Vehicle, energy conversion device and method for charging thereof

Abstract

The application provides a vehicle, an energy conversion device and a charging method thereof. The first switch module and the second switch module are arranged, and the second switch module is arranged between the power battery and the voltage conversion module. When the first switch module is turned on, the power battery, the first switch module, the energy storage module and the external power supply module form a first charging circuit. When the second switch module is turned on, the power battery, the second switch module, the voltage conversion module, the energy storage module and the external power supply module form a second charging circuit. When the high-voltage power supply platform direct-current charging pile is connected, the first charging circuit can be used for direct-current charging, and the charging speed of the power battery is improved. When the low-voltage power supply platform direct-current charging pile is connected, the second charging circuit can be used for step-up charging, and the problem that the power battery cannot be fully charged or cannot be charged by the low-voltage power supply platform direct-current charging pile in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobiles, in particular to a vehicle, an energy conversion device and a charging method thereof. BACKGROUND

[0002] At present, the energy crisis and environmental pollution problems are becoming increasingly serious. As a new type of transportation tool, electric vehicles can achieve "zero emissions", and electric vehicles have the advantages of simple structure, high energy utilization rate, low noise, etc. and will dominate the future development of automobiles. Under the background of relatively mature battery, motor and electric control three-electric technology, the demand for charging technology and battery heating control has become increasingly prominent, especially for electric vehicles taking the high-voltage route, the battery voltage will usually reach 700V, and the ordinary 500V output charging pile obviously cannot meet the demand of direct current fast charging of electric vehicles. SUMMARY

[0003] The purpose of the present application is to provide a vehicle, an energy conversion device and a charging method thereof to solve the problem that the charging pile cannot meet the demand of direct current fast charging of electric vehicles in the prior art.

[0004] The present application is realized in this way. The first aspect of the present application provides an energy conversion device, which comprises an energy storage module, a voltage conversion module, a first switch module, a second switch module and a control module. The energy storage module is connected to the voltage conversion module. The voltage conversion module is connected to a power battery through the second switch module and the first switch module. The first switch module is also connected to the energy storage module and the voltage conversion module. The control module is connected to the first switch module and the second switch module respectively.

[0005] The second aspect of the present application provides a charging method of an energy conversion device. Based on the energy conversion device of the first aspect, the charging method comprises:

[0006] When the energy conversion device is connected to an external power module and is in a charging mode, the maximum output voltage of the external power module is obtained.

[0007] When the maximum output voltage of the external power module is not greater than a 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 charges the power battery through the energy storage module, the voltage conversion module and the second switch module.

[0008] 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 charges the power battery through the energy storage module and the first switch module.

[0009] The third aspect of the present application provides a vehicle, wherein the vehicle further comprises the energy conversion device of the first aspect.

[0010] The present application provides a vehicle, an energy conversion device and a charging method thereof. The energy conversion device comprises a first switch module and a second switch module. When the first switch module is turned on, the power battery, the first switch module, the energy storage module and the external power supply module form a first charging circuit. When the second switch module is turned on, the power battery, the second switch module, the voltage conversion module, the energy storage module and the external power supply module form a second charging circuit. When the maximum output voltage of the external power supply module is not greater than a preset voltage, the second charging circuit is controlled to start working, so that the external power supply module charges the power battery through the voltage conversion module. When the maximum output voltage of the external power supply module is greater than the preset voltage, the first charging circuit is controlled to start working, so that the external power supply module charges the power battery through the first switch module. The technical scheme of the present application can realize power supply of the vehicle by using the power battery with high voltage, can reduce the current carrying capacity requirement of the cable connector, and further reduce the size and mass of the cable connector. When the high-voltage power supply platform direct-current charging pile is connected, direct-current charging can be performed through the first charging circuit, so as to improve the charging speed of the power battery. When the low-voltage power supply platform direct-current charging pile is connected, step-up charging can be performed through the second charging circuit, so as to solve the problem that the low-voltage power supply platform direct-current charging pile cannot charge the power battery. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0012] Figure 1 is a structural schematic diagram of an energy conversion device provided by an embodiment one of the present application;

[0013] Figure 2 is a circuit diagram of an energy conversion device provided by an embodiment one of the present application;

[0014] Figure 3 is a charging method flow chart of an energy conversion device provided by an embodiment two of the present application;

[0015] Figure 4 is a current path diagram of an energy conversion device provided by an embodiment two of the present application for pre-charging;

[0016] Figure 5 is another current path diagram of an energy conversion device provided by a second embodiment of the present application;

[0017] Figure 6 is another current path diagram of an energy conversion device provided by a second embodiment of the present application;

[0018] Figure 7 is another current path diagram of an energy conversion device provided by a second embodiment of the present application

[0019] Figure 8 is another current path diagram of an energy conversion device provided by a second embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0021] In order to illustrate the technical scheme of the present application, the following will be described by specific embodiments.

[0022] The embodiments of the present application provide an energy conversion device, as shown in Figure 1 The energy conversion device includes an energy storage module 103, a voltage conversion module 104, a first switch module 102, a second switch module 106 and a control module. The energy storage module 103 is connected to the voltage conversion module 104. The voltage conversion module 104 is connected to a power battery 101 and the first switch module 102 through the second switch module 106. The first switch module 102 is further connected to the energy storage module 103 and the voltage conversion module 104. The control module is connected to the first switch module 102 and the second switch module 106 respectively.

[0023] The energy storage module 103 is used for storing the electric energy output by the power battery 101. The two ends of the energy storage module 103 can be connected to the external power module 107. When the power battery 101 completes charging of the energy storage module 103, the voltage on the energy storage module 103 is the same as or similar to the voltage of the external power module 107, so that the external power module 107 can normally output the voltage. The energy storage module 103 can include a capacitor and other energy storage devices. The voltage conversion module 104 can include an energy storage unit and a power switch unit. The power switch unit in the voltage conversion module 104 is turned on or turned off according to the signal output by the control module, so that the energy storage unit is connected to different circuits for charging and discharging to realize voltage boosting or voltage reduction. The voltage conversion module 104 includes a low-voltage end, a high-voltage end, and a common end. The low-voltage end and the high-voltage end of the voltage conversion module 104 are defined according to the size of the input voltage and the output voltage. The low-voltage end and the common end of the voltage conversion module 104 receive the input voltage, boost the input voltage, and then output from the high-voltage end and the common end of the voltage conversion module. The high-voltage end and the common end of the voltage conversion module 104 receive the input voltage, reduce the input voltage, and then output from the low-voltage end and the common end of the voltage conversion module 104. 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 the charging circuit, the external power module 107 charges the battery. The second switch module 106 is used to connect the power battery 101 to 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 voltage conversion module 104, the energy storage module 103, and the external power module 107 form a second charging circuit. Through the charging circuit, the external power module 107 boosts the charging of the battery. The external power module 107 can be a non-vehicle-mounted charger, such as a charging pile, etc. The control module can collect the voltage, current, temperature of the power battery 101, and the phase current of the three-phase alternating current motor. The control module can include the control circuit of the vehicle controller, the motor controller 105, and the BMS battery manager circuit. The three are connected through the CAN line. Different modules in the control module control the turn-on or turn-off of the first switch module 102 and the second switch module 106 according to the obtained information, realize the turn-on of different charging circuits, and can also control the turn-on and turn-off of the power switch in the voltage conversion to realize the turn-on of different current circuits, thereby realizing the voltage boosting or voltage reduction of the input voltage.

[0024] As an implementation, the voltage conversion module 104 is further 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 voltage conversion module 104, the second end of the second switch module 106 is connected to the high-voltage end of the voltage conversion module 104 and the first bus end 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 voltage conversion module 104 and the second bus end of the motor controller 105, and the first end and the second end of the energy storage module 103 are the charging port of the energy conversion device.

[0025] When the maximum output voltage of the external power module 107 is not greater than the preset voltage, the preset voltage is the current voltage of the power battery 101, the external power module 107 cannot directly charge the charging battery, at this time, 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 starts to work, and the external power module 107 charges the power battery 101 through the voltage conversion 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 charging battery, 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 starts to work, and the external power module 107 directly charges the power battery 101 through the first switch module 102.

[0026] It should be noted that, as Figure 1As shown, the high-voltage end and the common end of the voltage conversion 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 the driving mode, the power battery 101 supplies power to the motor 108 through the first switch module 102, the voltage conversion module 104, the energy storage module 103, and the motor controller 105. When the energy conversion device is in the voltage boosting charging mode, the external power module 107 charges the power battery 101 through the energy storage module 103, the voltage conversion module 104, and the second switch module 106. As can be seen, in the above driving mode and voltage boosting charging mode, the energy storage module 103 and the voltage conversion module 104 are used, that is, the energy storage module 103 and the voltage conversion module 104 are multiplexed in different circuits to achieve different functions, thereby improving the utilization rate of the modules in the circuit. The external power module 107 can supply power to the motor controller 105 and the motor 108 through the voltage module, and the power battery 101 can also supply power to the motor controller 105 and the motor 108 through the voltage conversion module 104. The voltage conversion module can boost the voltage of the battery pack with a wide voltage range or the low-voltage platform battery pack to the efficient area demand voltage of the motor controller 105 when the vehicle is driving, thereby ensuring the power demand of the vehicle. When the low-voltage platform battery pack is fed, the motor controller 105 and the motor 108 can also be supplied with power by the low-voltage platform battery pack through the voltage conversion module 104.

[0027] The energy conversion device provided in the application comprises a first switch module 102 and a second switch module 106, and the second switch module 106 is arranged between the power battery 101 and the voltage conversion module 104. 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 supply module 107 form a first charging circuit. When the second switch module 106 is turned on, the power battery 101, the second switch module 106, the voltage conversion module 104, the energy storage module 103 and the external power supply module 107 form a second charging circuit. When the maximum output voltage of the external power supply module 107 is not greater than a preset voltage, the second charging circuit is controlled to start working, so that the external power supply module 107 charges the power battery 101 through the voltage conversion module 104. When the maximum output voltage of the external power supply module 107 is greater than the preset voltage, the first charging circuit is controlled to start working, so that the external power supply module 107 directly charges the power battery 101 through the first switch module 102. The technical scheme of the application can realize power supply of a vehicle by using a high-voltage power battery, can reduce the current-carrying capacity requirement of a cable connector, thereby reducing the size and mass of the cable connector, can directly charge the power battery through the first charging circuit when a high-voltage power supply platform direct current charging pile is connected, and can improve the charging speed of the power battery. When a low-voltage power supply platform direct current charging pile is connected, the power battery can be charged through the second charging circuit, thereby solving the problem that the power battery cannot be fully charged or cannot be charged by the low-voltage power supply platform direct current charging pile in the prior art.

[0028] As an embodiment, as shown in Figure 2 The energy storage module 103 comprises 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 comprises 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, and 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.

[0029] In the embodiment, the resistor R2 and the 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, for example, 80% of the preset voltage, through the resistor R2, thereby avoiding damage to the capacitor caused by too fast charging.

[0030] As an implementation, the voltage transformation module 104 includes a first inductor, a second inductor, 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 and the first end of the second inductor are connected together and constitute the low-voltage end of the voltage transformation 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 voltage transformation module, and 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 voltage transformation module. Specifically, the voltage transformation module 104 includes a first inductor L1, a second inductor L2, an IGBT Q1, an IGBT Q2, an IGBT Q3, and an IGBT Q4, the first end of the first inductor L1 and the first end of the second inductor L2 are connected together and constitute the low-voltage end of the voltage transformation module 104, the second end of the first inductor L1 is connected to the emitter of the IGBT Q1 and the collector of the IGBT Q2, the second end of the second inductor L2 is connected to the emitter of the IGBT Q3 and the collector of the IGBT Q4, the collector of the IGBT Q1 and the collector of the IGBT Q2 are connected together and constitute the high-voltage end of the voltage transformation module 104, and the emitter of the IGBT Q2 and the emitter of the IGBT Q4 are connected together and constitute the common end of the voltage transformation module 104.

[0031] In the voltage transformation module 104 in the embodiment, controllable switches and inductors are arranged, when the voltage is input from the low-voltage end and the common end of the voltage transformation module 104, the IGBT Q2 and the IGBT Q4 are controlled to be turned on and the IGBT Q1 and the IGBT Q3 are controlled to be turned off, so that the external power supply module 107 charges the inductor, the IGBT Q2 and the IGBT Q4 are controlled to be turned off and the IGBT Q1 and the IGBT Q3 are controlled to be turned on, so that the external power supply module 107 and the inductor discharge to the power battery 101 through the diode, and since there is a current output in the inductor, the voltage transformation module 104 realizes the boost charging of the power battery 101 by the external power supply module 107.

[0032] As an implementation, 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 supply 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 103, the first end of the switch K5 is connected to the second end of the external power supply module, and the second end of the switch K5 is connected to the second end of the energy storage module 103.

[0033] In this embodiment, by setting the switch K3, the output current of the power battery 101 can be controlled or stopped. For example, when the output current of the power battery fails, the switch K3 is controlled to be disconnected, so that the power battery is disconnected from the circuit, thereby protecting the safety of the circuit. By setting the third inductor L3, the third inductor L3 is designed according to the working frequency (for example, 20 kHz) of the voltage conversion module, so that the current ripple can be controlled within ±1%. By setting the switches K4 and K5, the connection and disconnection with the external power module can be realized.

[0034] For 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. 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 connected to the first end of the motor controller 105. The second end of the sixth power switch unit 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 to the second end of the motor controller 105. The first phase coil of the three-phase alternating current 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 alternating current 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 alternating current 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.

[0035] The specific control method of the control module is described in the following embodiments:

[0036] Embodiment two of the present application provides a charging method based on the energy conversion device provided in embodiment one. The charging method provided in embodiment two is used to charge the power battery by the external power module. As shown in the figure, Figure 3 The charging method includes the following steps:

[0037] Step S101. When the energy conversion device is connected to the external power module in the charging mode, the maximum output voltage of the external power module is obtained.

[0038] In step S101, the maximum output voltage of the external power module is obtained, including:

[0039] A constant current boost charging instruction is sent to the external power module until the voltage output by the external power module is the maximum output voltage.

[0040] The external power module (direct current charging pile) is communicated with the energy conversion device, and then sends an instruction to the direct current charging pile to make the direct current charging pile start constant current boost charging with a small current. The actual voltage of the direct current charging pile is identified during the constant current charging process, that is, the output voltage of the direct current charging pile is received in real time. When the voltage cannot be raised as required, it is determined that the output voltage of the direct current charging pile is less than a preset voltage value, for example, it is determined that the charging pile is not greater than 550V pile, and step S102 is performed. The charging current of the direct current charging pile is switched to the maximum target charging current required by the controller module to start charging.

[0041] 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 charges the power battery through the energy storage module, the voltage conversion module and the second switch module.

[0042] In step S102, the external power module charges the power battery through the voltage conversion module, including:

[0043] An actual current value output by the voltage conversion module is obtained, and the actual current value is compared with a target current value. The voltage conversion module outputs the target current value to the power battery to charge the power battery by outputting a PWM control signal to the voltage conversion module.

[0044] The control module exchanges information with the external power module, obtains a target current value according to the current charging capacity of the power battery, for example, the charging power, the target current value meets the specified standard of the output current of the power supply device, and the target current value is sent to the external power module, so that the external power module outputs according to the target current value. When the external power module outputs the current, the control module controls the power switch tube in the voltage conversion module to be turned on, and the inductance energy storage current increases. The control module controls the power switch tube to be turned off, and the inductance freewheeling current decreases. A direct current is formed in the inductance by repeatedly turning on and turning off the power switch tube by applying a PWM wave to the power switch tube. The size of the direct current is determined by the voltage of the external power module, the voltage of the power battery and the duty cycle of the PWM wave. The external power module works in a constant voltage mode, and the output voltage is controllable within a certain range. The output voltage of the non-vehicle-mounted charger can be set as the highest value of its output. Finally, the size of the charging current is controlled by adjusting the duty cycle of the PWM, so as to meet the demand of the control module for the charging current of the power battery.

[0045] 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 charges the power battery through the first switch module.

[0046] Wherein, when the maximum output voltage of the external power module is greater than the preset voltage, the power battery is directly charged by the external power module, and the charging speed of the power battery is improved.

[0047] The embodiment two of the application provides a charging method of an energy conversion device. When the maximum output voltage of the external power module is not greater than the preset voltage, the external power module is enabled to charge the power battery by the voltage conversion module. When the maximum output voltage of the external power module is greater than the preset voltage, the external power module is enabled to directly charge the power battery. The technical scheme of the application can realize the use of the high-voltage power battery to supply power to the vehicle, can reduce the current-carrying capacity requirement of the cable connector, and further reduce the size and mass of the cable connector. When the high-voltage power supply platform direct current charging pile is connected, the charging speed of the power battery can be improved by direct current charging. When the low-voltage power supply platform direct current charging pile is connected, the power battery can be charged by voltage conversion. The problem that the power battery cannot be fully charged or cannot be charged by the low-voltage power supply platform direct current charging pile in the prior art is solved.

[0048] Further, before step S101, the method further comprises:

[0049] The target demand voltage value is sent to the external power module, and the first switch module is controlled to be turned on, so that the power battery precharges the energy storage module through the first switch module, the voltage value of the energy storage module is the preset voltage, and then the voltage conversion module is controlled to make the energy storage module discharge through the voltage conversion module, so that the voltage value of the energy storage module is the target demand voltage value.

[0050] Wherein, the control module sends the target demand voltage to the direct current charging pile, and controls the first switch module to be turned on. The power battery, the first switch module and the energy storage module form a loop, so that the power battery precharges the energy storage module through the first switch module, the voltage value of the energy storage module (voltage conversion module low-voltage side capacitor) is the preset voltage. At this time, the voltage conversion module is also controlled to be turned on, so that the power battery, the voltage conversion module and the capacitor (voltage conversion module high-voltage side capacitor) in the motor controller form a loop, so that the voltage value of the voltage conversion module high-voltage side capacitor is the preset voltage. At this time, the voltage on the voltage conversion module low-voltage side capacitor and the voltage on the voltage conversion module high-voltage side capacitor are the same. Since the output voltage of the external power module needs to be the same as the voltage on the voltage conversion module low-voltage side capacitor when the external power module charges the energy conversion device, the voltage on the voltage conversion module low-voltage side capacitor is increased at this time, and needs to be discharged by voltage reduction. The voltage conversion module is controlled to make the energy storage module discharge through the voltage conversion module, so that the voltage value of the energy storage module is the target demand voltage value.

[0051] The embodiment first charges the low-voltage side capacitor of the voltage conversion module and the high-voltage side capacitor of the voltage conversion module by the power battery, and makes the voltage of the high-voltage side capacitor of the voltage conversion module a preset voltage, so as to avoid the impact on the voltage conversion module when the external power module charges the power battery, to realize the charging safety, and through the voltage conversion module, the voltage of the low-voltage side capacitor of the voltage conversion module is reduced, and the voltage of the low-voltage side capacitor of the voltage conversion module is the same as the output voltage of the external power module, so as to achieve the condition of the output current of the external power module.

[0052] Further, the step of "obtaining the maximum output voltage of the external power module" further comprises:

[0053] 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 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, it is determined that the target maximum output voltage is a false value, and the actual maximum output voltage is set as the maximum output voltage.

[0054] Among them, in order to meet the charging demand of electric vehicles as much as possible, the external power module (DC charging pile) in the actual market, many early installed DC charging piles use low voltage platform power module (maximum voltage 500V), the operator changes the DC charging pile control board program, when the DC charging and control module information interaction, the DC charging pile sends a false maximum voltage to the control module as a high voltage platform (maximum 750-1000V), in order to compatible with this situation, the pile can also be charged, optimize the logic of vehicle identification pile voltage platform in the charging process, control module sends instruction to DC charging pile to start with small current constant current boost charging, in the process of small current constant current charging, do DC charging pile real voltage identification, that is, real-time receive DC charging pile output voltage, when the voltage can not be raised as required, it is judged that the target maximum output voltage is a false value, and the actual maximum output voltage is set as the maximum output voltage. At this time, the control energy conversion device boosts the voltage output by the DC charging pile, solving the problem that the false voltage sent by the DC charging pile causes the charging battery to be not fully charged.

[0055] Further, the step of continuously sending a constant current boost charging instruction to the external power module further comprises:

[0056] The external power module obtains the actual voltage value of the energy storage module, and outputs current to the energy conversion device when it is determined that the target demand voltage value and the actual voltage value of the energy storage module meet the preset standard.

[0057] Among them, when the error between the actual voltage value of the sampling energy storage module and the target demand voltage value is in the range of-5% to 5%, it is determined that the preset standard is met.

[0058] 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.

[0059] 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.

[0060] Furthermore, the charging method further includes:

[0061] 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.

[0062] 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.

[0063] Below is Figure 2 Taking the circuit diagram in as an example, the charging method of the energy conversion device provided in the second embodiment is specifically described: During the DC charging process of the vehicle, the DC charging pile reports the actual internal power module voltage output range to the vehicle. During the parameter matching stage between the DC charging pile and the electric vehicle, the vehicle will receive the maximum voltage output range sent by the DC charging pile:

[0064] 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.

[0065] Specifically, when the maximum voltage of the direct current charging pile is not greater than the highest voltage limit value of the vehicle battery pack, the voltage conversion module is started to work, and the working state of the voltage conversion module includes a boost mode and a buck mode. The working control energy flow is specifically as shown in Figures 4 to 7 As shown in Figure 4 The power battery 101 pre-charges the capacitor C1 and the capacitor C2: the power battery 101, the switch K1, and the capacitor C1 form a first discharge circuit, and the power battery 101, the inductor L1, the inductor L2, the IGBT Q1, the IGBT Q3, and the capacitor C2 form a second discharge circuit, so that the voltages on the capacitor C1 and the capacitor C2 are equal. Then, as shown in Figure 5 The IGBT Q2 and the IGBT Q4 are controlled to be turned on, the capacitor C1 discharges the inductor L1 and the inductor L2 to a preset voltage, the voltage on the capacitor C1 is the same as the output voltage of the external power module 107, and then the external power module 107 outputs a current. As shown in Figure 6 The voltage conversion module works 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 Figure 7 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, and the first charging circuit and the second charging circuit are controlled to work alternately to realize boost charging of the power battery 101.

[0066] When the vehicle receives the maximum output voltage range of the direct current charging pile greater than 550V, the direct current charging process is performed: if the vehicle is in the OFF gear when the gun is inserted, pre-charging is performed, the switch K3 is first closed, and then the switch K2 is closed. When the control module determines that the pre-charging voltage meets the pre-charging completion condition, the switch K1 is closed, and the switch K2 is opened at the same time; the control module detects that the vehicle meets the charging condition, and closes the switches K4 and K5 to send the charging permission and the constant current charging mode to the direct current charging pile; the direct current charging pile closes the self-charging contactor according to the self-state to meet the charging demand, and starts charging; if the vehicle is in the OK gear when the gun is connected to the vehicle, the control module directly sends the target charging voltage and the constant current charging instruction to the direct current charging pile to start the charging process. As shown in Figure 8 The voltage conversion module works in the direct current charging mode: the external power module 107, the capacitor C1, the switch K1, and the power battery 101 form a direct current charging circuit to directly charge the power battery 101.

[0067] It should be noted that in order to meet the demand of electric vehicle charging as much as possible, many early installed DC charging piles use low voltage platform power modules (maximum voltage 500V). The operator changes the DC charging pile control panel program, and when the DC charging pile and the control module interact, the DC charging pile sends a false maximum voltage to the vehicle as a high voltage platform (maximum 750-1000V). In order to be compatible with this situation, the pile can also charge, and the logic of the vehicle identifying the voltage platform of the DC charging pile in the optimized charging process. When the gun is connected, before the DC charging pile closes the charging contactor, the DC charging pile and the transformer module output the target voltage required by the control module: the DC charging pile outputs the target voltage required by the control module, and the transformer module outputs the voltage within the error range, and after the DC charging pile closes the charging contactor, the control module sends a command to the DC charging pile to start charging with small current constant current boost. In the process of small current constant current charging, 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 raised as required, it is judged that the output voltage of the DC charging pile is not greater than 550V, and charging is carried out according to the boost process, and the charging current is switched to the maximum target charging current of the control module to start charging. If the output voltage of the DC charging pile can be raised to more than 550V as required, the maximum target of the control module is started to charge the DC charging. When the detection current of the charging loop is not greater than 5A, the vehicle disconnects the switch K4 / K5, and the switch sticking detection is carried out to complete the entire execution step.

[0068] Another embodiment of the present application provides a vehicle, which further comprises the energy conversion device provided in the above embodiments.

[0069] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope 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, 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, and the control module is connected to the first switch module and the second switch module respectively. 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.

2. The energy conversion device according to claim 1, wherein: 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.

3. The energy conversion device according to claim 1, wherein: 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.

4. The energy conversion device according to claim 1, wherein: 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.

5. The energy conversion device according to claim 2, 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.

6. A method for charging an energy conversion device, based on the energy conversion device according to any one of claims 1 to 5, 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.

7. The charging method according to claim 6, wherein: The above “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” also 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.

8. The charging method according to claim 6, wherein: The "obtaining 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.

9. The charging method according to claim 8, 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.

10. The charging method according to claim 6, 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.

11. The charging method according to claim 6, 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.

12. A vehicle, characterized in that: The vehicle further comprises the energy conversion device according to any one of claims 1 to 5.

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