A vehicle-mounted battery charging and heating system based on phase-shift full-bridge synchronous rectification

Abstract

The application provides a vehicle-mounted battery charging and heating system based on a phase-shift full-bridge synchronous rectification, which can fully utilize existing power electronic components in a vehicle-mounted charger, and only by additionally arranging a power switch tube and two relay switches, charging and heating functions of a power battery are realized, and the system has simple component structure, low cost, small space occupation and many other advantages. When heating, the system adopts a principle of internal AC heat generation of the battery, is beneficial to decoupling control of a current amplitude and a frequency, makes the heating process more easily controlled, and can significantly improve heating efficiency and uniformity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vehicle-mounted battery charging and heating, and particularly relates to a vehicle-mounted battery charging and heating system based on phase-shift full-bridge synchronous rectification. BACKGROUND

[0002] When the ambient temperature is lower than the normal range required for the normal operation of the battery, the performance of the battery will be seriously attenuated, so when the battery is used on a vehicle, an external heating device such as a PTC element is often matched to cope with the severe cold environment. The setting of the external heating device inevitably occupies the limited space on the vehicle and increases the cost, and the existing external heating means also generally has the problems of low heating efficiency, slow battery temperature rise and the like. The battery AC internal heating means adopted by part of the existing technologies can obviously improve the heating efficiency compared with the external heating, but since the three-phase winding in the vehicle motor needs to be used during the operation, unnecessary torque is easily generated, which has certain hidden dangers for the safety of battery heating. Therefore, how to improve the temperature rise rate, energy consumption efficiency and safety of the battery heating under low temperature conditions is an important problem to be solved in the field. SUMMARY

[0003] Therefore, in view of the technical problems in the prior art, the application provides a vehicle-mounted battery charging and heating system based on phase-shift full-bridge synchronous rectification, which comprises:

[0004] a vehicle-mounted charging and heating main circuit, a vehicle-mounted charging and heating control unit, a power battery and a battery management unit.

[0005] The vehicle-mounted charging and heating main circuit is connected with the power battery through a positive and negative direct-current bus, and is used for charging or heating the power battery. The power battery comprises two battery modules E1 and E2, the battery management unit is used for collecting voltage, current and temperature data of the power battery, calculating the SOC of the power battery, and providing the vehicle-mounted charging and heating control unit, the vehicle-mounted charging and heating control unit is used for obtaining voltage and current sensing data of the vehicle-mounted charging and heating main circuit, and providing mode switching and corresponding PWM control signals for charging or heating the power battery to the vehicle-mounted charging and heating main circuit.

[0006] The vehicle-mounted charging and heating main circuit is composed of a main active power factor correction module, a transformer and its primary and secondary circuits in series. The primary circuit includes two bridge arms respectively composed of two pairs of switching tubes Q1, Q2, Q3 and Q4. Each bridge arm is composed of the upper switching tube Q1, Q3 emitter and the lower switching tube Q2, Q4 collector. The collectors of the upper switching tubes Q1, Q3 of the two bridge arms are connected to the positive line of the primary DC input, and the emitters of the lower switching tubes Q2, Q4 are connected to the negative line of the primary DC input. A filter inductor and a primary winding are connected between the midpoints of the two bridge arms. A primary capacitor is connected between the positive and negative lines of the primary input. The two ends of the secondary winding in the secondary circuit are connected to the collectors of two switching tubes Q5 and Q6. The emitters of Q5 and Q6 are connected to the negative line of the secondary output. The midpoint of the secondary winding is connected to two paths. One path is connected to the positive line of the secondary output through a secondary inductor, a current sensor and the other path is connected to the emitter of a switching tube Q7. The collector of Q7 is connected to the positive pole of the battery module E2 through a single-pole single-throw relay SW1 and a single-pole double-throw relay SW2. The second contact of SW2 is connected to the negative line of the secondary output, and the common contact is connected to the negative pole of the battery module E1. The positive pole of the battery module E1 is connected to the positive line of the secondary output, and the negative pole of the battery module E2 is connected to the negative line of the secondary output. Each battery module is connected in parallel with a capacitor.

[0007] When the relay SW1 is disconnected and the common contact and the first contact of the relay SW2 are connected, the primary and secondary circuits of the transformer form a phase-shifted full-bridge synchronous rectification module, and the vehicle-mounted charging and heating main circuit works in charging mode. The system can be connected to the power frequency AC power supply through the charging interface on the vehicle and charge the power battery directly. When the relay SW1 is closed and the common contact and the second contact of the relay SW2 are connected, the primary side of the transformer has no current output, the secondary circuit forms a battery AC internal heating module in the form of a bidirectional boost circuit, and the vehicle-mounted charging and heating main circuit works in heating mode, which is used for AC internal heating of the battery module.

[0008] Further, the battery modules E1 and E2 are connected in series by closing the common contact and the first contact of the relay SW2 in the charging mode, and are disconnected from each other in the heating mode.

[0009] Further, the voltage of the battery module E1 is less than that of E2. In the heating mode, the switching tubes Q5 and Q6 synchronously perform the actions of conduction and cutoff and cooperate with Q7 to change the current direction in the circuit to make the battery module E1 perform AC internal heating cycle and synchronously transfer heat to E2 to make it warm up.

[0010] Further, the power battery module E1 transfers heat to E2 through the liquid cooling plate during the heating process. When the temperature difference between E1 and E2 is greater than a set threshold, the heating process is paused, and after the temperatures of the two tend to be consistent, the heating process continues.

[0011] The vehicle-mounted battery charging and heating system based on the phase-shifted full-bridge synchronous rectification provided by the present application can make full use of the existing power electronic components in the vehicle-mounted charger, and only by adding one power switch tube and two relay switches, the functions of charging and heating the power battery are realized, and the system has the advantages of simple structure, low cost, small space occupation, etc. The system uses the principle of internal AC heat generation of the battery during heating, which is beneficial to the decoupling control of current amplitude and frequency, makes the heating process easier to control, and can significantly improve the heating efficiency and uniformity. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The schematic diagram of the system provided by the present application is shown in the figure.

[0013] Figure 2 The phase-shifted full-bridge synchronous rectification circuit principle diagram provided by the system in the charging mode is shown in the figure.

[0014] Figure 3 The preferred complete cycle of AC internal heating provided by the present application is shown in the figure. DETAILED DESCRIPTION

[0015] The technical solutions of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0016] The vehicle-mounted battery charging and heating system based on the phase-shifted full-bridge synchronous rectification provided by the present application, as shown in the figure, comprises: Figure 1

[0017] A vehicle-mounted charging and heating main circuit 1, a vehicle-mounted charging and heating control unit 2, a power battery 3, and a battery management unit 4.

[0018] ​The vehicle-mounted charging and heating main circuit is connected with the power battery through positive and negative end direct current bus, and is used for charging or heating the power battery; the power battery comprises two battery modules E1 and E2, the battery management unit is used for collecting voltage, current and temperature data of the power battery, calculating the SOC of the power battery, and providing the vehicle-mounted charging and heating control unit; the vehicle-mounted charging and heating control unit is used for acquiring voltage and current sensing data of the vehicle-mounted charging and heating main circuit, and providing the vehicle-mounted charging and heating main circuit with mode switching and corresponding PWM control signals for charging or heating the power battery.

[0019] The vehicle-mounted charging and heating main circuit is as shown in Figure 2 The vehicle-mounted charging and heating main circuit is as shown in

[0020] When the relay SW1 is disconnected and the common contact and the first contact of the relay SW2 are connected, the primary and secondary circuits of the transformer constitute a phase-shifted full-bridge synchronous rectification module, and the vehicle-mounted charging and heating main circuit works in the charging mode, the system can be connected with the 220V / 50Hz power frequency alternating current power supply 5 through the charging interface on the vehicle and directly charges the power battery; when the relay SW1 is closed and the common contact and the second contact of the relay SW2 are connected, the primary side of the transformer has no current output, the secondary circuit constitutes a battery alternating current internal heating module in the form of a bidirectional boost circuit, and the vehicle-mounted charging and heating main circuit works in the heating mode, which is used for realizing alternating current internal heating of the battery module.

[0021] In a preferred embodiment of the present application, the battery modules E1 and E2 are connected in series by the common contact and the first contact of the relay SW2 in the charging mode, and disconnected from each other in the heating mode.

[0022] In a preferred embodiment of the present application, the voltage of the battery module E1 is less than that of E2; in the heating mode, the switch tubes Q5 and Q6 are synchronously turned on, which can be equivalent to Q56 in Figure 3 , cooperating with Q7, for changing the current direction in the circuit to make the battery module E1 perform the alternating internal heating cycle. Figure 3 A preferred complete heating cycle process performed based on the circuit structure is shown as follows: Figure 3 (a) In the first stage of the heating cycle, the switch tube Q56 is turned on and Q7 is turned off, the battery module E1 charges the inductor L1, and the current in the inductor L1 increases in the positive direction; as shown in Figure 3 (b) In the second stage of the heating cycle, the switch tube Q56 is turned off and Q7 is turned on in the reverse direction, the battery module E1 charges the module E2 together with the inductor L1, and the current in the inductor L1 decreases in the positive direction; as shown in Figure 3 (c) In the third stage of the heating cycle, the switch tube Q56 is turned off and Q7 is turned on in the positive direction, the battery module E2 charges the inductor L1 and the module E1, and the current in the inductor L1 increases in the reverse direction; as shown in Figure 3 (d) In the fourth stage of the heating cycle, the switch tube Q56 is turned on in the reverse direction and Q7 is turned off, the inductor L1 charges the battery module E1, and the current in the inductor L1 decreases in the reverse direction; as shown in

[0023] In the above heating process, the heat of the battery module E1 can be transferred to the module E2 through the liquid cooling plate. When the temperature difference between the module E1 and the module E2 is greater than a set threshold, the heating process can also be paused, and after the temperatures of the two modules tend to be consistent, the heating process is continued.

[0024] Based on the present application, those skilled in the art should know that the active power factor correction module shown can use various existing devices, and the communication between the components in the system can use bus communication methods including but not limited to CAN communication, FlexRay communication, Ethernet communication, etc.

[0025] It should be understood that the sequence numbers of the steps in the embodiments of the present application do not mean the order of execution, and the execution order of the processes should be determined according to their functions and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0026] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A vehicle battery charging and heating system based on phase-shifted full-bridge synchronous rectification, characterized in that: The system comprises: a vehicle-mounted charging and heating main circuit, a vehicle-mounted charging and heating control unit, a power battery, and a battery management unit; The vehicle-mounted charging and heating main circuit is connected with the power battery through positive and negative direct-current buses for charging or heating the power battery; the power battery comprises two battery modules E1 and E2, the battery management unit is used to collect voltage, current, and temperature data of the power battery, calculate the SOC of the power battery, and provide the data to the vehicle-mounted charging and heating control unit; the vehicle-mounted charging and heating control unit is used to acquire voltage and current sensing data of the vehicle-mounted charging and heating main circuit, and provide mode switching and corresponding PWM control signals for charging or heating the power battery to the vehicle-mounted charging and heating main circuit; The vehicle-mounted charging and heating main circuit is composed of a main active power factor correction module, a transformer, and primary and secondary circuits of the transformer; the primary circuit comprises two bridge arms formed by two pairs of switching tubes Q1, Q2, Q3, and Q4, each bridge arm is formed by connecting the emitter of the upper switching tube Q1 or Q3 with the collector of the lower switching tube Q2 or Q4, the collectors of the upper switching tubes Q1 and Q3 of the two bridge arms are connected with the positive line of the primary direct-current input, and the emitters of the lower switching tubes Q2 and Q4 are connected with the negative line of the primary direct-current input; a filter inductor and a primary winding are connected between the midpoints of the two bridge arms; a primary capacitor is connected between the positive and negative lines of the primary input; the two ends of the secondary winding of the secondary circuit are connected with the collectors of two switching tubes Q5 and Q6, the emitters of Q5 and Q6 are connected with the negative line of the secondary output; the midpoint of the secondary winding is led out of two paths, one path is connected with the positive line of the secondary output through a secondary inductor and a current sensor, and the other path is connected with the emitter of a switching tube Q7, the collector of Q7 is connected with the positive pole of the battery module E2 through a single-pole single-throw relay SW1 and a first contact of a single-pole double-throw relay SW2; the second contact of SW2 is connected with the negative line of the secondary output, and the common contact is connected with the negative pole of the battery module E1; the positive pole of the battery module E1 is connected with the positive line of the secondary output, and the negative pole of the battery module E2 is connected with the negative line of the secondary output; each battery module is connected in parallel with a capacitor; When the relay SW1 is disconnected and the common contact and the first contact of the relay SW2 are connected, the primary and secondary circuits of the transformer form a phase-shifted full-bridge synchronous rectification module, and the vehicle-mounted charging and heating main circuit works in the charging mode, so that the system can be connected with a power frequency alternating current power source through a charging interface on the vehicle and directly charge the power battery; when the relay SW1 is closed and the common contact and the second contact of the relay SW2 are connected, the primary winding of the transformer has no current output, the secondary circuit forms a battery alternating current internal heating module in the form of a bidirectional buck-boost circuit, and the vehicle-mounted charging and heating main circuit works in the heating mode, so as to realize alternating current internal heating of the battery modules.

2. The system of claim 1, wherein: The battery modules E1 and E2 are connected in series by closing the common contact and the first contact of the relay SW2 in the charging mode, and are disconnected from each other in the heating mode.

3. The system of claim 2, wherein: The voltage of the battery module E1 is less than the voltage of E2, otherwise it cannot work normally; in the heating mode, the switch tube Q5, Q6 synchronously performs the action of conduction and cut-off and cooperates with Q7, which is used to change the current direction in the loop to make the battery module E1 perform the alternating internal heating cycle, and synchronously transfer heat to E2 to make it warm up during the E1 warming process.

4. The system of claim 3, wherein: During the heating process, when the temperature difference between the battery modules E1 and E2 is greater than the set threshold, the heating process is paused, and after the temperatures of the two tend to be consistent, the heating process continues.

Images