Power transfer circuit and control method thereof, vehicle

Abstract

The application relates to an electric energy transmission circuit and a control method thereof and a vehicle. The electric energy transmission circuit comprises an energy storage capacitor, a motor circuit, a driving circuit and a controller. Without adding additional pre-charging relays and pre-charging resistors, only the original motor circuit and the driving circuit in the vehicle-mounted circuit are reused. The pre-charging function of the vehicle-mounted storage battery to the bus capacitor through the energy storage capacitor can be realized by controlling the conduction state of the semiconductor switch of the driving circuit. The pressure relief of the bus capacitor to the energy storage capacitor and the vehicle-mounted storage battery can be realized. Thus, the problems of large size and high cost of the pre-charging circuit in the related art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronics, and in particular to an electric energy transmission circuit, a control method thereof and a vehicle. BACKGROUND

[0002] When the whole vehicle is powered on at high voltage, the output voltage of the power battery is added to the high-voltage load and also to the bus capacitor. Since the internal resistance of the bus capacitor is very small, it is equivalent to a conductor when there is no charge, and a large instantaneous current will be generated, which may cause the high-voltage contactor to sinter or the high-voltage fuse to melt. To avoid this situation, before the high-voltage main circuit is turned on, the bus capacitor connected in parallel with the power battery is charged in a current-limiting manner, that is, reverse pre-charging, and after the bus capacitor is fully charged, the high-voltage main circuit is turned on.

[0003] The pre-charging circuit in the related art generally consists of a pre-charging relay and a pre-charging resistor. The pre-charging resistor can limit the charging current, and the high-voltage main circuit is turned on after the bus capacitor is fully charged. However, the pre-charging resistor is large in size and high in cost, which limits the implementation of the pre-charging circuit. SUMMARY

[0004] Embodiments of the present application provide an electric energy transmission circuit, which realizes the pre-charging function without adding an additional pre-charging resistor, to at least partially solve the above technical problems.

[0005] To achieve the above purpose, according to a first aspect of the present application, an electric energy transmission circuit is provided for transmitting electric energy between a vehicle-mounted battery and a bus capacitor; the electric energy transmission circuit comprises: an energy storage capacitor, which is electrically coupled with the vehicle-mounted battery; a motor circuit, comprising a plurality of motor windings; a drive circuit, comprising a plurality of semiconductor switches electrically connected with the motor windings, the drive circuit being electrically connected with the bus capacitor and the energy storage capacitor; and a controller, which is electrically connected with the control terminals of the semiconductor switches, respectively; wherein the controller is configured to control the conduction states of the semiconductor switches in the drive circuit to make the current output or received by the energy storage capacitor flow through only the motor windings; and the controller is further configured to control the conduction states of the semiconductor switches in the drive circuit to make the current output or received by the energy storage capacitor flow through the motor windings and the bus capacitor.

[0006] Optionally, the controller is further configured to: in the first working state, the controller controls the semiconductor switches in the drive circuit to execute a first conduction state in a first time period to make the current output by the energy storage capacitor only flow through the motor winding; the controller controls the semiconductor switches in the drive circuit to execute a second conduction state in a second time period to make the current output by the energy storage capacitor flow through the motor winding and the bus capacitor, so as to complete charging of the bus capacitor; in the second working state, the controller controls the semiconductor switches in the drive circuit to execute a third conduction state in a third time period to make the bus capacitor release energy, and the current flow through the motor winding and the energy storage capacitor; the controller controls the semiconductor switches in the drive circuit to execute a fourth conduction state in a fourth time period to make the motor winding release energy, so as to complete pressure relief of the bus capacitor; wherein the second time period is later than the first time period, the fourth time period is later than the third time period, and the duty cycle of the semiconductor switches is adjustable.

[0007] Optionally, the drive circuit is a six-arm full-bridge circuit, comprising a first semiconductor switch, a second semiconductor switch and a third semiconductor switch constituting an upper bridge, and a fourth semiconductor switch, a fifth semiconductor switch and a sixth semiconductor switch constituting a lower bridge.

[0008] Optionally, the controller is further configured to: the controller controls the first semiconductor switch, the second semiconductor switch and the sixth semiconductor switch to be turned off in the first time period, while the third semiconductor switch, the fourth semiconductor switch and the fifth semiconductor switch are turned on, so as to make the energy storage capacitor charge the motor winding; the controller controls the first semiconductor switch, the second semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch to be turned off in the second time period, while the third semiconductor switch is turned on, so as to make the energy storage capacitor and the motor winding jointly charge the bus capacitor.

[0009] Optionally, the controller is further configured to: the controller controls the first semiconductor switch and the second semiconductor switch to be turned on in the third time period, while the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch are turned off, so as to make the bus capacitor charge the motor winding; the controller controls the first semiconductor switch, the second semiconductor switch, the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch to be turned off in the fourth time period, so as to make the motor winding release energy through a freewheeling circuit composed of body diodes of the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch.

[0010] Optionally, the electric energy transmission circuit further comprises a first switch arranged between one end of the bus capacitor and one end of the energy storage capacitor, and the first switch is configured to be in a closed state when a difference between a voltage value across the energy storage capacitor and a voltage value of the vehicle-mounted power battery is less than or equal to a first preset value.

[0011] Optionally, the electric energy transmission circuit further comprises: a voltage boosting circuit comprising an inductor and a plurality of switching transistors, the voltage boosting circuit being electrically connected to the vehicle-mounted storage battery, and a duty cycle of the switching transistors being adjustable; a transformer comprising a primary winding and a secondary winding, the secondary winding of the transformer being electrically connected to the voltage boosting circuit; and a current conversion circuit electrically connected to the transformer and the energy storage capacitor, the current conversion circuit being configured to convert current between AC and DC.

[0012] Optionally, the voltage boosting circuit is configured to boost a voltage output by the vehicle-mounted storage battery, and output the boosted voltage to the energy storage capacitor through the transformer and the current conversion circuit to charge the energy storage capacitor.

[0013] According to a second aspect of the present application, a control method of an electric energy transmission circuit is provided, the electric energy transmission circuit comprising: an energy storage capacitor electrically coupled with a vehicle-mounted storage battery; a motor circuit comprising a plurality of motor windings; a drive circuit comprising a plurality of semiconductor switches electrically connected to the motor windings, the drive circuit being electrically connected to the bus capacitor and the energy storage capacitor; and a controller electrically connected to control terminals of the semiconductor switches, respectively; and the control method comprising: controlling conduction states of the semiconductor switches in the drive circuit to make current output or received by the energy storage capacitor flow through the motor windings.

[0014] Optionally, the method further comprises: in a first working state: controlling the semiconductor switches in the drive circuit to perform a first conduction state in a first time period to make current output by the energy storage capacitor flow only through the motor windings; and controlling the semiconductor switches in the drive circuit to perform a second conduction state in a second time period to make current output by the energy storage capacitor flow through the motor windings and the bus capacitor to complete charging of the bus capacitor; and in a second working state: controlling the semiconductor switches in the drive circuit to perform a third conduction state in a third time period to make the bus capacitor release energy, and current flow through the motor windings and the energy storage capacitor; and controlling the semiconductor switches in the drive circuit to perform a fourth conduction state in a fourth time period to make the motor windings release energy to complete pressure relief of the bus capacitor; wherein the second time period is later than the first time period, the fourth time period is later than the third time period, and a duty cycle of the semiconductor switches is adjustable.

[0015] Optionally, the drive circuit is a six-arm full-bridge circuit, comprising a first semiconductor switch, a second semiconductor switch and a third semiconductor switch constituting an upper bridge, and a fourth semiconductor switch, a fifth semiconductor switch and a sixth semiconductor switch constituting a lower bridge.

[0016] Optionally, the controlling the semiconductor switches in the drive circuit to execute the first conduction state in the first time comprises: controlling the first semiconductor switch, the second semiconductor switch and the sixth semiconductor switch to be turned off, and the third semiconductor switch, the fourth semiconductor switch and the fifth semiconductor switch to be turned on, so that the energy storage capacitor charges the motor winding; and the controlling the semiconductor switches in the drive circuit to execute the second conduction state in the second time comprises: controlling the first semiconductor switch, the second semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch to be turned off, and the third semiconductor switch to be turned on, so that the energy storage capacitor and the motor winding jointly charge the bus capacitor.

[0017] Optionally, the controlling the semiconductor switches in the drive circuit to execute the third conduction state in the third time comprises: controlling the first semiconductor switch and the second semiconductor switch to be turned on, and the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch to be turned off, so that the bus capacitor charges the motor winding; and the controlling the semiconductor switches in the drive circuit to execute the fourth conduction state in the fourth time comprises: controlling the first semiconductor switch, the second semiconductor switch, the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch to be turned off, so that the motor winding releases energy through a freewheeling loop composed of body diodes of the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch.

[0018] Optionally, the method further comprises: when a difference between a voltage value at both ends of the bus capacitor and a voltage value of the vehicle-mounted power battery is less than or equal to a first preset value, controlling a first switch to be in a closed state; wherein the first switch is connected to the bus capacitor and the vehicle-mounted power battery at both ends; and when a difference between a voltage value at both ends of the energy storage capacitor and the voltage value of the vehicle-mounted power battery is less than or equal to a second preset value, controlling a second switch to be in a closed state; wherein the second switch is connected to the bus capacitor and the energy storage capacitor at both ends.

[0019] Optionally, the method further comprises: boosting the voltage output by the vehicle-mounted storage battery through a boost circuit, and then outputting to the energy storage capacitor through a transformer and a current conversion circuit to charge the energy storage capacitor.

[0020] According to a third aspect of the present application, there is also provided a vehicle comprising the electric energy transmission circuit as described above.

[0021] In the electric energy transmission circuit of the embodiments of the present application, the energy storage capacitor and the vehicle-mounted storage battery are coupled in terms of electric energy, the motor circuit comprises a plurality of motor windings, the drive circuit comprises a plurality of semiconductor switches electrically connected to the motor windings, and the drive circuit is electrically connected to the bus capacitor and the energy storage capacitor. The controller is electrically connected to the control terminals of the semiconductor switches, respectively. The controller controls the conduction state of the semiconductor switches in the drive circuit to make the current output or received by the energy storage capacitor flow through only the motor windings, or to make the current output or received by the energy storage capacitor flow through the motor windings and the bus capacitor. Without adding additional pre-charge relays and pre-charge resistors, only the original motor circuit and drive circuit in the vehicle-mounted circuit are reused. By controlling the conduction state of the semiconductor switches in the drive circuit, the pre-charge function of the vehicle-mounted storage battery to the bus capacitor through the energy storage capacitor can be realized, and the pressure relief of the bus capacitor to the energy storage capacitor and the vehicle-mounted storage battery can be realized, thereby solving the problem of large size and high cost of the pre-charge circuit in the related art.

[0022] Other features and advantages of the present application will be described in detail in the following detailed description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0024] In order to more completely understand the present application and its beneficial effects, the following will be described in conjunction with the drawings, wherein the same reference numerals in the following description represent the same parts.

[0025] Figure 1 is a structural schematic diagram of the electric energy transmission circuit provided in the exemplary embodiments of the present application;

[0026] Figure 2 is a control timing diagram of the controller in the first working state according to the exemplary embodiments of the present application;

[0027] Figure 3is a schematic diagram of current flow in a first time according to an example embodiment of the present application;

[0028] Figure 4 is a schematic diagram of current flow in a second time according to an example embodiment of the present application;

[0029] Figure 5 is a schematic diagram of current flow according to an example embodiment of the present application;

[0030] Figure 6 is a schematic diagram of a partial structure of an electric energy transmission circuit according to an example embodiment of the present application;

[0031] Figure 7 is a schematic diagram of an optional current flow in a pre-charge state according to an example embodiment of the present application;

[0032] Figure 8 is a schematic diagram of another optional current flow in a pre-charge state according to an example embodiment of the present application;

[0033] Figure 9 is a control timing diagram of a controller in a second working state according to an example embodiment of the present application;

[0034] Figure 10 is a schematic diagram of current flow in a third time according to an example embodiment of the present application;

[0035] Figure 11 is a schematic diagram of current flow in a fourth time according to an example embodiment of the present application;

[0036] Figure 12 is a schematic diagram of an optional current flow in a pressure relief state according to an example embodiment of the present application;

[0037] Figure 13 is a schematic diagram of another optional current flow in a pressure relief state according to an example embodiment of the present application;

[0038] Figure 14 is a flow chart of a control method of an electric energy transmission circuit according to an example embodiment of the present application.

[0039] BRIEF DESCRIPTION OF THE DRAWINGS

[0040] 100, electric energy transmission circuit; 101, motor circuit; 102, driving circuit; 103, controller; 104, voltage boosting circuit; 105, transformer; 106, current conversion circuit;

[0041] C1, bus capacitor; C2, energy storage capacitor; C3, capacitor; BT1, vehicle storage battery; BT2, vehicle power battery; K1, first switch; K2, second switch; L1, L2, L3, motor winding; L4, inductor; T1, first time; T2, second time; T3, third time; T4, fourth time. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative effort fall within the protection scope of the present application.

[0043] Reference Figure 1 As shown in the figure, according to one embodiment of the present application, an electric energy transmission circuit 100 is provided for transmitting electric energy between a vehicle storage battery BT1 and a bus capacitor C1. The electric energy transmission circuit comprises an energy storage capacitor C2, a motor circuit 101, a drive circuit 102 and a controller 103.

[0044] Specifically, the electric energy transmission circuit 100 can further comprise a first switch K1 arranged between one end of the bus capacitor C1 and one end of the energy storage capacitor C2, mainly used for disconnecting the loop directly connected between the two during charging of the energy storage capacitor C2 to the bus capacitor C1 or charging of the bus capacitor C1 to the energy storage capacitor C2, so that the current flows through the motor circuit 101 and the drive circuit 102 for voltage boosting or voltage reduction. The first switch K1 can be realized by a relay, or can be realized by back-to-back MOS tubes to avoid the traditional mechanical switch such as relay from being easily sintered together by large current or arc.

[0045] Specifically, the energy storage capacitor C2 and the vehicle storage battery BT1 constitute an electric energy coupling; the motor circuit 101 comprises a plurality of motor windings; the drive circuit 102 comprises a plurality of semiconductor switches electrically connected with the motor windings, and the drive circuit 102 is electrically connected with the bus capacitor C1 and the energy storage capacitor C2; the controller 103 is electrically connected with the control end of the semiconductor switch respectively.

[0046] It should be noted that the vehicle storage battery BT1 can additionally be connected in parallel with one or more capacitors to store electric energy, or one or more capacitors can be directly used to realize the function of the storage battery, that is, in some application scenarios, a capacitor can be regarded as a storage battery.

[0047] In the embodiments of the present application, the bus capacitor C1 is a large parallel capacitor of the vehicle-mounted power battery, and thus the pre-charging process of the bus capacitor C1 can be understood as a process of making the voltage across the bus capacitor C1 close to the voltage of the vehicle-mounted power battery.

[0048] Specifically, the controller 103 is configured to control the conduction state of the semiconductor switch in the drive circuit 102 to make the current output or received by the energy storage capacitor C2 flow through only the motor winding, and is further configured to control the conduction state of the semiconductor switch in the drive circuit to make the current output or received by the energy storage capacitor C2 flow through the motor winding and the bus capacitor C1.

[0049] The current flowing through only the motor winding can be understood as charging the motor winding by the energy storage capacitor C2 or discharging the energy storage capacitor C2 by the motor winding. The current flowing through the motor winding and the bus capacitor C1 can be understood as charging the motor winding by the bus capacitor C1 to discharge or charging the bus capacitor C1 by the energy storage capacitor C2 and the motor winding.

[0050] Through the scheme provided in the embodiments of the present application, the controller controls the conduction state of the semiconductor switch in the drive circuit to make the current output or received by the energy storage capacitor flow through only the motor winding, or controls the conduction state of the semiconductor switch in the drive circuit to make the current output or received by the energy storage capacitor flow through the motor winding and the bus capacitor, without adding additional pre-charging relays and pre-charging resistors, only reusing the original motor circuit and drive circuit in the vehicle, and by controlling the conduction state of the semiconductor switch in the drive circuit, the pre-charging function can be realized, the vehicle-mounted storage battery can be pre-charged to the bus capacitor through the energy storage capacitor, and the bus capacitor can discharge to the energy storage capacitor and the storage battery, thereby solving the problem that the pre-charging circuit in the related art is large in size and high in cost due to the existence of the pre-charging resistor and the relay.

[0051] In some embodiments, the controller 103 can include multiple working states corresponding to different working states of the electric energy transmission circuit 100, and the charging state (which can also be referred to as the boost state) and the discharging state of the electric energy transmission circuit 100 are taken as examples for description in the embodiments of the present application.

[0052] Specifically, taking the reverse pre-charging state (the vehicle-mounted storage battery pre-charges the bus capacitor C1 in reverse) of the electric energy transmission circuit 100 as the first working state, the first working state can include two stages.

[0053] The first stage: the controller 103 controls the semiconductor switch in the drive circuit 102 to execute the first conduction state to make the current output by the energy storage capacitor C2 flow through only the motor winding in the first time.

[0054] Second stage: the controller 103 controls the semiconductor switch in the drive circuit 102 to perform the second conduction state in the second time to make the current output by the energy storage capacitor C2 flow through the motor winding and the bus capacitor C1, so as to complete the charging of the bus capacitor C1.

[0055] Wherein, the second time is later than the first time, and the length of the first time and the length of the second time can be set according to different charging requirements. In addition, the duty ratio of the semiconductor switch is adjustable, and by reasonably adjusting the duty ratio of the semiconductor switch, the charging requirements of the bus capacitor C1 of different levels can be effectively realized.

[0056] Specifically, the discharge state of the electric energy transmission circuit 100 is the second working state, which can include two stages.

[0057] First stage: the controller 103 controls the semiconductor switch in the drive circuit 102 to perform the third conduction state in the third time to make the bus capacitor C1 release energy, and the current flows through the motor winding and the energy storage capacitor C2.

[0058] Second stage: the controller 103 controls the semiconductor switch in the drive circuit 102 to perform the fourth conduction state in the fourth time to make the motor winding release energy, so as to complete the discharge of the bus capacitor C1.

[0059] Wherein, the fourth time is later than the third time, and the length of the third time and the length of the fourth time can be set according to different charging requirements. In addition, the duty ratio of the semiconductor switch is adjustable, and by reasonably adjusting the duty ratio of the semiconductor switch, the discharge requirements of the bus capacitor C1 of different levels can be effectively realized.

[0060] Specifically, in combination with Figures 2 to 5 , the control timing of the controller to the drive circuit and the current flow in the first working state (reverse pre-charging) are illustrated. Referring to the figure, the drive circuit 102 is a six-arm full-bridge circuit, including the first semiconductor switch Q1, the second semiconductor switch Q2 and the third semiconductor switch Q3 which constitute the upper bridge, and the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6 which constitute the lower bridge. The motor circuit 101 includes three cascaded motor windings L1, L2 and L3.

[0061] In some embodiments, a second switch K2 is arranged between the vehicle-mounted power battery BT2 and the bus capacitor C1, and when pressure relief or forward charging (the vehicle-mounted power battery charges the vehicle-mounted storage battery) is needed, K2 is in a closed state, and when reverse pre-charging (the vehicle-mounted storage battery reversely pre-charges the bus capacitor C1) is needed, K2 is first closed to charge the bus capacitor C1 by the energy storage capacitor C2, and when the voltage across the bus capacitor C1 reaches a preset value or the bus capacitor C1 is fully charged, K2 is closed, which can avoid generating a large instantaneous current, thereby causing the high-voltage contactor to sinter, the high-voltage fuse to melt, and the like. The preset value herein can be set according to a specific charging level, for example, K2 is closed when the voltage difference between the bus capacitor C1 and the power battery is less than or equal to 50V, or K2 is closed when the voltage difference between the bus capacitor C1 and the power battery is less than or equal to 40V or 60V.

[0062] Referring to Figure 2 , in the first time T1, the first semiconductor switch Q1, the second semiconductor switch Q2 and the sixth semiconductor switch Q6 are low, indicating that they are turned off; the third semiconductor switch Q3, the fourth semiconductor switch Q4 and the fifth semiconductor switch Q5 are high, indicating that they are turned on. In the second time T2, the first semiconductor switch Q1, the second semiconductor switch Q2, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6 are low, indicating that they are turned off; the third semiconductor switch Q3 is high, indicating that it is turned on.

[0063] Specifically, referring to the dashed arrows in Figure 3 , the controller 103 controls the first semiconductor switch Q1, the second semiconductor switch Q2 and the sixth semiconductor switch Q6 to be turned off in the first time T1, and controls the third semiconductor switch Q3, the fourth semiconductor switch Q4 and the fifth semiconductor switch Q5 to be turned on at the same time. The charge provided by the energy storage capacitor C2 is charged to the motor windings L1, L2 and L3 through Q3, and then forms a complete loop by grounding through Q4 and Q5, so that the energy storage capacitor C2 charges the motor windings L1, L2 and L3.

[0064] Referring to Figure 4 , in the second time T2, the controller 103 controls the first semiconductor switch Q1, the second semiconductor switch Q2, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6 to be turned off, and controls the third semiconductor switch Q3 to be turned on at the same time. The charge provided by the energy storage capacitor C2 and the motor windings L1, L2 and L3 flows to the bus capacitor C1 through Q1 and Q2, and charges the bus capacitor C1 together.

[0065] The voltage of the vehicle-mounted power battery BT2 is generally much higher than the voltage of the vehicle-mounted storage battery BT1. In the reverse pre-charging state, the voltage across C2 is provided by the vehicle-mounted storage battery BT1. When the voltage across C2 can meet the required voltage for pre-charging, for example, the voltage across C2 is equal to or close to the voltage of the vehicle-mounted power battery, for example, the difference between the two is less than or equal to 50V, that is, the voltage across C1 after charging is equal to or close to the voltage of the vehicle-mounted power battery, it is not necessary to use the motor circuit 101 and the driving circuit 102 to boost the voltage across C2, that is, it is not necessary to use the first working state. At this time, the first switch K1 can be directly closed, and C2 can directly charge C1, as shown in Figure 5

[0066] In some embodiments, in order to realize the reverse pre-charging of C2 to C1, C2 can be pre-charged by the vehicle-mounted storage battery first. Since the vehicle-mounted storage battery BT1 can provide power by means of a battery pack, capacitors can be connected in parallel to store power, or one or more capacitors connected in parallel can be used to realize the function of the storage battery, therefore, Figure 6 In some embodiments, a capacitor C3 is used as a vehicle-mounted storage battery for illustration.

[0067] As shown in Figure 6 In some embodiments, the power transmission circuit 100 further includes a boost circuit 104, a transformer 105, and a current conversion circuit 106.

[0068] Specifically, the boost circuit 104 includes an inductor and a plurality of switching transistors, the boost circuit 104 is electrically connected with the capacitor C3, and the duty cycle of the switching transistors is adjustable. The transformer 105 includes a primary winding and a secondary winding, the secondary winding of the transformer 105 is electrically connected with the boost circuit 104; the current conversion circuit 106 is electrically connected with the transformer 105 and the energy storage capacitor C2, and the current conversion circuit 106 is configured to convert alternating current into direct current.

[0069] Specifically, as shown in Figure 7 The boost circuit 104 includes an inductor L4, switching transistors Q11 and Q12, the transformer 105 includes a primary winding A, a first secondary winding B1 and a second secondary winding B2, and the current conversion circuit 106 is a four-arm full-bridge rectifier circuit including switching transistors Q7, Q8, Q9 and Q10.

[0070] According to the exemplary description of the embodiments of the present application, when C3 pre-charges C2, it generally includes two working modes, as shown in Figure 7 ​As shown, in the first working mode, the current flows as follows: on the low-voltage side, the inductor L4 releases electric energy, and the current flows from one end of the inductor L4, through the first secondary winding B1, the switch transistor Q11, the third capacitor C3, and back to the other end of the inductor L4. On the high-voltage side, based on electromagnetic induction, the primary winding A is powered through the first secondary winding B1, and the current flows from one end of the primary winding A, through the switch transistor Q9, the second capacitor C2, and the switch transistor Q8, and back to the other end of the primary winding A, thereby charging the second capacitor C2 and making the voltage of the second capacitor C2 reach or approach the voltage of the vehicle-mounted power battery BT2, so as to realize reverse pre-charging.

[0071] Referring to Figure 8 As shown, in the second working mode, the current flows as follows: on the low-voltage side, the inductor L4 releases electric energy, and the current flows from one end of the inductor L4, through the second secondary winding B2, the switch transistor Q12, the third capacitor C3, and back to the other end of the inductor L4; on the high-voltage side, based on electromagnetic induction, the primary winding A is powered through the second secondary winding B2, and the current flows from one end of the primary winding A, through the switch transistor Q7, the second capacitor C2, and the switch transistor Q10, and back to the other end of the primary winding A, thereby charging the second capacitor C2 and making the voltage of the second capacitor C2 reach or approach the voltage of the vehicle-mounted power battery BT2, so as to realize reverse pre-charging.

[0072] Specifically, in combination with Figures 9 to 11 , it is illustrated that, in the second working state, the controller controls the timing of the driving circuit and the flow direction of the current. As mentioned above, the second working state is the pressure relief state of C1 to C2, which can also be referred to as the positive charging state of the vehicle-mounted power battery to the vehicle-mounted storage battery.

[0073] In some embodiments, before the active pressure relief function is performed, the second switch K2 is disconnected, i.e., the vehicle-mounted power battery BT2 no longer continuously supplies power to the bus capacitor C1, and at this time the electric charge in the bus capacitor C1 is released. In order to avoid the direct release of the electric charge stored in C1 causing a large current impact on the low-voltage devices on the vehicle and thus causing damage, the first switch K1 is disconnected at this time, so that the electric charge output by C1 flows through the motor circuit 101 and the driving circuit 102 for voltage reduction.

[0074] Referring to Figure 9 As shown, in the third time T3, the first semiconductor switch Q1 and the second semiconductor switch Q2 are high, indicating that they are turned on; the third semiconductor switch Q3, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5, and the sixth semiconductor switch Q6 are low, indicating that they are turned off. In the fourth time T4, the first semiconductor switch Q1, the second semiconductor switch Q2, the third semiconductor switch Q3, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5, and the sixth semiconductor switch Q6 are all low, indicating that they are turned off.

[0075] The duration of T3 and T4 can be set according to the specific discharge requirements. Figure 9 In the example, T3 is greater than T4. In some application scenarios, T3 may also be less than or equal to T4. This embodiment of the present application does not limit this.

[0076] Specifically, refer to Figure 10 As shown by the dotted arrows, the controller 103 controls the first semiconductor switch Q1 and the second semiconductor switch Q2 to be turned on within the third time T3, and at the same time the third semiconductor switch Q3, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6 are turned off. The current flows from C1 to Q1 and Q2, then enters the motor windings L1, L2 and L3, and then flows to the energy storage capacitor C2 through Q3 to charge the motor windings L1, L2 and L3 and the energy storage capacitor C2.

[0077] Reference Figure 11 As shown by the dotted arrows, the controller 103 controls the first semiconductor switch Q1, the second semiconductor switch Q2, the third semiconductor switch Q3, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6 to be disconnected within the fourth time T4, and the current in the motor windings L1, L2 and L3 and the energy storage capacitor C2 is released through the freewheeling circuit formed by the body diodes of the third semiconductor switch, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6, thereby achieving a voltage reduction across C2.

[0078] After the above-mentioned pressure relief process, when the voltage across the energy storage capacitor C2 reaches a specific preset value, the third capacitor C3 can be charged through the current conversion circuit 106, the transformer 105 and the boost circuit 104, and the corresponding energy is stored through C3, so that the vehicle battery is maintained at a specific voltage, generally 9 to 15V.

[0079] According to the exemplary description of the embodiment of the present application, when C2 charges C3, there are generally two working modes. Figure 12 As shown, in the first working mode, the current flows as follows: on the high-voltage side, C2 provides voltage, and the current flows to the primary winding A through the switching transistor Q9; on the low-voltage side, based on electromagnetic induction, the first secondary winding B1 is energized through the primary winding A, and the current flows out from one end of the first secondary winding B1, flows through the inductor L4, the capacitor C3 and the switching transistor Q11, and then returns to the other end of the first secondary winding B1, thereby charging C3.

[0080] Reference Figure 13As shown, in the second working mode, the current flows as follows: on the high-voltage side, C2 provides voltage, and the current flows to the primary winding A through the switch transistor Q7; on the low-voltage side, based on electromagnetic induction, the second secondary winding B2 is powered through the primary winding A, and the current flows out from one end of the second secondary winding B2, flows through the inductor L4, the capacitor C3, and the switch transistor Q12, and then returns to the other end of the second secondary winding B2, thereby charging C3.

[0081] By the electric energy transmission circuit provided in the embodiments of the present application, without increasing the pre-charge resistor, the vehicle-mounted motor circuit 101 and the drive circuit 102 are multiplexed, the controller 103 controls the conduction or disconnection of the semiconductor switch in the drive circuit 102, the reverse pre-charging of the bus capacitor C1 can be effectively realized, without increasing the additional voltage reduction circuit, the positive pressure relief for the vehicle-mounted storage battery can be effectively realized. Meanwhile, by adjusting the duty cycle of the semiconductor switch in the drive circuit 102, the voltage pre-charging or pressure relief of different levels can be adapted.

[0082] According to another embodiment of the present application, a control method of an electric energy transmission circuit is also provided, which is used for controlling the electric energy transmission between the vehicle-mounted storage battery and the bus capacitor, and is mainly used for realizing the control method of the electric energy transmission circuit in the above-mentioned embodiments, and the content that has been discussed will not be repeated here.

[0083] Reference Figure 14 As shown, the control method of the electric energy transmission circuit comprises:

[0084] In step S1401, the conduction state of the semiconductor switch in the drive circuit is controlled to make the current output or received by the energy storage capacitor flow through the motor winding.

[0085] By the control method of the electric energy transmission circuit provided in the embodiments of the present application, without increasing the pre-charge resistor, the vehicle-mounted motor circuit and the drive circuit are multiplexed, the controller controls the conduction or disconnection of the semiconductor switch in the drive circuit, the reverse pre-charging of the bus capacitor can be effectively realized, without increasing the additional voltage reduction circuit, the positive pressure relief for the vehicle-mounted storage battery can be effectively realized. Meanwhile, by adjusting the duty cycle of the semiconductor switch in the drive circuit, the voltage pre-charging or pressure relief of different levels can be adapted.

[0086] In some embodiments, the control method of the electric energy transmission circuit further comprises:

[0087] In the first working state:

[0088] In the first time, the semiconductor switch in the drive circuit is controlled to execute the first conduction state to make the current output by the energy storage capacitor C2 flow only through the motor winding;

[0089] In the second time, the semiconductor switch in the drive circuit is controlled to execute the second conduction state to make the current output by the energy storage capacitor flow through the motor winding and the bus capacitor C1, so as to complete the charging of the bus capacitor C1.

[0090] In the second working state:

[0091] In the third time, the semiconductor switch in the drive circuit is controlled to execute the third conduction state to make the bus capacitor C1 release energy, and the current flows through the motor winding and the energy storage capacitor C2;

[0092] In the fourth time, the semiconductor switch in the drive circuit is controlled to execute the fourth conduction state, and the energy of the motor winding is released through the body diode of the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch, so as to complete the pressure relief of the bus capacitor.

[0093] It should be noted that the second time is later than the first time, and the fourth time is later than the third time, and the duty ratio of the semiconductor switch can be adjusted. Among them, the first time and the second time are alternately performed, and the third time and the fourth time are also alternately performed, and the length of time can be set or adjusted according to the specific charging demand, the first time can be greater than or equal to the second time, or can be less than the second time, and similarly, the third time can be greater than or equal to the fourth time, or can be less than the fourth time.

[0094] According to the second embodiment of the present application, a vehicle is also provided, which includes the electric energy transmission circuit as described above, and can realize all the functions of the electric energy transmission circuit, and the content has been described and will not be repeated here. The vehicle can be a fuel automobile, a plug-in hybrid electric vehicle or a new energy vehicle, etc., which is not limited in the present application.

[0095] Through the vehicle provided by the embodiment of the present application, without increasing the pre-charge resistor, the vehicle motor circuit and the drive circuit are multiplexed, and the controller controls the conduction or disconnection of the semiconductor switch in the drive circuit, so that the reverse pre-charging of the bus capacitor can be effectively realized. At the same time, without increasing the additional voltage reduction circuit, the positive pressure relief for the vehicle storage battery can be effectively realized. At the same time, by adjusting the duty ratio of the semiconductor switch in the drive circuit, different levels of voltage pre-charging or discharge can be adapted.

[0096] In the description of the present application, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0097] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0098] The embodiments, implementation manners and related technical features of the present application can be combined or replaced with each other without conflict.

[0099] The above are only the preferred embodiments of the present application, and do not limit the present application in any form. Any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution content of the present application and in accordance with the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. An electric energy transmission circuit for transmitting electric energy between a vehicle-mounted battery and a bus capacitor; characterized in that: The power transmission circuit includes: an energy storage capacitor, forming an electrical energy coupling with the onboard battery; a motor circuit, including a plurality of motor windings; a drive circuit, comprising a plurality of semiconductor switches electrically connected to the motor windings, the drive circuit being electrically connected to the bus capacitor and the energy storage capacitor; and a controller, electrically connected to the control terminals of the semiconductor switches respectively; Wherein, the controller is configured to control the conduction state of the semiconductor switch in the drive circuit so that the current output or received by the energy storage capacitor flows only through the motor winding; The controller is further configured to control the conduction state of the semiconductor switch in the drive circuit so that the current output or received by the energy storage capacitor flows through the motor winding and the bus capacitor; The controller is further configured to: In a first working state, the controller controls the semiconductor switch in the drive circuit to perform a first conduction state within a first time so that the current output by the energy storage capacitor flows only through the motor winding; and controls the semiconductor switch in the drive circuit to perform a second conduction state within a second time so that the current output by the energy storage capacitor flows through the motor winding and the bus capacitor, thereby completing charging of the bus capacitor. In the second working state, the controller controls the semiconductor switch in the drive circuit to execute a third conduction state within a third time period so that the bus capacitor releases energy, and current flows through the motor winding and the energy storage capacitor; and controls the semiconductor switch in the drive circuit to execute a fourth conduction state within a fourth time period so that the energy of the motor winding is released, thereby completing the pressure relief of the bus capacitor. The second time is later than the first time, the fourth time is later than the third time, and the duty cycle of the semiconductor switch is adjustable.

2. The power transmission circuit according to claim 1, characterized in that: The driving circuit is a six-arm full-bridge circuit, including a first semiconductor switch, a second semiconductor switch, and a third semiconductor switch constituting an upper bridge, and a fourth semiconductor switch, a fifth semiconductor switch, and a sixth semiconductor switch constituting a lower bridge.

3. The power transmission circuit according to claim 2, characterized in that: The controller is further configured to: The controller controls the first semiconductor switch, the second semiconductor switch, and the sixth semiconductor switch to be turned off within a first time, and the third semiconductor switch, the fourth semiconductor switch, and the fifth semiconductor switch to be turned on, so that the energy storage capacitor charges the motor winding; The controller controls the first semiconductor switch, the second semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch to be turned off within the second time, and the third semiconductor switch to be turned on, so that the energy storage capacitor and the motor winding charge the bus capacitor together.

4. The power transmission circuit according to claim 2, characterized in that: The controller is further configured to: The controller controls the first semiconductor switch and the second semiconductor switch to be turned on within a third time, and the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch to be turned off, so that the bus capacitor charges the motor winding; The controller controls the first semiconductor switch, the second semiconductor switch, the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch to be disconnected within a fourth time, so that the motor winding releases energy through a freewheeling circuit formed by the body diodes of the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch.

5. The power transmission circuit according to claim 1, characterized in that: The power transmission circuit further includes: The first switch is arranged between one end of the bus capacitor and one end of the energy storage capacitor. The first switch is configured so that when the difference between the voltage value at both ends of the energy storage capacitor and the voltage value of the on-board power battery is less than or equal to a first preset value, the first switch is in a closed state.

6. The power transmission circuit according to claim 1, characterized in that: The power transmission circuit further includes: A boost circuit, comprising an inductor and a plurality of switching transistors, wherein the boost circuit is electrically connected to the vehicle battery, and the duty cycle of the switching transistors is adjustable; a transformer, comprising a primary winding and a secondary winding, wherein the secondary winding of the transformer is electrically connected to the boost circuit; A current conversion circuit is electrically connected to the transformer and the energy storage capacitor, and the current conversion circuit is configured to perform AC-DC conversion on the current.

7. The power transmission circuit according to claim 6, characterized in that: The boost circuit configuration is: After the voltage output by the vehicle-mounted battery is boosted, it is output to the energy storage capacitor through the transformer and the current conversion circuit to charge the energy storage capacitor.

8. A control method for an electric energy transmission circuit for transmitting electric energy between an on-board battery and a bus capacitor, characterized in that: The power transmission circuit includes: an energy storage capacitor, which forms an electrical energy coupling with the vehicle battery; a motor circuit, which includes a plurality of motor windings; a drive circuit, which includes a plurality of semiconductor switches electrically connected to the motor windings, the drive circuit being electrically connected to the bus capacitor and the energy storage capacitor; and a controller, which is electrically connected to the control terminals of the semiconductor switches respectively; The control method includes: controlling the conduction state of the semiconductor switch in the drive circuit so that the current output or received by the energy storage capacitor flows through the motor winding; controlling the conduction state of the semiconductor switch in the drive circuit so that the current output or received by the energy storage capacitor flows through the motor winding and the bus capacitor; In the first working state: Controlling the semiconductor switch in the drive circuit to execute a first conduction state within a first time so that the current output by the energy storage capacitor flows only through the motor winding; Controlling the semiconductor switch in the drive circuit to execute a second conduction state within a second time period so that the current output by the energy storage capacitor flows through the motor winding and the bus capacitor, thereby completing charging of the bus capacitor; In the second working state: Controlling the semiconductor switch in the drive circuit to execute a third conduction state within a third time period so that the bus capacitor releases energy and current flows through the motor winding and the energy storage capacitor; Controlling the semiconductor switch in the drive circuit to execute a fourth conduction state within a fourth time period so as to release energy of the motor winding, thereby completing the pressure relief of the bus capacitor; The second time is later than the first time, the fourth time is later than the third time, and the duty cycle of the semiconductor switch is adjustable.

9. The control method of the power transmission circuit according to claim 8, characterized in that: The driving circuit is a six-arm full-bridge circuit, including a first semiconductor switch, a second semiconductor switch, and a third semiconductor switch constituting an upper bridge, and a fourth semiconductor switch, a fifth semiconductor switch, and a sixth semiconductor switch constituting a lower bridge.

10. The control method of the power transmission circuit according to claim 9, characterized in that: The controlling the semiconductor switch in the driving circuit to execute the first conducting state within the first time includes: controlling the first semiconductor switch, the second semiconductor switch, and the sixth semiconductor switch to be turned off within a first time, while controlling the third semiconductor switch, the fourth semiconductor switch, and the fifth semiconductor switch to be turned on, so that the energy storage capacitor charges the motor winding; The controlling the semiconductor switch in the driving circuit to execute the second conduction state within the second time includes: The controller controls the first semiconductor switch, the second semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch to be turned off within the second time, and the third semiconductor switch to be turned on, so that the energy storage capacitor and the motor winding charge the bus capacitor together.

11. The control method of the power transmission circuit according to claim 9, characterized in that: The controlling the semiconductor switch in the driving circuit to execute the third conduction state within the third time includes: controlling the first semiconductor switch and the second semiconductor switch to be turned on within a third time, while turning off the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch, so that the bus capacitor charges the motor winding; The controlling the semiconductor switch in the driving circuit to execute the fourth conducting state within the fourth time includes: The controller controls the first semiconductor switch, the second semiconductor switch, the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch to be disconnected within a fourth time, so that the motor winding releases energy through a freewheeling circuit formed by the body diodes of the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch, and the sixth semiconductor switch.

12. The method for controlling a power transmission circuit according to claim 8, wherein: The method further comprises: When the difference between the voltage across the bus capacitor and the voltage across the vehicle power battery is less than or equal to a first preset value, controlling the first switch to be in a closed state; wherein the two ends of the first switch are connected to the bus capacitor and the vehicle power battery, respectively; When the difference between the voltage value at both ends of the energy storage capacitor and the voltage value of the vehicle-mounted power battery is less than or equal to a second preset value, the second switch is controlled to be in a closed state; wherein, the two ends of the second switch are respectively connected to the bus capacitor and the energy storage capacitor.

13. The control method of the power transmission circuit according to claim 12, characterized in that: The method further comprises: After the voltage output by the vehicle-mounted battery is boosted by a boost circuit, it is output to the energy storage capacitor through a transformer and a current conversion circuit to charge the energy storage capacitor.

14. A vehicle, characterized in that: The power transmission circuit comprises the power transmission circuit according to any one of claims 1 to 7.

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