Electric energy transmission circuit, control method thereof and vehicle

Abstract

The invention 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, and only the original motor circuit and the original driving circuit in a vehicle-mounted circuit are reused on the premise of not adding an additional pre-charging relay and a pre-charging resistor, so that the cost of the vehicle-mounted circuit is reduced. By controlling the conduction state of the semiconductor switch of the driving circuit, the function of pre-charging the bus capacitor by the vehicle-mounted storage battery through the energy storage capacitor can be realized, and the voltage relief from the bus capacitor to the energy storage capacitor and the vehicle-mounted storage battery can be realized, so that the problems of large size and high cost of a pre-charging loop in the related technology are solved.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a power transmission circuit and a control method thereof, and a vehicle. Background Art

[0002] When the vehicle is powered on at high voltage, the output voltage of the power battery is added to the high-voltage load and the bus capacitor at the same time. Since the internal resistance of the bus capacitor is very small, it is equivalent to a conductor when there is no charge, which will generate a large instantaneous current, thus causing the high-voltage contactor to sinter or the high-voltage fuse to blow, etc. To avoid this situation, before the high-voltage main circuit is turned on, the bus capacitor connected in parallel with the power battery is first charged with limited current, that is, reverse pre-charge, and the high-voltage main circuit is turned on after the bus capacitor is fully charged.

[0003] The pre-charging circuit in the related art is generally composed of a pre-charging relay and a pre-charging resistor. The pre-charging resistor can limit the charging current and fully charge the bus capacitor before connecting to the high-voltage main circuit. However, the pre-charging resistor is large in size and high in cost, which leads to great limitations in the implementation of the pre-charging circuit. Summary of the invention

[0004] An embodiment of the present application provides a power transmission circuit, which realizes the pre-charging function without adding additional pre-charging resistance, so as to at least partially solve the above-mentioned technical problems.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, there is provided an electric energy transmission circuit for transmitting electric energy between a vehicle-mounted battery and a bus capacitor; the electric energy transmission circuit comprises: an energy storage capacitor, which forms an electric energy coupling 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 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 ends 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 only flows through the motor winding; the controller is also 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.

[0006] Optionally, the controller is further configured as follows: in a first working state, the controller controls 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; the controller controls the semiconductor switch in the drive circuit to execute 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 to complete the charging of the bus capacitor; in a second working state, the controller controls the semiconductor switch in the drive circuit to execute a third conduction state within a third time so that the bus capacitor releases energy, and the current flows through the motor winding and the energy storage capacitor; the controller controls the semiconductor switch in the drive circuit to execute a fourth conduction state within a fourth time so that the energy of the motor winding is released to complete the pressure relief of the bus capacitor; wherein, 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.

[0007] Optionally, 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.

[0008] Optionally, the controller is further configured as follows: the controller controls the first semiconductor switch, the second semiconductor switch and the sixth semiconductor switch to be disconnected 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 disconnected within a 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.

[0009] Optionally, the controller is further configured as follows: 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 turned off 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.

[0010] Optionally, the power transmission circuit also includes a first switch, which 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 vehicle-mounted power battery is less than or equal to a first preset value, the first switch is in a closed state.

[0011] Optionally, the electric energy transmission circuit also includes: a boost circuit, including an inductor and a plurality of switching transistors, the boost circuit is electrically connected to the vehicle battery, and the duty cycle of the switching transistor is adjustable; a transformer, including a primary winding and a secondary winding, the secondary winding of the transformer is electrically connected to the boost circuit; a current conversion circuit, electrically connected to the transformer and the energy storage capacitor, and the current conversion circuit is configured to convert current into AC / DC.

[0012] Optionally, the boost circuit is configured to: boost the voltage output by the vehicle-mounted battery, and then output it 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 for an electric energy transmission circuit is provided, wherein the electric energy transmission circuit comprises: an energy storage capacitor, which forms an electric energy coupling with a vehicle-mounted battery; a motor circuit, which comprises a plurality of motor windings; a drive circuit, which comprises a plurality of semiconductor switches electrically connected to the motor windings, wherein the drive circuit is electrically connected to the bus capacitor and the energy storage capacitor; and a controller, which is electrically connected to the control ends of the semiconductor switches, respectively; the control method comprises: controlling the conduction state of the semiconductor switches in the drive circuit so that the current output or received by the energy storage capacitor flows through the motor windings.

[0014] Optionally, the method also includes: in the first working state: controlling the semiconductor switch in the drive circuit to execute the first conduction state within the 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 the second conduction state within the second time so that the current output by the energy storage capacitor flows through the motor winding and the bus capacitor to complete the charging of the bus capacitor; in the second working state: controlling the semiconductor switch in the drive circuit to execute the third conduction state within the third time so that the bus capacitor releases energy, and the current flows through the motor winding and the energy storage capacitor; controlling the semiconductor switch in the drive circuit to execute the fourth conduction state within the fourth time so that the energy of the motor winding is released to complete the pressure relief of the bus capacitor; wherein, 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.

[0015] Optionally, 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.

[0016] Optionally, controlling the semiconductor switch in the drive circuit to execute the first conduction 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 the 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; controlling the semiconductor switch in the drive 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.

[0017] Optionally, controlling the semiconductor switches in the drive 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 the third time, while the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch are turned off, so that the bus capacitor charges the motor winding; controlling the semiconductor switches in the drive circuit to execute the fourth conduction state within the fourth time includes: the controller 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 within the fourth time, so that the motor winding releases energy through the 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.

[0018] Optionally, the method also includes: when the difference between the voltage value at both ends of the bus capacitor and the voltage value of 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 respectively connected to the bus capacitor and the vehicle power battery; when the difference between the voltage value at both ends of the energy storage capacitor and the voltage value of the vehicle power battery is less than or equal to a second preset value, controlling the second switch 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.

[0019] Optionally, the method further includes: boosting the voltage output by the vehicle-mounted battery through a boost circuit, and outputting the voltage 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, a vehicle is also provided, comprising the electric energy transmission circuit as described above.

[0021] The power transmission circuit of the embodiment of the present application includes an energy storage capacitor, a motor circuit, a drive circuit and a controller, wherein the energy storage capacitor and the vehicle-mounted battery form an electrical energy coupling, the motor circuit includes a plurality of motor windings, the drive circuit includes 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, and the controller is electrically connected to the control ends of the semiconductor switches, respectively. The controller controls the conduction state of the semiconductor switch in the drive circuit so that the current output or received by the energy storage capacitor only flows through the motor winding; or controls 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. Without adding additional pre-charging relays and pre-charging resistors, only the original motor circuit and drive circuit in the vehicle-mounted circuit are reused. By controlling the conduction state of the semiconductor switch in the drive circuit, the pre-charging function of the vehicle-mounted 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 battery can be realized, thereby solving the problem of large volume and high cost of the pre-charging circuit in the related art.

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

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

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

[0025] Figure 1 is a schematic diagram of the structure of a power transmission circuit provided in an exemplary embodiment of the present application;

[0026] Figure 2 is a control timing diagram of a controller in a first working state provided in an exemplary embodiment of the present application;

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

[0028] Figure 4 is a schematic diagram of current flow during a second time period provided in an exemplary embodiment of the present application;

[0029] Figure 5 is a current flow diagram provided in an exemplary embodiment of the present application;

[0030] Figure 6 is a partial structural schematic diagram of a power transmission circuit provided in an exemplary embodiment of the present application;

[0031] Figure 7 is an optional current flow diagram in a pre-charge state provided in an exemplary embodiment of the present application;

[0032] Figure 8 It is another optional current flow diagram in the pre-charge state provided in the exemplary embodiment of the present application;

[0033] Fig. 9 is a control timing diagram of the controller in the second working state provided in an exemplary embodiment of the present application;

[0034] Fig.10 is a schematic diagram of current flow during a third time period provided in an exemplary embodiment of the present application;

[0035] Fig.11 is a schematic diagram of current flow in a fourth time period provided in an exemplary embodiment of the present application;

[0036] Fig.12 is an optional current flow diagram in a pressure relief state provided in an exemplary embodiment of the present application;

[0037] Fig.13 is another optional current flow diagram in a pressure relief state provided in an exemplary embodiment of the present application;

[0038] Fig.14 is a flow chart of a control method of a power transmission circuit provided in an exemplary embodiment of the present application.

[0039] Description of reference numerals:

[0040] 100, power transmission circuit; 101, motor circuit; 102, drive circuit; 103, controller; 104, boost circuit; 105, transformer; 106, current conversion circuit;

[0041] C1, bus capacitor; C2, energy storage capacitor; C3, capacitor; BT1, vehicle-mounted storage battery; BT2, vehicle-mounted power battery; K1, first switch; K2, second switch; L1, L2, L3, motor windings; 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 described clearly and completely below in conjunction with 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 of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0043] Reference Figure 1 As shown, according to an embodiment of the present application, a power transmission circuit 100 is provided for transmitting power between a vehicle-mounted battery BT1 and a bus capacitor C1. The power transmission circuit includes: a storage capacitor C2, a motor circuit 101, a drive circuit 102 and a controller 103.

[0044] Specifically, the power transmission circuit 100 may further include a first switch K1, which is disposed between one end of the bus capacitor C1 and one end of the energy storage capacitor C2, and is mainly used to disconnect the loop directly connected between the two during the period when the energy storage capacitor C2 charges the bus capacitor C1 or the bus capacitor C1 charges the energy storage capacitor C2, so that the current flows through the motor circuit 101 and the drive circuit 102 to increase or decrease the voltage. The first switch K1 can be implemented by a relay or by a back-to-back MOS tube to avoid the sintering of the moving and static contacts due to large current or arcing caused by traditional mechanical switches such as relays.

[0045] Specifically, the energy storage capacitor C2 forms an electrical energy coupling with the vehicle battery BT1; the motor circuit 101 includes a plurality of motor windings; the drive circuit 102 includes a plurality of semiconductor switches electrically connected to the motor windings, and the drive circuit 102 is electrically connected to the bus capacitor C1 and the energy storage capacitor C2; the controller 103 is electrically connected to the control ends of the semiconductor switches respectively.

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

[0047] In the embodiment of the present application, the bus capacitor C1 is a large parallel capacitor of the vehicle-mounted power battery. Therefore, the process of pre-charging the bus capacitor C1 can be understood as the 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 so that the current output or received by the energy storage capacitor C2 only flows through the motor winding; the controller 103 is also 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 C2 flows through the motor winding and the bus capacitor C1.

[0049] The current only flows through the motor winding, which can be understood as the energy storage capacitor C2 charging the motor winding, or the motor winding releasing pressure to the energy storage capacitor C2. The current flows through the motor winding and the bus capacitor C1, which can be understood as the bus capacitor C1 charging the motor winding to release pressure, or the energy storage capacitor C2 and the motor winding jointly charging the bus capacitor C1.

[0050] Through the scheme provided in the embodiment of the present application, the controller controls 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; or controls 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. Without adding additional pre-charging relays and pre-charging resistors, only the original motor circuit and drive circuit in the vehicle are reused. The pre-charging function can be achieved by controlling the conduction state of the semiconductor switch in the drive circuit, and the vehicle-mounted battery can be pre-charged to the bus capacitor through the energy storage capacitor, and the bus capacitor can be depressurized to the energy storage capacitor and the battery, thereby solving the problem of the pre-charging circuit in the related art being large in size and high in cost due to the presence of pre-charging resistors and relays.

[0051] In some embodiments, the controller 103 may include multiple working states, corresponding to different working states of the power transmission circuit 100. The embodiment of the present application takes the charging state (also referred to as the boost state) and the pressure relief state of the above-mentioned power transmission circuit 100 as examples for explanation.

[0052] Specifically, the reverse pre-charging state of the power transmission circuit 100 (the vehicle-mounted battery reversely pre-charges the bus capacitor C1) is taken as the first working state, which may include two stages.

[0053] Phase 1: The controller 103 controls the semiconductor switch in the driving circuit 102 to execute a first conduction state within a first time so that the current output by the energy storage capacitor C2 only flows through the motor winding.

[0054] The second stage: the controller 103 controls the semiconductor switch in the drive circuit 102 to execute the second conduction state within the second time so that the current output by the energy storage capacitor C2 flows through the motor winding and the bus capacitor C1 to complete the charging of the bus capacitor C1.

[0055] 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 cycle of the semiconductor switch is adjustable, and by reasonably adjusting the duty cycle of the semiconductor switch, the charging requirements of bus capacitors C1 of different levels can be effectively achieved.

[0056] Specifically, the pressure relief state of the power transmission circuit 100 is taken as the second working state, which may include two stages.

[0057] Phase 1: the controller 103 controls the semiconductor switch in the drive circuit 102 to execute the third conduction state within the third time so that the bus capacitor C1 releases energy, and the current flows through the motor winding and the energy storage capacitor C2.

[0058] Phase 2: The controller 103 controls the semiconductor switch in the drive circuit 102 to execute the fourth conduction state within the fourth time so that the energy of the motor winding is released to complete the pressure relief of the bus capacitor C1.

[0059] 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 cycle of the semiconductor switch is adjustable, and by reasonably adjusting the duty cycle of the semiconductor switch, the pressure relief requirements for bus capacitors C1 of different levels can be effectively achieved.

[0060] Specific, combined Figures 2 to 5 , an example is given to illustrate the control timing of the controller to the drive circuit and the direction of the current in the first working state (reverse pre-charging). As shown in the figure, the drive circuit 102 is a six-arm full-bridge circuit, including a first semiconductor switch Q1, a second semiconductor switch Q2 and a third semiconductor switch Q3 constituting an upper bridge, and a fourth semiconductor switch Q4, a fifth semiconductor switch Q5 and a sixth semiconductor switch Q6 constituting a lower bridge. The motor circuit 101 includes three cascaded motor windings L1, L2 and L3.

[0061] In some embodiments, a second switch K2 is set between the vehicle-mounted power battery BT2 and the bus capacitor C1. When pressure relief or forward charging is required (the vehicle-mounted power battery charges the vehicle-mounted storage battery), K2 is in a closed state. When reverse pre-charging is required (the vehicle-mounted storage battery reversely pre-charges the bus capacitor C1), the energy storage capacitor C2 first charges the bus capacitor C1. When the voltage across the bus capacitor C1 reaches a preset value or the bus capacitor C1 is full, K2 is closed to avoid generating a large instantaneous current, which in turn causes the high-voltage contactor to sinter, the high-voltage fuse to blow, etc. The preset value here can be set according to the 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] Reference Figure 2 As shown, in the first time T1, the first semiconductor switch Q1, the second semiconductor switch Q2 and the sixth semiconductor switch Q6 are at a low level, indicating that they are turned off; the third semiconductor switch Q3, the fourth semiconductor switch Q4 and the fifth semiconductor switch Q5 are at a high level, 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 at a low level, indicating that they are turned off; the third semiconductor switch Q3 is at a high level, indicating that they are turned on.

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

[0064] Reference Figure 4 As shown by the dotted arrows, 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 disconnected, and the third semiconductor switch Q3 to be turned on within the second time T2, so that 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 power battery BT2 is generally much higher than the voltage of the vehicle storage battery BT1. In the reverse pre-charging state, the voltage across C2 is provided by the vehicle storage battery BT1. When the voltage across C2 can meet the voltage required for pre-charging, for example, the voltage across C2 is equal to or close to the voltage of the vehicle power battery, for example, the difference between the two is less than or equal to 50V, that is, the voltage across C1 after charging can be equal to or close to the voltage of the vehicle power battery. In this case, there is no need to use the motor circuit 101 and the drive circuit 102 to boost the voltage across C2, that is, the above-mentioned first working state is not required. At this time, the first switch K1 can be directly closed to charge C1 directly from C2. Refer to Figure 5 shown.

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

[0067] Reference Figure 6 As shown, 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 switch transistors, the boost circuit 104 is electrically connected to the capacitor C3, and the duty cycle of the switch transistor is adjustable. The transformer 105 includes a primary winding and a secondary winding, and the secondary winding of the transformer 105 is electrically connected to the boost circuit 104; the current conversion circuit 106 is electrically connected to the transformer 105 and the energy storage capacitor C2, and the current conversion circuit 106 is configured to convert the current into AC and DC.

[0069] Specifically, refer to Figure 7 As shown, 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 a switching transistor Q7, a switching transistor Q8, a switching transistor Q9 and a switching transistor Q10.

[0070] According to the exemplary description of the embodiment of the present application, when C3 performs reverse pre-charging to C2, generally two working modes are included, referring to Figure 7As shown, in the first working mode, the current flow is as follows: on the low-voltage side, the inductor L4 releases electric energy, and the current flows from one end of L4 through the first secondary winding B1, the switching transistor Q11, and the third capacitor C3 and then returns to the other end of the inductor L4. On the high-voltage side, based on electromagnetic induction, the primary winding A is energized through the first secondary winding B1, and the current is output from one end of the primary winding A, flows to the switching transistor Q9, and then flows through the second capacitor C2, and returns to the other end of the primary winding 121 through the switching transistor Q8, thereby charging the second capacitor C2, so that the voltage of C2 reaches or approaches the voltage of the vehicle power battery BT2, thereby realizing reverse pre-charging.

[0071] Reference Figure 8 As shown, in the second working mode, the current flow is as follows: on the low-voltage side, the inductor L4 releases electric energy, and the current flows from one end of L4 through the second secondary winding B2, the switching transistor Q12, the third capacitor C3, and then returns to the other end of the inductor L4; on the high-voltage side, based on electromagnetic induction, the primary winding A is energized through the second secondary winding B2, and the current flows from one end of the primary winding A to the switching transistor Q7, and then flows through the second capacitor C2 and the switching transistor Q10, and then returns to the other end of the primary winding A, thereby charging C2, so that the voltage of C2 reaches or is close to the voltage of the vehicle power battery BT2, and reverse pre-charging is achieved.

[0072] Specific, combined Figures 9 to 11 , an example is given to illustrate the control sequence of the controller on the drive circuit and the direction of the current in the second working state. As mentioned above, the second working state is the pressure release state from C1 to C2, which can also be called the positive charging state from the vehicle power battery to the vehicle storage battery.

[0073] In some embodiments, before executing the active discharge function, the second switch K2 is disconnected first, that is, the vehicle-mounted power battery BT2 no longer continuously supplies power to the bus capacitor C1, and the charge in the bus capacitor C1 is released. In order to avoid directly discharging the charge stored in C1 and causing a large current impact on the low-voltage components on the vehicle and causing damage, the first switch K1 is disconnected at this time, so that the charge output by C1 flows through the motor circuit 101 and the drive circuit 102 for voltage reduction.

[0074] Reference Fig. 9 As shown, in the third time T3, the first semiconductor switch Q1 and the second semiconductor switch Q2 are at a high level, indicating conduction; the third semiconductor switch Q3, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6 are at a low level, indicating cut-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 at a low level, indicating cut-off.

[0075] The duration of T3 and T4 can be set according to specific discharge requirements. Fig. 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 Fig.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, while the third semiconductor switch Q3, the fourth semiconductor switch Q4, the fifth semiconductor switch Q5 and the sixth semiconductor switch Q6 are turned off, and 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 Fig.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 releases energy 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, referring to Fig.12 As shown, in the first working mode, the current flow is 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 Fig.13As shown, in the second working mode, the current flow is as follows: on the high-voltage side, C2 provides voltage, and the current flows to the primary winding A through the switching transistor Q7; on the low-voltage side, based on electromagnetic induction, the second secondary winding B2 is energized 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 switching transistor Q12, and then returns to the other end of the second secondary winding B2, thereby charging C3.

[0081] Through the power transmission circuit provided in the embodiment of the present application, without increasing the pre-charging resistance, the vehicle motor circuit 101 and the drive circuit 102 are reused, and the semiconductor switch in the drive circuit 102 is controlled by the controller 103 to be turned on or off, so that the bus capacitor C1 can be effectively pre-charged in the reverse direction, and at the same time, without adding an additional step-down circuit, the forward pressure relief for the vehicle battery can be effectively achieved. At the same time, by adjusting the duty cycle of the semiconductor switch in the drive circuit 102, different levels of voltage pre-charging or discharge can be adapted.

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

[0083] Reference Fig.14 As shown, the control method of the power transmission circuit includes:

[0084] Step S1401, controlling the conduction state of the semiconductor switch in the driving circuit so that the current output or received by the energy storage capacitor flows through the motor winding.

[0085] Through the control method of the power transmission circuit provided in the embodiment of the present application, without increasing the pre-charging resistance, the vehicle-mounted motor circuit and the drive circuit are reused, and the conduction or disconnection of the semiconductor switch in the drive circuit is controlled by the controller, so that the reverse pre-charging of the bus capacitor can be effectively realized, and at the same time, without adding an additional step-down circuit, the positive pressure discharge for the vehicle-mounted battery can be effectively realized. At the same time, by adjusting the duty cycle of the semiconductor switch in the drive circuit, different levels of voltage pre-charging or discharge can be adapted.

[0086] In some embodiments, the control method of the power transmission circuit further includes:

[0087] In the first working state:

[0088] Controlling the semiconductor switch in the driving circuit to execute a first conduction state within a first time so that the current output by the energy storage capacitor C2 only flows through the motor winding;

[0089] In the second time, the semiconductor switch in the driving circuit is controlled to execute the second conducting state so that the current output by the energy storage capacitor flows through the motor winding and the bus capacitor C1 to complete the charging of the bus capacitor C1.

[0090] In the second working state:

[0091] Controlling the semiconductor switch in the driving circuit to execute the third conduction state within the third time so that the bus capacitor C1 releases energy, and the current flows through the motor winding and the energy storage capacitor C2;

[0092] During the fourth time, the semiconductor switch in the drive circuit is controlled to execute the fourth conduction state, and a freewheeling path is formed by releasing energy for the motor winding through the body diodes of the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch, so that the energy of the motor winding is released to complete the pressure relief of the bus capacitor.

[0093] It should be noted that 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. The first time and the second time are performed alternately, and the third time and the fourth time are also performed alternately. The length of time can be set or adjusted according to specific charging needs. The first time can be greater than or equal to the second time, or less than the second time. Similarly, the third time can be greater than or equal to the fourth time, or less than the fourth time.

[0094] According to another embodiment of the present application, a vehicle is also provided, including the power transmission circuit as described above, which can realize all the functions of the power transmission circuit, and the contents already described are not repeated here. The vehicle can be a fuel vehicle, a plug-in hybrid vehicle or a new energy vehicle, etc., and the present application does not make specific limitations on this.

[0095] The vehicle provided by the embodiment of the present application reuses the on-board motor circuit and the drive circuit without increasing the pre-charging resistance, and controls the on or off of the semiconductor switch in the drive circuit by the controller, so as to effectively realize the reverse pre-charging of the bus capacitor, and effectively realize the positive pressure discharge of the on-board battery without adding an additional step-down circuit. At the same time, by adjusting the duty cycle of the semiconductor switch in the drive circuit, different levels of voltage pre-charging or discharge can be adapted.

[0096] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0097] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

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

[0099] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within 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 comprises: An energy storage capacitor, which forms an electrical energy coupling with the vehicle-mounted 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, wherein the drive circuit is 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.

2. The power transmission circuit according to claim 1, characterized in that: The controller is also configured to: In the first working state, the controller controls the semiconductor switch in the drive circuit to execute the first conduction state within a first time so that the current output by the energy storage capacitor flows only through the motor winding; the controller controls the semiconductor switch in the drive circuit to execute the 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 to complete the charging of the bus capacitor; In the second working state, the controller controls the semiconductor switch in the drive circuit to execute the third conduction state within a third time so that the bus capacitor releases energy, and current flows through the motor winding and the energy storage capacitor; the controller controls the semiconductor switch in the drive circuit to execute the fourth conduction state within a fourth time so that the energy of the motor winding is released to complete 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.

3. The power transmission circuit according to claim 2, 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.

4. The power transmission circuit according to claim 3, characterized in that: The controller is also 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 disconnected 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.

5. The power transmission circuit according to claim 3, characterized in that: The controller is also 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 the 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.

6. 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 vehicle-mounted power battery is less than or equal to a first preset value, the first switch is in a closed state.

7. 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 switch transistors, the boost circuit being electrically connected to the vehicle-mounted battery, and the duty cycle of the switch transistors being 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.

8. The power transmission circuit according to claim 1, characterized in that: The boost circuit is configured as follows: 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.

9. A control method for an electric energy transmission circuit, characterized in that: The power transmission circuit includes: an energy storage capacitor, which forms an energy coupling with the vehicle-mounted 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, and the drive circuit is electrically connected to the bus capacitor and the energy storage capacitor; and a controller, which is electrically connected to the control ends of the semiconductor switches respectively; The control method comprises: The conduction state of the semiconductor switch in the drive circuit is controlled so that the current output or received by the energy storage capacitor flows through the motor winding.

10. The control method of the power transmission circuit according to claim 9, characterized in that: The method further comprises: 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 so that the current output by the energy storage capacitor flows through the motor winding and the bus capacitor to complete 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 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 so that the energy of the motor winding is released to complete 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.

11. The control method of the power transmission circuit according to claim 10, 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.

12. The control method of the power transmission circuit according to claim 11, characterized in that: The controlling the semiconductor switch in the driving circuit to execute the first conduction 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, 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 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 disconnected 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.

13. The control method of the power transmission circuit according to claim 11, characterized in that: The step of controlling the semiconductor switch in the driving circuit to execute a third conduction state within a third time period includes: Controlling the first semiconductor switch and the second semiconductor switch to be turned on within a third time, while the third semiconductor switch, the fourth semiconductor switch, the fifth semiconductor switch and the sixth semiconductor switch are turned off, so that the bus capacitor charges the motor winding; The controlling the semiconductor switch in the driving circuit to execute a fourth conduction state within a fourth time period 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 the 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.

14. The control method of the power transmission circuit according to claim 9, characterized in that: The method further comprises: When the difference between the voltage value at both ends of the bus capacitor and the voltage value of the vehicle-mounted power battery is less than or equal to a first preset value, the first switch is controlled to be in a closed state; wherein the two ends of the first switch are respectively connected to the bus capacitor and the vehicle-mounted power battery; 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.

15. The control method of the power transmission circuit according to claim 9, 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.

16. A vehicle, characterized in that: A power transmission circuit comprising the power transmission circuit according to any one of claims 1 to 8.

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