies, providing suitable charging power for electric vehicle batteries. The system mainly includes EMI circuit, rectifier module, filter module, PFC switch tube (GaN), LLC switch tube (GaN), high-frequency transformer, synchronous rectification module and other key parts. Each part works together to complete the charging task, as follows:

[0031] The EMI circuit, as the front-end protection and processing unit of the charging system, is mainly responsible for electromagnetic interference filtering processing of the input 220V alternating current. In the power grid environment, alternating current is often subject to various electromagnetic interferences, such as radio interference, harmonic interference generated by switching power supply, etc. These interferences not only affect the normal operation of the charging circuit itself, but also may have adverse effects on other electronic devices. The EMI circuit forms a low-pass filter through internal capacitors, inductors and other filter elements, effectively suppresses high-frequency interference signals and removes the noise interference in the input alternating current, providing relatively pure alternating current for the subsequent circuit. The output end of the EMI circuit is connected with the rectifier module, and the processed alternating current is transmitted to the rectifier module for further processing, which is the initial processing link of the entire charging circuit.

[0032] The rectifier module receives the alternating current processed by the EMI circuit, and its core function is to convert alternating current into pulsating direct current. The rectifier module usually adopts a rectifier bridge circuit composed of diodes, which utilizes the unidirectional conductivity of diodes to convert the positive half cycle and negative half cycle of alternating current into direct current of the same direction. However, the output direct current still has a large pulsating component, and the voltage and current will periodically change with time. The output end of the rectifier module is connected with the filter module, and the pulsating direct current is transmitted to the filter module for smoothing processing, which is the key conversion link of alternating current to direct current.

[0033] The main task of the filter module is to filter the pulsating DC output by the rectifier module to obtain a smooth DC voltage. It usually consists of a large-capacity electrolytic capacitor and inductance elements in the filter circuit. The electrolytic capacitor has the characteristics of charging and discharging. When the voltage rises, it stores electrical energy, and when the voltage decreases, it releases electrical energy, thereby smoothing the voltage fluctuations. The inductance uses its energy storage characteristics to suppress changes in current, further reducing current pulsations. Through the processing of the filter module, the ripple coefficient of the output voltage is greatly reduced, providing a stable DC power supply for the subsequent circuit. The output end of the filter module is connected to the PFC switch tube (GaN), which transmits the smooth DC voltage to the PFC circuit for power factor correction. It is an important link in the stable processing of DC power.

[0034] The PFC switch tube is made of gallium nitride (GaN) material. Compared with traditional silicon-based switch tubes, it has the advantages of high frequency, high efficiency, low loss, etc. Under the action of the PFC controller, the PFC switch tube performs high-frequency chopping operation, adjusts the waveform and phase of the input current through rapid conduction and shutdown, and makes it consistent with the waveform and phase of the input voltage, thereby realizing power factor correction. Power factor correction can improve power utilization, reduce the loss of reactive power, reduce harmonic pollution to the power grid, and improve the efficiency of the entire charging system.

[0035] The PFC controller is the core control unit of the PFC circuit. It monitors the input voltage and current signals in real time and uses specific control algorithms such as average current control algorithm and peak current control algorithm to accurately control the conduction and shutdown time of the PFC switch tube. The PFC controller can dynamically adjust the control parameters according to the changes in input voltage and load to ensure that the power factor correction effect remains at a high level at all times.

[0036] The output end of the PFC switch tube is connected to the LLC switch tube (GaN), which transmits the DC power after power factor correction to the LLC circuit for further electrical energy conversion. The PFC controller is directly connected to the PFC switch tube and precisely controls it, which is the core control part of the power factor correction link.

[0037] The LLC switch tube also uses gallium nitride (GaN) material. Under the action of the LLC controller, it inverts the PFC output DC into high-frequency AC. High-frequency AC has a higher frequency, which is convenient for voltage transformation and electrical isolation through a high-frequency transformer. The LLC switch tube realizes the conversion from DC to high-frequency AC through precise switching control. Its high-frequency characteristics greatly reduce the size of the transformer, improving the power density of the charging system.

[0038] The LLC controller is responsible for controlling the working state of the LLC switch tube, and realizes the accurate control of the output voltage and current by adjusting the switching frequency and duty cycle of the switch tube and other parameters. It dynamically adjusts the control strategy according to the requirements of the charging system, such as the charging stage of the battery (constant current charging, constant voltage charging, etc.) and the state of the battery (power, voltage, etc.), and adjusts the high-frequency alternating current to the voltage and current suitable for the battery charging of the electric vehicle. The output end of the LLC switch tube is connected with the high-frequency transformer, and the high-frequency alternating current is transmitted to the high-frequency transformer. The LLC controller is directly connected with the LLC switch tube and controls it, which is the key control link of electric energy conversion and voltage adjustment.

[0039] The high-frequency transformer is a key element in the LLC circuit, which mainly plays the role of voltage conversion and electrical isolation. By adjusting the turns ratio of the high-frequency transformer, the voltage of the high-frequency alternating current output by the LLC switch tube can be converted to the voltage suitable for the battery charging of the electric vehicle. For example, if the battery needs a lower charging voltage, the voltage conversion can be realized by increasing the secondary turns ratio, and the electrical isolation function can effectively prevent the fault current on the battery side from affecting the main circuit and improve the safety of the charging system. When a short circuit or other fault occurs on the battery side, the high-frequency transformer can block the transmission of current, protecting the elements in the main circuit from being damaged. The output end of the high-frequency transformer is connected with the synchronous rectification module, and the converted high-frequency alternating current is transmitted to the synchronous rectification module for rectification, which is an important link of electric energy conversion and isolation.

[0040] The synchronous rectification module uses MOSFET and other devices with low on-resistance to replace traditional diodes for rectification. Under the action of the high-frequency alternating current output by the high-frequency transformer, the synchronous rectification module controls the MOSFET to turn on and off at the right time. Since the on-resistance of the MOSFET is much lower than the forward voltage drop of the diode, the synchronous rectification technology can greatly reduce the loss in the rectification process and improve the charging efficiency. Especially in high-frequency and high-current application scenarios, the advantages of synchronous rectification are more obvious. The output end of the synchronous rectification module is connected with the anti-reverse connection relay, and the converted DC power is transmitted to the anti-reverse connection relay, which is the key link of converting high-frequency alternating current to DC and reducing loss.

[0041] When the system is working, the following steps are included:

[0042] 1、220V AC power first into the EMI circuit, the EMI circuit for electromagnetic interference filtering processing, remove the noise interference, the processed AC into the rectifier module, the rectifier module converts it to pulsating DC, pulsating DC through the filter module for smoothing, get smooth DC voltage, for subsequent power factor correction and power conversion to provide stable power supply, in the process of processing, the need for real-time monitoring of input voltage and current parameters, to ensure the normal work of EMI circuit and rectifier filter circuit, such as abnormal situation (such as input voltage is too high or too low, current is too large, etc.), should take protective measures, such as cutting off the input power or adjusting the circuit parameters;

[0043] 2、PFC controller drives PFC switch tube (GaN) for high frequency chopping operation, PFC controller real-time monitoring of input voltage and current phase, by adjusting the PFC switch tube conduction and off time, the input current phase and the phase of the input voltage tend to be consistent, so as to complete the power factor correction, in the process of power factor correction, the need for accurate control of PFC switch tube switching frequency and duty cycle, to ensure that the power factor reaches a high level (generally requires greater than 0.9), at the same time, to monitor the output voltage and current of PFC circuit, to ensure that it is stable in the appropriate range, for subsequent LLC circuit provides stable input;

[0044] 3、LLC controller drives LLC switch tube (GaN) work, the PFC output DC inverter into high frequency AC, high frequency AC into high frequency transformer, through the voltage transformation and electrical isolation of high frequency transformer, the voltage is adjusted to the voltage suitable for electric vehicle battery charging, then, high frequency AC into synchronous rectifier module, synchronous rectifier module converts it into a DC power suitable for battery charging, in the process of power conversion, LLC controller needs to be according to the charging state and demand of the battery, dynamic adjustment of switching frequency and duty cycle, to realize the accurate control of output voltage and current, at the same time, to monitor the working state of high frequency transformer and synchronous rectifier module, to ensure its normal work, such as abnormal situation (such as transformer overheating, synchronous rectification MOSFET failure, etc.), should take protective measures in time;

[0045] 4、anti-reverse connection relay real-time detection of battery wiring polarity. If the battery reverse connection is detected, the anti-reverse connection relay will automatically disconnect the charging circuit to prevent the battery reverse connection from damaging the charging circuit, in the process of anti-reverse connection protection, the detection sensitivity and response speed of anti-reverse connection relay need to be ensured, which can cut off the charging circuit in time when the battery is reversed, at the same time, the anti-reverse connection relay needs to be detected and maintained regularly to ensure its normal work;

[0046] 5. The charging MCU communicates with the electric vehicle's BMS via the CAN protocol to obtain battery status information such as charge, voltage, and temperature. Based on this information, the charging MCU dynamically adjusts the output current / voltage parameters of the charging DC controller to achieve precise control of the charging process. For example, during the constant current charging stage, the charging MCU adjusts the output current of the charging DC controller according to the battery's charge and voltage to keep it within a suitable range; during the constant voltage charging stage, the charging MCU adjusts the output voltage of the charging DC controller according to the battery's voltage to stabilize it at the battery's charging cutoff voltage. During battery status monitoring and charging parameter adjustment, it is necessary to ensure the stability and accuracy of communication, obtain battery status information in a timely manner, and adjust charging parameters quickly and accurately based on the information.

[0047] 6. The battery power display module displays the remaining power of the electric vehicle battery in real time based on the power information obtained from the charging MCU, so that users can understand the charging status of the battery. The battery power display module can use LCD screen, LED indicator, etc. During the battery power display process, it is necessary to ensure the accuracy and timeliness of the displayed information, so as to truly reflect the remaining power of the battery. At the same time, the battery power display module should be calibrated regularly to ensure its display accuracy.

[0048] 7. The DC auxiliary current module converts the main circuit power into low-voltage DC to provide a stable operating power supply for the PFC controller, LLC controller, charging MCU, and communication module, ensuring the stable operation of each control and communication module. During the auxiliary power supply process, it is necessary to ensure that the output voltage and current of the DC auxiliary current module are stable and can meet the working requirements of each control and communication module. At the same time, the DC auxiliary current module should be monitored and protected. If abnormal output voltage or overload is found, protective measures should be taken in time.

[0049] Through the above technical solution, the electric vehicle charging circuit logic control system can provide electric vehicles with efficient, safe and stable charging services, meet the needs of electric vehicle users, and also help extend the battery life and improve the overall performance of electric vehicles.

[0050] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A logic control system for an electric vehicle charging circuit, characterized in that, The system includes, in sequence, an EMI circuit, a rectifier module, a filter module, a PFC switch, an LLC switch, a high-frequency transformer, and a synchronous rectifier module. It also includes a PFC controller connected to the PFC switch, an LLC controller connected to the LLC switch, and a charging DC controller, a reverse connection protection relay, and a DC auxiliary current module connected to the synchronous rectifier module. The charging DC controller is connected to the charging MCUCAN protocol management and control module and the charging DC output terminal. The charging MCUCAN protocol management and control module is connected to the battery power display module and the electric vehicle BMS. The electric vehicle BMS is connected to the battery. The control method includes the following steps: S1, 220V AC power is filtered out by EMI circuit to remove electromagnetic interference, then converted into pulsating DC power by rectifier module, and then smoothed into stable DC voltage by filter module; S2, the PFC controller drives the PFC switching transistor to chop at high frequency, adjust the phase of the input current, make the current and voltage in phase, and complete the power factor correction. S3, LLC controller drives LLC switching transistor to work, inverting the DC output of PFC into high-frequency AC power. After being isolated and the voltage is adjusted by high-frequency transformer, it is converted into DC power adapted to battery charging by synchronous rectification module. S4. The reverse connection protection relay detects the battery wiring polarity in real time. If reverse connection is detected, the charging circuit will be disconnected. S5. The charging MCU communicates with the electric vehicle BMS via the CAN protocol to obtain status information such as battery power, voltage, and temperature, and dynamically adjusts the output current / voltage parameters of the charging DC controller. S6. The battery power display module displays the remaining battery power in real time based on the power information obtained from the charging MCU. The S7 DC auxiliary current module converts the main circuit power into low-voltage DC, providing a stable power supply for the PFC controller, LLC controller, charging MCU, and communication module.

2. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The EMI circuit is used to filter electromagnetic interference from the 220V AC input, removing noise interference from the input AC power.

3. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The rectifier module converts the AC power processed by the EMI circuit into DC power, and the filter module filters the rectified DC power to obtain a stable DC voltage.

4. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The PFC controller controls the PFC switch to operate, thereby achieving power factor correction, improving energy utilization, and making the input current and voltage phase more consistent.

5. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The LLC controller controls the LLC switching transistor, and through a high-frequency transformer and synchronous rectification module, converts the electrical energy processed by PFC into DC electrical energy suitable for charging electric vehicle batteries.

6. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The reverse connection protection relay is used to prevent damage to the charging circuit when the battery is connected in reverse. When a reverse connection is detected, the charging circuit is automatically disconnected.

7. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The charging MCUCAN protocol management and control module communicates with the electric vehicle BMS via the CAN protocol to obtain battery status information, including battery power, voltage, temperature, etc., and controls the charging DC controller to output appropriate charging parameters based on this information.

8. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The battery power display module displays the remaining battery power of the electric vehicle battery based on the battery power information obtained by the charging MCUCAN protocol management and control module, making it convenient for users to view.

9. The electric vehicle charging circuit logic control system according to claim 1, characterized in that, The DC auxiliary current module provides auxiliary DC power to the control circuit, communication circuit, etc. in the charging circuit, ensuring the stable operation of each control and communication module.

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