Electric vehicle electric drive multiplexing charging system and method

Abstract

The invention provides an electric drive multiplexing charging system for an electric vehicle. The electric drive multiplexing charging system comprises a power battery, an inverter, a motor, a relay, a diode and a triode, the motor is used as a variable voltage inductor for storing electric energy from the charging pile and outputting the electric energy to the power battery; the diode is used for limiting current flowing from the neutral point of the motor to the power battery anode; the relay, the triode and the upper bridge arm and the lower bridge arm of the inverter are all jointly used as a switch of the electric vehicle electric drive multiplexing charging circuit under the control of a driving circuit of a motor controller to which the inverter belongs, and a charging current path is constructed in cooperation with the current direction limited by the diode. The core three-electric system (the power battery, the motor controller to which the relay belongs and the driving motor) of the electric automobile is creatively integrated, the neutral point of the motor winding is led out, on one hand, the neutral point is connected to the positive electrode of the battery through a diode, on the other hand, the neutral point is connected to the negative electrode of the battery through a triode, and the structure is simple and efficient.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle charging technology, and specifically to an electric vehicle electric drive multiplexing charging system and method. Background Technology

[0002] In recent years, the rapid development of electric vehicles in China has become a shining benchmark for the global new energy transformation. The core driving force behind this leap is its deep integration with the new energy system. On the one hand, electric vehicles, as mobile energy storage units, have effectively absorbed fluctuating renewable energy sources such as wind and solar power through large-scale applications, improving grid flexibility and the proportion of green electricity. On the other hand, the rapid construction of fast-charging networks and battery swapping stations covering urban and rural areas, especially highway service areas, has provided a solid guarantee for electric mobility. The rise of the electric vehicle industry has not only significantly reduced carbon emissions in the transportation sector but has also become a key force in promoting energy structure optimization and leading the global green transportation revolution. At the same time, in order to reduce losses and increase charging speed, the voltage level of the electric vehicle's three-electric system (battery, motor, and electronic control system) is gradually increasing, with 800V high-voltage platforms becoming increasingly common, and some automakers have begun research on kilovolt high-voltage platforms.

[0003] However, many charging stations on the market are still built on the 400V voltage platform of a few years ago, which cannot directly charge high-voltage batteries. This leads to poor charging compatibility and charging difficulties, hindering user experience. Compared with using a separate charging circuit, reusing the electric drive system for boost charging has a significant cost advantage. Many companies have researched this and proposed some solutions, but these solutions all have certain drawbacks. For example, CN112937332A only reuses the MCU (motor controller chip) and inverter transistors, adding extra inductors and multiple transistors, significantly increasing costs. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing an electric vehicle electric drive reuse charging system, comprising: Power batteries, inverters, motors, relays, diodes, and transistors; The motor is used as a transformer inductor to store electrical energy from the charging station and output it to the power battery; Diodes are used to limit the flow of current from the neutral point of the motor to the positive terminal of the power battery; The relay, transistor, and the upper and lower bridge arms of the inverter are all used together as switches in the electric drive multiplexing charging circuit of the electric vehicle under the control of the drive circuit of the motor controller of the inverter. Together with the diode to limit the current direction, they form a charging current path.

[0005] Furthermore, when the output voltage of the charging pile is higher than the rated charging voltage of the power battery, the transistor and relay are kept disconnected throughout the charging process. Under the condition that the upper and lower bridge arms of the inverter cannot be turned on at the same time, the upper bridge arm of the inverter is first controlled to turn on according to the first preset duty cycle. The charging current path passes through the charging pile, motor, diode and power battery in sequence to form a series closed loop. Then the lower bridge arm of the inverter is controlled to turn on according to the second preset duty cycle. The charging current path passes through the motor, diode and power battery in sequence to form a series closed loop.

[0006] Furthermore, when the output voltage of the charging pile is lower than the rated charging voltage of the power battery, the relay is kept open, the upper bridge arm of the inverter is turned on, and the lower bridge arm of the inverter is turned off throughout the charging process. First, the control transistor is turned on according to the third preset duty cycle, and the charging current path passes through the charging pile and the motor in sequence to form a series closed loop. Then, the control transistor is turned off according to the third preset duty cycle, and the charging current path passes through the charging pile, the motor, the diode, and the power battery in sequence to form a series closed loop.

[0007] Furthermore, when the output voltage of the charging pile is equal to the rated charging voltage of the power battery, the relay remains closed, the transistor is open, and the upper and lower bridge arms of the inverter are both open throughout the charging process. The charging current path passes through the charging pile and the power battery in sequence and forms a series closed loop.

[0008] Furthermore, it also includes capacitors to maintain voltage stability in the electric vehicle's electric drive multiplexing charging circuit.

[0009] Furthermore, the peak current of the motor does not exceed the saturation current of each winding in the motor.

[0010] Furthermore, the calculation methods for the first preset duty cycle and the second preset duty cycle are as follows: in, It is the rated charging voltage of the power battery. It is the first preset duty cycle. It is the output voltage of the charging station; Second preset duty cycle =1- .

[0011] Furthermore, the calculation method for the third preset duty cycle is as follows: in, It is the rated charging voltage of the power battery. It is the third preset duty cycle. It is the output voltage of the charging station.

[0012] Furthermore, when the output voltage of the charging pile is higher than the rated charging voltage of the power battery, when the charging pile, motor, diode and power battery form a series closed loop, a portion of the electrical energy output by the charging pile is input into the motor and converted into magnetic energy and stored in the phase windings of the motor. The remaining electrical energy output by the charging pile is output to the power battery. When the motor, diode, and power battery form a series closed loop, the magnetic energy in the motor is converted into electrical energy and output to the power battery.

[0013] Furthermore, when the output voltage of the charging pile is lower than the rated charging voltage of the power battery, when the charging pile and the motor form a series closed loop, the electrical energy output by the charging pile is input into the motor and converted into magnetic energy and stored in the phase windings, phase windings, and phase windings of the motor. When the charging pile, motor, diode, and power battery form a series closed loop, the magnetic energy in the motor is converted into electrical energy and together with the electrical energy output from the charging pile E, it is output to the power battery.

[0014] A method for reusing and charging electric drive systems in electric vehicles, comprising: Power batteries, inverters, motors, relays, diodes, and transistors; The motor acts as a transformer inductor, storing electrical energy from the charging station and outputting it to the power battery; The diode limits the current flow from the neutral point of the motor to the positive terminal of the power battery; The relay, transistor, and the upper and lower bridge arms of the inverter are all controlled by the drive circuit of the motor controller to which the inverter belongs, and together they serve as the switch of the electric vehicle electric drive multiplexing charging circuit. Together with the diode to limit the current direction, they form the charging current path.

[0015] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the calculation process of the first preset duty cycle, the second preset duty cycle, and the third preset duty cycle in the electric vehicle electric drive multiplexing charging circuit system described above.

[0016] The beneficial effects of this invention are as follows: 1. The circuit innovatively integrates the core three-electric system of electric vehicles—power battery, Figure 1 The DC-AC relay is used to control the motor controller and drive motor. The power battery and motor controller are connected controllably via a relay, which can be disconnected or connected as needed. The neutral point of the motor windings is brought out, connected to the positive terminal of the battery via a diode and to the negative terminal via a transistor (such as an IGBT or MOSFET), resulting in a simple and efficient structure.

[0017] 2. Compared to traditional drive systems, this invention only introduces an additional diode, a transistor, and a small number of wires, resulting in minimal hardware modifications and a compact overall structure. Compared to configuring a separate DC-DC converter circuit, it significantly reduces system complexity and manufacturing costs, offering a clear economic advantage.

[0018] 3. This circuit has a high degree of functional integration and flexibility. By controlling the three-phase winding inductance of the motor, the six-phase power module in the motor controller, and the newly added diodes and transistors, different power topologies can be dynamically constructed: it can form a step-down circuit to achieve step-down charging of the battery, or a step-up circuit to complete step-up charging, or it can be directly connected to a charging pile for direct charging, making it widely compatible with charging facilities with different voltage platforms.

[0019] 4. Under normal driving conditions of the electric vehicle, the newly added transistor device is in the off state. At the same time, due to the unidirectional conductivity and clamping effect of the diode, no additional current is generated at the neutral point of the motor, which does not affect the original control performance and operating efficiency of the motor at all, ensuring safe isolation between the drive and charging functions. Attached Figure Description

[0020] Figure 1 This invention relates to a multiplexed charging circuit for electric vehicle electric drive systems.

[0021] Figure 2 When the output voltage of the charging pile E is higher than the rated charging voltage of the power battery B, the charging pile E, the motor M, the diode D1 and the power battery B form a closed loop connected in series.

[0022] Figure 3 When the output voltage of the charging pile E is higher than the rated charging voltage of the power battery B, the motor M, diode D1 and power battery B form a closed loop connected in series.

[0023] Figure 4 The equivalent circuit diagram is shown when the output voltage of the charging pile E is higher than the rated charging voltage of the power battery B.

[0024] Figure 5 When the output voltage of the charging pile E is lower than the rated charging voltage of the power battery B, the charging pile E and the motor M form a closed loop connected in series.

[0025] Figure 6 When the output voltage of the charging pile E is lower than the rated charging voltage of the power battery B, the charging pile E, the motor M, the diode D1 and the power battery B form a closed loop connected in series.

[0026] Figure 7 The equivalent circuit diagram is shown when the output voltage of the charging pile E is lower than the rated charging voltage of the power battery B.

[0027] Figure 8 When the output voltage of the charging pile E is equal to the rated charging voltage of the power battery B, the charging pile E and the power battery B form a closed loop connected in series. Detailed Implementation

[0028] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0029] Definitions: IGBT (Insulated Gate Bipolar Transistor) is a crucial composite power semiconductor device in the field of power electronics. The structure of an IGBT can be seen as a clever combination of a MOSFET (input stage) and a BJT (output stage). Control terminal (gate G): It borrows the insulated gate structure of a MOSFET. When a forward voltage higher than the threshold voltage is applied between the gate (G) and emitter (E), a conductive channel is formed on the semiconductor surface. This process only requires charging the gate capacitance, resulting in very low drive power. Conduction path (collector C to emitter E): Once the channel is formed, it creates conditions for the BJT to conduct, allowing current to flow from the collector (C) to the emitter (E). Simultaneously, the special internal structure of the IGBT (P+ substrate) injects minority carriers into the drift region, generating a "conductivity modulation effect," significantly reducing its resistance and achieving a low on-state voltage drop. Simply put, a small voltage signal (controlling the gate) can efficiently connect or disconnect a high-current circuit (connecting the collector and emitter).

[0030] MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is a semiconductor device that uses an electric field to control the flow of current. It can be imagined as a precisely controlled "faucet": the gate voltage is like the hand turning the faucet, and a tiny change in voltage controls the amount or interruption of the "water flow" (current) between the source and drain. At its core is a capacitor based on a metal-oxide-semiconductor structure. When a voltage is applied between the gate and source, the electric field penetrates the insulating oxide layer, inducing a conductive channel called the "inversion layer" on the surface of the underlying semiconductor substrate. This channel connects the source and drain, allowing current to flow. When the voltage is removed, the channel disappears, and the current is turned off. Example 1 This invention is applicable to various electric vehicle charging scenarios, and is particularly effective in solving the voltage mismatch problem encountered by high-voltage platform vehicles (such as 800V battery systems) when using existing 400V public charging facilities. For example, when an electric vehicle equipped with an 800V power battery enters a charging station that only provides 400V DC output, this invention can automatically activate the boost charging mode, completing charging efficiently and safely without the need for additional external conversion equipment, significantly improving vehicle charging compatibility and user convenience.

[0031] like Figure 1 As shown, an electric vehicle electric drive reuse charging system includes: The system comprises a power battery B, an inverter DCAC, a motor M, a relay k1, a diode D1, a transistor g1 (such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor); in this embodiment, an IGBT is used), and a capacitor C. Motor M acts as a transformer inductor, storing electrical energy from the charging pile E and outputting it to the power battery B. Diode D1 limits the current flow from the neutral point N of motor M to the positive terminal of power battery B. Relay k1, transistor g1, and the upper and lower arms of the inverter DCAC together function as switches in the electric vehicle's electric drive multiplexing charging circuit, working in conjunction with the current direction defined by diode D1 to construct the charging current path. Power battery B receives and stores electrical energy during charging. Capacitor C maintains voltage stability in the electric vehicle's electric drive multiplexing charging circuit.

[0032] The circuit of this invention greatly reduces cost and complexity. By defining the motor M as an inductor and the inverter bridge arm as a transistor for functional reuse, it fundamentally avoids the high cost and inconvenience of requiring an additional independent DC-DC charging module in traditional solutions.

[0033] The specific connection method is as follows: The positive terminal of charging pile E is connected to the positive DC bus of inverter DCAC, and the negative terminal of charging pile E is connected to the negative DC bus of inverter DCAC. The positive DC bus of inverter DCAC is also connected to the positive terminal of power battery B through relay k1, and the negative DC bus of inverter DCAC is connected to the negative terminal of power battery B. Inverter DCAC is connected to the U-phase winding, V-phase winding, and W-phase winding of motor M through U-phase line, V-phase line, and W-phase line, respectively. The neutral point N of motor M is connected to the anode of diode D1, and the cathode of diode D1 is connected to the positive terminal of power battery B. The neutral point N of motor M is also connected to the negative DC bus through transistor g1. The two ends of capacitor C are connected to the positive and negative terminals of power battery B, respectively, to suppress voltage fluctuations and current ripples during charging, providing a stable and smooth charging current for the power battery, thereby protecting battery life and improving charging quality. The power battery B, inverter DCAC, and charging pile E share a common ground, avoiding potential differences and electromagnetic compatibility (EMC) issues that may arise from floating ground.

[0034] In the charging mode of the aforementioned system, the drive components (inverter, motor windings) are reconfigured as the front-end rectifier of the charging circuit. By reusing the drive system components with the highest power, a separate on-board charger (OBC) can be eliminated or simplified, effectively reducing system manufacturing costs, weight, and size. The reused drive inverter typically has a power rating far exceeding that of traditional on-board chargers (usually not exceeding 11kW), enabling the system to support higher-power charging and even achieve DC fast charging, breaking through the capacity bottleneck of on-board chargers.

[0035] Ensuring the motor generates no torque during charging is a key technical challenge, which this circuit effectively solves by controlling the neutral point (N point). During charging, current flows through the motor windings. By controlling the neutral point potential and current path, this circuit adjusts the stator magnetomotive force, ensuring the armature reaction magnetic field and permanent magnet magnetic field spatially satisfy the zero-torque condition, thus preventing the motor rotor from rotating or generating harmful vibrations. This is the core of realizing the practical application of "drive-charging multiplexing." Diode D1 and transistor G1 together constitute the dynamic control of the neutral point potential. D1 clamps the neutral point voltage near the battery voltage, preventing overvoltage, and provides an auxiliary path for the charging current. Furthermore, by precisely controlling the switching state of transistor G1, the magnitude and phase of the current flowing through the neutral point can be adjusted, a crucial means of achieving zero-torque control. Effective torque suppression means the vehicle will not experience unexpected movement or shaking during charging, greatly improving charging safety and user experience.

[0036] By reducing intermediate energy conversion steps and connection losses between independent components, the energy efficiency of the entire charging path is improved. The reuse of high-power inverters provides the hardware foundation for achieving higher-power charging and helps to shorten charging time. The upper arm of the aforementioned inverter DCAC includes transistors S1, S3, and S5, and the lower arm of the inverter DCAC includes transistors S2, S4, and S6. Transistors S1, S2, S3, S4, S5, S6 and g1 are IGBTs; The gates of transistors S1, S2, S3, S4, S5, S6 and g1 are all connected to the output terminal of the drive circuit of the motor controller of the inverter DCAC. The collectors of transistors S1, S3, and S5 are all connected to the positive terminal of the DC bus. The emitter of transistor S1 is connected to the U-phase line, the emitter of transistor S3 is connected to the V-phase line, and the emitter of transistor S5 is connected to the W-phase line. The collector of transistor S2 is connected to the U-phase line, the collector of transistor S4 is connected to the V-phase line, and the collector of transistor S6 is connected to the W-phase line. The emitters of transistors S2, S4, and S6 are all connected to the negative terminal of the DC bus. The collector of transistor g1 is connected to the neutral point N of motor M, and the emitter of transistor g1 is connected to the negative terminal of DC bus. The coil pin of relay k1 is connected to the output terminal of the drive circuit of the motor controller of the inverter DCAC, and the contact pin of relay k1 is connected in series between the positive terminal of power battery B and the positive terminal of DC bus.

[0037] Composed of six IGBTs (S1-S6), forming three bridge arms (U-phase: S1 & S2, V-phase: S3 & S4, W-phase: S5 & S6). This is the standard configuration for the drive motor. By controlling the alternating conduction of the upper and lower bridge arms, the electrical energy from the DC bus is converted into three-phase AC power to drive the motor. Relay K1 is connected in series between the positive terminal of the power battery and the positive terminal of the DC bus. Its on / off state determines whether the battery is directly connected to the DC bus. Switch g1 is connected between the neutral point (N point) of the motor's three-phase windings and the negative terminal of the DC bus. Its function, in charging mode, is to work with the inverter bridge to precisely control the storage and release of energy in the motor windings.

[0038] The aforementioned inverter DCAC is a motor controller, one of the three components of an electric vehicle's electric system. For ease of explanation, this invention only describes the circuit connection method of the inverter DCAC. Since the motor controller is existing technology, other components of the motor controller do not need to be described in detail in this patent.

[0039] In this invention, the U, V, and W three-phase windings inside the motor M are essentially large-sized coil inductors. According to the law of electromagnetic induction, when current flows through an inductor, a magnetic field is established around it, thereby storing electrical energy in the form of magnetic field energy.

[0040] In boost charging mode, motor M exists in the following states, state one (inductive energy storage): such as Figure 5 As shown, transistor g1 is turned on. Current flows out from charging pile E, through the upper bridge arm of the inverter DCAC (S1, S3, S5 are turned on), the three-phase windings of the motor, the neutral point N, and transistor g1, finally flowing back to the charging pile. During this process, current flows through the motor windings, and electrical energy is converted into magnetic field energy and stored; State two (inductor energy release): as shown Figure 6 As shown, transistor G1 is turned off. Due to the inductive characteristics, the current flowing through the motor windings cannot change abruptly and needs to find a freewheeling path. At this time, the current path becomes: motor winding inductance, neutral point N, diode D1, power battery B, and back to charging pile E. The stored magnetic field energy is converted into electrical energy, which, together with the electrical energy provided by charging pile E, charges power battery B. Since the inductor generates an induced electromotive force when releasing energy, its direction is superimposed on the input voltage, thus making the voltage at the power battery B higher than the charging pile voltage, achieving voltage boost.

[0041] In buck charging mode, the motor windings also act as energy storage inductors, but the circuit operates in a buck state, state one (inductor and battery charging): as shown Figure 2 As shown, the upper bridge arm (S1, S3, S5) of the motor controller is turned on, and current flows out from the charging pile E, through the upper bridge arm transistor, the three-phase winding of the motor, and diode D1, ultimately charging the power battery B. During this process, the current simultaneously stores energy for the motor inductor and charges the battery; State two (inductor freewheeling): as shown... Figure 3 As shown, all transistors in the upper bridge arm are turned off. The current flowing through the inductor forms a loop through the freewheeling diode in the lower bridge arm (such as the diode in S2), continuing to charge the power battery B, thus achieving freewheeling. By controlling the duty cycle of the transistors in the upper bridge arm, the average value of the output voltage can be controlled, achieving step-down charging.

[0042] The principle of energy storage in motor M in this invention can be summarized as follows: During the charging process, the non-rotating three-phase windings of motor M are multiplexed into a large energy storage inductor through a specific combination of transistors in the inverter DCAC. By controlling the PWM switching of transistors (S1-S6, g1), this inductor periodically stores and releases energy, forming a boost or buck circuit together with components such as diode D1, ultimately achieving boost or buck charging of the power battery B. This design cleverly utilizes the inherent winding characteristics of the motor, achieving a multi-functional charging solution with minimal hardware cost. All transistors are driven by the existing motor controller, eliminating the need for a separate control system, further reducing costs and saving space.

[0043] By changing the on / off states of transistors S1~S6, relay K1, and transistor g1, the following circuit is formed: When the output voltage of charging pile E is higher than the rated charging voltage of power battery B (see equivalent circuit diagram). Figure 4 Throughout the charging process, both transistor G1 and relay K1 remain open. Under the condition that the upper and lower arms of the inverter DCAC cannot be simultaneously turned on, the upper arm of the inverter DCAC is first controlled to turn on according to the first preset duty cycle, so that the charging pile E, motor M, diode D1, and power battery B form a series closed loop (refer to...). Figure 2 At this time, a portion of the electrical energy output from charging pile E is input into motor M and converted into magnetic energy, stored in the U-phase, V-phase, and W-phase windings of motor M. The remaining electrical energy output from charging pile E is supplied to power battery B, which then controls the lower arm of the inverter DCAC to conduct according to the second preset duty cycle, so that motor M, diode D1, and power battery B form a series closed loop (see reference). Figure 3 At this point, the magnetic energy in motor M is converted into electrical energy and output to the power battery B. The charging process repeats cyclically according to the transistor sequence described above. The most ingenious aspect of this scheme is using the motor's three-phase windings (U / V / W) as energy storage inductors in a buck-boost circuit. In state one, current flows through the windings, and electrical energy is converted into magnetic energy for storage; in state two, the windings release magnetic energy, converting it into current to continue charging the battery. This achieves ultimate hardware reuse. Since the charging pile's output voltage is higher than the battery's rated voltage, direct connection would damage the battery. This scheme uses PWM (Pulse Width Modulation) control of the inverter, particularly adjusting the first preset duty cycle, to precisely control the average voltage applied to the motor windings and the battery, "chopping" the high voltage to a safe range acceptable to the battery. This is exactly the same as the buck principle of a switching power supply.

[0044] When the output voltage of charging pile E is lower than the rated charging voltage of power battery B (see equivalent circuit diagram). Figure 7 Throughout the charging process, relay k1 remains open, the upper arm of the inverter DCAC is on, and the lower arm of the inverter DCAC is open. First, transistor g1 is controlled to conduct according to the third preset duty cycle, forming a series closed loop between the charging pile E and the motor M (refer to...). Figure 5 At this time, the electrical energy output from the charging pile E is input into the motor M and converted into magnetic energy stored in the U-phase winding, V-phase winding, and W-phase winding of the motor M. Then, the transistor g1 is controlled to disconnect according to the third preset duty cycle, so that the charging pile E, the motor M, the diode D1, and the power battery B form a series closed circuit (refer to...). Figure 6At this point, the magnetic energy in motor M is converted into electrical energy, which, together with the electrical energy output from charging pile E, is supplied to power battery B. The charging process repeats cyclically according to the transistor sequence described above. The most ingenious aspect of this scheme is that the three-phase windings (U / V / W) of the motor act as the energy storage inductor in the boost circuit. State 1 (Energy Storage Stage): When transistor G1 is turned on, the windings of charging pile E and motor M form a closed loop. Current flows through the motor windings, and electrical energy is converted into magnetic energy and stored in the windings. At this time, because the anode potential of diode D1 is lower than that of the cathode (connected to the positive terminal of the battery), D1 is cut off, and the battery does not participate in this stage. State 2 (Energy Release and Boost Stage): When transistor G1 is turned off, the original circuit current is cut off. Since the current in the inductor (motor winding) cannot change abruptly, it generates an induced electromotive force (positive on the right and negative on the left). This electromotive force is superimposed in series with the voltage of the charging pile, thus making the voltage higher than that of the power battery. At this time, diode D1 is forward-biased, and the superimposed high-voltage electrical energy can charge power battery B. Continuous boost charging can be achieved by repeatedly controlling the on and off states of G1. The setting of the third preset duty cycle is crucial, as it directly determines the boost voltage and the output current.

[0045] When the output voltage of charging pile E is equal to the rated charging voltage of power battery B, relay k1 remains closed, transistor g1 remains open, and both the upper and lower arms of the inverter DCAC are open throughout the charging process, forming a series closed circuit between charging pile E and power battery B (reference). Figure 8Charging pile E directly charges the power battery B. When the voltage matches, the system closes relay K1 and disconnects all other switches, entering "direct connection mode." The upper and lower bridge arms of the inverter (DCAC) are completely disconnected, and transistor G1 is also disconnected, meaning all power switching devices are inactive. Electrical energy is directly delivered from charging pile E to power battery B without any high-frequency switching losses or semiconductor conduction losses. Compared to the buck-boost mode, which requires energy conversion through the inverter and motor windings, energy loss is minimized, and the overall energy efficiency of the charging system is maximized. This solution greatly simplifies the control logic of the charging process. There is no need to generate complex PWM (pulse width modulation) signals to control the inverter or G1, nor is there concern about shoot-through risks (dead-time control) of the upper and lower bridge arms, significantly reducing system complexity and software reliability requirements. Simultaneously, allowing the inverter and motor windings to rest completely avoids losses and heat generation in these core drive system components during charging, helping to extend their lifespan, especially in high-power charging scenarios where thermal management is less stressful. The direct connection means the charging process is entirely controlled collaboratively by the charging pile and the battery management system (BMS). The charging station executes a standard constant current-constant voltage (CC-CV) charging curve based on the required parameters (such as voltage and current) provided by the BMS. This mature charging strategy, combined with the real-time monitoring and protection of the BMS, effectively prevents battery overcharging and overcurrent, ensuring charging safety.

[0046] When the output voltage of charging pile E is higher than the rated charging voltage of power battery B, or lower than the rated charging voltage of power battery B, the charging current loop passes through the motor windings, diode D1, and transistor g1, instead of directly entering power battery B through the DC bus port of the inverter DCAC. Disconnecting K1 ensures that the circuit operates according to the predetermined boost or buck path, preventing current backflow or the formation of unnecessary loops, thus ensuring system safety. During normal operation, K1 must be closed. The electrical energy from power battery B is delivered to the DC bus of the inverter DCAC through the closed K1 relay, and then inverted to drive the motor.

[0047] In summary, a single circuit, controlled by software, can intelligently adapt to charging stations of all voltage levels (buck / boost / direct charging), completely solving the charging compatibility problem and greatly improving the user experience.

[0048] The peak current of motor M does not exceed the saturation current of each winding in motor M, protecting the motor windings from over-magnetization and saturation or overheating damage. This ensures that the charging process takes place within the safe operating conditions of the motor, improving the reliability and service life of the system. This is a safety measure that must be considered under the premise of functional reuse.

[0049] In the above scheme, the calculation methods for the first preset duty cycle and the second preset duty cycle are as follows: in, This is the rated charging voltage of power battery B. It is the first preset duty cycle. This refers to the output voltage of the charging station E; for example, if the charging station voltage is 500V and the battery requires 400V for charging, then the required duty cycle is... =400 / 500=0.8. In "State One" (upper bridge arm on), current flows through the motor windings (acting as inductors), storing energy and simultaneously charging the battery. This is achieved by controlling the on-time (duty cycle) of the upper bridge arm. This is used to "chop" the average voltage, reducing it to the level required by the battery. .

[0050] Second preset duty cycle =1- The setting of the second preset duty cycle is crucial. This ensures that a freewheeling path is provided for the inductor current in "State Two" (lower bridge arm is on), allowing the energy stored in the inductor to be released. This conforms to the basic principle of "volt-second balance" in switching power supplies, that is, the algebraic sum of the product of the voltages applied across the inductor (volt-second product) is zero within one switching cycle, which is a necessary condition for the circuit to reach a steady state.

[0051] The calculation method for the third preset duty cycle is as follows: in, This is the rated charging voltage of power battery B. It is the third preset duty cycle. This is the output voltage of charging pile E. In this mode, transistor g1 acts as the main switch. When transistor g1 is turned on (duty cycle...), (Conducting part): The electrical energy of the charging pile is stored in the motor windings (inductance). When transistor g1 is turned off (duty cycle...) The shut-off part, i.e., 1− The inductor generates an induced electromotive force, the direction of which is superimposed on the input voltage in series. This electromotive force is supplied to the battery through diode D1, thereby generating a voltage higher than the input voltage. .

[0052] By precisely controlling the duty cycle, it is ensured that the battery can ultimately be provided with its required rated charging voltage under any input voltage, thus achieving efficient and controllable energy transfer.

[0053] This invention maximizes the reuse of expensive components (motor, inverter, controller) from existing electric drive systems, adding only a few low-cost components and avoiding the cost of installing a separate high-power DC-DC charging module. Software control intelligently handles all charging scenarios (input voltage higher, lower, or equal to battery voltage), perfectly solving the charging challenges between different voltage platforms. Hardware modifications are minimal, the structure is compact, and valuable interior space is saved. All controls are integrated into the existing motor controller, eliminating the need for additional control units. Through diode-defined current direction, common ground design, capacitor filtering, peak current limiting, and software control strategies, the safety and stability of the charging process are ensured without affecting the vehicle's original drive functions.

[0054] Example 2 An electric vehicle electric drive multiplexing charging method includes: a power battery, an inverter, a motor, a relay, a diode, and a transistor; the motor acts as a transformer inductor, storing electrical energy from a charging pile and outputting it to the power battery; the diode limits the current flow from the neutral point of the motor to the positive terminal of the power battery; the relay, transistor, and the upper and lower bridge arms of the inverter all act as switches of the electric vehicle electric drive multiplexing charging circuit under the control of the drive circuit of the motor controller to which the inverter belongs, and together with the current direction limited by the diode, construct a charging current path.

[0055] In boost charging mode, motor M exists in the following states, state one (inductive energy storage): such as Figure 5 As shown, transistor g1 is turned on. Current flows out from charging pile E, through the upper bridge arm of the inverter DCAC (S1, S3, S5 are turned on), the three-phase windings of the motor, the neutral point N, and transistor g1, finally flowing back to the charging pile. During this process, current flows through the motor windings, and electrical energy is converted into magnetic field energy and stored; State two (inductor energy release): as shown Figure 6 As shown, transistor G1 is turned off. Due to the inductive characteristics, the current flowing through the motor windings cannot change abruptly and needs to find a freewheeling path. At this time, the current path becomes: motor winding inductance, neutral point N, diode D1, power battery B, and back to charging pile E. The stored magnetic field energy is converted into electrical energy, which, together with the electrical energy provided by charging pile E, charges power battery B. Since the inductor generates an induced electromotive force when releasing energy, its direction is superimposed on the input voltage, thus making the voltage at the power battery B higher than the charging pile voltage, achieving voltage boost.

[0056] In buck charging mode, the motor windings also act as energy storage inductors, but the circuit operates in a buck state, state one (inductor and battery charging): as shown Figure 2As shown, the upper bridge arm (S1, S3, S5) of the motor controller is turned on, and current flows out from the charging pile E, through the upper bridge arm transistor, the three-phase winding of the motor, and diode D1, ultimately charging the power battery B. During this process, the current simultaneously stores energy for the motor inductor and charges the battery; State two (inductor freewheeling): as shown... Figure 3 As shown, all transistors in the upper bridge arm are turned off. The current flowing through the inductor forms a loop through the freewheeling diode in the lower bridge arm (such as the diode in S2), continuing to charge the power battery B, thus achieving freewheeling. By controlling the duty cycle of the transistors in the upper bridge arm, the average value of the output voltage can be controlled, achieving step-down charging.

[0057] The principle of energy storage in motor M in this invention can be summarized as follows: During the charging process, the non-rotating three-phase windings of motor M are multiplexed into a large energy storage inductor through a specific combination of transistors in the inverter DCAC. By controlling the PWM switching of transistors (S1-S6, g1), this inductor periodically stores and releases energy, forming a boost or buck circuit together with components such as diode D1, ultimately achieving boost or buck charging of the power battery B. This design cleverly utilizes the inherent winding characteristics of the motor, achieving a multi-functional charging solution with minimal hardware cost. All transistors are driven by the existing motor controller, eliminating the need for a separate control system, further reducing costs and saving space.

[0058] By changing the on / off states of transistors S1~S6, relay K1, and transistor g1, the following circuit is formed: When the output voltage of charging pile E is higher than the rated charging voltage of power battery B (see equivalent circuit diagram). Figure 4 Throughout the charging process, both transistor G1 and relay K1 remain open. Under the condition that the upper and lower arms of the inverter DCAC cannot be simultaneously turned on, the upper arm of the inverter DCAC is first controlled to turn on according to the first preset duty cycle, so that the charging pile E, motor M, diode D1, and power battery B form a series closed loop (refer to...). Figure 2 At this time, a portion of the electrical energy output from charging pile E is input into motor M and converted into magnetic energy, stored in the U-phase, V-phase, and W-phase windings of motor M. The remaining electrical energy output from charging pile E is supplied to power battery B, which then controls the lower arm of the inverter DCAC to conduct according to the second preset duty cycle, so that motor M, diode D1, and power battery B form a series closed loop (see reference). Figure 3At this point, the magnetic energy in motor M is converted into electrical energy and output to the power battery B. The charging process repeats cyclically according to the transistor sequence described above. The most ingenious aspect of this scheme is using the motor's three-phase windings (U / V / W) as energy storage inductors in a buck-boost circuit. In state one, current flows through the windings, and electrical energy is converted into magnetic energy for storage; in state two, the windings release magnetic energy, converting it into current to continue charging the battery. This achieves ultimate hardware reuse. Since the charging pile's output voltage is higher than the battery's rated voltage, direct connection would damage the battery. This scheme uses PWM (Pulse Width Modulation) control of the inverter, particularly adjusting the first preset duty cycle, to precisely control the average voltage applied to the motor windings and the battery, "chopping" the high voltage to a safe range acceptable to the battery. This is exactly the same as the buck principle of a switching power supply.

[0059] When the output voltage of charging pile E is lower than the rated charging voltage of power battery B (see equivalent circuit diagram). Figure 7 Throughout the charging process, relay k1 remains open, the upper arm of the inverter DCAC is on, and the lower arm of the inverter DCAC is open. First, transistor g1 is controlled to conduct according to the third preset duty cycle, forming a series closed loop between the charging pile E and the motor M (refer to...). Figure 5 At this time, the electrical energy output from the charging pile E is input into the motor M and converted into magnetic energy stored in the U-phase winding, V-phase winding, and W-phase winding of the motor M. Then, the transistor g1 is controlled to disconnect according to the third preset duty cycle, so that the charging pile E, the motor M, the diode D1, and the power battery B form a series closed circuit (refer to...). Figure 6 At this point, the magnetic energy in motor M is converted into electrical energy, which, together with the electrical energy output from charging pile E, is supplied to power battery B. The charging process repeats cyclically according to the transistor sequence described above. The most ingenious aspect of this scheme is that the three-phase windings (U / V / W) of the motor act as the energy storage inductor in the boost circuit. State 1 (Energy Storage Stage): When transistor G1 is turned on, the windings of charging pile E and motor M form a closed loop. Current flows through the motor windings, and electrical energy is converted into magnetic energy and stored in the windings. At this time, because the anode potential of diode D1 is lower than that of the cathode (connected to the positive terminal of the battery), D1 is cut off, and the battery does not participate in this stage. State 2 (Energy Release and Boost Stage): When transistor G1 is turned off, the original circuit current is cut off. Since the current in the inductor (motor winding) cannot change abruptly, it generates an induced electromotive force (positive on the right and negative on the left). This electromotive force is superimposed in series with the voltage of the charging pile, thus making the voltage higher than that of the power battery. At this time, diode D1 is forward-biased, and the superimposed high-voltage electrical energy can charge power battery B. Continuous boost charging can be achieved by repeatedly controlling the on and off states of G1. The setting of the third preset duty cycle is crucial, as it directly determines the boost voltage and the output current.

[0060] When the output voltage of charging pile E is equal to the rated charging voltage of power battery B, relay k1 remains closed, transistor g1 remains open, and both the upper and lower arms of the inverter DCAC are open throughout the charging process, forming a series closed circuit between charging pile E and power battery B (reference). Figure 8 Charging pile E directly charges the power battery B. When the voltage matches, the system closes relay K1 and disconnects all other switches, entering "direct connection mode." The upper and lower bridge arms of the inverter (DCAC) are completely disconnected, and transistor G1 is also disconnected, meaning all power switching devices are inactive. Electrical energy is directly delivered from charging pile E to power battery B without any high-frequency switching losses or semiconductor conduction losses. Compared to the buck-boost mode, which requires energy conversion through the inverter and motor windings, energy loss is minimized, and the overall energy efficiency of the charging system is maximized. This solution greatly simplifies the control logic of the charging process. There is no need to generate complex PWM (pulse width modulation) signals to control the inverter or G1, nor is there concern about shoot-through risks (dead-time control) of the upper and lower bridge arms, significantly reducing system complexity and software reliability requirements. Simultaneously, allowing the inverter and motor windings to rest completely avoids losses and heat generation in these core drive system components during charging, helping to extend their lifespan, especially in high-power charging scenarios where thermal management is less stressful. The direct connection means the charging process is entirely controlled collaboratively by the charging pile and the battery management system (BMS). The charging station executes a standard constant current-constant voltage (CC-CV) charging curve based on the required parameters (such as voltage and current) provided by the BMS. This mature charging strategy, combined with the real-time monitoring and protection of the BMS, effectively prevents battery overcharging and overcurrent, ensuring charging safety.

[0061] When the output voltage of charging pile E is higher than the rated charging voltage of power battery B, or lower than the rated charging voltage of power battery B, the charging current loop passes through the motor windings, diode D1, and transistor g1, instead of directly entering power battery B through the DC bus port of the inverter DCAC. Disconnecting K1 ensures that the circuit operates according to the predetermined boost or buck path, preventing current backflow or the formation of unnecessary loops, thus ensuring system safety. During normal operation, K1 must be closed. The electrical energy from power battery B is delivered to the DC bus of the inverter DCAC through the closed K1 relay, and then inverted to drive the motor.

[0062] In summary, a single circuit, controlled by software, can intelligently adapt to charging stations of all voltage levels (buck / boost / direct charging), completely solving the charging compatibility problem and greatly improving the user experience.

[0063] Example 3 A computer program product includes a computer program / instruction, which, when executed by a processor, implements the calculation process of the first preset duty cycle, the second preset duty cycle, and the third preset duty cycle in Embodiment 2.

[0064] The contents not described in detail in this specification are prior art known to those skilled in the art. Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0065] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0066] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0067] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. An electric vehicle electric drive reuse charging system, characterized in that, include: Power batteries, inverters, motors, relays, diodes, and transistors; The motor is used as a transformer inductor to store electrical energy from the charging station and output it to the power battery; Diodes are used to limit the flow of current from the neutral point of the motor to the positive terminal of the power battery; The relay, transistor, and the upper and lower bridge arms of the inverter are all used together as switches in the electric drive multiplexing charging circuit of the electric vehicle under the control of the drive circuit of the motor controller of the inverter. Together with the diode to limit the current direction, they form a charging current path.

2. The electric vehicle electric drive reuse charging system according to claim 1, characterized in that: When the output voltage of the charging pile is higher than the rated charging voltage of the power battery, the transistor and relay are kept disconnected throughout the charging process. Under the condition that the upper and lower bridge arms of the inverter cannot be turned on at the same time, the upper bridge arm of the inverter is first controlled to turn on according to the first preset duty cycle. The charging current path passes through the charging pile, motor, diode and power battery in sequence to form a series closed loop. Then the lower bridge arm of the inverter is controlled to turn on according to the second preset duty cycle. The charging current path passes through the motor, diode and power battery in sequence to form a series closed loop.

3. The electric vehicle electric drive reuse charging system according to claim 1, characterized in that: When the output voltage of the charging pile is lower than the rated charging voltage of the power battery, the relay is kept open, the upper bridge arm of the inverter is turned on and the lower bridge arm of the inverter is turned off throughout the charging process. First, the control transistor is turned on according to the third preset duty cycle. The charging current path passes through the charging pile and the motor in sequence to form a series closed loop. Then, the control transistor is turned off according to the third preset duty cycle. The charging current path passes through the charging pile, the motor, the diode and the power battery in sequence to form a series closed loop.

4. The electric vehicle electric drive reuse charging system according to claim 1, characterized in that: When the output voltage of the charging pile is equal to the rated charging voltage of the power battery, the relay remains closed, the transistor is open, and the upper and lower bridge arms of the inverter are both open throughout the charging process. The charging current path passes through the charging pile and the power battery in sequence and forms a series closed loop.

5. The electric vehicle electric drive reuse charging system according to claim 1, characterized in that: It also includes capacitors to maintain voltage stability in the electric drive multiplexing charging circuit of electric vehicles.

6. The electric vehicle electric drive reuse charging system according to claim 1, characterized in that: The peak current of the motor does not exceed the saturation current of each winding in the motor.

7. The electric vehicle electric drive reuse charging system according to claim 2, characterized in that: The calculation methods for the first preset duty cycle and the second preset duty cycle are as follows: in, It is the rated charging voltage of the power battery. It is the first preset duty cycle. It is the output voltage of the charging station; Second preset duty cycle =1- .

8. The electric vehicle electric drive reuse charging system according to claim 3, characterized in that: The calculation method for the third preset duty cycle is as follows: in, It is the rated charging voltage of the power battery. It is the third preset duty cycle. It is the output voltage of the charging station.

9. The electric vehicle electric drive reuse charging system according to claim 2, characterized in that: When the output voltage of the charging pile is higher than the rated charging voltage of the power battery, when the charging pile, motor, diode and power battery form a series closed loop, part of the electrical energy output by the charging pile is input into the motor and converted into magnetic energy and stored in the phase windings of the motor. The remaining electrical energy output by the charging pile is output to the power battery. When the motor, diode, and power battery form a series closed loop, the magnetic energy in the motor is converted into electrical energy and output to the power battery.

10. The electric vehicle electric drive reuse charging system according to claim 3, characterized in that: When the output voltage of the charging pile is lower than the rated charging voltage of the power battery, when the charging pile and the motor form a series closed loop, the electrical energy output by the charging pile is input into the motor and converted into magnetic energy and stored in the phase windings, phase windings and phase windings of the motor. When the charging pile, motor, diode, and power battery form a series closed loop, the magnetic energy in the motor is converted into electrical energy and together with the electrical energy output from the charging pile E, it is output to the power battery.

11. A method for reusing electric drive charging in electric vehicles, characterized in that, include: Power batteries, inverters, motors, relays, diodes, and transistors; The motor acts as a transformer inductor, storing electrical energy from the charging station and outputting it to the power battery; The diode limits the current flow from the neutral point of the motor to the positive terminal of the power battery; The relay, transistor, and the upper and lower bridge arms of the inverter are all controlled by the drive circuit of the motor controller to which the inverter belongs, and together they serve as the switch of the electric vehicle electric drive multiplexing charging circuit. Together with the diode to limit the current direction, they form the charging current path.

12. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it performs the calculation process of the first preset duty cycle, the second preset duty cycle in claim 7, or the third preset duty cycle in claim 8.

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