Vehicle, and energy conversion apparatus and charging method thereof

Abstract

A vehicle, which has an energy conversion apparatus. The energy conversion apparatus is provided with a first switch module and a second switch module, wherein the second switch module is arranged between a power battery and a voltage transformation module; when the first switch module is turned on, the power battery, the first switch module, an energy storage module and an external power supply module form a first charging loop; and when the second switch module is turned on, the power battery, the second switch module, the voltage transformation module, the energy storage module and the external power supply module form a second charging loop.

Description

Vehicle, energy conversion device and charging method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202111007075.9, filed on August 30, 2021, entitled “Vehicle, Energy Conversion Device and Charging Method Thereof,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of automobile technology, and in particular to a vehicle, an energy conversion device, and a charging method thereof. Background Art

[0004] At present, energy crisis and environmental pollution problems are becoming increasingly serious. As electric vehicles become a new type of transportation, the demand for electric vehicle charging technology has become increasingly prominent, especially for electric vehicles that take high-voltage routes. In related technologies, the battery voltage usually reaches 700V, and ordinary 500V output charging piles obviously cannot meet the needs of electric vehicles for DC fast charging.

[0005] Summary of the Invention

[0006] The present disclosure proposes a vehicle, an energy conversion device and a charging method thereof to solve the problem that charging piles in the prior art cannot meet the DC fast charging requirements of electric vehicles.

[0007] A first aspect of the present disclosure provides an energy conversion device, which includes an energy storage module, a voltage transformation module, a first switch module, a second switch module, and a control module. The energy storage module is connected to the voltage transformation module, and the voltage transformation module is connected to a power battery and the first switch module via the second switch module. The first switch module is also connected to the energy storage module and the voltage transformation module. The control module is connected to the first switch module and the second switch module, respectively.

[0008] In one embodiment, the transformer module is also connected to the motor controller, the positive pole of the power battery is connected to the first end of the first switch module and the first end of the second switch module, the second end of the first switch module is connected to the first end of the energy storage module and the low voltage end of the transformer module, the second end of the second switch module is connected to the high voltage end of the transformer module and the first bus terminal of the motor controller, the second end of the energy storage module is connected to the negative pole of the power battery, the common end of the transformer module and the second bus terminal of the motor controller, and the first end and the second end of the energy storage module are the charging ports of the energy conversion device.

[0009] In one embodiment, the motor controller is connected to the motor, and when the energy conversion device is in driving mode, the power battery supplies power to the motor through the first switch module, the transformer module, the energy storage module, and the motor controller; when the energy storage module is connected to an external power supply module and the energy conversion device is in boost charging mode, the external power supply module charges the power battery through the energy storage module, the transformer module, and the second switch module.

[0010] In one embodiment, the first switch module includes a switch K1, a switch K2, and a resistor R2; a first end of the resistor R2 is connected to the first end of the switch K1 and constitutes the first end of the first switch module, a second end of the resistor R2 is connected to the first end of the switch K2, and a second end of the switch K2 is connected to the second end of the switch K1 and constitutes the second end of the first switch module.

[0011] In one embodiment, the transformer module includes a first inductor, a second inductor, a first power switch unit, a second power switch unit, a third power switch unit and a fourth power switch unit. The first end of the first inductor and the first end of the second inductor are connected together and constitute the low-voltage end of the transformer module. The second end of the first inductor is connected to the second end of the first power switch unit and the first end of the second power switch unit. The second end of the second inductor is connected to the second end of the third power switch unit and the first end of the fourth power switch unit. The first end of the first power switch unit and the first end of the third power switch unit are connected together and constitute the high-voltage end of the transformer module. The second end of the second power switch unit and the second end of the fourth power switch unit are connected together and constitute the common end of the transformer module.

[0012] In one embodiment, the energy conversion device further includes a switch K3, a switch K4, a switch K5, and a third inductor L3. The first end of the switch K3 is connected to the negative electrode of the power battery, the second end of the switch K3 is connected to the second end of the energy storage module, the first end of the switch K4 is connected to the first end of the external power module, the second end of the switch K4 is connected to the first end of the third inductor L3, the second end of the third inductor L3 is connected to the first end of the energy storage module, the first end of the switch K5 is connected to the second end of the external power module, and the second end of the switch K5 is connected to the second end of the energy storage module.

[0013] A second aspect of the present disclosure provides a charging method for an energy conversion device, based on the energy conversion device described in the first aspect, the charging method comprising: when the energy conversion device is connected to an external power supply module and is in a charging mode, obtaining the maximum output voltage of the external power supply module; when the maximum output voltage of the external power supply module is not greater than a preset voltage, controlling the first switch module to be turned off and the second switch module to be turned on, so that the external power supply module performs boost charging on the power battery through the energy storage module, the transformer module and the second switch module; when the maximum output voltage of the external power supply module is greater than a preset voltage, controlling the first switch module to be turned on and the second switch module to be turned off, so that the external power supply module performs DC charging on the power battery through the energy storage module and the first switch module.

[0014] In one embodiment, when the energy conversion device is connected to an external power module and is in a charging mode, obtaining the maximum output voltage of the external power module also includes: sending a target required voltage value to the external power module, and controlling the first switch module to be turned on, so that the power battery pre-charges the energy storage module through the first switch module, so that the voltage value of the energy storage module is a preset voltage, and then controlling the transformer module to discharge the energy storage module through the transformer module, so that the voltage value of the energy storage module is the target required voltage value.

[0015] In one embodiment, obtaining the maximum output voltage of the external power supply module further includes: obtaining the target maximum output voltage of the external power supply module, continuously sending a constant current boost charging instruction to the external power supply module, and when detecting that the current output by the external power supply module is not a constant current or the actual maximum output voltage is less than the target maximum output voltage, determining that the target maximum output voltage is a false value, and setting the actual maximum output voltage as the maximum output voltage.

[0016] In one embodiment, the continuously sending constant current boost charging instructions to the external power supply module further includes: the external power supply module obtains the actual voltage value of the energy storage module, and outputs current to the energy conversion device when it determines that the target required voltage value and the actual voltage value of the energy storage module meet the preset standard.

[0017] In one embodiment, enabling the external power module to boost and charge the power battery through the voltage conversion module includes: obtaining an actual current value and a target current value output by the voltage conversion module, comparing the actual current value with the target current value, and outputting a PWM control signal to the voltage conversion module so that the voltage conversion module outputs the target current value to the power battery to charge the power battery.

[0018] In one embodiment, the charging method further includes: when the energy conversion device is in driving mode, controlling the first switch module to be turned on, and controlling the transformer module so that the power battery boosts the power supply to the motor controller through the first switch module, the transformer module, and the energy storage module.

[0019] A third aspect of the present disclosure provides a vehicle, which further includes the energy conversion device described in the first aspect.

[0020] The vehicle, energy conversion device, and charging method provided by the present disclosure are configured by providing a first switch module and a second switch module, and arranging the second switch module between the power battery and the transformer module. When the first switch module is turned on, the power battery, the first switch module, the energy storage module, and the external power module constitute a first charging circuit. When the second switch module is turned on, the power battery, the second switch module, the transformer module, the energy storage module, and the external power module constitute a second charging circuit. When the maximum output voltage of the external power module is not greater than a preset voltage, the second charging circuit is controlled to start operating, causing the external power module to boost and charge the power battery through the transformer module. When the maximum output voltage of the external power module is greater than the preset voltage, the first charging circuit is controlled to start operating, causing the external power module to perform DC charging of the power battery through the first switch module. The technical solution disclosed in the present invention can realize the use of high-voltage power batteries to power vehicles, which can reduce the current-carrying capacity requirements of cable connectors, thereby reducing the volume and mass of cable connectors. When connected to a high-voltage power supply platform DC charging pile, DC charging can be performed through the first charging circuit, thereby improving the charging speed of the power battery. When connected to a low-voltage power supply platform DC charging pile, boost charging can be performed through the second charging circuit, thereby solving the problem in related technologies that the low-voltage power supply platform DC charging pile cannot fully charge or cannot charge the power battery.

[0021] Additional aspects and advantages of the present disclosure will be given in part in the description below and in part will be obvious from the description below, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the embodiments of the present disclosure.

[0023] FIG1 is a schematic structural diagram of an energy conversion device provided by a first embodiment of the present disclosure;

[0024] FIG2 is a schematic structural diagram of a specific energy conversion device provided by a first embodiment of the present disclosure;

[0025] FIG3 is a circuit diagram of an energy conversion device provided by a first embodiment of the present disclosure;

[0026] FIG4 is a flow chart of a charging method for an energy conversion device provided in a second embodiment of the present disclosure;

[0027] FIG5 is a current path diagram of a pre-charging energy conversion device provided by a second embodiment of the present disclosure;

[0028] FIG6 is a first current path diagram of an energy conversion device provided by a second embodiment of the present disclosure;

[0029] FIG7 is a second current path diagram of an energy conversion device provided by a second embodiment of the present disclosure;

[0030] FIG8 is a third current path diagram of an energy conversion device provided by a second embodiment of the present disclosure;

[0031] FIG9 is a fourth current path diagram of an energy conversion device provided by a second embodiment of the present disclosure;

[0032] FIG10 is a schematic structural diagram of a vehicle provided in a third embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0034] The following describes a vehicle, an energy conversion device, and a charging method thereof proposed in embodiments of the present disclosure with reference to the accompanying drawings.

[0035] An embodiment of the present disclosure provides an energy conversion device, as shown in Figure 1, the energy conversion device includes an energy storage module 103, a voltage transformation module 104, a first switch module 102, a second switch module 106 and a control module 109. The energy storage module 103 is connected to the voltage transformation module 104, the voltage transformation module 104 is connected to the power battery 101 and the first switch module 102 through the second switch module 106, the first switch module 102 is also connected to the energy storage module 103 and the voltage transformation module 104, and the control module 109 is respectively connected to the first switch module 102 and the second switch module 106.

[0036] The energy storage module 103 is used to store the electrical energy output by the power battery 101. Both ends of the energy storage module 103 can be connected to an external power module 107, as shown in Figure 2. When the power battery 101 has finished charging the energy storage module 103, the voltage on the energy storage module 103 is the same as or similar to the voltage on the external power module 107, allowing the external power module 107 to output voltage normally. Optionally, the energy storage module 103 may include energy storage devices such as capacitors.

[0037] The transformer module 104 may include an energy storage unit and a power switch unit. The power switch unit in the transformer module 104 is turned on or off according to the signal output by the control module 109, so that the energy storage unit is connected to different circuits for charging and discharging, thereby achieving voltage step-up or step-down. The transformer module 104 includes a low-voltage terminal, a high-voltage terminal, and a common terminal. The low-voltage terminal and high-voltage terminal of the transformer module 104 are defined based on the magnitude of the input voltage and the output voltage. The low-voltage terminal and the common terminal of the transformer module 104 receive the input voltage, step up the input voltage, and output it from the high-voltage terminal and the common terminal of the transformer module 104. The high-voltage terminal and the common terminal of the transformer module 104 receive the input voltage, step down the input voltage, and output it from the low-voltage terminal and the common terminal of the transformer module 104.

[0038] The first switch module 102 is used to connect the power battery 101 to the energy storage module 103 and the external power module 107. When the first switch module 102 is turned on, the power battery 101, the first switch module 102, the energy storage module 103, and the external power module 107 form a first charging circuit, through which the external power module 107 charges the power battery 101.

[0039] The second switch module 106 is used to connect the power battery 101 to the transformer module 104, the energy storage module 103, and the external power module. When the second switch module 106 is turned on, the power battery 101, the second switch module 106, the transformer module 104, the energy storage module 103, and the external power module 107 form a second charging circuit, through which the external power module 107 boosts and charges the power battery 101. The external power module 107 can be an off-board charger, such as a charging station.

[0040] As shown in Figure 2, the control module 109 can collect information about the voltage, current, and temperature of the power battery 101, as well as the phase current of the motor 108, which is a three-phase AC motor. The control module 109 includes a vehicle controller, the control circuitry of the motor controller 105, and the battery management system (BMS) circuitry, all connected via a CAN bus. Based on this information, the various modules within the control module 109 control the on / off switching of the first and second switch modules 102, 106, to enable different charging circuits. The control module 109 can also control the on / off switching of the power switches in the transformer module 104 to enable different current circuits, thereby boosting or stepping down the input voltage.

[0041] As an embodiment, as shown in Figure 3, the transformer module 104 is also connected to the motor controller 105, the positive pole of the power battery 101 is connected to the first end of the first switch module 102 and the first end of the second switch module 106, the second end of the first switch module 102 is connected to the first end of the energy storage module 103 and the low voltage end of the transformer module 104, the second end of the second switch module 106 is connected to the high voltage end of the transformer module 104 and the first bus terminal of the motor controller 105, the second end of the energy storage module 103 is connected to the negative pole of the power battery 101, the common end of the transformer module 104 and the second bus terminal of the motor controller 105, and the first end and the second end of the energy storage module 103 are charging ports of the energy conversion device.

[0042] When the maximum output voltage of the external power module 107 is not greater than a preset voltage, which is the current voltage of the power battery 101, the external power module 107 cannot directly charge the power battery 101. In this case, the first switch module 102 is controlled to be turned off and the second switch module 106 is controlled to be turned on. The second charging circuit begins to operate, causing the external power module 107 to boost and charge the power battery 101 through the transformer module 104. When the maximum output voltage of the external power module 107 is greater than the preset voltage, the external power module 107 can directly charge the power battery 101. The first switch module 102 is controlled to be turned on and the second switch module 106 is controlled to be turned off. The first charging circuit begins to operate, causing the external power module 107 to perform DC charging of the power battery 101 through the first switch module 102.

[0043] It should be noted that, as shown in FIG2 , the high-voltage end and the common end of the transformer module 104 are also connected to the motor controller 105 , and the motor controller 105 is connected to the motor 108 . When the energy conversion device is in driving mode, the power battery 101 supplies power to the motor 108 through the first switch module 102 , the transformer module 104 , the energy storage module 103 , and the motor controller 105 . When the energy storage module 103 is connected to the external power supply module 107 and the energy conversion device is in boost charging mode, the external power supply module 107 charges the power battery 101 through the energy storage module 103 , the transformer module 104 , and the second switch module 106 . It can be seen that the energy storage module 103 and the transformer module 104 are used in both the driving mode and the boost charging mode. That is, by reusing the energy storage module 103 and the transformer module 104 in different circuits, different functions are achieved, thereby improving the utilization rate of the modules in the circuit. The external power supply module 107 can boost the voltage and supply power to the motor controller 105 and the motor 108 through the transformer module 104. The power battery 101 can also boost the voltage and supply power to the motor controller 105 and the motor 108 through the transformer module 104. When the vehicle is driving, the transformer module 104 can boost the voltage of the battery pack with a wide voltage range or the low-voltage platform battery pack to the high-efficiency zone required voltage of the motor controller 105 to ensure the vehicle's power requirements. When feeding power to the low-voltage platform battery pack, the motor controller 105 and the motor 108 can also reduce the voltage of the low-voltage platform battery pack through the transformer module 104.

[0044] The present disclosure provides an energy conversion device, which comprises a first switch module 102 and a second switch module 106, with the second switch module 106 being disposed between a power battery 101 and a transformer module 104. When the first switch module 102 is on, the power battery 101, the first switch module 102, the energy storage module 103, and the external power module 107 form a first charging circuit. When the second switch module 106 is on, the power battery 101, the second switch module 106, the transformer module 104, the energy storage module 103, and the external power module 107 form a second charging circuit. When the maximum output voltage of the external power module 107 is not greater than a preset voltage, the second charging circuit is controlled to start operating, causing the external power module 107 to boost and charge the power battery 101 through the transformer module 104. When the maximum output voltage of the external power module 107 is greater than a preset voltage, the first charging circuit is controlled to start operating, causing the external power module 107 to perform DC charging on the power battery 101 through the first switch module 102. The technical solution disclosed in the present invention can realize the use of a high-voltage power battery 101 to power the vehicle, which can reduce the current-carrying capacity requirements of the cable connector, thereby reducing the volume and mass of the cable connector. When connected to a high-voltage power supply platform DC charging pile, DC charging can be performed through the first charging circuit, thereby improving the charging speed of the power battery 101. When connected to a low-voltage power supply platform DC charging pile, boost charging can be performed through the second charging circuit, thereby solving the problem in the prior art that the low-voltage power supply platform DC charging pile cannot fully charge or cannot charge the power battery 101.

[0045] As an embodiment, as shown in FIG3 , the energy storage module 103 includes a capacitor C1 and a resistor R1. The first end of the capacitor C1 and the first end of the resistor R1 are connected to form the first end of the energy storage module 103, and the second end of the capacitor C1 and the second end of the resistor R1 are connected to form the second end of the energy storage module 103. The first switch module 102 includes a switch K1, a switch K2, and a resistor R2. The first end of the resistor R2 is connected to the first end of the switch K1 and forms the first end of the first switch module 102. The second end of the resistor R2 is connected to the first end of the switch K2. The second end of the switch K2 is connected to the second end of the switch K1 and forms the second end of the first switch module 102.

[0046] In this embodiment, a resistor R2 and a switch K2 are connected in series and then connected to the capacitor C1. When the power battery 101 charges the capacitor C1, the switch K2 is first turned on for pre-charging, so that the power battery 101 slowly charges the capacitor C1 to a preset voltage through the resistor R2, for example, 80% of the preset voltage, to avoid over-rapid charging of the capacitor C1 and thus damage to the capacitor C1.

[0047] As an embodiment, the transformer module 104 includes a first inductor L1, a second inductor L2, a first power switch unit Q1, a second power switch unit Q2, a third power switch unit Q3 and a fourth power switch unit Q4. The first end of the first inductor L1 and the first end of the second inductor L2 are connected together and constitute a low-voltage end of the transformer module 104. The second end of the first inductor L1 is connected to the second end of the first power switch unit Q1 and the first end of the second power switch unit Q2. The second end of the second inductor L2 is connected to the second end of the third power switch unit Q3 and the first end of the fourth power switch unit Q4. The first end of the first power switch unit Q1 and the first end of the third power switch unit Q3 are connected together and constitute a high-voltage end of the transformer module 104. The second end of the second power switch unit Q2 and the second end of the fourth power switch unit Q4 are connected together and constitute a common end of the transformer module 104. Specifically, the transformer module 104 includes a first inductor L1, a second inductor L2, IGBT Q1, IGBT Q2, IGBT Q3 and IGBT Q4. The first end of the first inductor L1 and the first end of the second inductor L2 are connected together and constitute a low-voltage end of the transformer module 104. The second end of the first inductor L1 is connected to the emitter of IGBT Q1 and the collector of IGBT Q2. The second end of the second inductor L2 is connected to the emitter of IGBT Q3 and the collector of IGBT Q4. The collector of IGBT Q1 and the collector of IGBT Q2 are connected together and constitute a high-voltage end of the transformer module 104. The emitter of IGBT Q2 and the emitter of IGBT Q4 are connected together and constitute a common end of the transformer module 104.

[0048] In this embodiment, a controllable switch and an inductor are provided in the transformer module 104. When a voltage is input from the low-voltage end and the common end of the transformer module 104, IGBT Q2 and IGBT Q4 are controlled to be turned on and IGBT Q1 and IGBT Q3 are controlled to be turned off, so that the external power module 107 charges the inductor. When IGBT Q2 and IGBT Q4 are controlled to be turned off and IGBT Q1 and IGBT Q3 are controlled to be turned on, the external power module 107 and the inductor are discharged to the power battery 101 through the diode. Since there is current output in the inductor, the external power module 107 can boost and charge the power battery 101.

[0049] As an embodiment, the energy conversion device further includes a switch K3, a switch K4, a switch K5 and a third inductor L3. The first end of the switch K3 is connected to the negative electrode of the power battery 101, the second end of the switch K3 is connected to the second end of the energy storage module 103, the first end of the switch K4 is connected to the first end of the external power module 107, the second end of the switch K4 is connected to the first end of the third inductor L3, the second end of the third inductor L3 is connected to the first end of the energy storage module 103, the first end of the switch K5 is connected to the second end of the external power module 107, and the second end of the switch K5 is connected to the second end of the energy storage module 103.

[0050] In this embodiment, the switch K3 is provided to control or stop the output current of the power battery 101. For example, if the power battery 101 output current fails, the switch K3 is controlled to disconnect the power battery 101 from the circuit, protecting the circuit safety. By providing a third inductor L3, designed according to the operating frequency of the transformer module 104 (e.g., 20kHz), the current ripple can be controlled within ±1%. By providing switches K4 and K5, the connection and disconnection with the external power module 107 can be achieved.

[0051] Regarding the motor controller 105, the motor controller 105 includes a resistor R3, a capacitor C2, a fifth power switch unit Q5, a sixth power switch unit Q6, a seventh power switch unit Q7, an eighth power switch unit Q8, a ninth power switch Q9, and a tenth power switch Q10. The control end of each power switch unit is connected to the control module 109. The first end of the fifth power switch unit Q5, the first end of the seventh power switch unit Q7, the first end of the ninth power switch unit Q9, the first end of the resistor R3, and the first end of the capacitor C2 are commonly connected to the first end of the motor controller 105. The control end of the sixth power switch unit Q6, the seventh power switch unit Q7, the eighth power switch unit Q8, the ninth power switch unit Q9, the first end of the resistor R3, and the first end of the capacitor C2 are commonly connected to the first end of the motor controller 105. The second end of Q6, the second end of the eighth power switch unit Q8, the second end of the tenth power switch unit Q10, the second end of the resistor R3, and the second end of the capacitor C2 are connected together as the second end of the motor controller 105. The first phase coil of the three-phase AC motor is connected to the second end of the fifth power switch unit Q5 and the first end of the sixth power switch unit Q6. The second phase coil of the three-phase AC motor is connected to the second end of the seventh power switch unit Q7 and the first end of the eighth power switch unit Q8. The third phase coil of the three-phase AC motor is connected to the second end of the ninth power switch unit Q9 and the first end of the tenth power switch unit Q10.

[0052] The specific control method of the control module 109 is shown in the following embodiments:

[0053] A second embodiment of the present disclosure provides a charging method for the energy conversion device provided in the first embodiment. The charging method provided in the second embodiment is used to enable an external power module to charge a power battery. As shown in FIG4 , the charging method includes:

[0054] Step S101: When the energy conversion device is connected to the external power module and is in a charging mode, the maximum output voltage of the external power module is obtained.

[0055] The step S101 of obtaining the maximum output voltage of the external power module includes:

[0056] A constant current boost charging instruction is sent to the external power module until the voltage output by the external power module reaches the maximum output voltage.

[0057] Among them, after the external power supply module (DC charging pile) is connected to the energy conversion device, an instruction is sent to the DC charging pile to enable the DC charging pile to start charging with a small current constant current boost. During the small current constant current charging process, the actual voltage of the DC charging pile is identified, that is, the output voltage of the DC charging pile is received in real time. When the voltage cannot be increased as required, it is judged that the output voltage of the DC charging pile is less than the preset voltage value. For example, the charging pile is determined to be no more than 550V, and step S102 is executed. The charging current of the DC charging pile is switched to the maximum target charging current required by the control module to start charging; if the output voltage of the DC charging pile can be increased to the preset voltage value as required, for example, greater than 550V and follows the voltage increase of the power battery, step S103 is executed.

[0058] Step S102: When the maximum output voltage of the external power module is not greater than the preset voltage, the first switch module is controlled to be turned off and the second switch module is controlled to be turned on, so that the external power module boosts and charges the power battery through the energy storage module, the transformer module and the second switch module.

[0059] The step S102 of enabling the external power module to boost and charge the power battery through the voltage transformation module includes:

[0060] The actual current value output by the transformer module is obtained, the actual current value is compared with the target current value, and a PWM control signal is output to the transformer module so that the transformer module outputs the target current value to the power battery to charge the power battery.

[0061] The control module exchanges information with the external power module, obtaining a target current value based on the power battery's current charging capacity, such as charging power. This target current value meets the specified output current standards for the power supply equipment. The control module then transmits this target current value to the external power module, enabling it to output current according to the target current value. When the external power module outputs current, the control module controls the power switch in the transformer module to turn on, increasing the inductor energy storage current. When the control module controls the power switch to turn off, reducing the inductor freewheeling current. By applying a PWM wave to the power switch, the repeated on-and-off cycles generate a DC current in the inductor. The magnitude of this DC current is determined by the external power module voltage, the power battery voltage, and the duty cycle of the PWM wave. When the external power module operates in constant voltage mode, its output voltage is controllable within a certain range. The output voltage of the off-board charger can be set to its maximum output value. Finally, the charging current is controlled by adjusting the PWM duty cycle to meet the control module's demand for the power battery's charging current.

[0062] Step S103: When the maximum output voltage of the external power module is greater than the preset voltage, the first switch module is controlled to be turned on and the second switch module is controlled to be turned off, so that the external power module performs DC charging on the power battery through the first switch module.

[0063] Wherein, in this step, when the maximum output voltage of the external power module is greater than the preset voltage, the power battery is directly charged through the external power module, thereby improving the charging speed of the power battery.

[0064] The second embodiment of the present disclosure provides a charging method for an energy conversion device. When the maximum output voltage of the external power module is not greater than a preset voltage, the external power module is caused to boost and charge the power battery through the transformer module. When the maximum output voltage of the external power module is greater than the preset voltage, the external power module is caused to DC charge the power battery through the first switch module. The technical solution disclosed herein can realize the use of high-voltage power batteries to power vehicles, can reduce the current carrying capacity requirements of cable connectors, and thus reduce the volume and weight of cable connectors. When connected to a high-voltage power supply platform DC charging pile, the charging speed of the power battery can be improved through DC charging. When connected to a low-voltage power supply platform DC charging pile, boost charging can be performed, solving the problem in the prior art that the low-voltage power supply platform DC charging pile cannot fully charge or cannot charge the power battery.

[0065] In some embodiments, before step S101, the method further includes:

[0066] The target required voltage value is sent to the external power supply module, and the first switch module is controlled to be turned on, so that the power battery pre-charges the energy storage module through the first switch module, so that the voltage value of the energy storage module is a preset voltage, and then the transformer module is controlled to discharge the energy storage module through the transformer module, so that the voltage value of the energy storage module is the target required voltage value.

[0067] Among them, the control module sends a target required voltage to the DC charging pile, and controls the first switch module to be turned on, so that the power battery, the first switch module and the energy storage module form a loop, so that the power battery pre-charges the energy storage module through the first switch module, so that the voltage value of the energy storage module (the low-voltage side capacitor of the transformer module) is a preset voltage. At this time, the transformer module is also controlled to be turned on, so that the power battery, the transformer module and the capacitor in the motor controller (the high-voltage side capacitor of the transformer module) form a loop, so that the voltage value of the high-voltage side capacitor of the transformer module is a preset voltage. At this time, the voltage on the low-voltage side capacitor of the transformer module is the same as the voltage on the high-voltage side capacitor of the transformer module. Since the external power supply module needs to be the same as the voltage on the low-voltage side capacitor of the transformer module when charging the energy conversion device, the voltage on the low-voltage side capacitor of the transformer module increases at this time, and it is necessary to step down and discharge. The transformer module is controlled to discharge the energy storage module through the transformer module, so that the voltage value of the energy storage module is the target required voltage value.

[0068] In this embodiment, when the energy conversion device is connected to the external power supply module to charge the power battery, the power battery first charges the low-voltage side capacitor and the high-voltage side capacitor of the transformer module, and the voltage of the high-voltage side capacitor of the transformer module is set to a preset voltage to avoid the impact on the subsequent circuit of the transformer module when the external power supply module charges the power battery, thereby achieving charging safety. In addition, by setting up the transformer module, the low-voltage side capacitor of the transformer module is stepped down by the transformer module, and then the voltage of the low-voltage side capacitor of the transformer module is made the same as the output voltage of the external power supply module, thereby meeting the condition for the external power supply module to output current.

[0069] In some embodiments, the step of “obtaining the maximum output voltage of the external power module” further includes:

[0070] The target maximum output voltage of the external power module is obtained, and a constant current boost charging instruction is continuously sent to the external power module. When it is detected that the current output by the external power module is not a constant current or the actual maximum output voltage is less than the target maximum output voltage, the target maximum output voltage is determined to be a false value, and the actual maximum output voltage is set as the maximum output voltage.

[0071] Among them, in order to meet the charging needs of electric vehicles as much as possible, many external power modules (DC charging piles) on the actual market use low-voltage platform power modules (maximum voltage 500V) for early DC charging pile installations. Operators change the DC charging pile control board program. When DC charging interacts with the control module, the DC charging pile sends a false maximum voltage of a high-voltage platform (maximum 750-1000V) to the control module. In order to be compatible with this situation, the pile can also be charged. The logic of the vehicle identification pile voltage platform in the charging process is optimized. The control module sends instructions to the DC charging pile to start charging with a small current constant current boost. During the small current constant current charging process, the real voltage of the DC charging pile is identified, that is, the output voltage of the DC charging pile is received in real time. When the voltage cannot be increased as required, it is judged that the target maximum output voltage is a false value, and the actual maximum output voltage is set to the maximum output voltage. At this time, the energy conversion device is controlled to boost the voltage output by the DC charging pile, which solves the problem of the DC charging pile sending a false voltage and causing the power battery to be fully charged.

[0072] In some embodiments, the step of continuously sending a constant current boost charging instruction to the external power module further includes:

[0073] The external power supply module obtains the actual voltage value of the energy storage module, and outputs current to the energy conversion device when it determines that the target required voltage value and the actual voltage value of the energy storage module meet a preset standard.

[0074] When the error between the actual voltage value of the sampled energy storage module and the target required voltage value is within the range of -5% to 5%, it is determined that the preset standard is met.

[0075] Among them, the external power module detects the battery voltage at the vehicle end and the battery voltage at the communication message in an error range of ≤±5% according to the national standard. The external power module can output current only when this standard is met.

[0076] In this embodiment, the external power supply module determines whether the charging conditions in the preset standard are met based on the target required voltage value sent by the control module and the actual voltage of the energy storage module. When the preset standard is met, it outputs current to the transformer module, making the control of power battery charging simpler and ensuring the safety of vehicle charging.

[0077] In some embodiments, the charging method further comprises:

[0078] When the energy conversion device is in driving mode, the first switch module is controlled to be turned on, and the voltage conversion module is controlled to enable the power battery to boost the power supply to the motor controller through the first switch module, the voltage conversion module and the energy storage module.

[0079] Among them, when the vehicle is in operation, the voltage of the power battery may be low. At this time, the first switch module is controlled to be turned on, and a boost circuit is formed by the power battery, the first switch module, the transformer module, the energy storage module, and the motor controller to achieve the voltage boost of the power battery output, thereby ensuring the normal operation of the vehicle.

[0080] The following uses the circuit diagram in FIG3 as an example to specifically illustrate the charging method of the energy conversion device provided in the second embodiment: During the DC charging process of the vehicle, the DC charging pile reports the actual voltage output range of the internal power module to the vehicle. During the parameter matching phase between the DC charging pile and the electric vehicle, the vehicle receives the maximum voltage output range sent by the DC charging pile:

[0081] If the maximum output voltage range of the DC charging pile received by the vehicle is no more than 550V, the transformer module is activated for DC charging. If the vehicle is in the OFF position when the charger is plugged in, pre-charging is performed first, closing switch K3 and then switch K2. When the control module determines that the pre-charging voltage meets the pre-charging completion conditions, switch K6 is switched on and switch K2 is opened at the same time. The control module sends the target required voltage to the DC charging pile and controls the transformer module to make the power battery step down and charge the energy storage module to the preset voltage. After detecting that the DC charging pile has reached the voltage required by the message, the control module closes switches K4 and K5 and simultaneously sends a charging permission to the DC charging pile and the transformer module. The charging method is constant current charging. The DC charging pile closes its own charging contactor when its own state meets the charging requirements and starts charging. When the charger is connected to the vehicle in the OK position, the main switch K1 of the entire vehicle must be disconnected before starting DC charging, and the vehicle OFF charging process must be repeated.

[0082] Specifically, when the maximum voltage of the DC charging station is no greater than the maximum voltage limit of the vehicle battery pack, the transformer module is activated. The transformer module operates in two modes: boost mode and buck mode. Its operational control energy flow is specifically shown in Figures 5 to 8. As shown in Figure 5, the power battery 101 pre-charges capacitors C1 and C2: the power battery 101, switch K1, and capacitor C1 form a first discharge loop, while the power battery 101, inductor L1, inductor L2, IGBT Q1, IGBT Q3, and capacitor C2 form a second discharge loop, equalizing the voltages across capacitors C1 and C2. Subsequently, as shown in Figure 6, IGBT Q2 and IGBT Q4 are controlled to conduct, causing capacitor C1 to discharge into inductors L1 and L2 to a preset voltage, making the voltage across capacitor C1 the same as the output voltage of the external power module 107, thereby causing the external power module 107 to output current. As shown in FIG7 , the transformer module 104 operates in the boost mode: the external power module 107, the switch K4, the inductor L3, the inductor L1, the inductor L2, the IGBT Q2, and the IGBT Q4 form a first charging circuit. As shown in FIG8 , the external power module 107, the switch K4, the inductor L3, the inductor L1, the inductor L2, the IGBT Q1, the IGBT Q2, the switch K6, the power battery 101, and the switch K3 form a second charging circuit. The first charging circuit and the second charging circuit are controlled to operate alternately to achieve boost charging of the power battery 101.

[0083] When the vehicle receives a DC charging station with a maximum output voltage greater than 550V, the DC charging process begins: If the vehicle is in the OFF position when the charger is connected, pre-charging begins by first closing switch K3 and then switch K2. When the control module determines that the pre-charge voltage meets the pre-charge completion conditions, switch K1 is closed and switch K2 is opened. The control module detects that the vehicle meets the charging conditions and closes switches K4 and K5, simultaneously sending a charging permission and constant current charging mode to the DC charging station. The DC charging station closes its own charging contactor when its status meets the charging requirements, starting charging. If the vehicle is in the OK position when the charger is connected, the control module directly sends the target charging voltage and constant current charging instructions to the DC charging station, initiating the charging process. As shown in Figure 9, the transformer module operates in DC charging mode: the external power module 107, capacitor C1, switch K1, and power battery 101 form a DC charging circuit, directly charging power battery 101.

[0084] It should be noted that in order to best meet the charging needs of electric vehicles, many early DC charging piles used low-voltage platform power modules (maximum voltage 500V). Operators modified the DC charging pile control board program, so that when the DC charging pile and the control module communicate, the DC charging pile sends a false maximum voltage of the high-voltage platform (maximum 750-1000V) to the vehicle. To accommodate this situation, the charging pile can also charge, and the logic for vehicles to identify the DC charging pile voltage platform during the charging process has been optimized. When the plug is connected and the DC charging process is in progress, before the DC charging pile closes the charging contactor, the DC charging pile and the transformer module meet the control module's target voltage. The DC charging pile outputs the target voltage, and the transformer module stabilizes the measured voltage when it is within the tolerance range. After the DC charging pile closes the charging contactor, the control module sends a command to the DC charging pile to begin charging with a low-current constant-current boost. During this process, the control module identifies the DC charging pile's actual voltage, receiving the DC charging pile's output voltage in real time. If the voltage fails to increase as required, it is determined that the DC charging pile's output voltage is less than 550V. Charging is then resumed according to the boost process, with the charging current switched to the control module's maximum target current. If the DC charging pile's output voltage can be increased to greater than 550V as required, DC charging begins at the control module's maximum target current. At the end of charging, when the charging circuit current is detected to be less than 5A, the vehicle-side disconnects switches K4 / K5, performing a switch sticking test to complete the entire process.

[0085] Another embodiment of the present disclosure provides a vehicle 200 , as shown in FIG10 , the vehicle 200 further includes the energy conversion device 100 provided in the above embodiment.

[0086] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. An energy conversion device, characterized in that: The energy conversion device includes an energy storage module, a voltage transformation module, a first switch module, a second switch module and a control module. The energy storage module is connected to the voltage transformation module, and the voltage transformation module is connected to the power battery and the first switch module through the second switch module. The first switch module is also connected to the energy storage module and the voltage transformation module. The control module is respectively connected to the first switch module and the second switch module.

2. The energy conversion device according to claim 1, wherein: The transformer module is also connected to the motor controller, the positive pole of the power battery is connected to the first end of the first switch module and the first end of the second switch module, the second end of the first switch module is connected to the first end of the energy storage module and the low-voltage end of the transformer module, the second end of the second switch module is connected to the high-voltage end of the transformer module and the first bus terminal of the motor controller, the second end of the energy storage module is connected to the negative pole of the power battery, the common end of the transformer module and the second bus terminal of the motor controller, and the first and second ends of the energy storage module are charging ports of the energy conversion device.

3. The energy conversion device according to claim 2, characterized in that The motor controller is connected to the motor, and when the energy conversion device is in driving mode, the power battery supplies power to the motor through the first switch module, the voltage conversion module, the energy storage module, and the motor controller; When the energy storage module is connected to the external power module and the energy conversion device is in the boost charging mode, the external power module charges the power battery through the energy storage module, the voltage transformation module, and the second switch module.

4. The energy conversion device according to claim 2 or 3, characterized in that: The first switch module includes a switch K1, a switch K2, and a resistor R2; the first end of the resistor R2 is connected to the first end of the switch K1 and constitutes the first end of the first switch module, the second end of the resistor R2 is connected to the first end of the switch K2, and the second end of the switch K2 is connected to the second end of the switch K1 and constitutes the second end of the first switch module.

5. The energy conversion device according to any one of claims 2 to 4, characterized in that: The transformer module includes a first inductor, a second inductor, a first power switch unit, a second power switch unit, a third power switch unit and a fourth power switch unit. The first end of the first inductor and the first end of the second inductor are connected together and constitute a low-voltage end of the transformer module. The second end of the first inductor is connected to the second end of the first power switch unit and the first end of the second power switch unit. The second end of the second inductor is connected to the second end of the third power switch unit and the first end of the fourth power switch unit. The first end of the first power switch unit and the first end of the third power switch unit are connected together and constitute a high-voltage end of the transformer module. The second end of the second power switch unit and the second end of the fourth power switch unit are connected together and constitute a common end of the transformer module.

6. The energy conversion device according to any one of claims 2 to 5, characterized in that: The energy conversion device also includes a switch K3, a switch K4, a switch K5, and a third inductor L3. The first end of the switch K3 is connected to the negative electrode of the power battery, the second end of the switch K3 is connected to the second end of the energy storage module, the first end of the switch K4 is connected to the first end of the external power module, the second end of the switch K4 is connected to the first end of the third inductor L3, the second end of the third inductor L3 is connected to the first end of the energy storage module, the first end of the switch K5 is connected to the second end of the external power module, and the second end of the switch K5 is connected to the second end of the energy storage module.

7. A method for charging an energy conversion device, based on the energy conversion device according to any one of claims 1 to 6, characterized in that: The charging method includes: When the energy conversion device is connected to the external power module and is in a charging mode, obtaining the maximum output voltage of the external power module; When the maximum output voltage of the external power module is not greater than a preset voltage, controlling the first switch module to be turned off and the second switch module to be turned on, so that the external power module boosts and charges the power battery through the energy storage module, the voltage transformation module, and the second switch module; When the maximum output voltage of the external power module is greater than a preset voltage, the first switch module is controlled to be turned on and the second switch module is controlled to be turned off, so that the external power module performs DC charging on the power battery through the energy storage module and the first switch module.

8. The charging method according to claim 7, wherein: When the energy conversion device is connected to the external power module and is in the charging mode, obtaining the maximum output voltage of the external power module, the method further includes: The target required voltage value is sent to the external power supply module, and the first switch module is controlled to be turned on, so that the power battery pre-charges the energy storage module through the first switch module, so that the voltage value of the energy storage module is a preset voltage, and then the voltage transformation module is controlled to discharge the energy storage module through the voltage transformation module, so that the voltage value of the energy storage module is the target required voltage value.

9. The charging method according to claim 7 or 8, wherein: The obtaining of the maximum output voltage of the external power module further includes: Obtain the target maximum output voltage of the external power module, continuously send a constant current boost charging instruction to the external power module, and when detecting that the current output by the external power module is not a constant current or the actual maximum output voltage is less than the target maximum output voltage, determine that the target maximum output voltage is a false value, and set the actual maximum output voltage as the maximum output voltage.

10. The charging method according to claim 9, wherein: The continuously sending a constant current boost charging instruction to the external power module further includes: The external power supply module obtains the actual voltage value of the energy storage module, and outputs current to the energy conversion device when it determines that the target required voltage value and the actual voltage value of the energy storage module meet a preset standard.

11. The charging method according to any one of claims 7 to 10, wherein: The step of enabling the external power module to boost and charge the power battery through the voltage transformation module includes: The actual current value and the target current value output by the transformer module are obtained, the actual current value is compared with the target current value, and a PWM control signal is output to the transformer module so that the transformer module outputs the target current value to the power battery to charge the power battery.

12. The charging method according to any one of claims 7 to 11, wherein: The charging method further includes: When the energy conversion device is in driving mode, the first switch module is controlled to be turned on, and the voltage conversion module is controlled to enable the power battery to boost the power supply to the motor controller through the first switch module, the voltage conversion module, and the energy storage module.

13. A vehicle, characterized in that: The vehicle further comprises an energy conversion device as claimed in any one of claims 1 to 6.

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