Charging circuit, charging method, power system and vehicle

Abstract

The invention relates to a charging circuit, a charging method, a power system and a vehicle. The charging circuit comprises a first direct charging loop, a boost charging loop, an up-flow charging loop and a second direct charging loop composed of a part of the boost charging loop and a part of the up-flow charging loop. The first direct charging loop, the boost charging loop, the current-rising charging loop and the second direct charging loop are electrically connected between the charging power supply and the power battery respectively; the first direct charging loop is used for transmitting a first direct charging current, the second direct charging loop is used for transmitting a second direct charging current, and the first direct charging current is smaller than the second direct charging current. According to the direct charging circuit, the partial loop of the boost charging loop capable of bearing the large current and the partial loop of the current-rising charging loop are multiplexed, so that the second direct charging loop capable of bearing the large current is formed, the first direct charging loop is only used for bearing the small current, and then at least partial hardware cost of the first direct charging loop can be saved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle charging, and in particular, to a charging circuit, a charging method, a power system, and a vehicle. Background Art

[0002] New energy vehicles usually design multiple charging circuits to meet different charging requirements and optimize charging efficiency, including a direct charging circuit, a boost charging circuit, and a current boost charging circuit. The direct charging circuit is the most basic charging path and is usually used for the vehicle to directly obtain electrical energy from an external charging power source (such as a home charging pile or a public charging station). The current boost charging circuit is mainly used to adjust the current when it is necessary to increase the charging speed. The function of the boost charging circuit is to boost a lower input voltage to a level suitable for charging the power battery.

[0003] When the direct charging mode is selected, charging is carried out through the direct charging circuit. In the direct charging mode, the required current of the power battery may be large or small. To ensure the reliability of the circuit, it is required that the direct charging circuit has the ability to withstand large currents, which ultimately leads to an increase in the required hardware cost. Summary of the Invention

[0004] Embodiments of the present application provide a charging circuit, a charging method, a power system, and a vehicle, which reuse part of the boost charging circuit capable of withstanding large currents and part of the current boost charging circuit to form a second direct charging circuit capable of withstanding large currents, so that the first direct charging circuit is only used to withstand small currents, thereby saving at least part of the hardware cost of the first direct charging circuit and at least partially solving the above technical problems.

[0005] To achieve the above object, according to the first aspect of the present application, a charging circuit is provided, including a first direct charging circuit, a boost charging circuit, a current boost charging circuit, and a second direct charging circuit composed of part of the boost charging circuit and part of the current boost charging circuit;

[0006] The first direct charging circuit, the boost charging circuit, the current boost charging circuit, and the second direct charging circuit are respectively electrically connected between a charging power source and a power battery;

[0007] The first direct charging circuit is used to transmit a first direct charging current, and the second direct charging circuit is used to transmit a second direct charging current, and the first direct charging current is less than the second direct charging current.

[0008] Optionally, the charging circuit includes a three-phase inverter, a three-phase AC motor, a first switching device, a second switching device, a third switching device, and a fourth switching device;

[0009] The first access terminal of the first switching device is electrically connected to the first access terminal of the second switching device at a first common terminal and is used to be electrically connected to the positive pole of the charging power supply. The second access terminal of the first switching device is electrically connected to the first access terminal of the third switching device at a second common terminal and is electrically connected to the Y-type common terminal of the three-phase AC motor. The second access terminal of the second switching device is electrically connected to the first access terminal of the fourth switching device at a third common terminal and is electrically connected to the DC terminal of the three-phase inverter. The second access terminal of the third switching device is electrically connected to the second access terminal of the fourth switching device at a fourth common terminal and is used to be electrically connected to the positive pole of the power battery;

[0010] The first direct charging circuit includes the second switching device and the fourth switching device;

[0011] The boost charging circuit includes the first switching device, the three-phase AC motor, the three-phase inverter and the fourth switching device;

[0012] The current boost charging circuit includes the second switching device, the three-phase inverter, the three-phase AC motor and the third switching device;

[0013] The second direct charging circuit includes the first switching device and the third switching device.

[0014] Optionally, the second switching device uses a switching device with a specification of a first maximum current, and the first switching device, the third switching device and the fourth switching device respectively use switching devices with a specification of a second maximum current;

[0015] The first maximum current is less than the second maximum current.

[0016] Optionally, the wire harness between the first common terminal and the third common terminal uses a wire harness with a specification of a first square value, and other wire harnesses use wire harnesses with a specification of a second square value;

[0017] The first square value is less than the second square value.

[0018] Optionally, the charging circuit further includes an energy storage capacitor;

[0019] The first end of the energy storage capacitor is electrically connected to the second access terminal of the second switching device and the first access terminal of the fourth switching device respectively, and the second end of the energy storage capacitor is respectively used to be electrically connected to the negative pole of the power battery and the negative pole of the charging power supply.

[0020] Optionally, the charging circuit further includes a fifth switching device and a sixth switching device;

[0021] The second access terminal of the fifth switching device is electrically connected to the second end of the energy storage capacitor and the first access terminal of the sixth switching device respectively. The first access terminal of the fifth switching device is used to be electrically connected to the negative pole of the power battery, and the second access terminal of the sixth switching device is used to be electrically connected to the negative pole of the charging power supply;

[0022] The first direct charging circuit, the boost charging circuit, the boost current charging circuit, and the second direct charging circuit further include a fifth switching device and a sixth switching device respectively.

[0023] According to a second aspect of the present application, a charging method is provided, which is applied to the charging circuit in any of the above embodiments; the charging method includes:

[0024] Controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct charging mode, a boost current charging mode, a boost charging mode, or a second direct charging mode.

[0025] Optionally, controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes:

[0026] Controlling the second switching device and the fourth switching device to be closed and the first switching device and the third switching device to be open to charge the power battery in a first direct charging mode.

[0027] Optionally, controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes:

[0028] Controlling the first switching device and the third switching device to be closed and the second switching device and the fourth switching device to be open to charge the power battery in a second direct charging mode.

[0029] Optionally, controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes:

[0030] Controlling the first switching device and the fourth switching device to be closed and the second switching device and the third switching device to be open to charge the power battery in a boost charging mode.

[0031] Optionally, controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes:

[0032] Controlling the second switching device and the third switching device to be closed and the first switching device and the fourth switching device to be open to charge the power battery in a boost current charging mode.

[0033] According to a third aspect of the present application, a power system is provided, including a power battery and the charging circuit in any of the above embodiments.

[0034] According to a fourth aspect of the present application, a vehicle is provided, including the charging circuit in any of the above embodiments, or including the power system in any of the above embodiments.

[0035] In the present application, the charging circuit multiplexes part of the boost charging circuit and part of the current boost charging circuit that can withstand large currents, thereby forming a second direct charging circuit that can withstand large currents, such that the first direct charging circuit is only used to withstand small currents, and thus at least part of the hardware cost of the first direct charging circuit can be saved.

[0036] Other features and advantages of the present application will be described in detail in the following specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] To more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0038] To more fully understand the present application and its beneficial effects, the following description will be made in conjunction with the drawings, where the same reference numerals represent the same parts in the following description.

[0039] Figure 1 is a schematic structural diagram of the charging circuit provided in an exemplary embodiment of the present application;

[0040] Figure 2 is a schematic circuit diagram of the charging circuit provided in an exemplary embodiment of the present application;

[0041] Figure 3 is a schematic diagram of the relationship of the control main body provided in an exemplary embodiment of the present application;

[0042] Figure 4 is a schematic structural diagram of the power system provided in an exemplary embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0044] According to the first aspect of the present application, as Figure 1 shown, a charging circuit is provided, which includes a first direct charging circuit, a boost charging circuit, a boost current charging circuit, and a second direct charging circuit composed of a partial circuit of the boost charging circuit and a partial circuit of the boost current charging circuit.

[0045] The first direct charging circuit, the boost charging circuit, the boost current charging circuit, and the second direct charging circuit are respectively electrically connected between a charging power source and a power battery.

[0046] Among them, the first direct charging circuit and the second direct charging circuit generally only include corresponding wiring harnesses and switching devices. When the switching devices in the circuits are turned on, the charging current output by the charging power source is directly transmitted to the power battery through the corresponding wiring harnesses.

[0047] Among them, in addition to including corresponding wiring harnesses and switching devices, the boost charging circuit also includes corresponding boosting devices, such as inductors, etc. Similar to the boost charging circuit, in addition to including corresponding wiring harnesses and switching devices, the boost current charging circuit also includes corresponding current boosting devices, such as inductors, etc.

[0048] Among them, the charging power source can be a charging pile or a charging station.

[0049] The first direct charging circuit is used to transmit a first direct charging current, and the second direct charging circuit is used to transmit a second direct charging current, and the first direct charging current is less than the second direct charging current.

[0050] Among them, the first direct charging current transmitted by the first direct charging circuit does not exceed a first maximum current, such as transmitting a current of 250A; the second direct charging current transmitted by the second direct charging circuit does not exceed a second maximum current, such as transmitting a current of 400A. In the direct charging mode, if the required current of the power battery is below 250A, the first direct charging circuit can be selected for transmission; if the required current of the power battery is between 250A and 400A, the second direct charging circuit can be selected for transmission.

[0051] The above-mentioned first maximum current and second maximum current can be used as the basis for hardware material selection of the first direct charging circuit and the second direct charging circuit. Since the boost charging circuit and the boost current charging circuit generally have the ability to withstand the second maximum current, the hardware material selection of the second direct charging circuit obtained by multiplexing the boost charging circuit and the boost current charging circuit does not need to be changed. For the first direct charging circuit, it is only used to withstand the first maximum current lower than the second maximum current, so the hardware material selection of the first direct charging circuit can consider devices and wiring harnesses with lower costs.

[0052] It should be noted that some of the wiring harnesses and components of the first direct charging circuit may also be used to form the discharge circuit of the power battery. Therefore, when selecting hardware for the first direct charging circuit, it is necessary to consider the scenario of high-current discharge. In any case, the first direct charging circuit that only bears small current during the charging stage can at least consider components and wiring harnesses with lower costs in terms of some hardware selections.

[0053] In the present application, the charging circuit multiplexing reuses part of the boost charging circuit and part of the current-boosting charging circuit that can withstand high current, so as to form a second direct charging circuit that can withstand high current, enabling the first direct charging circuit to only bear small current, and thus at least part of the hardware cost of the first direct charging circuit can be saved.

[0054] As Figure 2 shown, optionally, the charging circuit includes a three-phase inverter, a three-phase AC motor, a first switching device K1, a second switching device K2, a third switching device K3, a fourth switching device K4, a fifth switching device K5, a sixth switching device K6, and an energy storage capacitor C1.

[0055] Among them, for any one of the first switching device K1, the second switching device K2, the third switching device K3, the fourth switching device K4, the fifth switching device K5, and the sixth switching device K6, a contactor, a relay, etc. can be adopted.

[0056] The first access end of the first switching device K1 and the first access end of the second switching device K2 are electrically connected to a first common terminal J1 and are used to be electrically connected to the positive pole of the charging power supply. The second access end of the first switching device K1 and the first access end of the third switching device K3 are electrically connected to a second common terminal J2 and are electrically connected to the Y-type common terminal of the three-phase AC motor. The second access end of the second switching device K2 and the first access end of the fourth switching device K4 are electrically connected to a third common terminal J3 and are electrically connected to the DC end of the three-phase inverter. The second access end of the third switching device K3 and the second access end of the fourth switching device K4 are electrically connected to a fourth common terminal J4 and are used to be electrically connected to the positive pole of the power battery.

[0057] The first end of the energy storage capacitor C1 is electrically connected to the second access end of the second switching device K2 and the first access end of the fourth switching device K4 respectively. The second end of the energy storage capacitor C1 is electrically connected to the second access end of the fifth switching device K5 and the first access end of the sixth switching device K6 respectively. The first access end of the fifth switching device K5 is used to be electrically connected to the negative pole of the power battery. The second access end of the sixth switching device K6 is used to be electrically connected to the negative pole of the charging power supply.

[0058] Among them, the fourth switching device K4 serves as the main positive switching device of the power battery, and the fifth switching device K5 serves as the main negative switching device of the power battery. In practice, it also includes a pre-charging unit connected in parallel with the fourth switching device K4, and the pre-charging unit includes a series-connected pre-charging switching device and a current-limiting device.

[0059] Among them, through the combination of the above-mentioned first switching device K1, second switching device K2, third switching device K3, fourth switching device K4, fifth switching device K5, sixth switching device K6, three-phase inverter, and three-phase AC motor, the corresponding first direct charging circuit, boost charging circuit, current boost charging circuit, and second direct charging circuit can be obtained.

[0060] Specifically:

[0061] The first direct charging circuit includes the second switching device K2, fourth switching device K4, fifth switching device K5, and sixth switching device K6.

[0062] Among them, when the second switching device K2, fourth switching device K4, fifth switching device K5, and sixth switching device K6 are simultaneously turned on, a direct connection path is formed between the charging power supply and the power battery. The charging current flows out from the positive pole of the charging power supply and passes through the second switching device K2, fourth switching device K4, positive pole of the power battery, negative pole of the power battery, fifth switching device K5, and sixth switching device K6 in sequence, and then returns to the negative pole of the charging power supply.

[0063] The boost charging circuit includes the first switching device K1, three-phase AC motor, three-phase inverter, fourth switching device K4, fifth switching device K5, and sixth switching device K6.

[0064] Among them, when the first switching device K1, fourth switching device K4, fifth switching device K5, and sixth switching device K6 are simultaneously turned on, a boost path is formed between the charging power supply and the power battery. The charging current flows out from the positive pole of the charging power supply and passes through the first switching device K1, three-phase AC motor, three-phase inverter, fourth switching device K4, fifth switching device K5, and sixth switching device K6 in sequence, and then returns to the negative pole of the charging power supply.

[0065] The current boost charging circuit includes the second switching device K2, three-phase inverter, three-phase AC motor, third switching device K3, fifth switching device K5, and sixth switching device K6.

[0066] Among them, when the second switching device K2, third switching device K3, fifth switching device K5, and sixth switching device K6 are simultaneously turned on, a current boost path is formed between the charging power supply and the power battery. The charging current flows out from the positive pole of the charging power supply and passes through the second switching device K2, three-phase inverter, three-phase AC motor, third switching device K3, fifth switching device K5, and sixth switching device K6 in sequence, and then returns to the negative pole of the charging power supply.

[0067] The second direct charging circuit includes a first switching device K1, a third switching device K3, a fifth switching device K5, and a sixth switching device K6.

[0068] Wherein, when the first switching device K1, the third switching device K3, the fifth switching device K5, and the sixth switching device K6 are simultaneously turned on, a direct connection path is formed between the charging power supply and the power battery. The charging current flows out from the positive pole of the charging power supply, passes through the first switching device K1, the third switching device K3, the positive pole of the power battery, the negative pole of the power battery, the fifth switching device K5, and the sixth switching device K6 in sequence, and then returns to the negative pole of the charging power supply.

[0069] As Figure 2 shown, optionally, the second switching device K2 uses a switching device with a specification of the first maximum current (represented by a blue switch pattern in Figure 2 ), and the first switching device K1, the third switching device K3, the fourth switching device K4, the fifth switching device K5, and the sixth switching device K6 respectively use switching devices with a specification of the second maximum current (represented by a red switch pattern in Figure 2 ); the first maximum current is less than the second maximum current.

[0070] Wherein, if the first direct charging circuit needs to transmit a current of 250A, then the first maximum current is greater than 250A; similarly, if the second direct charging circuit needs to transmit a current of 400A, then the second maximum current is greater than 400A.

[0071] Wherein, for the first direct charging circuit composed of the second switching device K2, the fourth switching device K4, the fifth switching device K5, and the sixth switching device K6, since the fourth switching device K4 also needs to be used as the switching device when the power battery discharges, in order to improve the reliability, the fourth switching device K4 uses a switching device with a specification of the second maximum current; since the fifth switching device K5 and the sixth switching device K6 also need to form other high-current charging circuits, the fifth switching device K5 and the sixth switching device K6 use switching devices with a specification of the second maximum current. That is to say, on the basis of ensuring the all-round reliability of the charging circuit, at least the second switching device K2 can use a switching device with a specification of the first maximum current to reduce the hardware cost.

[0072] As Figure 2 shown, optionally, the wire harness between the first common terminal J1 and the third common terminal J3 uses a wire harness with a specification of the first square value (represented by a blue wire harness pattern in Figure 2 ), and other wire harnesses use wire harnesses with a specification of the second square value (represented by a blue wire harness pattern in Figure 2 ); the first square value is less than the second square value.

[0073] Among them, if the first direct charging circuit needs to transmit a current of 250 A, the first square value is 70 square; similarly, if the second direct charging circuit needs to transmit a current of 400 A, the second square value is 95 square.

[0074] Among them, in the discharge scenario of the power battery, the positive electrode of the power battery outputs a discharge current to the three-phase inverter through the fourth switching device K4. Therefore, the wire harness for this part needs to use a wire harness with a specification of the second square value. That is to say, on the basis of ensuring the all-round reliability of the charging circuit, at least the wire harness between the first common terminal J1 and the third common terminal J3 can also use a wire harness with a specification of the first square value to reduce the hardware cost.

[0075] According to the second aspect of the present application, a charging method is provided, which is applied to the charging circuit in any of the above embodiments.

[0076] Among them, the charging method is executed by a PDC (Power domain controller), as Figure 3 shown, the PDC respectively performs data interaction with the charging power supply, the MCU (Motor Control Unit), and the BASU (Battery Sampling and Execution Unit). The MCU also performs data interaction with the BASU, so that the PDC is the main one to implement the charging method in this embodiment. The data flow of the interaction is as follows:

[0077] 1. The data stream ① sent by the charging pile and received by the PDC includes message signals such as CHM, CRM, CTS, CML, CRO, CCS, CST, CSD, CEM, etc.;

[0078] 2. The data stream ② sent by the PDC and received by the charging pile includes message signals such as BHM, BRM, BCP, BRO, BCL, BCS, BSM, BMV, BMT, BSP, BST, BSD, BEM, etc.;

[0079] 3. The data stream ③ sent by the PDC and received by the BASU includes signals such as DC gun connection status, DC charging status, DC charging up / down power command, insulation detection command, discharge status, contactor control command, etc.;

[0080] 4. The data stream ④ sent by the BASU and received by the PDC includes signals such as charging information, remaining battery power, contactor control status, discharge command, etc.;

[0081] 5. The data stream ⑤ sent by the PDC and received by the MCU includes signals such as OK light, gun connection status, DC charge and discharge mode, charge and discharge mode, voltage regulation target value, voltage regulation module switching wave command, contactor status, etc.;

[0082] 6. The data stream ⑥ sent by the MCU and received by the PDC includes signals such as the fully open state, the state of the voltage regulating module, the voltage on the voltage regulating side, the current on the voltage regulating side, and the maximum allowable current on the voltage regulating side;

[0083] 7. The data stream ⑦ sent by the BASU and received by the MCU includes signals such as charge permission.

[0084] Refer to Figure 2 , the charging method includes:

[0085] Controlling the switching states of the first switching device K1, the second switching device K2, the third switching device K3, and the fourth switching device K4 to charge the power battery in the first direct charging mode, the current increasing charging mode, the voltage increasing charging mode, or the second direct charging mode.

[0086] It should be noted that, regardless of the charging mode adopted, the corresponding loop requires the fifth switching device K5 and the sixth switching device K6 to be turned on. Therefore, the charging method in this embodiment will not be elaborated further.

[0087] The charging circuit applied by the charging method in this application multiplexes part of the loop of the boost charging loop that can withstand large currents and part of the loop of the current increasing charging loop, thereby forming a second direct charging loop that can withstand large currents, so that the first direct charging loop is only used to withstand small currents, and thus at least part of the hardware cost of the first direct charging loop can be saved.

[0088] Refer to Figure 2 , optionally, controlling the switching states of the first switching device K1, the second switching device K2, the third switching device K3, and the fourth switching device K4 to charge the power battery in the first DC charging mode, the current increasing mode, the voltage increasing mode, or the second DC charging mode, includes:

[0089] Controlling the second switching device K2 and the fourth switching device K4 to be closed and the first switching device K1 and the third switching device K3 to be open to charge the power battery in the first direct charging mode.

[0090] It can be understood that the fifth switching device K5 and the sixth switching device K6 also need to be controlled to be closed.

[0091] Refer to Figure 2 , optionally, controlling the switching states of the first switching device K1, the second switching device K2, the third switching device K3, and the fourth switching device K4 to charge the power battery in the first DC charging mode, the current increasing mode, the voltage increasing mode, or the second DC charging mode, includes:

[0092] Controlling the first switching device K1 and the third switching device K3 to be closed and the second switching device K2 and the fourth switching device K4 to be open to charge the power battery in the second direct charging mode.

[0093] Among them, it can be understood that it is also necessary to control the fifth switching device K5 and the sixth switching device K6 to be closed.

[0094] Referring to Figure 2 , optionally, controlling the switching states of the first switching device K1, the second switching device K2, the third switching device K3, and the fourth switching device K4 to charge the power battery in the first DC charging mode, the current boosting mode, the voltage boosting mode, or the second DC charging mode, including:

[0095] Controlling the first switching device K1 and the fourth switching device K4 to be closed and the second switching device K2 and the third switching device K3 to be disconnected to charge the power battery in the boost charging mode.

[0096] Among them, it can be understood that it is also necessary to control the fifth switching device K5 and the sixth switching device K6 to be closed.

[0097] Referring to Figure 2 , optionally, controlling the switching states of the first switching device K1, the second switching device K2, the third switching device K3, and the fourth switching device K4 to charge the power battery in the first DC charging mode, the current boosting mode, the voltage boosting mode, or the second DC charging mode, including:

[0098] Controlling the second switching device K2 and the third switching device K3 to be closed and the first switching device K1 and the fourth switching device K4 to be disconnected to charge the power battery in the current boosting mode.

[0099] Among them, it can be understood that it is also necessary to control the fifth switching device K5 and the sixth switching device K6 to be closed.

[0100] It should be added that the first direct charging mode and the second direct charging mode are usually switched according to the required current of the power battery after the current boosting mode.

[0101] Before entering the current boosting mode, relevant control methods need to be executed. An example method includes:

[0102] Step 1: First send a control command for K1 to pull in. After 100 ms, send a control command for K6 to pull in, and send the initial value of the voltage regulation target value as the total voltage of the battery pack V_pack + 20V.

[0103] Step 2: After sending the voltage regulation target value, if the full-open flag of the MCU is received within 2.5 s, delay 200 ms to send the control state of K2 to pull in, and delay 200 ms to send a turn-off wave request to the MCU. Otherwise, it is considered that the charging fails and BST is reported.

[0104] Step 3: Check if the status of the voltage regulation module is stopped within 2 s. If yes, send the K1 control command to disconnect and the K3 control command to engage. Otherwise, report BST for charging failure.

[0105] Step 4: If the status of K3 feedback from BASU is engaged within 2 s, send the K4 control command to disconnect. Otherwise, report BST for charging failure.

[0106] Step 5: If the status of K4 feedback from BASU is disconnected within 2 s, send the off-wave request not to turn off the wave and the voltage regulation target value to the total voltage of the battery pack V_pack + 230 V. Otherwise, report BST for charging failure.

[0107] Step 6: If the status of the voltage regulation module is voltage regulation completed within 2.5 s, send BRO = 0xAA and enter the current boost charging stage. Otherwise, report BST for charging failure.

[0108] After entering the current boost charging mode, the state of charge of the power battery increases rapidly. When it reaches a certain level, it is considered that the mode can be switched. Specifically, the switching method includes:

[0109] Step 1: During the entire process of current boost charging, first determine whether the conditions for switching from the current boost charging mode to the direct charging mode are met. If not, maintain the current boost charging mode. If yes, proceed to Step 2.

[0110] Step 2: PDC sends a request to the charging pile to reduce the required current to min{the minimum charging current I_min during the switching process, the current I_trans converted by constant power after voltage regulation}. If the current on the voltage regulation side drops to within (min{the minimum charging current I_min during the switching process, the current I_trans converted by constant power after voltage regulation} + 10 A) within 10 s, proceed to Step 3. If not, maintain the current boost charging mode.

[0111] Step 3: Adjust the voltage regulation target value downward at a rate of 10 V / s to (the total voltage of the battery pack V_pack - 20 V), and proceed to Step 4. If the fully open control status of the MCU is fully open during the voltage regulation process, directly adjust the voltage regulation target value to (the total voltage of the battery pack V_pack - 20 V).

[0112] Step 4: If the fully open status of the MCU is received as fully open within 10 s, proceed to Step 5. Otherwise, consider the switching failed.

[0113] Step 5: PDC determines the magnitude of the maximum allowable charging current sent by BASU. If the maximum allowable charging current is less than 250 A, proceed to Step 6. Otherwise, execute Step 10.

[0114] Step 6: The PDC sends a K4 control command to the BASU to be pulled in. If the K4 control status feedback from the BASU is pulled in within 2 s, proceed to Step 7; otherwise, consider the handover to have failed.

[0115] Step 7: The PDC sends a wave-off request to the MCU to request wave-off. If the status of the MCU voltage regulation module is stopped and the current on the voltage regulation side is less than (min{the minimum charging current I_min during the handover process, the current I_trans after constant power conversion through voltage regulation}+10 A) within 2 s, proceed to Step 8; otherwise, consider the handover to have failed.

[0116] Step 8: The PDC sends a K3 control command to the BASU to be disconnected. If the K3 control status feedback received from the BASU is disconnected within 2 s, proceed to Step 9; otherwise, consider the handover to have failed.

[0117] Step 9: The PDC sends a demand current Ibcl to the charging pile as min{250 A, the maximum allowable charging current I_max}, completing the handover from the current-up charging mode to the first direct charging mode.

[0118] Step 10: The PDC sends a K3 control command to the BASU to be pulled in. If the K3 control status feedback from the BASU is pulled in within 2 s, proceed to Step 11; otherwise, consider the handover to have failed.

[0119] Step 11: The PDC sends a wave-off request to the MCU to request wave-off. If the status of the MCU voltage regulation module is stopped and the current on the voltage regulation side is less than (min{the minimum charging current I_min during the handover process, the current I_trans after constant power conversion through voltage regulation}+10 A) within 2 s, proceed to Step 12; otherwise, consider the handover to have failed.

[0120] Step 12: The PDC sends a K4 control command to the BASU to be disconnected. If the K4 control status feedback received from the BASU is disconnected within 2 s, proceed to Step 13; otherwise, consider the handover to have failed.

[0121] Step 13: The PDC sends a demand current Ibcl to the charging pile as min{250 A, the maximum allowable charging current I_max}, completing the handover from the current-up charging mode to the second direct charging mode.

[0122] According to the third aspect of the present application, as Figure 4 shown, a power system is provided, including a power battery and the charging circuit in any of the above embodiments.

[0123] The charging circuit multiplexing included in the power system in this application can withstand part of the boost charging circuit and part of the current boosting charging circuit that can withstand large currents, thereby constituting a second direct charging circuit that can withstand large currents, enabling the first direct charging circuit to only be used to withstand small currents, and thus at least part of the hardware cost of the first direct charging circuit can be saved.

[0124] According to the fourth aspect of this application, a vehicle is provided, including the charging circuit in any of the above embodiments, or including the power system in any of the above embodiments.

[0125] The charging circuit multiplexing included in the vehicle in this application can withstand part of the boost charging circuit and part of the current boosting charging circuit that can withstand large currents, thereby constituting a second direct charging circuit that can withstand large currents, enabling the first direct charging circuit to only be used to withstand small currents, and thus at least part of the hardware cost of the first direct charging circuit can be saved.

[0126] In the description of this application, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, "a plurality" means two or more, unless otherwise specifically defined.

[0127] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0128] Among the embodiments, implementation manners, and related technical features of this application, they can be combined and replaced with each other without conflict.

[0129] The above are only the preferred embodiments of this application and do not impose any form of limitation on this application. In the embodiments of this application, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant content of other embodiments. However, as long as it does not depart from the content of the technical solution of this application, any brief modification, equivalent change, and modification made to the above embodiments based on the technical essence of this application still fall within the scope of the technical solution of this application.

Claims

1. A charging circuit, characterized in that, It includes a first direct charging circuit, a boost charging circuit, a current boosting charging circuit, and a second direct charging circuit composed of partial circuits of the boost charging circuit and partial circuits of the current boosting charging circuit; The first direct charging circuit, the boost charging circuit, the current boosting charging circuit, and the second direct charging circuit are respectively electrically connected between a charging power source and a power battery; The first direct charging circuit is used to transmit a first direct charging current, the second direct charging circuit is used to transmit a second direct charging current, and the first direct charging current is less than the second direct charging current.

2. The charging circuit according to claim 1, wherein, The charging circuit includes a three-phase inverter, a three-phase AC motor, a first switching device, a second switching device, a third switching device, and a fourth switching device; A first access end of the first switching device and a first access end of the second switching device are electrically connected to a first common end and are used to be electrically connected to the positive pole of the charging power source. A second access end of the first switching device and a first access end of the third switching device are electrically connected to a second common end and are electrically connected to the Y-type common end of the three-phase AC motor. A second access end of the second switching device and a first access end of the fourth switching device are electrically connected to a third common end and are electrically connected to the DC end of the three-phase inverter. A second access end of the third switching device and a second access end of the fourth switching device are electrically connected to a fourth common end and are used to be electrically connected to the positive pole of the power battery; The first direct charging circuit includes the second switching device and the fourth switching device; The boost charging circuit includes the first switching device, the three-phase AC motor, the three-phase inverter, and the fourth switching device; The current boosting charging circuit includes the second switching device, the three-phase inverter, the three-phase AC motor, and the third switching device; The second direct charging circuit includes the first switching device and the third switching device.

3. The charging circuit according to claim 2, wherein The second switching device uses a switching device with a specification of a first maximum current, and the first switching device, the third switching device, and the fourth switching device respectively use switching devices with a specification of a second maximum current; The first maximum current is less than the second maximum current.

4. The charging circuit according to claim 2, wherein The wiring harness between the first common end and the third common end uses a wiring harness with a specification of a first square value, and other wiring harnesses use wiring harnesses with a specification of a second square value; The first square value is less than the second square value.

5. The charging circuit according to claim 2, wherein The charging circuit further includes an energy storage capacitor; A first end of the energy storage capacitor is respectively electrically connected to a second access end of the second switching device and a first access end of the fourth switching device, and a second end of the energy storage capacitor is respectively used to be electrically connected to the negative pole of the power battery and the negative pole of the charging power source.

6. The charging circuit according to claim 5, wherein The charging circuit further includes a fifth switching device and a sixth switching device; A second access end of the fifth switching device is respectively electrically connected to a second end of the energy storage capacitor and a first access end of the sixth switching device. A first access end of the fifth switching device is used to be electrically connected to the negative pole of the power battery, and a second access end of the sixth switching device is used to be electrically connected to the negative pole of the charging power source; The first direct charging circuit, the boost charging circuit, the boost current charging circuit, and the second direct charging circuit further respectively include the fifth switching device and the sixth switching device.

7. A charging method, characterized in that, Applied to the charging circuit according to any one of claims 2 to 6; the charging method includes: Controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct charging mode, a boost current charging mode, a boost charging mode, or a second direct charging mode.

8. The charging method according to claim 7, wherein The controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes: Controlling the second switching device and the fourth switching device to be closed and the first switching device and the third switching device to be opened to charge the power battery in the first direct charging mode.

9. The charging method according to claim 7, wherein The controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes: Controlling the first switching device and the third switching device to be closed and the second switching device and the fourth switching device to be opened to charge the power battery in the second direct charging mode.

10. The charging method according to claim 7, characterized in that, The controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes: Controlling the first switching device and the fourth switching device to be closed and the second switching device and the third switching device to be opened to charge the power battery in the boost charging mode.

11. The charging method according to claim 7, wherein The controlling the switching states of the first switching device, the second switching device, the third switching device, and the fourth switching device to charge the power battery in a first direct current charging mode, a boost current mode, a boost mode, or a second direct current charging mode includes: Controlling the second switching device and the third switching device to be closed and the first switching device and the fourth switching device to be opened to charge the power battery in the boost current charging mode.

12. A power system, characterized in that, Including a power battery and the charging circuit according to any one of claims 1 to 6.

13. A vehicle, characterized in that, Including the charging circuit according to any one of claims 1 to 6, or including the power system according to claim 12.

Images