Charging and discharging circuit and vehicle

Abstract

The utility model relates to a charging and discharging circuit and a vehicle, the charging and discharging circuit comprises a controller, a transformer, a first secondary circuit and a second secondary circuit, the second secondary circuit comprises a rectification branch, a voltage reduction branch, a first switch tube and a first capacitor, a first secondary winding is connected with the first secondary circuit, and a second secondary winding is connected with the second secondary circuit. The input end of the rectification branch is connected with the second secondary winding, and the first switch tube and the first capacitor are connected in series to form a target branch, so that the controller can control the first switch tube to be switched off under the condition that the charging and discharging circuit is determined to be in the first working mode, and current output by the rectification branch is effectively cut off from passing through the target branch; therefore, the current output by the rectification branch is prevented from damaging the first capacitor, and the control logic of the controller under the condition that the charging and discharging circuit is in the first working mode is simplified by arranging the first switching tube, so that the discharging performance of the charging and discharging circuit is improved, and the efficiency of the DC / DC converter is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle technology, and in particular, to a charging and discharging circuit and a vehicle. Background Art

[0002] Normally, the on-board charger and DC / DC converter of a vehicle are independently set up, and the integration method of the on-board charger and DC / DC converter is physical assembly integration, for example: placing the on-board charger and DC / DC converter on a PCB board or in a housing. This physical integration has the defects of large assembly space and high cost, and cannot bring substantial changes to the vehicle's power control system. In the prior art, the defect of physical integration is solved by integrating the charger and DC / DC converter through a transformer. However, this integration method will reduce the conversion efficiency of the DC / DC converter, thereby reducing the reliability of the vehicle. Utility Model Content

[0003] In order to achieve the above objectives, the present disclosure provides a charging and discharging circuit and a vehicle.

[0004] A first aspect of the present disclosure provides a charge-discharge circuit, the charge-discharge circuit comprising: a controller, a transformer, a first secondary circuit and a second secondary circuit, the second secondary circuit comprising a rectifier branch, a step-down branch, a first switch tube and a first capacitor, the transformer comprising a first secondary winding and a second secondary winding;

[0005] The first secondary winding is connected to the first secondary circuit, the input end of the rectifier branch is connected to the second secondary winding, the first switch tube and the first capacitor are connected in series to form a target branch, the target branch is connected to the output end of the rectifier branch and the input end of the step-down branch, and the output end of the step-down branch is used to connect a low-voltage electrical device;

[0006] The controller is connected to the first secondary circuit, the rectifier branch, the step-down branch and the first switch tube, and is used to control the first switch tube to be disconnected when it is determined that the charge and discharge circuit is in the first working mode, control the first secondary circuit to provide the first alternating current to the rectifier branch through the first secondary winding and the second secondary winding, and control the rectifier branch to provide the first direct current to the step-down branch, so that the step-down branch outputs the second direct current.

[0007] Optionally, the charging and discharging circuit further includes: a primary circuit, and the transformer further includes a primary winding;

[0008] The primary winding is connected to the primary circuit;

[0009] The controller is also connected to the primary circuit, and is also used to control the primary circuit to provide the second alternating current to the rectifier branch through the primary winding and the second secondary winding when it is determined that the charge and discharge circuit is in the second operating mode, control the rectifier branch to provide the third direct current to the step-down branch so that the step-down branch outputs the fourth direct current, and control the first switch tube to close so that the first capacitor filters out ripples in the third direct current.

[0010] Optionally, the primary circuit includes: a first bridge arm and a second bridge arm;

[0011] The first end of the first bridge arm and the first end of the second bridge arm are connected together to form a first bus terminal, and the second end of the first bridge arm and the second end of the second bridge arm are connected together to form a second bus terminal;

[0012] The midpoint of the first bridge arm is connected to the opposite end of the primary winding;

[0013] The midpoint of the second bridge arm is connected to the same-name end of the primary winding;

[0014] The first bus terminal and the second bus terminal are used to connect to an external charging power source;

[0015] The controller is also connected to the first bridge arm and the second bridge arm, and is used to control the upper bridge switch tube of the first bridge arm and the lower bridge switch tube of the second bridge arm, and alternately turn on the lower bridge switch tube of the first bridge arm and the upper bridge switch tube of the second bridge arm when it is determined that the charging and discharging circuit is in the second operating mode, so that the primary circuit provides the third alternating current to the first secondary circuit through the primary winding and the first secondary winding.

[0016] Optionally, the first secondary circuit includes: a third bridge arm and a fourth bridge arm;

[0017] The first end of the third bridge arm and the third end of the fourth bridge arm are connected together to form a third bus terminal, and the third bus terminal is used to connect the positive electrode of the vehicle battery. The second end of the third bridge arm and the second end of the fourth bridge arm are connected together to form a fourth bus terminal, and the fourth bus terminal is used to connect the negative electrode of the vehicle battery.

[0018] The midpoint of the third bridge arm is connected to the same-name end of the first secondary winding;

[0019] The midpoint of the fourth bridge arm is connected to the opposite end of the first secondary winding;

[0020] The controller is also connected to the third bridge arm and the fourth bridge arm, and is used to control the upper bridge switch tube of the third bridge arm and the lower bridge switch tube of the fourth bridge arm, and alternately turn on the lower bridge switch tube of the third bridge arm and the upper bridge switch tube of the fourth bridge arm when it is determined that the charging and discharging circuit is in the first operating mode, so that the first secondary circuit provides the first alternating current to the rectifier branch through the first secondary winding and the second secondary winding.

[0021] Optionally, the controller is used to, when determining that the charging and discharging circuit is in the second operating mode, control the upper bridge switch tube of the third bridge arm and the lower bridge switch tube of the fourth bridge arm to be turned on, and the lower bridge switch tube of the third bridge arm and the upper bridge switch tube of the fourth bridge arm to be disconnected, if the upper bridge switch tube of the first bridge arm and the lower bridge switch tube of the second bridge arm are turned on, and control the upper bridge switch tube of the third bridge arm and the lower bridge switch tube of the fourth bridge arm to be disconnected, and the lower bridge switch tube of the third bridge arm and the upper bridge switch tube of the fourth bridge arm to be turned on, so that the third alternating current connected to the first secondary circuit is converted into a fifth direct current.

[0022] Optionally, the rectifying branch includes: a second switch tube and a third switch tube;

[0023] The input end of the second switch tube is connected to the first same-name end of the second secondary winding, and the output end of the second switch tube is connected to the output end of the first switch tube, the output end of the third switch tube and the input end of the step-down branch;

[0024] The input end of the third switch tube is connected to the opposite end of the second secondary winding;

[0025] The controller is also connected to the second switch tube and the third switch tube, and is used for controlling the second switch tube to be turned on and the third switch tube to be turned off if the upper switch tube of the third bridge arm and the lower switch tube of the fourth bridge arm are turned on when the charge and discharge circuit is in the first working mode, and controlling the second switch tube to be turned off and the third switch tube to be turned on if the lower switch tube of the third bridge arm and the upper switch tube of the fourth bridge arm are turned on, so that the rectifier branch provides the first direct current to the step-down branch.

[0026] Optionally, the controller is used to control the second switch tube to be turned off and the third switch tube to be turned on if the upper bridge switch tube of the first bridge arm and the lower bridge switch tube of the second bridge arm are turned on when the charge and discharge circuit is in the second operating mode; and to control the second switch tube to be turned on and the third switch tube to be turned off if the lower bridge switch tube of the first bridge arm and the upper bridge switch tube of the second bridge arm are turned on, so that the rectifier branch provides the third direct current to the step-down branch.

[0027] Optionally, the voltage-reducing branch includes: a fourth switch tube, an inductor, a second capacitor and a freewheeling element;

[0028] The input end of the fourth switch tube is connected to the first end of the first capacitor and the second end of the second secondary winding, and the output end of the fourth switch tube is connected to one end of the freewheeling element and one end of the inductor;

[0029] The other end of the inductor is connected to one end of the second capacitor;

[0030] The other end of the second capacitor is connected to the other end of the freewheeling element, the output end of the first switch tube and the output end of the rectifier branch;

[0031] The controller is also connected to the fourth switch tube, and is used to control the fourth switch tube to close when the charge and discharge circuit is in the first working mode so that the step-down branch outputs the second direct current, and to control the fourth switch tube to be alternately turned on when the charge and discharge circuit is in the second working mode. If the fourth switch tube is turned on, the freewheeling element is controlled to be turned off so that the second secondary winding forms a path with the inductor and the second capacitor. If the fourth switch tube is turned off, the freewheeling element is controlled to be turned on so that the inductor, the second capacitor and the freewheeling element form a loop.

[0032] Optionally, the second secondary winding comprises: a first coil and a second coil;

[0033] After the first coil and the second coil are connected in series, one end is connected to the first input end of the rectifier branch, and the other end is connected to the second input end of the rectifier branch. The connecting end of the first coil and the second coil is connected to the input end of the target branch and the step-down branch.

[0034] A second aspect of the present disclosure provides a vehicle, comprising: the charging and discharging circuit as described in the first aspect above.

[0035] Through the above technical solution, the charging and discharging circuit includes: a controller, a transformer, a first secondary circuit and a second secondary circuit, the second secondary circuit includes a rectifier branch, a step-down branch, a first switch tube and a first capacitor, the transformer includes a first secondary winding and a second secondary winding, the first secondary winding is connected to the first secondary circuit, the input end of the rectifier branch is connected to the second secondary winding, the first switch tube is connected in series with the first capacitor to form a target branch, the target branch is connected to the output end of the rectifier branch and the input end of the step-down branch, the output end of the step-down branch is used to connect a low-voltage electrical device, the controller is connected to the first secondary circuit, the rectifier branch, the step-down branch and the first switch tube, and is used to determine the charging and discharging circuit When in the first working mode, the first switch tube is controlled to be disconnected, the first secondary circuit is controlled to provide the first alternating current to the rectifier branch through the first secondary winding and the second secondary winding, and the rectifier branch is controlled to provide the first direct current to the step-down branch, so that the step-down branch outputs the second direct current. In this way, when the controller determines that the charge and discharge circuit is in the first working mode, the first switch tube can be controlled to be disconnected, and the current output by the rectifier branch can be effectively cut off from passing through the target branch, thereby preventing the current output by the rectifier branch from damaging the first capacitor. In addition, by setting the first switch tube, the control logic of the controller when the charge and discharge circuit is in the first working mode is simplified, thereby improving the discharge performance of the charge and discharge circuit, which is beneficial to improving the efficiency of the DC / DC converter.

[0036] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0038] Figure 1 is a schematic diagram of a charging and discharging circuit according to an exemplary embodiment of the present disclosure;

[0039] Figure 2 is a schematic diagram of a charging and discharging circuit according to an exemplary embodiment of the present disclosure.

[0040] Description of Reference Numerals

[0041] 101 Controller 102 Transformer

[0042] 103 first secondary circuit 104 second secondary circuit

[0043] 1041 Rectification branch 1042 Buck branch

[0044] Q1 First switch tube C1 First capacitor

[0045] 105 Primary circuit 1051 First bridge arm

[0046] 1052 Second bridge arm 1031 Third bridge arm

[0047] 1032 Fourth bridge arm Q2 Second switch tube

[0048] Q3 The third switch tube Q4 The fourth switch tube

[0049] L Inductor C2 Second Capacitor DETAILED DESCRIPTION

[0050] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0051] Figure 1 is a schematic diagram of a charging and discharging circuit according to an exemplary embodiment of the present disclosure, such as Figure 1 As shown, the charging and discharging circuit includes: a controller 101, a transformer 102, a first secondary circuit 103 and a second secondary circuit 104, the second secondary circuit includes a rectifier branch 1041, a step-down branch 1042, a first switch tube Q1 and a first capacitor C1, the transformer 102 includes a first secondary winding and a second secondary winding; the first secondary winding is connected to the first secondary circuit 103, the input end of the rectifier branch 1041 is connected to the second secondary winding, the first switch tube Q1 is connected in series with the first capacitor C1 to form a target branch, the target branch is connected to the output end of the rectifier branch 1041 and the input end of the step-down branch 1042 The controller 101 is connected to the first secondary circuit 103, the rectifying branch 1041, the step-down branch 1042 and the first switch tube Q1, and is used to control the first switch tube Q1 to disconnect when it is determined that the charge and discharge circuit is in the first working mode, control the first secondary circuit 103 to provide the first alternating current to the rectifying branch 1041 through the first secondary winding and the second secondary winding, and control the rectifying branch 1041 to provide the first direct current to the step-down branch 1042, so that the step-down branch 1042 outputs the second direct current.

[0052] Among them, the output end of the first secondary circuit 103 can be connected to the vehicle battery, and the output end of the step-down branch 1042 can be used as the output end of the second secondary circuit. The controller 101 can be understood as a BMS (Battery Management System), or as a pre-set control device, which can be used to control the switch tube in the charging and discharging circuit to turn on the charging and discharging circuit. The first secondary circuit 103 can be used to convert the input direct current into alternating current, and the first switch tube Q1 can be a MOS (Metal Oxide Semiconductor Field Effect Transistor) tube, a BJT (Bipolar Junction Transistor, bipolar junction transistor) tube, a JFET (Junction Field-Effect Transistor, junction field effect transistor) tube or an IGBT (Insulate-Gate Bipolar Transistor, insulated gate bipolar transistor) tube. The first working mode can be understood as the vehicle battery supplying power to the vehicle load through the first secondary circuit 103 and the second secondary circuit 104. When it is determined that the vehicle battery is discharged through the first secondary circuit 103, it can be determined that the charge and discharge circuit is in the first working mode. The second secondary winding includes: a first coil and a second coil; the first coil and the second coil are connected in series at one end connected to the first input end of the rectifier branch 1041, and the other end connected to the second input end of the rectifier branch 1041, and the connection end of the first coil and the second coil is connected to the input end of the target branch and the step-down branch 1042.

[0053] It should be noted that, when the charge-discharge circuit is in the first working mode, the controller 101 controls the switch tube in the first secondary circuit 103 and the switch tube in the rectifier branch 1041 to be turned on at the first preset frequency and the first preset duty cycle, the first input end of the rectifier branch 1041 can be connected to the first same-name end of the secondary machine winding, the second input end of the rectifier branch 1041 can be connected to the opposite-name end of the secondary machine winding, the output end of the rectifier branch 1041 is connected to the output end of the first switch tube Q1 and the first input end of the step-down branch 1042, the second input end of the step-down branch 1042 is connected to the second same-name end of the secondary machine winding and one end of the first capacitor C1, and the other end of the first capacitor C1 can be connected to the input end of the first switch tube Q1. The first end of the first secondary circuit 103 can be connected to the same-name end of the first secondary winding, and the second end of the first secondary circuit 103 is connected to the opposite-name end of the first secondary winding. When the controller 101 determines that the charging and discharging circuit is in the first operating mode, it can convert the current input to the first secondary circuit 103 by controlling the first secondary circuit 103, and provide the first alternating current to the rectifier branch 1041 through the first secondary winding and the second machine winding. It can control the rectifier branch 1041 to convert the first alternating current into a first direct current, and transmit the first direct current to the step-down circuit 1042, and control the step-down circuit 1042 to convert the input first direct current into a second direct current, and output it to the vehicle load.

[0054] The above technical scheme can control the first switch tube to be disconnected when the controller determines that the charge and discharge circuit is in the first working mode, thereby effectively cutting off the current output by the rectifier branch from passing through the target branch, thereby preventing the current output by the rectifier branch from damaging the first capacitor. In addition, by setting the first switch tube, the control logic of the controller when the charge and discharge circuit is in the first working mode is simplified, thereby improving the discharge performance of the charge and discharge circuit, which is beneficial to improving the efficiency of the DC / DC converter.

[0055] Optionally, Figure 1 As shown, the charging and discharging circuit also includes: a primary circuit 105, and the transformer 102 also includes a primary winding; the primary winding is connected to the primary circuit 105; the controller 101 is also connected to the primary circuit 105, and is also used to control the primary circuit 105 to provide the second alternating current to the rectifier branch 1041 through the primary winding and the second secondary winding when it is determined that the charging and discharging circuit is in the second working mode, control the rectifier branch 1041 to provide the third direct current to the step-down branch 1042, so that the step-down branch 1042 outputs a fourth direct current, and control the first switch tube Q1 to be closed, so that the first capacitor C1 filters out ripples in the third direct current.

[0056] Among them, the input end of the primary circuit 105 can be connected to an external charging power supply, and the second working mode can be understood as the primary circuit 105 is connected to the external charging power supply, and the vehicle battery is charged through the first secondary circuit 103. When it is determined that the external charging power supply is discharged through the primary circuit 105, it can be determined that the charging and discharging circuit is in the second working mode.

[0057] It should be noted that, when the charge-discharge circuit is in the second working mode, the controller 101 controls the switch tube in the primary circuit 105 and the switch tube in the first secondary circuit 103 and the switch tube in the rectifier branch 1041 to be turned on at the second preset frequency and the second preset duty cycle. When the charge-discharge circuit is in the first working mode, the controller 101 controls the switch tube of the primary circuit 105 to be turned on at the first preset frequency and the first preset duty cycle, wherein the first preset frequency and the second preset frequency may be the same or different, and the first preset duty cycle and the second preset duty cycle may be the same or different. The first output terminal of the primary circuit 105 may be connected to the same-name terminal of the primary winding, and the second output terminal of the primary circuit 105 may be connected to the opposite-name terminal of the primary winding. When the controller 101 determines that the charging and discharging circuit is in the second operating mode, it can control the primary circuit 105 to convert the current input to the primary circuit 105, and provide a second alternating current to the rectifier branch 1041 through the primary winding and the second secondary winding. It can control the rectifier DC 1041 to convert the second alternating current into a third direct current, and control the first switch tube Q1 to close, turn on the first capacitor C1 and the rectifier DC 1041, so that the first capacitor C1 can filter out the ripples in the third direct current output by the rectifier branch 1041, provide a stable current to the step-down branch 1042, and control the step-down branch 1042 to output a fourth direct current to supply power to the vehicle load.

[0058] The above technical scheme can control the first switch tube to be disconnected when the controller determines that the charge and discharge circuit is in the first working mode, thereby effectively cutting off the current output by the rectifier branch from passing through the target branch, thereby preventing the current output by the rectifier branch from damaging the first capacitor. In addition, by setting the first switch tube, the control logic of the controller when the charge and discharge circuit is in the first working mode is simplified, thereby improving the discharge performance of the charge and discharge circuit, which is beneficial to improving the efficiency of the DC / DC converter.

[0059] Figure 2 is a schematic diagram of a charging and discharging circuit according to an exemplary embodiment of the present disclosure, such as Figure 2As shown, the primary circuit 105 includes: a first bridge arm 1051 and a second bridge arm 1052; the first end of the first bridge arm 1051 and the first end of the second bridge arm 1052 are connected together to form a first bus terminal, and the second end of the first bridge arm 1051 and the second end of the second bridge arm 1052 are connected together to form a second bus terminal; the midpoint of the first bridge arm 1051 is connected to the opposite end of the primary winding; the midpoint of the second bridge arm 1052 is connected to the same end of the primary winding; the first bus terminal and the second bus terminal are used to connect to an external charging power supply; the controller 101 is also connected to the first bridge arm 1051 and the The second bridge arm 1052 is connected and is used to control the upper bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052 at a first preset frequency and a first preset duty cycle when it is determined that the charging and discharging circuit is in the second working mode, and alternately turn on the lower bridge switch tube of the first bridge arm 1051 and the upper bridge switch tube of the second bridge arm 1052, so that the primary circuit 105 provides the third alternating current to the first secondary circuit 103 through the primary winding and the first secondary winding, and provides the fourth alternating current to the second secondary circuit 104 through the primary winding and the second secondary winding.

[0060] Among them, the first preset frequency can be used to characterize the number of times the upper bridge switch tube of the first bridge arm 1051, the lower bridge switch tube of the first bridge arm 1051, the upper bridge switch tube of the second bridge arm 1052, and the lower bridge switch tube of the second bridge arm 1052 are turned on within 1s. The first preset frequency can be preset according to the actual needs of the charging and discharging circuit. The first preset duty cycle can be used to characterize the turn-on time of the upper bridge switch tube of the first bridge arm 1051, the lower bridge switch tube of the first bridge arm 1051, the upper bridge switch tube of the second bridge arm 1052, and the lower bridge switch tube of the second bridge arm 1052. The first preset duty cycle can be preset according to the voltage inputted by the first secondary circuit 103. The upper bridge switch tube of the first bridge arm 1051, the lower bridge switch tube of the first bridge arm 1051, the upper bridge switch tube of the second bridge arm 1052, and the lower bridge switch tube of the second bridge arm 1052 can be a MOS tube, a BJT tube, a JFET tube, or an IGBT tube.

[0061] It should be noted that, when the controller 101 determines that the charge and discharge circuit is in the second working mode, it can control the upper bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052 to close, and the lower bridge switch tube of the first bridge arm 1051 and the upper bridge switch tube of the second bridge arm 1052 to disconnect, or control the upper bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052 to disconnect, and the lower bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052 to close. The upper bridge switch tube of arm 1052 is closed, and the upper bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052, as well as the lower bridge switch tube of the first bridge arm 1051 and the upper bridge switch tube of the second bridge arm 1052, convert the direct current input into the primary circuit 105 into alternating current by alternating conduction, and provide a third alternating current to the first secondary circuit 103 through the primary winding and the first secondary winding, and provide a fourth alternating current to the second secondary circuit 104 through the primary winding and the second secondary winding.

[0062] The above technical scheme can control the first switch tube to be disconnected when the controller determines that the charge and discharge circuit is in the first working mode, thereby effectively cutting off the current output by the rectifier branch from passing through the target branch, thereby preventing the current output by the rectifier branch from damaging the first capacitor. In addition, by setting the first switch tube, the control logic of the controller when the charge and discharge circuit is in the first working mode is simplified, thereby improving the discharge performance of the charge and discharge circuit, which is beneficial to improving the efficiency of the DC / DC converter.

[0063] Optionally, Figure 2 For example, the first secondary circuit 103 includes: a third bridge arm 1031 and a fourth bridge arm 1032; the first end of the third bridge arm 1031 and the third end of the fourth bridge arm 1032 are connected together to form a third bus terminal, and the third bus terminal is used to connect the positive electrode of the vehicle battery, and the second end of the third bridge arm 1031 and the second end of the fourth bridge arm 1032 are connected together to form a fourth bus terminal, and the fourth bus terminal is used to connect the negative electrode of the vehicle battery; the midpoint of the third bridge arm 1031 is connected to the same-name end of the first secondary winding; the midpoint of the fourth bridge arm 1032 is connected to the opposite-name end of the first secondary winding. The controller 101 is also connected to the third bridge arm 1031 and the fourth bridge arm 1032, and is used to control the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032 at a second preset frequency and a second preset duty cycle when it is determined that the charge and discharge circuit is in the first working mode, and alternately turn on the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032, so that the first secondary circuit 103 provides the first alternating current to the rectifier branch through the first secondary winding and the second secondary winding.

[0064] The second preset frequency may be the same as or different from the first preset frequency, and the second preset duty cycle may be the same as or different from the first preset duty cycle. The upper bridge switch tube of the third bridge arm 1031, the lower bridge switch tube of the fourth bridge arm 1032, the lower bridge switch tube of the third bridge arm 1031, and the upper bridge switch tube of the fourth bridge arm 1032 may be a MOS tube, a BJT tube, a JFET tube, or an IGBT tube.

[0065] It should be noted that, when the controller 101 determines that the charging and discharging circuit is in the first operating mode, it can control the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032 to close, and the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 to disconnect, or control the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032 to disconnect, and the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 to close, and the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032, and the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 can be alternately turned on to convert the direct current input into alternating current into alternating current, and provide the first alternating current to the second secondary circuit 104 through the first secondary winding and the second secondary winding.

[0066] Optionally, the controller 101 is also used to, when determining that the charging and discharging circuit is in the first operating mode, if the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032 are closed, the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 are disconnected, and the upper bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052 are turned on; if the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 are closed, the lower bridge switch tube of the first bridge arm 1051 and the upper bridge switch tube of the second bridge arm 1052 are turned on, so that the primary circuit 105 consumes the first secondary circuit 103 to provide alternating current to the primary circuit through the primary winding and the first secondary winding.

[0067] Optionally, the controller 101 is used to, when determining that the charging and discharging circuit is in the second operating mode, control the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032 to be turned on, and the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 to be turned off, if the upper bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052 are turned on, and control the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032 to be turned off, and the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 to be turned on, so that the third alternating current connected to the first secondary circuit 103 is converted into a fifth direct current.

[0068] The above technical scheme can control the first switch tube to be disconnected when the controller determines that the charge and discharge circuit is in the first working mode, thereby effectively cutting off the current output by the rectifier branch from passing through the target branch, thereby preventing the current output by the rectifier branch from damaging the first capacitor. In addition, by setting the first switch tube, the control logic of the controller when the charge and discharge circuit is in the first working mode is simplified, thereby improving the discharge performance of the charge and discharge circuit, which is beneficial to improving the efficiency of the DC / DC converter.

[0069] Optionally, Figure 2 For example, the rectifier branch 1041 includes: a second switch tube Q2 and a third switch tube Q3; the input end of the second switch tube Q2 is connected to the first same-name end of the second secondary winding, the output end of the second switch tube Q2 is connected to the output end of the first switch tube Q1, the output end of the third switch tube Q3 and the input end of the step-down branch 1042; the input end of the third switch tube Q3 is connected to the opposite-name end of the second secondary winding; the controller 101 is also connected to the second switch tube Q2 and the third switch tube Q3, It is used to control the second switch tube Q2 to be turned on and the third switch tube Q3 to be turned off if the upper bridge switch tube of the third bridge arm 1031 and the lower bridge switch tube of the fourth bridge arm 1032 are turned on when the charge and discharge circuit is in the first working mode; and to control the second switch tube Q2 to be turned off and the third switch tube Q3 to be turned on if the lower bridge switch tube of the third bridge arm 1031 and the upper bridge switch tube of the fourth bridge arm 1032 are turned on, so that the rectifier branch 1041 provides the first direct current to the step-down branch 1042.

[0070] The second switch tube Q2 and the third switch tube Q3 may be MOS tubes, BJT tubes, JFET tubes or IGBT tubes.

[0071] Optionally, the controller 101 is used to, when the charge and discharge circuit is in the second operating mode, control the second switch tube Q2 to be turned off and the third switch tube Q3 to be turned on if the upper bridge switch tube of the first bridge arm 1051 and the lower bridge switch tube of the second bridge arm 1052 are turned on; and control the second switch tube Q2 to be turned on and the third switch tube Q3 to be turned off if the lower bridge switch tube of the first bridge arm 1051 and the upper bridge switch tube of the second bridge arm 1052 are turned on, so that the rectifier branch 1041 provides the third direct current to the step-down branch 1042.

[0072] The above technical scheme can control the first switch tube to be disconnected when the controller determines that the charge and discharge circuit is in the first working mode, thereby effectively cutting off the current output by the rectifier branch from passing through the target branch, thereby preventing the current output by the rectifier branch from damaging the first capacitor. In addition, by setting the first switch tube, the control logic of the controller when the charge and discharge circuit is in the first working mode is simplified, thereby improving the discharge performance of the charge and discharge circuit, which is beneficial to improving the efficiency of the DC / DC converter.

[0073] Optionally, Figure 2 For example, the step-down branch 1042 includes: a fourth switch tube Q4, an inductor L, a second capacitor C2 and a freewheeling element; the input end of the fourth switch tube Q4 is connected to the first end of the first capacitor C1 and the second end of the second secondary winding, the output end of the fourth switch tube Q4 is connected to one end of the freewheeling element and one end of the inductor L; the other end of the inductor L is connected to one end of the second capacitor C2; the other end of the second capacitor C2 is connected to the other end of the freewheeling element, the output end of the first switch tube Q1 and the output end of the rectifier branch 1041; the controller 101 is also connected to the fourth switch tube Q4 The device is used for controlling the fourth switch tube Q4 to be closed when the charge and discharge circuit is in the first working mode, and the step-down branch 1042 to output the second direct current. When the charge and discharge circuit is in the second working mode, the fourth switch tube Q4 is controlled to be alternately turned on at a third preset frequency and a third preset duty cycle. If the fourth switch tube Q4 is turned on, the freewheeling element is controlled to be turned off so that the second secondary winding forms a path with the inductor L and the second capacitor C2. If the fourth switch tube Q4 is turned off, the freewheeling element is controlled to be turned on so that the inductor L, the second capacitor C2 and the freewheeling element form a loop.

[0074] The freewheeling element may be a diode, a MOS tube, a BJT tube, a JFET tube or an IGBT tube.

[0075] It should be noted that the inductor L and the second capacitor C2 in the step-down circuit 1042 are connected in series to form a low-pass filter.

[0076] The above technical scheme can control the first switch tube to be disconnected when the controller determines that the charge and discharge circuit is in the first working mode, thereby effectively cutting off the current output by the rectifier branch from passing through the target branch, thereby preventing the current output by the rectifier branch from damaging the first capacitor. In addition, by setting the first switch tube, the control logic of the controller when the charge and discharge circuit is in the first working mode is simplified, thereby improving the discharge performance of the charge and discharge circuit, which is beneficial to improving the efficiency of the DC / DC converter.

[0077] In an exemplary embodiment of the present disclosure, a vehicle is also provided, the vehicle comprising: Figure 1 or Figure 2 The charging and discharging circuit.

[0078] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0079] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0080] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A charging and discharging circuit, characterized in that: The charging and discharging circuit includes: a controller, a transformer, a first secondary circuit and a second secondary circuit, the second secondary circuit includes a rectifying branch, a step-down branch, a first switch tube and a first capacitor, and the transformer includes a first secondary winding and a second secondary winding; The first secondary winding is connected to the first secondary circuit, the input end of the rectifier branch is connected to the second secondary winding, the first switch tube and the first capacitor are connected in series to form a target branch, the target branch is connected to the output end of the rectifier branch and the input end of the step-down branch, and the output end of the step-down branch is used to connect a low-voltage electrical device; The controller is connected to the first secondary circuit, the rectifier branch, the step-down branch and the first switch tube, and is used to control the first switch tube to be disconnected when it is determined that the charge and discharge circuit is in the first working mode, control the first secondary circuit to provide the first alternating current to the rectifier branch through the first secondary winding and the second secondary winding, and control the rectifier branch to provide the first direct current to the step-down branch, so that the step-down branch outputs the second direct current.

2. The charge and discharge circuit according to claim 1, characterized in that: The charging and discharging circuit further includes: a primary circuit, and the transformer further includes a primary winding; The primary winding is connected to the primary circuit; The controller is also connected to the primary circuit, and is also used to control the primary circuit to provide the second alternating current to the rectifier branch through the primary winding and the second secondary winding when it is determined that the charge and discharge circuit is in the second operating mode, control the rectifier branch to provide the third direct current to the step-down branch so that the step-down branch outputs the fourth direct current, and control the first switch tube to close so that the first capacitor filters out ripples in the third direct current.

3. The charge and discharge circuit according to claim 2, characterized in that: The primary circuit comprises: a first bridge arm and a second bridge arm; The first end of the first bridge arm and the first end of the second bridge arm are connected together to form a first bus terminal, and the second end of the first bridge arm and the second end of the second bridge arm are connected together to form a second bus terminal; The midpoint of the first bridge arm is connected to the opposite end of the primary winding; The midpoint of the second bridge arm is connected to the same-name end of the primary winding; The first bus terminal and the second bus terminal are used to connect to an external charging power source; The controller is also connected to the first bridge arm and the second bridge arm, and is used to control the upper bridge switch tube of the first bridge arm and the lower bridge switch tube of the second bridge arm, and alternately turn on the lower bridge switch tube of the first bridge arm and the upper bridge switch tube of the second bridge arm when it is determined that the charging and discharging circuit is in the second operating mode, so that the primary circuit provides the third alternating current to the first secondary circuit through the primary winding and the first secondary winding.

4. The charge and discharge circuit according to claim 3, characterized in that: The first secondary circuit comprises: a third bridge arm and a fourth bridge arm; The first end of the third bridge arm and the third end of the fourth bridge arm are connected together to form a third bus terminal, and the third bus terminal is used to connect the positive electrode of the vehicle battery. The second end of the third bridge arm and the second end of the fourth bridge arm are connected together to form a fourth bus terminal, and the fourth bus terminal is used to connect the negative electrode of the vehicle battery. The midpoint of the third bridge arm is connected to the same-name end of the first secondary winding; The midpoint of the fourth bridge arm is connected to the opposite end of the first secondary winding; The controller is also connected to the third bridge arm and the fourth bridge arm, and is used to control the upper bridge switch tube of the third bridge arm and the lower bridge switch tube of the fourth bridge arm, and alternately turn on the lower bridge switch tube of the third bridge arm and the upper bridge switch tube of the fourth bridge arm when it is determined that the charging and discharging circuit is in the first operating mode, so that the first secondary circuit provides the first alternating current to the rectifier branch through the first secondary winding and the second secondary winding.

5. The charge and discharge circuit according to claim 4, characterized in that: The controller is used for, when determining that the charging and discharging circuit is in the second working mode, if the upper bridge switch tube of the first bridge arm and the lower bridge switch tube of the second bridge arm are turned on, controlling the upper bridge switch tube of the third bridge arm and the lower bridge switch tube of the fourth bridge arm to be turned on, and the lower bridge switch tube of the third bridge arm and the upper bridge switch tube of the fourth bridge arm to be turned off, and if the lower bridge switch tube of the first bridge arm and the upper bridge switch tube of the second bridge arm are turned on, controlling the upper bridge switch tube of the third bridge arm and the lower bridge switch tube of the fourth bridge arm to be turned off, and the lower bridge switch tube of the third bridge arm and the upper bridge switch tube of the fourth bridge arm to be turned on, so that the third alternating current connected to the first secondary circuit is converted into a fifth direct current.

6. The charge and discharge circuit according to claim 4, characterized in that: The rectifying branch comprises: a second switch tube and a third switch tube; The input end of the second switch tube is connected to the first same-name end of the second secondary winding, and the output end of the second switch tube is connected to the output end of the first switch tube, the output end of the third switch tube and the input end of the step-down branch; The input end of the third switch tube is connected to the opposite end of the second secondary winding; The controller is also connected to the second switch tube and the third switch tube, and is used for controlling the second switch tube to be turned on and the third switch tube to be turned off if the upper switch tube of the third bridge arm and the lower switch tube of the fourth bridge arm are turned on when the charge and discharge circuit is in the first working mode, and controlling the second switch tube to be turned off and the third switch tube to be turned on if the lower switch tube of the third bridge arm and the upper switch tube of the fourth bridge arm are turned on, so that the rectifier branch provides the first direct current to the step-down branch.

7. The charge and discharge circuit according to claim 6, characterized in that: The controller is used for, when the charge and discharge circuit is in the second working mode, if the upper bridge switch tube of the first bridge arm and the lower bridge switch tube of the second bridge arm are turned on, controlling the second switch tube to be turned on and the third switch tube to be turned on, and if the lower bridge switch tube of the first bridge arm and the upper bridge switch tube of the second bridge arm are turned on, controlling the second switch tube to be turned on and the third switch tube to be turned off, so that the rectifier branch provides the third direct current to the step-down branch.

8. The charge and discharge circuit according to claim 1, characterized in that: The voltage-reducing branch includes: a fourth switch tube, an inductor, a second capacitor and a freewheeling element; The input end of the fourth switch tube is connected to the first end of the first capacitor and the second end of the second secondary winding, and the output end of the fourth switch tube is connected to one end of the freewheeling element and one end of the inductor; The other end of the inductor is connected to one end of the second capacitor; The other end of the second capacitor is connected to the other end of the freewheeling element, the output end of the first switch tube and the output end of the rectifier branch; The controller is also connected to the fourth switch tube, and is used to control the fourth switch tube to close when the charge and discharge circuit is in the first working mode so that the step-down branch outputs the second direct current, and to control the fourth switch tube to be alternately turned on when the charge and discharge circuit is in the second working mode. If the fourth switch tube is turned on, the freewheeling element is controlled to be turned off so that the second secondary winding forms a path with the inductor and the second capacitor. If the fourth switch tube is turned off, the freewheeling element is controlled to be turned on so that the inductor, the second capacitor and the freewheeling element form a loop.

9. The charge and discharge circuit according to claim 1, characterized in that: The second secondary winding comprises: a first coil and a second coil; After the first coil and the second coil are connected in series, one end is connected to the first input end of the rectifier branch, and the other end is connected to the second input end of the rectifier branch. The connecting end of the first coil and the second coil is connected to the input end of the target branch and the step-down branch.

10. A vehicle, characterized in that: The vehicle comprises: a charging and discharging circuit as described in any one of claims 1 to 9 above.

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