WO2022127109A1

WO2022127109A1 - Voltage conversion device, electric drive system, and vehicle

Info

Publication number: WO2022127109A1
Application number: PCT/CN2021/107332
Authority: WO
Inventors: 甘银华; 何亮; 柯枫; 洪文成; 兰红玉; 潘丽雯
Original assignee: 蔚来汽车科技(安徽)有限公司
Priority date: 2020-12-14
Filing date: 2021-07-20
Publication date: 2022-06-23
Also published as: CN112600411A

Abstract

The present application relates to a voltage conversion device. The device comprises: a first terminal, a second terminal, and a third terminal; an inverter assembly in a power electronic unit (PEU), connected to the first terminal and the second terminal, the inverter assembly being configured to convert, when a first DC voltage is inputted by means of the first terminal and the second terminal, the first DC voltage to an AC voltage to drive a motor, and being configured to boost, when a second DC voltage is inputted by means of the second terminal and the third terminal, the second DC voltage into the first DC voltage and output same by means of the first terminal and the second terminal; and a motor winding connected to the inverter assembly, a center point of the motor winding being connected to the third terminal. The present application further relates to an electric drive system (EDS), a charging and driving system, and a vehicle.

Description

Voltage conversion equipment, electric drive systems and vehicles

This application takes the Chinese patent application with the filing date of December 14, 2020 and the application number of 202011465455.2 as the priority.

technical field

The present application relates to the field of DC/DC conversion, and more particularly, to a voltage conversion device, an electric drive system EDS, a charging and driving system, and a vehicle.

Background technique

At present, the mainstream electric vehicle high-voltage system platforms on the market are all 400V. For higher efficiency and more convenient charging experience, and with the gradual maturity of the automotive supply chain and market products, the next-generation electric vehicle high-voltage system platform will gradually change from 400V to 800V transition, the entire transition process has the following ways: 1) The power battery and drive system are switched from 400V to 800V, but other high-voltage accessory systems, including the charging system and air conditioning system, are still part or all of the 400V platform; 2) The power battery, The drive system and other high-voltage accessory systems are switched to 800V together, that is, the entire high-voltage system is full 800V.

Mode 1) On the one hand, it is considered that there are no mature 800V products for the charging system and air conditioning system, and more importantly, it is compatible with the 400V charging infrastructure on the market. When the power battery is switched to the 800V platform, in order to be compatible with 400V charging, the current solution on the market is to add a first-stage boost DC/DC converter (ie, DC/DC converter), and when encountering a 400V DC charging pile At this time, the voltage of the charging pile will not be directly applied to the power battery, but the high-power DC/DC converter will increase the voltage to 800V and then charge the power battery, but this solution has the following shortcomings: First, 400V The high power of the 800V to 800V DC/DC converter leads to high unit cost, which increases the cost of the whole vehicle; secondly, the high power of the 400V to 800V DC/DC converter leads to large volume and weight, which is not conducive to the layout and lightweight of the vehicle; Finally, as the charging infrastructure gradually switches from 400V to 800V, the 400V charging facilities will be gradually updated, but the schedule of this process cannot be estimated. For charging facilities, if the whole vehicle is still developed according to this system, the 400V to 800V DC/DC converter will bring a lot of silent cost, and the input and output are disproportionate.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a voltage conversion device is provided, the device includes: a first terminal, a second terminal and a third terminal; an inverter assembly in a power control unit PEU, connected to the first terminal and the third terminal; the second terminal is connected, the inverter assembly is configured to convert the first direct current voltage into an alternating voltage to drive a motor when the first direct current voltage is input via the first terminal and the second terminal, and for boosting the second DC voltage to the first DC voltage when the second DC voltage is input via the second terminal and the third terminal and passing the first terminal and the second terminal an output; and a motor winding connected to the inverter assembly, wherein a center point of the motor winding is connected to the third terminal.

As a supplement or replacement of the above solution, in the above device, the first voltage is 800V, and the second voltage is 400V.

As a supplement or alternative to the above solution, the above device may further include a capacitor, one end of the capacitor is connected to the first terminal, and the other end of the capacitor is connected to the second terminal.

As a supplement or replacement of the above solution, in the above device, the inverter assembly includes a first switch assembly, a second switch assembly, a third switch assembly, a fourth switch assembly, a fifth switch assembly, and a sixth switch assembly, Wherein, the first end of the first switch assembly is connected to the first terminal, the second end of the first switch assembly is connected to the first end of the second switch assembly, and the second switch assembly The second end is connected to the second terminal, the first end of the third switch assembly is connected to the first terminal, the second end of the third switch assembly is connected to the first end of the fourth switch assembly The second end of the fourth switch assembly is connected to the second terminal, the first end of the fifth switch assembly is connected to the first terminal, and the second end of the fifth switch assembly is connected to the second terminal. The first end of the sixth switch assembly is connected to the second terminal, and the second end of the sixth switch assembly is connected to the second terminal.

As a supplement or alternative to the above solution, in the above device, the motor winding includes a first inductor, a second inductor and a third inductor, wherein one end of the first inductor is connected to the first switch component. The second end is connected to the second end, the other end of the first inductor is connected to the third terminal, one end of the second inductor is connected to the second end of the third switch component, the first The other end of the second inductor is connected to the third terminal, one end of the third inductor is connected to the second end of the fifth switch component, and the other end of the third inductor is connected to the first The three terminals are connected.

As a supplement or replacement of the above solution, in the above device, the first switch assembly, the second switch assembly, the third switch assembly, the fourth switch assembly, the fifth switch assembly and the Each of the sixth switch assemblies includes a triode and a diode connected in parallel with each other, wherein one end of the diode is connected to the collector of the triode, and the other end of the diode is connected to the emitter of the triode.

According to another aspect of the present invention, there is provided an electric drive system EDS, the electric drive system comprising the voltage conversion device as previously described.

According to yet another aspect of the present invention, there is provided a charging and driving system for a vehicle, the system comprising: a battery; the electric drive system EDS as previously described; and a switching device configured to The first DC voltage is supplied to the battery when a DC voltage is input, and the second DC voltage is boosted to the first DC via the electric drive system EDS when the second DC voltage is input voltage to supply the battery.

As a supplement or alternative to the above solution, in the above charging and driving system, the switching device is configured to enable the battery to directly supply power to the relevant accessories in the driving mode.

According to yet another aspect of the present invention, there is provided a vehicle including the charging and driving system as previously described.

The voltage conversion scheme of the embodiment of the present invention multiplexes the inverter and the motor winding in the power control unit PEU, and realizes the boosting function from the second DC voltage (for example, 400V) to the first DC voltage (for example, 800V), thereby The lower voltage provided by the external charging pile can be converted into a higher voltage to charge the power battery, which can greatly reduce the cost, weight and space of the vehicle.

The electric drive system EDS of the embodiment of the present invention and the charging and driving system including the EDS have the characteristics of high integration, high efficiency time-sharing and multiplexing, etc., which not only takes into account the infrastructure of different voltage levels on the market, but also protects the high-voltage system of the whole vehicle portability and scalability.

Description of drawings

The above and other objects and advantages of the present invention will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein the same or similar elements are designated by the same reference numerals.

FIG. 1 shows a schematic structural diagram of a voltage conversion device according to an embodiment of the present invention;

FIG. 2 shows a schematic structural diagram of a voltage conversion device operating in a boost mode according to an embodiment of the present invention;

FIG. 3 shows a schematic structural diagram of a voltage conversion device according to an embodiment of the present invention when it operates in a driving mode; and

FIG. 4 shows a schematic structural diagram of a charging and driving system according to an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

In addition, it should be noted that, for the convenience of description, the drawings only show some but not all of the contents related to the present invention. Although example embodiments are described as using multiple units to perform example processes, it should be understood that these example processes may also be performed by one or more modules. Unless specifically mentioned or obvious from context, as used herein, the term "about" is understood to mean within a range of normal tolerance in the art, eg, within 2 standard deviations of the mean.

It should be understood that the term "vehicle" or other similar terms as used herein includes motor vehicles in general, such as passenger cars (including sport utility vehicles, buses, trucks, etc.), various commercial vehicles, and the like, and includes Hybrid electric vehicles, pure electric vehicles, extended-range electric vehicles, etc. A hybrid vehicle is a vehicle that has two or more power sources, such as gasoline-powered and electric vehicles.

Hereinafter, a voltage conversion scheme according to various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a schematic structural diagram of a voltage conversion device 1000 according to an embodiment of the present invention. As shown in FIG. 1 , the voltage conversion apparatus 1000 includes a first terminal P1 , a second terminal P2 , a third terminal P3 , an inverter assembly 100 in a power control unit PEU, and a motor winding 200 .

Power control unit PEU, namely Power Electronic Unit, also known as power electronic unit. The core components of the power control unit PEU of new energy hybrid electric vehicles/pure electric vehicles are IGBT modules or MOSFET modules (ie inverter components), drive control circuits and film capacitors. With the development of technology, the requirements for power density are getting higher and higher, the integration and performance requirements of core components are higher and higher, and the functions of the power electronic controller PEU are also becoming more and more complex. In one embodiment, the power control unit PEU integrates power electronic components such as a drive motor controller, an accessory motor controller, an on-board charger OBC, and a PDU high-voltage power distribution to realize the drive control of the drive motor, steering oil pump motor, and brake air pump motor. , charge the low-voltage small battery on the vehicle, slowly charge, etc., and cooperate with the vehicle control system to realize special functions such as active discharge and limp. Referring to FIG. 1 , the inverter assembly 100 includes a plurality of switch assemblies 110 to 160 , each of which includes a triode and a diode. Of course, those skilled in the art can understand that other elements can be used to form the switch assemblies 110 to 160 , such as IGBT modules or MOSFET modules, etc., which are not limited in the present invention.

In the context of the present invention, motor windings refer to windings mounted on the stator, also referred to as stator windings. The motor winding can be a copper wire wound on the stator, and the winding is a general term for a phase or the entire electromagnetic circuit formed by a plurality of coils or coil groups. As shown in FIG. 1, the motor winding 200 consists of three parallel inductors, namely L1, L2 and L3.

Continuing to refer to FIG. 1 , the inverter assembly 100 in the power control unit PEU is connected to the first terminal P1 and the second terminal P2, and the inverter assembly 100 is used for a first DC voltage (eg, 800V) via the first terminal P1 When inputting with the second terminal P2, the first DC voltage is converted into an AC voltage to drive the motor, and when a second DC voltage (eg 400V) is input via the second terminal P2 and the third terminal P3 The voltage is boosted to a first DC voltage and output via the first terminal P1 and the second terminal P2. In addition, the center point of the motor winding 200 is drawn out and connected to the third terminal P3. In one or more embodiments, the motor windings 200 are Y-connected.

As shown in FIG. 1 , the voltage conversion device 1000 further includes a capacitor C1, one end of the capacitor is connected to the first terminal P1, and the other end is connected to the second terminal P2. In the embodiment of FIG. 1 , the inverter assembly 100 includes a first switch assembly 110 , a second switch assembly 120 , a third switch assembly 130 , a fourth switch assembly 140 , a fifth switch assembly 150 and a sixth switch assembly 160 , The first end of the first switch assembly 110 is connected to the first terminal P1, the second end of the first switch assembly 110 is connected to the first end of the second switch assembly 120, and the second end of the second switch assembly 120 is connected to the first end of the second switch assembly 120. The two terminals P2 are connected, the first end of the third switch assembly 130 is connected to the first terminal P1, the second end of the third switch assembly 130 is connected to the first end of the fourth switch assembly 140, and the second end of the fourth switch assembly 140 is connected to the first end of the fourth switch assembly 140. The terminal is connected to the second terminal P2, the first terminal of the fifth switch component 150 is connected to the first terminal P1, the second terminal of the fifth switch component 150 is connected to the first terminal of the sixth switch component 160, and the sixth switch component 160 The second end is connected to the second terminal P2.

More specifically, referring to FIG. 1 , the first switch assembly 110 includes a triode Q1 and a diode D1 connected in parallel with each other, the second switch assembly 120 includes a triode Q2 and a diode D2 in parallel with each other, and the third switch assembly 130 includes a triode Q3 and a diode D2 connected in parallel with each other. Diode D3, the fourth switch assembly 140 includes a triode Q4 and a diode D4 connected in parallel, the fifth switch assembly 150 includes a triode Q5 and a diode D5 connected in parallel, and the sixth switch assembly 160 includes a triode Q6 and a diode D6 connected in parallel. The collector of the transistor Q1 is connected to the first terminal P1, the emitter of the transistor Q1 is connected to the collector of the transistor Q2, the cathode of the diode D1 is connected to the collector of the transistor Q1, and the anode of the diode D1 is connected to the emitter of the transistor Q1 The emitter of the transistor Q2 is connected to the second terminal P2, the cathode of the diode D2 is connected to the collector of the transistor Q2, the anode of the diode D2 is connected to the emitter of the transistor Q2; the collector of the transistor Q3 is connected to the first terminal P1, the transistor The emitter of Q3 is connected to the collector of the transistor Q4, the cathode of the diode D3 is connected to the collector of the transistor Q3, the anode of the diode D3 is connected to the emitter of the transistor Q3; the emitter of the transistor Q4 is connected to the second terminal P2, and the diode D4 The cathode of the transistor Q4 is connected to the collector of the transistor Q4, the anode of the diode D4 is connected to the emitter of the transistor Q4; the collector of the transistor Q5 is connected to the first terminal P1, the emitter of the transistor Q5 is connected to the collector of the transistor Q6, and the The negative pole is connected to the collector of the transistor Q5, the positive pole of the diode D5 is connected to the emitter of the transistor Q5; the emitter of the transistor Q6 is connected to the second terminal P2, the negative pole of the diode D6 is connected to the collector of the transistor Q6, and the positive pole of the diode D6 is connected to the second terminal P2. The emitter of transistor Q6 is connected.

The motor winding 200 in the embodiment of FIG. 1 includes a first inductor L1 , a second inductor L2 and a third inductor L3 , wherein one end of the first inductor L1 is connected to the second end of the first switching component 110 (ie the triode The emitter of Q1) is connected, the other end of the first inductor L1 is connected to the third terminal P3, one end of the second inductor L2 is connected to the second end of the third switch component 130 (ie the emitter of the transistor Q3), the first The other end of the second inductor L2 is connected to the third terminal P3, one end of the third inductor L3 is connected to the second end of the fifth switch component 150 (ie the emitter of the transistor Q5), and the other end of the third inductor is connected to the second end of the fifth switch component 150 (ie, the emitter of the transistor Q5). The three terminals P3 are connected.

FIG. 2 shows a schematic structural diagram of a voltage conversion device 2000 operating in a boost mode according to an embodiment of the present invention. As shown in FIG. 2 , in the boost mode, the third terminal P3 and the second terminal P2 are used as input terminals (eg, input 400V), and the first terminal P1 and the second terminal P2 are used as output terminals (eg, output 800V). That is to say, the voltage conversion device 2000 shown in FIG. 2 is input from the right side and output from the left side, so that the function of boosting can be realized.

The boosting principle of the voltage conversion device 2000 of the embodiment shown in FIG. 2 is as follows: when the switching transistors (such as the transistors Q2, Q4 and Q6) are turned on, they are equivalent to a wire, and the input DC voltage flows through the inductor. L1, L2 and L3. The functions of the diodes D1, D3 and D5 are to prevent the capacitor C1 from discharging to the ground, and at the same time play the role of freewheeling. Since the input voltage is direct current, the current on the inductor increases linearly at a certain ratio. This ratio is related to the inductance factor. As the inductor current increases, some energy is stored in the inductor.

When the switches (such as transistors Q2, Q4 and Q6) are turned off, since the currents on the inductors L1, L2 and L3 cannot change suddenly, that is to say, the currents flowing through the inductors L1, L2 and L3 will not change immediately. is zero, but slowly changes from the value at the time of charging to zero, which requires a process, and the original circuit loop has been disconnected, so the inductor can only pass through the new circuit (for example, via the third terminal P3, the inductor L1, diode D1, capacitor C1 return to the second terminal P2) to discharge, that is, the inductors L1, L2 and L3 begin to charge the capacitor C1, the voltage across the capacitor C1 increases, and the voltage is higher than the input voltage at this time, the boost During the process, the capacitor C1 should be large enough so that a continuous current can be maintained at the output end (ie, the first terminal P1 and the second terminal P2) during the discharge process.

By repeating the two steps of turning off and turning on the switch, a voltage higher than the input voltage of 400V (for example, 800V) is obtained at both ends of the output (ie, the first terminal P1 and the second terminal P2), so as to achieve a boosted voltage. Function.

Referring to FIG. 3 , FIG. 3 shows a schematic structural diagram of a voltage conversion device 3000 operating in a driving mode according to an embodiment of the present invention. As shown in FIG. 3 , when the voltage conversion device operates in the driving mode, a first DC voltage (eg, 800V) is applied to the first terminal P1 and the second terminal P2, and the third terminal P3 is disconnected. At this time, the inverter assembly composed of the switch assembly (including the transistors Q1 to Q6 and the diodes D1 to D6) can realize the frequency modulation of the 800V DC voltage at the input end into an AC power to supply the electric energy to the motor (or the motor windings L1 to L3) . This can be achieved, for example, by sending control signals to the bases of the transistors Q1 to Q6. As mentioned above, in the context of the present invention, in addition to a triode and a diode, the switch assembly can also be composed of other components, such as an IGBT module or a MOSFET module, which is not limited in the present invention. For example, in an embodiment in which a MOSFET module is used to implement the switching component, the function of frequency-modulating a DC voltage into an AC power can be achieved by applying a control signal to the gate of the MOSFET.

It should be noted that, the voltage conversion devices 1000 to 3000 in the foregoing embodiments may be integrated into the electric drive system EDS. In one embodiment, the electric drive system EDS can be used as the center of energy conversion. In addition to the DC/DC conversion device, the electric drive system EDS is equipped with a copper rotor induction motor, a motor controller and a high-torque gearbox to convert the battery pack. The electrical energy in the car is converted into the mechanical energy required to drive the electric vehicle forward.

In one embodiment, when the external voltage is at the 800V level, the external 800V DC power is connected to the EDS through the 800V+ port (ie the first terminal) and the 400V/800V- port (ie the second terminal). car mode. When the external voltage is 400V level, the external 400V DC power is connected to the EDS through the 400V+ port (ie the third terminal) and the 400V/800V- port (ie the second terminal), and the 400V/800V DC/DC converter integrated in the EDS starts When working, the motor winding is connected into a Y shape, which is used as the energy storage inductor of the DC/DC converter, and the rectifier tube of the EDS inverter is used as the DC/DC switch tube. At this time, the DC/DC converter works in the boost mode, and the external 400V The DC power is boosted to 800V, and then connected to the power battery through the 800V+ port (ie the first terminal) and the 400V/800V- port (ie the second terminal) to charge the battery. It can be seen that the electric drive system EDS can work in the inverter mode and the boost mode, wherein when the vehicle is in the drive mode, the electric drive system is in the inverter mode, and when the vehicle is in the charging mode, the electric drive system is in the charging mode model.

FIG. 4 further shows a schematic structural diagram of a charging and driving system 4000 according to an embodiment of the present invention. As shown in FIG. 4 , the charging and driving system 4000 includes a battery 430 , an electric driving system EDS 410 and a switching device 460 . Wherein, the switching device 460 is configured to provide the first DC voltage to the battery 430 when a first DC voltage is input (eg, 800V), and to supply the battery 430 via the battery when the second DC voltage is input (eg, 400V). The driving system EDS 410 boosts the second DC voltage to the first DC voltage to supply the battery 430 .

In one embodiment, the switching device 460 is further configured to enable the battery 430 to directly supply power to the associated accessory 440 in the drive mode.

Continuing to refer to FIG. 4, in one embodiment, the system includes: an 800V power battery 430, a time-division multiplexed electric drive system EDS 410 (in which a 400V/800V DC/DC converter is integrated), a switching device 460, a high-voltage distribution Box PDU 450, DC charging port 420 and other 800V high voltage accessories 440. The high voltage distribution box PDU 450 is used to switch the first DC voltage and the second DC voltage (eg, 800V and 400V) for charging. In one embodiment, when the voltage of the external charging pile via the DC charging port 420 is at the level of 800V, the switches S1 and S2 in the switch device 460 are closed, and the switches S3 are opened, and the 400V/800V DC/DC integrated in the electric drive system EDS 410 The converter does not work, and the external 800V direct current is directly connected to the power battery to charge the battery 430. In one embodiment, when the voltage of the external charging pile is 400V, the switches S1 and S3 in the switch device 460 are closed, and the switches S2 are opened, and the electric drive system EDS 410 integrates the 400V/800V DC/DC converter to work, and the external The 400V direct current of the charging pile is first boosted to 800V through the DC/DC converter, and then connected to the power battery 430 for charging.

When the whole system is in the driving mode, the switches S1, S2 and S3 in the switching device 460 are all turned off, and the 800V voltage in the power battery 430 directly supplies power to all high-voltage devices including the electric drive system EDS410.

To sum up, the voltage conversion scheme of the embodiment of the present invention multiplexes the inverter and the motor winding in the power control unit PEU, so as to realize the boost from the second DC voltage (for example, 400V) to the first DC voltage (for example, 800V). Function, so that the lower voltage provided by the external charging pile can be converted into a higher voltage to charge the power battery, which can greatly reduce the cost, weight and space of the vehicle.

The electric drive system EDS and the charging and driving system including the EDS according to the embodiments of the present invention can also realize a DC charging system compatible with 400V and 800V without adding an additional DC/DC converter from 400V to 800V, which has a high degree of integration , high-efficiency time-sharing multiplexing and other characteristics, improve the economy of the vehicle, reduce the weight of the vehicle and save space.

Although the foregoing specification describes only some of these embodiments of the present invention, those of ordinary skill in the art will appreciate that the present invention may be embodied in many other forms without departing from the spirit and scope thereof. Accordingly, the examples and embodiments shown are to be regarded as illustrative and not restrictive, and various modifications are possible within the present invention without departing from the spirit and scope of the invention as defined by the appended claims. with replacement.

Claims

A voltage conversion device, characterized in that the device comprises:

a first terminal, a second terminal and a third terminal;

an inverter assembly in the power control unit PEU, connected to the first terminal and the second terminal, the inverter assembly is used for a first direct current voltage via the first terminal and the second terminal The first DC voltage is converted into an AC voltage to drive a motor when input, and is used for boosting the second DC voltage to a desired value when a second DC voltage is input through the second terminal and the third terminal the first DC voltage and output via the first terminal and the second terminal; and

A motor winding connected to the inverter assembly, wherein a center point of the motor winding is connected to the third terminal.
The apparatus of claim 1, wherein the first voltage is 800V and the second voltage is 400V.
The apparatus of claim 1, further comprising: a capacitor having one end connected to the first terminal and the other end connected to the second terminal.
The apparatus of claim 1, wherein the inverter assembly includes a first switch assembly, a second switch assembly, a third switch assembly, a fourth switch assembly, a fifth switch assembly, and a sixth switch assembly, wherein, The first end of the first switch assembly is connected to the first terminal, the second end of the first switch assembly is connected to the first end of the second switch assembly, and the second end of the second switch assembly is connected to the first end of the second switch assembly. The terminal is connected to the second terminal, the first terminal of the third switch component is connected to the first terminal, the second terminal of the third switch component is connected to the first terminal of the fourth switch component, The second end of the fourth switch assembly is connected to the second terminal, the first end of the fifth switch assembly is connected to the first terminal, and the second end of the fifth switch assembly is connected to the first terminal. The first end of the six switch assembly is connected to the second terminal, and the second end of the sixth switch assembly is connected to the second terminal.
5. The apparatus of claim 4, wherein the motor winding includes a first inductor, a second inductor, and a third inductor, wherein one end of the first inductor is connected to the one end of the first switch assembly The second end is connected to the second end, the other end of the first inductor is connected to the third terminal, one end of the second inductor is connected to the second end of the third switch component, the second inductor The other end of the inductor is connected to the third terminal, one end of the third inductor is connected to the second end of the fifth switch component, and the other end of the third inductor is connected to the third terminal connected.
5. The apparatus of claim 4, wherein the first switch assembly, the second switch assembly, the third switch assembly, the fourth switch assembly, the fifth switch assembly, and the sixth switch assembly Each of the switch assemblies includes a triode and a diode connected in parallel with each other, wherein one end of the diode is connected to the collector of the triode and the other end of the diode is connected to the emitter of the triode.
An electric drive system EDS comprising a voltage conversion device as claimed in any one of claims 1 to 6.
A charging and driving system for a vehicle, characterized in that the system comprises:

Battery;

The electric drive system EDS of claim 7; and

a switching device configured to provide the first DC voltage to the battery when a first DC voltage is input, and to supply the first DC voltage to the battery via the electric drive system EDS when the second DC voltage is input The two DC voltages are boosted to the first DC voltage to be supplied to the battery.
9. The system of claim 8, wherein the switching device is configured to cause the battery to directly power an associated accessory in a drive mode.
A vehicle comprising a system as claimed in claim 8 or 9.