CN112224062A

CN112224062A - Energy conversion device, power system and vehicle

Info

Publication number: CN112224062A
Application number: CN201910582157.2A
Authority: CN
Inventors: 刘伟冬; 王超; 王兴辉
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2019-06-30
Filing date: 2019-06-30
Publication date: 2021-01-15
Anticipated expiration: 2039-06-30
Also published as: CN112224062B

Abstract

The application belongs to the technical field of electronics, and especially relates to an energy conversion device, a power system and a vehicle. In the application, by adopting the energy conversion device which comprises the motor coil, the bridge arm converter, the bidirectional bridge arm, the first capacitor, the second capacitor and the bidirectional DC module and integrates the driving and charging functions, the energy conversion device can work in a driving mode, a direct current charging mode and an alternating current charging mode, so that the aim of capacitor multiplexing is fulfilled while the motor driving and battery charging of a vehicle are carried out by adopting the same system, the multiplexing degree of components is high, the system integration level is high, the structure is simple, the system cost is reduced, the system volume is reduced, the voltage at two ends of the first capacitor can be precharged, and the problems of complex structure, low integration level, large volume, high cost and large heat loss during capacitor precharging existing in the overall circuit of the conventional motor driving and charging system are solved.

Description

Energy conversion device, power system and vehicle

Technical Field

The application belongs to the technical field of electronics, especially relates to an energy conversion device, driving system and vehicle.

Background

With the development and rapid popularization of electric vehicles, motor control and battery charging of electric vehicles become more and more important. At present, the motor drive, the ac charging of the battery and the dc charging of the battery of the existing electric vehicle are all separated independently, and in order to ensure the charging power or the normal operation of the drive, a capacitor is usually required to be arranged in the drive circuit, the dc charging circuit and the ac charging circuit.

However, although the above method can effectively ensure the normal operation of the motor driving and the battery charging of the vehicle, the above method has a complicated circuit structure, a low integration level, a large volume and a high cost because the motor driving circuit and the battery charging circuit are independent and irrelevant to each other and each circuit needs to be separately provided with a capacitor.

In addition, in the above method, no matter the capacitor in the driving circuit or the capacitor in the charging circuit, when a current is connected, the capacitor C1 will be charged, and due to the loop impedance at this time, the voltage difference between the connected power supply and the capacitor will be large, so that the circuit will be damaged by an excessive current generated by the circuit. However, although this method can pre-charge the voltage across the capacitor, it increases the circuit cost because it requires an additional contactor and pre-charge resistor; in addition, the principle of the pre-charging method is to convert the current into heat for pre-charging, which causes heat loss.

In summary, the prior art has the problems of complex overall circuit structure, low integration level, large volume, high cost and large thermal loss during capacitor pre-charging of the motor driving and charging system.

Disclosure of Invention

The application aims to provide an energy conversion device, a power system and a vehicle, and aims to solve the problems that the overall circuit of the existing motor driving and charging system is complex in structure, low in integration level, large in size, high in cost and large in heat loss during capacitor pre-charging.

The energy conversion device comprises a motor coil, a bridge arm converter, a bidirectional bridge arm, a first capacitor, a second capacitor and a bidirectional DC module;

the bridge arm converter is respectively connected with the motor coil, the bidirectional bridge arm and the bidirectional DC module;

the motor coil, the bridge arm converter and the bidirectional bridge arm are all connected with an external charging port, and the bridge arm converter and the bidirectional bridge arm are all connected with an external power battery;

the first capacitor is connected with the bidirectional bridge arm in parallel;

the bidirectional DC module comprises a first direct current end and a second direct current end, the first direct current end is connected with the first capacitor, and the second direct current end is connected with an external power battery and the second capacitor;

the motor coil, the bridge arm converter, the first capacitor and the external charging port form a direct current charging circuit to charge an external power battery;

the motor coil, the bridge arm converter, the bidirectional bridge arm, the first capacitor and an external charging port form an alternating current charging circuit to charge an external power battery;

the motor coil, the bridge arm converter, the first capacitor and an external power battery form a motor driving circuit;

the first capacitor, the bidirectional DC module, the second capacitor and the power battery form a voltage pre-charging loop so as to pre-charge the voltage at two ends of the first capacitor when the first capacitor meets a pre-charging condition.

Another objective of the present application is to provide a power system, which includes the above energy conversion device and a control module, wherein when the first capacitor meets a pre-charging condition, the control module controls the energy conversion device to pre-charge the voltage across the first capacitor.

It is also an object of the present application to provide a vehicle including the powertrain described above.

In the application, by adopting the energy conversion device which comprises the motor coil, the bridge arm converter, the bidirectional bridge arm, the first capacitor, the second capacitor and the bidirectional DC module and integrates the driving and charging functions, the energy conversion device can work in a driving mode, a direct current charging mode and an alternating current charging mode, so that the aim of capacitor multiplexing is fulfilled while the motor driving and battery charging of a vehicle are carried out by adopting the same system, the multiplexing degree of components is high, the system integration level is high, the structure is simple, the system cost is reduced, the system volume is reduced, the voltage at two ends of the first capacitor can be precharged, and the problems of complex structure, low integration level, large volume, high cost and large heat loss during capacitor precharging existing in the overall circuit of the conventional motor driving and charging system are solved.

Drawings

Fig. 1 is a schematic block diagram of an energy conversion device according to a first embodiment of the present application;

fig. 2 is a schematic diagram of a partial circuit structure of an energy conversion device according to a second embodiment of the present application;

fig. 3 is a schematic diagram of a partial circuit structure of an energy conversion device according to a third embodiment of the present application;

fig. 4 is a schematic circuit diagram of an energy conversion device according to a fourth embodiment of the present application;

fig. 5 is a schematic circuit diagram of an energy conversion device according to a fifth embodiment of the present application;

fig. 6 is a schematic block diagram of an energy conversion device according to a sixth embodiment of the present application;

fig. 7 is a schematic circuit diagram of an energy conversion device according to a seventh embodiment of the present application;

fig. 8 is a schematic circuit diagram of an energy conversion device according to an eighth embodiment of the present application;

fig. 9 is a schematic timing diagram of the operation of the bridge arm inverter of the energy conversion device shown in fig. 1 to 8;

FIG. 10 is a schematic current path diagram of an energy conversion device according to a ninth embodiment of the present application;

fig. 11 is a schematic view of another current path of an energy conversion device according to a ninth embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

Implementations of the present application are described in detail below with reference to the following detailed drawings:

fig. 1 shows a module structure of a capacitor voltage precharge circuit provided in a first embodiment of the present application, and for convenience of description, only the parts related to this embodiment are shown, and detailed descriptions are as follows:

as shown in fig. 1, the energy conversion device provided by the embodiment of the present application includes a motor coil 11, an arm converter 12, a bidirectional arm 13, a first capacitor C1, a second capacitor C2, and a bidirectional DC module 15.

The bridge arm converter 12 is respectively connected with the motor coil 11, the bidirectional bridge arm 13 and the bidirectional DC module 15;

the motor coil 11, the bridge arm converter 12 and the bidirectional bridge arm 13 are all connected with an external charging port 10, and the bridge arm converter 12 and the bidirectional bridge arm 13 are all connected with an external power battery 200;

a first capacitor C1 is connected in parallel with the bidirectional bridge arm 13;

the bidirectional DC module 15 includes a first DC terminal connected to the first capacitor C1 and a second DC terminal connected to the external power battery 200 and the second capacitor C2.

Specifically, the motor coil 11, the bridge arm inverter 12 and the first capacitor C1 form a dc charging circuit with the external charging port 10 to charge the external power battery 200;

the motor coil 11, the bridge arm converter 12, the bidirectional bridge arm 13 and the first capacitor C1 form an alternating current charging circuit with an external charging port 10 to charge an external power battery 200;

the motor coil 11, the bridge arm converter 12, the first capacitor C1 and the external power battery 200 form a motor driving circuit;

the first capacitor C1, the bidirectional DC module 15, the second capacitor C2, and the power battery 200 form a voltage pre-charging circuit to pre-charge the voltage across the first capacitor C1 when the first capacitor C1 satisfies the pre-charging condition.

Specifically, in the embodiment of the present application, the first capacitor C1 satisfying the precharge condition refers to a state when the vehicle is in the OFF range and the charging gun is detected to be connected, or a state when the vehicle is in the OK range and the vehicle is in driving. Since the first capacitor C1 needs to be precharged with the voltage across the first capacitor C1 in order to reduce the voltage difference between the first capacitor C1 and the power supply (power supply) when the first capacitor C1 is in a charging or driving state; in addition, in implementation, the bidirectional DC module 15 may be implemented by using an existing vehicle-mounted charger.

In the embodiment, the first capacitor, the bidirectional DC module, the second capacitor and the power battery form a voltage pre-charging circuit to pre-charge the voltage at two ends of the capacitor when the capacitor meets the pre-charging condition, and the bidirectional DC module is implemented by using the existing vehicle-mounted charger without resetting an additional circuit to pre-charge the voltage of the capacitor, so that the circuit cost is reduced, the heat loss in the capacitor pre-charging process is eliminated, and the problems of high cost and heat loss in the existing capacitor pre-charging method are solved.

In view of the above, in specific implementation, when the energy conversion device is used for dc charging or ac charging, the energy conversion device may be connected to an external dc power supply or an external ac power supply through the charging port 10, the dc power supply may be a dc power obtained by rectifying an external ac power supply through the charging port, or a dc power input by the external dc power supply through the charging port, the ac power supply may be an ac power obtained by inverting an external dc power supply through the charging port, or an ac power input by the external ac power supply through the charging port, and no specific limitation is made herein.

In addition, when the energy conversion device operates in the dc charging mode or the ac charging mode, the first capacitor C1 may filter the voltage output by the arm converter 12 or the arm converter 12 and the bidirectional arm 13 and may store energy according to the voltage output by the arm converter 12 or the arm converter 12 and the bidirectional arm 13 during the dc charging process or the ac charging process of the power battery 200, so as to complete the dc charging or the ac charging of the battery 200.

In this embodiment, the first capacitor C1 is arranged in the energy conversion device, so that the first capacitor C1 can filter the voltage output by the bridge arm converter 12 or the bridge arm converter 12 and the bidirectional bridge arm 13, and can store energy according to the voltage output by the bridge arm converter 12 or the bridge arm converter 12 and the bidirectional bridge arm 13 to complete direct current charging or alternating current charging of the power battery 200, thereby ensuring that the normal charging function of the energy conversion device is ensured, and other noise waves can not interfere with the charging process; in addition, when the energy conversion device works in the motor driving mode, the first capacitor C1 can be used as a capacitor of a motor controller, so that the first capacitor C1 can be used as a PFC capacitor and can also be used as a capacitor of the motor controller for multiplexing, the utilization rate of electronic elements in the energy conversion device is improved, and the structure of the energy conversion device is simplified.

In addition, it should be noted that, during specific operation, the energy conversion device may not only operate in the driving mode, the dc charging mode and the ac charging mode, but also operate in the dc discharging mode, the ac discharging mode, the driving discharging mode, the emergency mode, and so on, which are not described herein again.

In addition, in the present application, "external battery" and "external charging port" described in the present embodiment are "external" with respect to the energy conversion device, and are not "external" of the vehicle in which the energy conversion device is located.

In this embodiment, by using the energy conversion device integrating the driving and charging functions, which includes the motor coil, the bridge arm converter, the bidirectional bridge arm, the first capacitor, the second capacitor, and the bidirectional DC module, the energy conversion device can operate in the driving mode, the DC charging mode, and the ac charging mode, so that the purpose of capacitor multiplexing is achieved while the motor driving and the battery charging of the vehicle are performed by using the same system.

In addition, because the charging power difference distance between current alternating current charging system and direct current charging system is great between the two, consequently two charging system's circuit topology difference is great, general two systems independent settings, multiplexing degree is lower, and the commonality of the energy conversion device that this application shows is strong, it is no matter to face direct current charging station or alternating current charging station, this energy conversion device all can charge, the system cost has been reduced, the system volume has been reduced, the problem that current alternating current charging system and direct current charging system overall structure are complicated has been solved, multiplexing degree is low.

Further, the bridge arm converter 12 can realize bidirectional current conversion, and when the energy conversion device works in a driving mode, the bridge arm converter 12 serves as a three-phase inversion function to realize the function of the motor controller. When the energy conversion device operates in the ac charging mode, the bridge arm converter 12 performs rectification and power correction functions, and when the energy conversion device operates in the dc charging mode, the bridge arm converter 12 performs a dc boosting function.

In the related art, an alternating current charging module is required for realizing alternating current charging, a direct current charging module is required for realizing direct current charging, an inverter module is required for realizing motor driving, and none of the related technologies integrates the three functions into one module, so that the circuit structure is complex, the integration level is low, the size is large, and the cost is high. The three functions are creatively integrated in the same circuit, the function multiplexing of a plurality of components is realized, and after the functions are integrated, the split type product with mutually independent current charging module, alternating current charging module and inversion module is compared.

Further, the motor coil 11, the bridge arm converter 12 and the bidirectional bridge arm 13 realize function multiplexing. In the motor driving circuit, a motor coil 11 is used for generating induced electromotive force after being electrified, and a bridge arm converter 12 is used for realizing a three-phase inversion function; in the ac charging circuit, the motor coil 11 functions as an inductor in the PFC circuit, the leg converter 12 functions as one leg in the PFC circuit, and the bidirectional leg 13 functions as the other leg in the PFC circuit; in the DC charging circuit, the motor coil 11 functions as a boost inductor in the boost DC on the one hand and reduces ripple in the circuit on the other hand, and the arm converter 12 functions as an arm in the boost DC.

In addition, in the prior art, the alternating current charging system and the direct current charging system are independently arranged, the multiplexing degree is low, the two systems are large in size and high in cost, the energy conversion device can realize the alternating current charging function and the direct current charging function, and the function multiplexing is realized, namely, the motor coil and the bridge arm converter participate in alternating current charging and direct current charging, the multiplexing of components is realized, and the problems of complex structure, low multiplexing degree, high cost and large size in the prior art are solved through the function multiplexing and the component multiplexing.

Further, since a household socket is generally used for ac charging, a power of a commonly used ac power source is generally seven kilowatts (kW), and a professional charging pile is generally used for dc charging, a power of the professional charging pile is generally 60kW to 150kW, and a rapid dc charging pile larger than 100kW is a development trend, and in addition, a power of a motor driving is generally about 100kW, it can be known from the above description that power levels of a vehicle in three cases of motor driving, dc charging, and ac charging are greatly different, and the power difference is very important for selecting a switching tube.

For the switching tubes, since the high-power switching tube is more expensive than the low-power switching tube, based on the consideration of different powers required when the energy conversion device works in the motor driving mode, the direct-current charging mode and the alternating-current charging mode, the type of the switching tube in the bridge arm converter 12 is different from that of the switching tube in the bidirectional bridge arm 13, that is, the bidirectional bridge arm 13 and the bridge arm converter 12 use switching tubes with different power levels, in one embodiment, the power level of the switching tube used by the bridge arm converter 12 is greater than that of the switching tube used by the bidirectional bridge arm 13. For example: among the same type of switching tubes, the bridge arm converter 12 adopts a high-current-level MOSFET switching tube, and the bidirectional bridge arm 13 adopts a low-current-level MOSFET switching tube; or for example: among the different types of switching tubes, the bridge arm converter 12 adopts a high-power IGBT switching tube, and the bidirectional bridge arm 13 adopts a low-power MOSFET switching tube. Specifically, in the present embodiment, since the bridge arm converter 12 is used in the high-power modes such as the dc charging and the motor driving, the bridge arm converter 12 in the present embodiment is implemented by using the high-power IGBT switching tube or the high-current MOSFET switching tube, and since the bidirectional bridge arm 13 mainly works during the ac charging, the bidirectional bridge arm 13 can be implemented by using the low-power MOSFET, so that the effective work of the energy conversion device is ensured, and the circuit cost can be reduced.

On the other hand, when ac charging is performed, the switching frequency required by the bidirectional arm 13 is high (for example, 60kHz), so that it is necessary to use a MOSFET switching tube or a silicon carbide MOSFET switching tube that can realize high-frequency operation, and since the arm converter 12 has a three-phase arm and its operation mode is three-phase interleaved control, the frequency required by the switching tube of the arm converter 12 is low, so the type of the switching tube in the arm converter 12 is different from the type of the switching tube in the bidirectional arm 13, for example: the switching tube type in the bridge arm converter 12 is an IGBT switching tube with high efficiency in low-frequency operation.

In addition, when the energy conversion device operates in an ac charging mode or a dc charging mode, the three-phase interleaved control operation mode adopted by the bridge arm converter 12 can reduce the dc-side ripple and increase the charging power when the energy conversion device is charging.

When the energy conversion device is used for testing the alternating current and direct current charging performance, the inventor proposes a design concept of improving the overall inductance of the energy conversion device to improve the charging efficiency, and finds that improving the inductance of a motor coil is one of feasible ways by researching the structure of the motor.

Further, as an embodiment of the present application, as shown in fig. 2, the motor coil 11 includes three-phase windings, each phase winding includes N coil branches, first ends of the N coil branches in each phase winding are connected to the bridge arm converter 12 after being connected in common, second ends of the N coil branches in each phase winding are connected to second ends of the N coil branches in the other two-phase windings in a one-to-one correspondence manner to form N neutral points, and the charging port 10 is connected to the M neutral points; wherein N is an integer greater than 1, and M is a positive integer less than N.

Specifically, in fig. 2, a specific structure of the motor coil 11 of the present application is described by taking an example where M is 2 and N is 4, that is, two neutral points among four neutral points are connected to the charging port 10; in the present embodiment, the number of coil branches included in each phase winding of the motor coil 11 is described by taking 4 as an example, and the number of coil branches is not limited to a specific number.

The three-phase winding of the motor coil 11 will be described in detail below by way of specific examples, as follows:

specifically, as shown in fig. 2, the motor coil 11 includes a U-phase winding, a V-phase winding, and a W-phase winding, and each of the U-phase winding, the V-phase winding, and the W-phase winding includes N coil branches.

Further, as shown in fig. 2, first ends of N coil branches in the U-phase winding are connected to a first phase bridge arm of the bridge arm converter 12 after being connected in common, first ends of N coil branches in the V-phase winding are connected to a second phase bridge arm of the bridge arm converter 12 after being connected in common, first ends of N coil branches in the W-phase winding are connected to a third phase bridge arm of the bridge arm converter 12 after being connected in common, and second ends of N coil branches in each of the U-phase winding, the V-phase winding and the W-phase winding are connected to second ends of N coil branches in other two-phase windings in one-to-one correspondence, so as to form N neutral points N1, N2 and N3., and the N neutral points may be directly connected to the charging port 10 or may be connected to the charging port 10 through other connecting circuits, which is exemplified in this embodiment by that M neutral points of the N neutral points are directly connected to the charging port 10, and the connection circuit will be described in detail later, and will not be described in detail here.

In this embodiment, compare all neutral points of motor coil and all be connected with the mouth that charges, in this embodiment, be connected partial neutral point with the mouth that charges, lead to parallelly connected motor coil to reduce, motor coil's equivalent inductance increases, and energy conversion device's whole inductance increases to charging efficiency has been promoted.

In another embodiment, the inventor comprehensively considers the factors of charging power and charging efficiency, the charging power is positively correlated with the overcurrent capacity of the motor coils, and the more the motor coils are connected in parallel, the stronger the overcurrent capacity is; the charging efficiency is inversely related to the inductance of the motor coil, and the fewer the motor coils are connected in parallel, the greater the inductance of the motor coil is. This embodiment is through adopting every phase winding all to include the motor coil 11 of N coil branch road for this energy conversion device can realize direct current charging or alternating current charging under the different power through the inductance value that changes motor coil 11, and then realizes the purpose that this energy conversion device's charging power accessible inductance value was adjusted.

Further, as an embodiment of the present application, as shown in fig. 3, the energy conversion apparatus further includes a neutral switch 130. Neutral point switch 130 controls M neutral points among N neutral points of motor coil 11 to be connected to charging port 10.

In specific implementation, the neutral point switch 130 may be implemented by N single-pole single-throw switches, or may be implemented by a plurality of single-pole double-throw switches. When the neutral point switch 130 is implemented by N single-pole single-throw switches, first ends of the N single-pole single-throw switches are connected to N neutral points of the motor coil 11 in a one-to-one correspondence, and second ends of the N single-pole single-throw switches are connected to the charging port 10. When the neutral point switch 10 is implemented by using a plurality of single-pole double-throw switches, the moving ends of the plurality of single-pole double-throw switches are all connected with the charging port 10, and the two fixed ends of each single-pole double-throw switch are correspondingly connected with two neutral points in the motor coil 11 one by one according to requirements. In addition, the neutral point switch 10 can also be implemented by a single-pole multi-throw switch, a moving end of the single-pole multi-throw switch is connected with the charging port 10, and stationary ends of the single-pole multi-throw switch are respectively connected with the neutral points in the motor coils 11 in a one-to-one correspondence manner according to requirements.

In this embodiment, the neutral point switch 130 is added to the energy conversion device, and the neutral point switch is selectively turned on and off, so that the neutral point switch 130 connects the charging port 10 with M neutral points of N neutral points of the motor coil 11, and the energy conversion device is further facilitated to turn on or off the switches of the neutral point switch 130 as required, so that different numbers of coil branches are selected from three-phase windings of the motor coil 11, and thus the adjustment of the charging power is realized.

Further, as an embodiment of the present application, as shown in fig. 4, the energy conversion apparatus further includes a switch module 14.

One end of the switch module 14 is connected to the charging port 10, the other end is connected to the motor coil 11, the bridge arm converter 12, and the bidirectional bridge arm 13, and the switch module 14 is configured to switch a driving mode, a dc charging mode, and an ac charging mode.

In this embodiment, the switch module 14 is added to the energy conversion device, so that the switch module 14 can facilitate the energy conversion device to switch among the driving mode, the dc charging mode and the ac charging mode, thereby effectively preventing the energy conversion device from failing due to the failure of the energy conversion device in accurate mode switching, and improving the reliability of the energy conversion device.

Further, as an embodiment of the present application, as shown in fig. 4, the charging port 10 includes a dc charging port 101 and an ac charging port 102; the switch module 14 includes a first switch unit 141 and a second switch unit 142.

The direct-current charging port 101, the first switching unit 141, the motor coil 11, the arm converter 12 and the power battery 200 form a direct-current charging circuit; ac charging port 102, second switching unit 142, motor coil 11, arm converter 12, bidirectional arm 13, and power battery 200 form an ac charging circuit.

In this embodiment, by using the charging port 10 formed by the dc charging port 101 and the ac charging port 102 and using the switch module 14 formed by the first switch unit 141 and the second switch unit 142, when the energy conversion device operates in the dc charging mode or the ac charging mode, the energy conversion device has charging circuits corresponding to different modes, and thus the dc charging circuit and the ac charging circuit do not interfere with each other, and the circuit has strong reliability and high stability.

Further, as an embodiment of the present application, as shown in fig. 4, the first switching unit 141 includes a first switch K1 and a second switch K2, one end of the first switch K1 is connected to the dc charging port 101, and the other end is connected to the motor coil 11; one end of the second switch K2 is connected to the dc charging port 101, and the other end is connected to the bridge arm converter 12; the second switch unit 142 includes a third switch K3 and a fourth switch K4, one end of the third switch K3 is connected to the ac charging port 102, the other end is connected to the motor coil 11, one end of the fourth switch K4 is connected to the ac charging port 102, the other end is connected to the bidirectional arm 13, and specifically, the second switch K3526 is connected to a midpoint of the bidirectional arm 13.

Specifically, referring to fig. 4 again, in this embodiment, in an implementation, the first switch K1, the second switch K2, the third switch K3, and the fourth switch K4 are implemented by single-pole single-throw switches, a first end of the first switch K1 and a first end of the second switch K2 are connected to the dc charging port 101, a second end of the first switch K1 is connected to the neutral point of the motor coil 11, and a second end of the second switch K2 is connected to the negative end of the bridge arm inverter 12. Similarly, a first terminal of the third switch K3 and a first terminal of the fourth switch K4 are connected to the ac charging port 102, a second terminal of the third switch K3 is connected to the neutral point of the motor coil 11, and a second terminal of the fourth switch K4 is connected to the midpoint of the bidirectional arm 13.

In specific implementation, when the energy conversion device works in the driving mode, the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4 are all turned off, and at this time, the power battery 200, the bridge arm inverter 12 and the motor coil 11 form a motor driving loop; when the energy conversion device works in a direct-current charging mode, the first switch K1 and the second switch K2 are closed, the third switch K3 and the fourth switch K4 are opened, and at the moment, the direct-current charging port 101, the first switch K1, the second switch K2, the motor coil 11, the bridge arm converter 12 and the power battery 200 form a direct-current charging loop; when the energy conversion device works in an alternating current charging mode, the third switch K3 and the fourth switch K4 are closed, the first switch K1 and the second switch K2 are opened, and at the moment, the alternating current charging port 101, the third switch K3 and the fourth switch K4, the motor coil 11, the bridge arm converter 12, the bidirectional bridge arm 13 and the power battery 200 form an alternating current charging loop.

Further, as another embodiment of the present application, as shown in fig. 5, the charging port 10 includes an ac/dc charging port, and the switch module 14 includes a third switch unit 143 and a fourth switch unit 144. One end of the third switching unit 143 is connected to the ac/dc charging port 103, the other end is connected to the motor coil 11, one end of the fourth switching unit 144 is connected to the ac/dc charging port 103, and the other end of the fourth switching unit 144 is connected to the bridge arm converter 12 or the bidirectional bridge arm 13.

In a specific implementation, a first end of the third switching unit 143 is connected to the ac/dc charging port 103, a second end of the third switching unit 143 is connected to the neutral point of the motor coil 11, one end of the fourth switching unit 144 is connected to the ac/dc charging port 103, and the other end of the fourth switching unit is selectively connected to the negative end of the bridge arm converter 12 or the midpoint of the bidirectional bridge arm 13.

Further, when the fourth switching unit 144 is connected to the bridge arm converter 12, the ac/dc charging port 103, the third switching unit 143, the fourth switching unit 144, the motor coil 11, the bridge arm converter 12, and the power battery 200 form a dc charging circuit; when the fourth switching unit 144 is connected to the bidirectional arm 13, the ac/dc charging port 103, the third switching unit 143, the fourth switching unit 144, the motor coil 11, the arm converter 12, the bidirectional arm 13, and the power battery 200 form an ac charging circuit.

In this embodiment, by using the charging port 10 formed by the ac/dc charging port 103 and the switch module 14 formed by the third switch unit 143 and the fourth switch unit 144, when the energy conversion device operates in the dc charging mode or the ac charging mode, the external ac power or the dc power can provide charging energy to the energy conversion device through the ac/dc charging port 10, and the fourth switch unit 144 enables the energy conversion device to have the dc charging circuit or the ac charging circuit corresponding to different modes, so that the dc charging circuit and the ac charging circuit do not interfere with each other, and the circuit reliability is high, the stability is high, and the circuit integration level is high.

Further, as an embodiment of the present application, as shown in fig. 5, the third switching unit 143 includes a fifth switch K5, one end of the fifth switch K5 is connected to the ac/dc charging port 103, and the other end is connected to the neutral point of the motor coil 11. The fourth switch unit 144 includes a single-pole double-throw switch K6, the single-pole double-throw switch K6 includes a moving end and two immobile ends, the moving end is connected with the ac/dc charging port 103, one immobile end is connected with the bridge arm converter 12, and the other immobile end is connected with the midpoint of the bidirectional bridge arm 13; alternatively, the fourth switching unit 144 includes two switches, one end of one switch is connected to the ac/dc charging port 103, and the other end is connected to the bridge arm converter 12; one end of the other switch is connected with the alternating current/direct current charging port 103, and the other end is connected with the bidirectional bridge arm 13.

It should be noted that fig. 5 illustrates that the fourth switch unit 144 is implemented by using a single-pole double-throw switch K6, and when the fourth switch unit 144 is implemented by using two single-pole single-throw switches, first ends of the two single-pole single-throw switches are both connected to the ac/dc charging port, a second end of the first single-pole single-throw switch is connected to the negative end of the bridge arm converter 12, and a second end of the second single-pole single-throw switch is connected to the midpoint of the bidirectional bridge arm 13.

In addition, in specific implementation, when the energy conversion device operates in the driving mode, the fifth switch K5 and the single-pole double-throw switch are both turned off, and at this time, the power battery 200, the bridge arm converter 12 and the motor coil 11 form a motor driving circuit; when the energy conversion device works in a direct-current charging mode, the fifth switch K5 is closed, the first fixed end of the single-pole double-throw switch K6 is closed, and at the moment, the alternating-current/direct-current charging port 103, the fifth switch K5, the single-pole double-throw switch K6, the motor coil 11, the bridge arm converter 12 and the power battery 200 form a direct-current charging loop; when the energy conversion device works in an alternating current charging mode, the fifth switch K5 is closed, and the second stationary end of the single-pole double-throw switch is closed, so that the alternating current/direct current charging port 103, the fifth switch K5, the single-pole double-throw switch K6, the motor coil 11, the bridge arm converter 12, the bidirectional bridge arm 13 and the power battery 200 form an alternating current charging loop.

In this embodiment, the switch K5 and the single-pole double-throw switch K6 are adopted, so that the switch K5 and the single-pole double-throw switch K6 can replace the first switch K1 to the fourth switch K4 in another embodiment, and further, when switching among the driving mode, the direct-current charging mode and the alternating-current charging mode is realized, electronic components used by the switch module 14 are reduced, so that the number of electronic components of the energy conversion device is reduced, the cost of the energy conversion device is reduced, and meanwhile, the circuit structure is simpler.

As an embodiment of the present invention, as shown in fig. 6, the switch module further includes a fifth switch unit 145, one end of the fifth switch unit 145 is connected to the battery 200, and the other end is connected to the arm converter 12 and the bidirectional arm 13, respectively.

In the present embodiment, the fifth switching unit 145 is additionally provided in the switching module, and the power battery 200 is connected to the arm converter 12 and the bidirectional arm 13 through the fifth switching unit 145, so that when the front-end circuit fails (for example, when any one of the switching module 14, the motor coil 11, the arm converter 12, and the bidirectional arm 13 fails), the energy conversion device can prevent the power battery 200 from being damaged by controlling the fifth switching unit 145, thereby improving the service life of the power battery 200.

Further, as an embodiment of the present application, as shown in fig. 7, the fifth switching unit 145 includes a switch K7 and a switch K8. The first end of the switch K7 is connected with the negative end of the power battery 200, the first end of the switch K8 is connected with the negative end of the power battery 200, the second end of the switch K7 is connected with the positive end of the bridge arm converter 12 and the positive end of the bidirectional bridge arm 13, and the second end of the switch K8 is connected with the negative end of the bridge arm converter 12 and the negative end of the bidirectional bridge arm 13.

Further, as an embodiment of the present invention, as shown in fig. 6, the bidirectional DC module 15 includes a first inverter 151, a second inverter 152, and a transformation unit 154, a primary side and a first secondary side of the transformation unit 154 are respectively connected to the first inverter 151 and the second inverter 152, the first inverter 151 is connected in parallel to a first capacitor C1, the second inverter 152 is connected in parallel to the power battery 200 and a second capacitor C2, and the first capacitor C1, the first inverter 151, the second inverter 152, the transformation unit 154, the second capacitor C2, and the power battery 200 form a voltage pre-charging circuit.

In the embodiment, the bidirectional DC module including the first converter, the second converter, and the transforming unit enables the first capacitor, the first converter, the second converter, the transforming unit, the second capacitor, and the power battery to form the voltage pre-charging circuit, so that the first capacitor C1 is pre-charged with voltage, and the circuit is simple in structure, easy to implement, and low in cost.

Further, as an embodiment of the present application, as shown in fig. 7, the first converter 151 includes a first switching element Q3, a second switching element Q4, a third switching element Q5, a fourth switching element Q6, a first inductor L1, and a third capacitor C3; a first terminal of the first switching element Q3 is connected to a first terminal of the third switching element Q5 and a first terminal of the first capacitor C1, a second terminal of the first switching element Q3 is connected to a first terminal of the second switching element Q4 and a first terminal of the third capacitor C3, a second terminal of the third element Q5 is connected to a first terminal of the fourth switching element Q6 and a first terminal of the first inductor L1, a second terminal of the first inductor L1 and a second terminal of the third capacitor C3 are both connected to the primary side of the transforming unit 154, and a second terminal of the second switching element Q4 is connected to a second terminal of the fourth switching element Q6 and a second terminal of the first capacitor C1.

In a specific implementation, each of the switching elements included in the first converter may be implemented by a device capable of performing a switching operation, such as a power Transistor, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), and other switching devices.

Further, as an embodiment of the present application, as shown in fig. 7, the second converter 152 includes a fifth switching element Q7, a sixth switching element Q8, a seventh switching element Q9, an eighth switching element Q10, a second inductor L2, and a fourth capacitor C4; a first end of the fifth switching element Q7 is connected to the first end of the seventh switching element Q9, the first end of the second capacitor C2 and the positive terminal of the power battery 200, a second end of the seventh switching element Q9 is connected to the first end of the eighth switching element Q10 and the first end of the fourth capacitor C4, a second end of the fifth switching element Q7 is connected to the first end of the sixth switching element Q8 and the first end of the second inductor L2, a second end of the second inductor L2 and a second end of the fourth capacitor C4 are both connected to the primary side of the transformer unit 154, and a second end of the sixth switching element Q8 is connected to the second end of the eighth switching element Q10, the second end of the second capacitor C2 and the negative terminal of the power battery 200.

In a specific implementation, each of the switching elements included in the third converter may be implemented by a device capable of performing a switching operation, such as a power Transistor, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), and other switching devices.

Specifically, during operation, the first capacitor C1, the third switching element Q5, the second switching element Q4, the voltage transforming unit 154, the fifth switching element Q7, the eighth switching element Q10, the second capacitor C2 and the power battery 200 form a first voltage pre-charging circuit, the first capacitor C1, the first switching element Q3, the fourth switching element Q6, the voltage transforming unit 154, the sixth switching element Q8, the seventh switching element Q9, the second capacitor C2 and the power battery 200 form a second voltage pre-charging circuit, the first voltage circuit is pre-charged in the first pre-charging state, the second voltage pre-charging circuit is pre-charged in the second pre-charging state, and the first pre-charging circuit and the second voltage pre-charging circuit alternately operate to pre-charge the voltage across the first capacitor C1.

In the embodiment, the first voltage pre-charging circuit and the second voltage pre-charging circuit alternately operate between the first pre-charging state and the second pre-charging state, so that the voltage transformation unit induces a current, and the voltage at two ends of the first capacitor C1 is pre-charged by charging the first capacitor C1 with the current, thereby increasing the pre-charging speed, reducing the heat loss, and improving the energy utilization rate.

Further, as an embodiment of the present application, as shown in fig. 6, the bidirectional DC module 15 further includes a third converter 153. The third inverter 153 is connected to the second secondary side of the voltage transforming unit 154, and is connected to an external battery or a vehicle-mounted discharge port.

In this embodiment, the bidirectional DC module 15 including the first converter 151, the second converter 152, the voltage transforming unit 154 and the third converter 153 is adopted, so that the bidirectional DC module 15 can be connected with the battery and the vehicle-mounted discharge port through the third converter 153, and the energy conversion device can be driven by the energy provided by the battery, or power is supplied to an external device through the vehicle-mounted discharge port, thereby enriching the working mode of the energy conversion device and improving the application range of the energy conversion device.

Further, as an embodiment of the present application, as shown in fig. 6, the third converter 153 includes a first sub-converter 153a and a second sub-converter 153b, and the first sub-converter 153a and the second sub-converter 153b are both connected to the second sub-side of the voltage transformation unit 154.

Specifically, the operation mode of the third converter 153 includes a first state in which the first sub-converter 153a and the second sub-converter 153b operate simultaneously, and a second state in which the first sub-converter 153a and the second sub-converter 153b operate in a switching manner. That is, when the third converter 153 operates, the first sub-converter 153a inside thereof may function as a converter alone for use, or the second sub-converter 153b may function as a converter alone for use, or the first sub-converter 153a and the second sub-converter 153b may operate simultaneously to perform a converter function of the third converter 153.

In this embodiment, the third converter 153 is implemented by using the first sub-converter 153a and the second sub-converter 152b, so that when the energy conversion device works, any one of the first sub-converter 153a and the second sub-converter 152b can complete the function of the third converter 153, and further, when any one of the first sub-converter 153a and the second sub-converter 152b fails, the energy conversion device is not affected; in addition, when the first sub-converter 153a and the second sub-converter 152b simultaneously perform the function of the third converter 153, the rectification capability of the third converter 153 may be enhanced.

Further, as an embodiment of the present invention, as shown in fig. 7, the first sub-converter 153a includes a ninth switching element Q11 and a tenth switching element Q12, a first end of the ninth switching element Q11, a first end of the tenth switching element Q12, and a positive end (or a vehicle-mounted discharge port) of the battery are connected to the secondary side of the transformer unit 154, and a second end of the ninth switching element Q11 and a second end of the tenth switching element Q12 are connected to the negative end or the vehicle-mounted discharge port of the battery 300.

Similarly, in a specific implementation, the ninth switching element Q11 and the tenth switching element Q12 included in the first sub-converter may be implemented by devices capable of performing switching operations, such as switching devices, for example, a power Transistor, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), and the like.

As an embodiment of the present invention, as shown in fig. 7, the second sub-converter 153b includes an eleventh switching element Q13 and a twelfth switching element Q14, a first end of the eleventh switching element Q13, a first end of the twelfth switching element Q14, and a positive end (vehicle-mounted discharge port) of the battery 300 are connected to the secondary side of the transformer unit 154, and a second end of the eleventh switching element Q13 and a second end of the twelfth switching element Q14 are connected to the negative end or the vehicle-mounted discharge port of the battery 300.

In specific implementation, the eleventh switching element Q13 and the twelfth switching element Q14 included in the second sub-converter may be implemented by devices capable of performing switching operations, such as a power Transistor, a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), an Insulated Gate Bipolar Transistor (IGBT), and other switching devices.

Further, as an embodiment of the present application, as shown in fig. 6, the switch module further includes a sixth switch unit 146, one end of the sixth switch unit 146 is connected to the second inverter 152, and the other end of the sixth switch unit 146 is connected to the power battery 200.

In this embodiment, the sixth switching unit 146 is additionally arranged in the switching module, so that the sixth switching unit 146, the charging port 10, the motor coil 11 and the bidirectional DC module 15 in the energy conversion device form another ac or DC charging circuit, thereby enriching the ac/DC charging mode of the energy conversion device, and when the energy conversion device is performing DC charging, not only isolated DC charging can be performed, but also non-isolated DC charging can be performed, and further the charging process of the energy conversion device can be redundant in multiple schemes, thereby improving the safety of the energy conversion device in the ac charging process.

Further, as an embodiment of the present application, as shown in fig. 7, the sixth switching unit 146 includes a switch K9 and a switch K10. Wherein the first terminal of the switch K9 is connected to the positive terminal of the power battery 200, the first terminal of the switch K10 is connected to the negative terminal of the battery 200, the second terminal of the switch K9 is connected to the second DC terminal of the bi-directional DC module 15, and the second terminal of the switch K10 is connected to the second DC terminal of the bi-directional DC module 15.

Further, as an embodiment of the present application, as shown in fig. 8, the energy conversion apparatus further includes a voltage inductor L, one end of which is connected to the charging port 10, and the other end of which is connected to the motor coil 11.

Specifically, as an embodiment of the present application, as shown in fig. 8, a first end of an inductor L is connected to the second end of the switch K1 and the second end of the switch K3, and the second end of the inductor L is connected to a neutral point of a three-phase winding of the motor coil 11.

Specifically, in the dc charging mode, the charging port 10, the inductor L, the motor coil 11, and the bridge arm converter 12 form a dc charging circuit for the power battery 200;

in the ac charging mode, the charging port 10, the inductor L, the motor coil 11, the arm converter 12, and the bidirectional arm 13 form an ac charging circuit for the power battery 200.

In this embodiment, when the energy conversion device operates in the ac charging mode, the inductor L and the bidirectional bridge arm 13 cooperate to convert the ac power received by the charging port 10 into the target voltage and then perform ac charging on the battery 200, that is, in the charging process of the battery 200, when an ideal voltage needs to be output to charge the battery 200, the output voltage in the charging process can be adjusted through the combined action of the inductor L and the bidirectional bridge arm 13, so as to ensure the voltage conversion function of the energy conversion device.

Further, as an embodiment of the present application, as shown in fig. 7 or fig. 8, the energy conversion apparatus further includes a switch K11 and a resistor R1, and the switch K11 and the resistor R1 form a pre-charge module to pre-charge the switch K7 and the switch K9 when the energy conversion apparatus is in operation, so as to prevent the switch K7 and the switch K9 from malfunctioning, thereby reducing the failure rate of the energy conversion apparatus.

Specifically, as shown in fig. 7 or 8, the first terminal of the switch K11 is connected to the second terminal of the switch K7, the second terminal of the switch K11 is connected to the second terminal of the switch K9 and the first terminal of the resistor R1, and the second terminal of the resistor R1 is connected to the first terminal of the switch K7, the first terminal of the switch K9, and the positive terminal of the battery 200.

Further, as an embodiment of the present invention, as shown in fig. 7 or 8, the bridge arm converter 12 in the energy conversion device includes a three-phase bridge arm formed by a first power switch cell 1 and a second power switch cell 2 connected in series, a third power switch cell 3 and a fourth power switch cell 4 connected in series, and a fifth power switch cell 5 and a sixth power switch cell 6 connected in series.

Specifically, the first end of the first power switch unit 1, the first end of the third power switch unit 3 and the first end of the fifth power switch unit 5 are connected in common to form a positive end of the bridge arm converter 12, and the positive end of the bridge arm converter 12 is connected with the positive end of the bidirectional bridge arm 13;

the second end of the second power switch unit 2, the second end of the fourth power switch unit 4 and the second end of the sixth power switch unit 6 are connected together to form a negative end of the bridge arm converter 12, and the negative end of the bridge arm converter 12 is connected with the negative end of the bidirectional bridge arm 13;

the connection point of the second end of the first power switch unit 1 and the first end of the second power switch unit 2 is connected with the first phase coil of the motor coil 11, the connection point of the second end of the third power switch unit 3 and the first end of the fourth power switch unit 4 is connected with the second phase coil of the motor coil 11, and the connection point of the second end of the fifth power switch unit 5 and the first end of the sixth power switch unit 6 is connected with the third phase coil of the motor coil 11.

In the embodiment of the present application, the plurality of power switch cells in the bridge arm converter 12 may be implemented by devices that are connected in parallel with diodes and can perform switching operations, such as power transistors, Metal-Oxide-Semiconductor Field-Effect transistors (MOSFETs), Insulated Gate Bipolar Transistors (IGBTs), and other switching devices.

Further, when the bridge arm converter 12 works, the power switch unit in the first phase bridge arm, the power switch unit in the second phase bridge arm and the power switch unit in the third phase bridge arm sequentially receive the control signals with the preset phase difference to enter a three-phase staggered control mode; it should be noted that, in the present embodiment, the preset phase is preferably 120 degrees, and the preferred angle does not limit the preset phase.

Specifically, when the bridge arm converter 12 is in operation, as can be seen from the operation timing chart shown in fig. 9, the control signal PWM1 controls the on/off of the first power switch unit 1 and the second power switch unit 2 in the first phase bridge arm in the bridge arm converter 12, and controls the first power switch unit 1 to be turned on and the second power switch unit 2 to be turned off when the control signal PWM1 is at a high level, and controls the second power switch unit 2 to be turned on and the first power switch unit 1 to be turned off when the control signal PWM1 is at a low level; after a preset phase difference from the control signal PWM1, the control signal PWM2 controls the third power switch unit 3 and the fourth power switch unit 4 in the second phase arm of the arm converter 12 to be turned on and off, and controls the third power switch unit 3 to be turned on and the fourth power switch unit 4 to be turned off at the high level of the control signal PWM2, and controls the fourth power switch unit 4 to be turned on and the third power switch unit 3 to be turned off at the low level of the control signal PWM 2; and after a preset phase difference from the control signal PWM2, the control signal PWM3 controls the fifth power switch unit 5 and the sixth power switch unit 6 in the third phase arm of the arm converter 12 to be turned on and off, controls the fifth power switch unit 5 to be turned on and the sixth power switch unit 6 to be turned off when the control signal PWM3 is at a high level, and controls the sixth power switch unit 6 to be turned on and the fifth power switch unit 5 to be turned off when the control signal PWM3 is at a low level, thereby implementing three-phase interleaved control of the arm controller 120.

In this embodiment, a three-phase interleaved control operation mode is adopted to control a three-phase bridge arm of the bridge arm converter 12, so that when the energy conversion device is charged, an equivalent inductance value is effectively increased, and further, the charging power is increased, and an inductance L does not need to be added to the energy conversion device, so that the number of electronic components in the energy conversion device is reduced, and the cost of the energy conversion device is reduced.

Further, as an embodiment of the present application, as shown in fig. 7 or fig. 8, bidirectional arm 13 in the energy conversion device includes a seventh power switch unit Q1 and an eighth power switch unit Q2 connected in series; the first end of the seventh power switch unit Q1 is the positive end of the bidirectional arm 13, the second end of the eighth power switch unit Q2 is the negative end of the bidirectional arm 13, and the connection point between the second end of the seventh power switch unit Q1 and the first end of the eighth power switch unit Q2 is the midpoint of the bidirectional arm 13.

The operation principle of the energy conversion device provided by the present application in different embodiments is specifically described below by taking the circuits shown in fig. 7 and fig. 8 as an example, and the following details are described below:

specifically, as shown in fig. 8, when the energy conversion device operates in the dc charging mode, and the dc charging mode is non-isolated dc charging, the first switch K1, the second switch K2, the switch K11, the switch K7, and the switch K8 are closed, and the other switch elements K3, K4, K9, and K10 are opened, at this time, the dc voltage received by the dc charging port 101 is boosted through the inductor L, the three-phase winding U, V, W of the motor coil 11, and the arm converter 12, and then output to the power battery 200 through the first capacitor C1, so as to implement dc charging of the power battery 200.

Or as shown in fig. 7, when the energy conversion device operates in the dc charging mode, and the dc charging mode is non-isolated dc charging, the first switch K1, the second switch K2, the switch K11, the switch K7, and the switch K8 are closed, and the other switch elements K3, K4, K9, and K10 are opened, at this time, the dc voltage received by the dc charging port 101 is boosted by the three-phase winding U, V, W of the motor coil 11 and the arm converter 12, and then output to the power battery 200 through the first capacitor C1, so as to implement dc charging of the power battery 200.

In addition, when the energy conversion device operates in a dc charging mode, and the dc charging mode is isolated dc charging, as shown in fig. 8, the first switch K1, the second switch K2, the switch K9 and the switch K10 are closed, and the other switch elements K3, K4, K6, K7 and K11 are opened, at this time, the dc voltage received by the dc charging port 101 is pumped into the three-phase winding U, V, W of the motor coil 11 from the motor through the inductor L, and then is boosted through the bridge arm converter 12 to output the voltage U0, the voltage U0 is filtered through the first capacitor C1, and then is rectified through the switch tubes Q3, Q4, Q5 and Q6 to output the voltage T1 after being inverted through the transformer T1, and rectified through the switch tubes Q7, Q8, Q9 and Q10, and then the voltage is output to the power battery 200 through the filter capacitor C2 to realize the isolated dc charging of the power battery 200; it should be noted that, in this embodiment, the isolated dc charging is mainly used when it is difficult to match the battery voltage of the electric vehicle with a special charging facility, and it needs to be completed through two-stage voltage regulation.

Or as shown in fig. 7, the first switch K1, the second switch K2, the switch K9 and the switch K10 are closed, and the other switch elements K3, K4, K6, K7 and K11 are opened, at this time, the dc voltage received by the dc charging port 101 is pumped from the motor into the three-phase winding U, V, W of the motor coil 11, and is boosted by the bridge arm converter 12 to output a voltage U0, the voltage U0 is filtered by the first capacitor C1, and is rectified by the switch tubes Q3, Q4, Q5 and Q6 through a full-bridge rectifier to output a value transformer T1, and is inverted by the transformer T1, rectified by the switch tubes Q7, Q8, Q9 and Q10, and then outputs a voltage to the power battery 200 through the filter capacitor C2, so as to implement isolated dc charging of the power battery 200.

Further, as shown in fig. 8, when the energy conversion apparatus operates in the ac charging mode, the third switch K3, the fourth switch K4, the switch K11, the switch K9 and the switch K10 are closed, and the other switch elements K1, K2, K7 and K8 are opened, at this time, one end of the ac voltage received by the ac charging port 102 enters the three-phase winding U, V, W of the motor coil 11 through the inductor L and the neutral wire led out from the neutral point of the motor, and then enters the arm converter 102, and the other end passes through the bidirectional arm Q1 and Q2, and then forms a full-bridge rectified output voltage U0 through the arm converter 102 and the Q1 and Q2, the voltage U0 is rectified through the full bridge consisting of Q3 to Q6 after being filtered by the first capacitor C1, then is inverted by the transformer T1, and then passes through the full bridge arm composed of Q7 to Q10 and then is filtered by the capacitor C2 to output the voltage to the power battery 200, to achieve ac charging of the power cell 200.

Or, when the energy conversion device operates in the ac charging mode, the third switch K3, the fourth switch K4, the switch K11, the switch K7 and the switch K8 are closed, and the other switches K1, K2, K9 and K10 are opened, at this time, one end of the ac voltage received by the ac charging port 102 enters the three-phase winding U, V, W of the motor coil 11 through the inductor L and the neutral wire led out from the neutral point of the motor, and then enters the arm converter 12, and the other end passes through the arms Q1 and Q2, and then the arms Q1 and Q2 and the arm converter 12 form a rectified output voltage U0, and the output voltage U0 is filtered by the first capacitor C1 and then charges the power battery 200, so as to realize the ac charging of the power battery 200.

Or as shown in fig. 7, when the energy conversion device works in the alternating current charging mode, the third switch K3, the fourth switch K4, the switch K11, the switch K9 and the switch K10 are pulled in, and the other switching elements K1, K2, K7, and K8 are turned off, and at this time, one end of the ac voltage received by ac charging port 102 enters three-phase winding U, V, W of motor coil 11 from the neutral line drawn from the motor neutral point, and then enters arm converter 102, and the other end passes through first arm Q1 and Q2, further, bridge arm Q1 and Q2 and bridge arm inverter 102 form a full bridge rectified output voltage U0, the voltage U0 is rectified by a full bridge composed of Q3 to Q6 after being filtered by a first capacitor C1, inverted by a transformer T1, the voltage is rectified through a full bridge composed of Q7-Q10 and filtered through a capacitor C2 to output voltage to charge the power battery 200, so that alternating current charging of the power battery 200 is realized;

or the third switch K3, the fourth switch K4, the switch K11, the switch K7 and the switch K8 are closed, and the other switches K1, K2, K9 and K10 are opened, at this time, one end of the alternating current voltage received by the alternating current charging port 102 enters the three-phase winding U, V, W of the motor coil 11 from a neutral line led out from a neutral point of the motor, and then enters the bridge arm converter 12, while the other end passes through the bridge arms Q1 and Q2, and then the bridge arms Q1 and Q2 and the bridge arm converter 12 form a full-bridge rectified output voltage U0, and the voltage U0 outputs a voltage to the battery 200 after being filtered by the first capacitor C1, so as to realize the alternating current charging of the battery 200.

In this embodiment, the energy conversion device provided by the present application controls on/off of each switch, so that ac power received by ac charging port 102 is ac-charged to battery 200 through inductor L, motor coil 11, bridge arm converter 12, and bidirectional bridge arm 13, and the ac charging method is not limited to a method, that is, the ac charging method of the energy conversion device is multi-scheme redundant, and the working voltage can be automatically adjusted, so that charging efficiency is improved, and the ac charging function of the energy conversion device can be effectively ensured.

Further, as shown in fig. 7, when the energy conversion device operates in the motor driving mode, the switch K11, the switch K7 and the switch K8 are closed, and the other switches K1 to K4 and K9 to K10 are opened, at this time, the battery 200 outputs high-voltage direct current, and the high-voltage direct current outputs three-phase alternating current to the three-phase winding of the motor coil 11 through the three-phase motor driving bridge of the bridge arm inverter 12, so that the driving of the motor is realized.

In the embodiment, the motor coil 11, the arm converter 12, the bidirectional arm 13 and the bidirectional DC module 15 are integrated in one circuit, so that the energy conversion device can drive the vehicle motor and perform ac charging and discharging of the vehicle battery, thereby improving the circuit integration level, reducing the circuit cost and the circuit volume, and having a simple circuit structure.

In view of the above, for the circuit shown in fig. 7 or fig. 8, no matter the circuit works in the charging mode or the driving mode, a certain voltage difference is generated between the first capacitor C1 and the power supply during the working process, and in order to reduce the voltage difference, it is necessary to precharge the capacitors at both ends of the first capacitor C1 when the first capacitor C1 meets the preset condition, and the specific precharging process is described as follows.

Specifically, when the whole vehicle is powered on, the energy conversion device firstly detects the gear position of the whole vehicle, detects the pressure difference between the first capacitor C1 and the power supply when the gear position of the whole vehicle is in an OFF gear position and the state when the charging gun is connected is detected, or when the vehicle is in an OK gear position and the vehicle is driven, and pre-charges the voltage of the first capacitor C1 if the pressure difference is greater than a preset threshold value.

Further, referring to fig. 10 and fig. 11, when the voltage across the first capacitor C1 is precharged, at this time, the power battery 200 charges the second capacitor C2 first, then the switching element Q5, the switching element Q4, the switching element Q7 and the switching element Q10 in the energy conversion device are turned on, at this time, the voltage across the second capacitor C2 flows through the switching element Q7, the transformer and the switching element Q10, and further an electromotive force is induced on the main side of the transformer, and after being rectified by the switching element Q4 and the switching element Q5, the first capacitor C1 is charged, that is, the switching element Q5, the switching element Q4, the transformer, the switching element Q7, the switching element Q10 and the power battery 200 form a first voltage precharge circuit to precharge the voltage across the first capacitor C1, and a specific current path diagram is shown in fig. 10.

When the first voltage pre-charging circuit of the energy conversion device operates for a certain time, at this time, the power battery 200 charges the second capacitor C2, then the switching element Q3, the switching element Q6, the switching element Q8, and the switching element Q9 in the energy conversion device are turned on, at this time, the voltage across the second capacitor C2 flows through the switching element Q8, the transformer, and the switching element Q9, and further an electromotive force is induced at the main side of the transformer, and after being rectified by the switching element Q3 and the switching element Q6, the second capacitor C2 is charged, that is, the switching element Q3, the switching element Q6, the transformer, the switching element Q8, the switching element Q9, and the power battery 200 form a second voltage pre-charging circuit, so as to pre-charge the voltage across the first capacitor C1, and a specific current path diagram is shown in fig. 11.

In view of the above, the energy conversion device can alternately operate between the first voltage pre-charging circuit and the second voltage pre-charging circuit, and pre-charge the voltage at the two ends of the first capacitor C1 in a manner of continuously charging the first capacitor C1 through the power battery 200.

Further, the application also provides a power system, which comprises an energy conversion device and a control module, wherein when the first capacitor meets the pre-charging condition, the control module controls the energy conversion device to pre-charge the voltage at two ends of the first capacitor.

It should be noted that, since the energy conversion device included in the power system provided by the embodiment of the present application is the same as the energy conversion device shown in fig. 1 to 11, reference may be made to the foregoing detailed description about fig. 1 to 11 for specific working principles of the energy conversion device in the power system provided by the embodiment of the present application, and details are not repeated here

Further, the present application also provides a vehicle that includes a powertrain. It should be noted that, because the powertrain included in the vehicle provided in the embodiment of the present application is the same as the powertrain described above, reference may be made to the foregoing related description for specific operating principles of the powertrain in the vehicle provided in the embodiment of the present application, and details are not described herein again.

In the application, the vehicle provided by the application adopts the energy conversion device which comprises the motor coil, the bridge arm converter, the bidirectional bridge arm, the first capacitor, the second capacitor and the bidirectional DC module and integrates the driving and charging functions, so that the energy conversion device can work in a driving mode, a direct current charging mode and an alternating current charging mode, further, the aim of capacitor multiplexing is fulfilled while the motor driving and battery charging of the vehicle are carried out by adopting the same system, the multiplexing degree of components is high, the system integration degree is high, the structure is simple, the system cost is reduced, the system volume is reduced, the voltage at two ends of the first capacitor can be precharged, and the problems of complex structure, low integration degree, large volume, high cost and large heat loss during capacitor precharging existing in the overall circuit of the existing motor driving and charging system are solved.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An energy conversion device is characterized by comprising a motor coil, a bridge arm converter, a bidirectional bridge arm, a first capacitor, a second capacitor and a bidirectional DC module;

the first capacitor is connected with the bidirectional bridge arm in parallel;

2. The energy conversion device according to claim 1, wherein the bidirectional DC module includes a first converter, a second converter, and a transformation unit, a primary side and a secondary side of the transformation unit are respectively connected to the first converter and the second converter, the first converter is connected in parallel to the first capacitor, the second converter is connected in parallel to the power battery and the second capacitor, and the first capacitor, the first converter, the second converter, the transformation unit, the second capacitor, and the power battery form the voltage pre-charging circuit.

3. The energy conversion apparatus according to claim 2, wherein the first converter includes a first switching element, a second switching element, a third switching element, a fourth switching element, a first inductance, and a third capacitance; the first end of the first switching element is connected with the first end of the third switching element and the first end of the first capacitor, the second end of the first switching element is connected with the first end of the second switching element and the first end of the third capacitor, the second end of the third element is connected with the first end of the fourth switching element and the first end of the first inductor, the second end of the first inductor and the second end of the third capacitor are both connected with the primary side of the transformation unit, and the second end of the second switching element is connected with the second end of the fourth switching element and the second end of the first capacitor.

4. The energy conversion device according to claim 3, wherein the second converter includes a fifth switching element, a sixth switching element, a seventh switching element, an eighth switching element, a second inductance, and a fourth capacitance; the first end of the fifth switch element is connected with the first end of the seventh switch element, the first end of the second capacitor and the positive end of the power battery, the second end of the seventh switch element is connected with the first end of the eighth switch element and the first end of the fourth capacitor, the second end of the fifth switch element is connected with the first end of the sixth switch element and the first end of the second inductor, the second end of the second inductor and the second end of the fourth capacitor are both connected with the primary side of the transformer unit, and the second end of the sixth switch element is connected with the second end of the eighth switch element, the second end of the second capacitor and the negative end of the power battery.

5. The energy conversion device according to claim 4, wherein the first capacitor, the third switching element, the second switching element, the transforming unit, the fifth switching element, the eighth switching element, the second capacitor, and the power battery form a first voltage pre-charge circuit, the first capacitor, the first switch element, the fourth switch element, the transformer unit, the sixth switch element, the seventh switch element, the second capacitor and the power battery form a second voltage pre-charging loop, the first voltage pre-charging circuit is pre-charged in a first pre-charging state, the second voltage pre-charging circuit is pre-charged in a second pre-charging state, the first voltage pre-charging loop and the second voltage pre-charging loop work alternately to pre-charge the voltage at two ends of the first capacitor.

6. The energy conversion device of claim 1, wherein the motor coils comprise three-phase windings, each phase winding comprises N coil branches, first ends of the N coil branches in each phase winding are connected with the bridge arm converter after being connected in common, second ends of the N coil branches in each phase winding are connected with second ends of the N coil branches in the other two-phase windings in a one-to-one correspondence manner to form N neutral points, and the charging ports are connected with the M neutral points; wherein N is an integer greater than 1, and M is a positive integer less than N.

7. The energy conversion device of claim 6, further comprising a neutral switch for controlling M of the N neutral points of the motor coil to be connected to the charging port.

8. A power system comprising the energy conversion device of any of claims 1-7 and a control module that controls the energy conversion device to precharge the voltage across the first capacitor when the first capacitor meets a precharge condition.

9. A vehicle characterized by comprising the powertrain of claim 8.