Electric drive system and electric vehicle

Abstract

The invention provides an electric drive system and an electric vehicle. The electric drive system comprises a motor and a filtering voltage stabilizing capacitor, the electric drive system comprises a first end connected with the positive electrode of the vehicle battery, a second end connected with the negative electrode of the charging device and the negative electrode of the vehicle battery and a third end connected with the positive electrode of the charging device, and the first end is connected with the motor through an upper bridge of an inverter circuit of the motor; the second end is connected with the motor through a lower bridge of an inverter circuit of the motor, the third end is connected with a neutral point of the motor, and two ends of the filtering voltage stabilizing capacitor are bridged between the second end and the third end. According to the electric drive system provided by the invention, the occupied space is reduced and the cost is reduced while the functions of vehicle driving and boosting charging are realized.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicles, and in particular to an electric drive system and an electric vehicle. Background Art

[0002] At present, the 800V high-voltage architecture of electric vehicles is becoming mainstream, and the voltage of the entire high-voltage architecture can reach more than 900V. The 800V architecture can obtain greater charging power at the same charging current, thereby shortening the charging time, improving the charging speed and the efficiency of the whole vehicle. However, the voltage of existing charging piles is generally 400V, and the highest voltage is only 500-700V, which cannot adapt to the charging needs of cars with 800V high-voltage architecture. Electric vehicles need to be equipped with a boost function to achieve charging. The incompatibility between the voltage of the charging device and the voltage of the electric vehicle seriously affects the charging function of the electric vehicle and restricts the rapid development of electric vehicles with 800V high-voltage architecture.

[0003] Please refer to Figure 1 , Figure 1 A schematic diagram of a topological circuit of a charging and driving module of an existing electric vehicle is shown.

[0004] like Figure 1 As shown, existing electric vehicles achieve boost charging and motor drive through two power units: an electric drive unit and a boost auxiliary module unit. The three-phase motor of the electric drive unit adopts a Y-type connection, and the neutral point is led out and connected to the boost auxiliary module unit external to the electric drive unit. The inductor in the boost auxiliary module unit can provide additional potential for the entire charging circuit after pre-charging. In this way, through the boost auxiliary module unit, the electric vehicle can achieve the boost function and charge the battery with a voltage significantly higher than the charging device.

[0005] However, the space occupied by the above-mentioned electric drive unit and boost auxiliary module unit is relatively large, and it is difficult to realize the integration scheme of the same shell. Therefore, the existing electric drive unit and boost auxiliary module unit adopt a split solution, that is, the electric drive unit and the boost auxiliary module unit are in separate shells, and the interaction of power and control signals is realized by power linearity and low-voltage control linearity. The split solution has low integration, large space occupation, and high cost, and cannot meet the existing vehicle's requirements for high integration and low cost of power conversion units. In addition, since the existing charging circuit requires multiple electrical system components to cooperate with each other, the control difficulty is high and the risk of failure is high; the electric vehicle also needs to arrange a complex high-voltage wiring harness circuit, which is difficult to design.

[0006] In order to overcome the above-mentioned defects of the prior art, there is an urgent need in the art for a highly integrated electric drive system that can achieve vehicle driving and boost charging functions while reducing the occupied space and reducing costs. Summary of the invention

[0007] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0008] In order to overcome the above-mentioned defects in the prior art, the present invention provides a highly integrated electric drive system and an electric vehicle, which can reduce the occupied space and reduce the cost while realizing the vehicle driving and boost charging functions.

[0009] Specifically, the electric drive system provided according to the first aspect of the present invention includes a motor and a filtering and stabilizing capacitor, the electric drive system includes a first end connected to the positive pole of a vehicle battery, a second end connected to the negative pole of a charging device and the negative pole of the vehicle battery, and a third end connected to the positive pole of the charging device, wherein the first end is connected to the motor via the upper bridge of the inverter circuit of the motor, the second end is connected to the motor via the lower bridge of the inverter circuit of the motor, the third end is connected to the neutral point of the motor, and the two ends of the filtering and stabilizing capacitor are bridged between the second end and the third end.

[0010] Preferably, in one embodiment of the present invention, a first switch is provided between the first connection point between the filtering and stabilizing capacitor and the second end and the neutral point of the motor; in the boost charging mode, the first switch is configured to be in a closed state; and in the motor driving mode, the first switch is configured to be in an open state to prevent the filtering and stabilizing capacitor from failing.

[0011] Preferably, in an embodiment of the present invention, the first switch is provided between the second connection point between the filtering and stabilizing capacitor and the third end and the neutral point of the motor.

[0012] Preferably, in one embodiment of the present invention, a first branch is connected between the first end and the third end, and a second switch is provided on the first branch; in the direct charging mode, the second switch is configured to be in a closed state; and in the boost charging mode, the second switch is configured to be in an open state.

[0013] Preferably, in one embodiment of the present invention, a first branch is connected between the first end and the third end, a second branch is connected between the neutral point of the motor and the first end, a third switch is provided between the second connection point between the filtering and stabilizing capacitor and the third end and the third connection point between the first branch and the third end, a fourth switch is provided between the fourth connection point between the first branch and the first end and the fifth connection point between the second branch and the first end, and the third switch and the fourth switch realize a step-down and step-up current mode when in the disconnected state.

[0014] Preferably, in one embodiment of the present invention, the second branch is provided with a fifth switch, and the first branch is provided with a second switch; in the boost charging mode, the third switch and the fourth switch are configured to be in a closed state, and the fifth switch and the second switch are configured to be in an open state.

[0015] Preferably, in one embodiment of the present invention, a first switch is provided between the second connection point and the neutral point of the motor, and in the motor driving mode, the third switch, the fifth switch, the second switch and the first switch are configured to be in an open state, and the fourth switch is configured to be in a closed state; and in the direct charging mode, the third switch, the fifth switch and the first switch are configured to be in an open state, and the fourth switch and the second switch are configured to be in a closed state.

[0016] Preferably, in an embodiment of the present invention, the electric drive system further includes a DC bus capacitor, and two ends of the DC bus capacitor are connected between the first end and the second end.

[0017] Preferably, in an embodiment of the present invention, the electric drive system further includes an integrated filter, and the integrated filter is respectively connected to the first end, the second end and the third end.

[0018] In addition, the electric vehicle provided according to the second aspect of the present invention includes a vehicle battery and an electric drive system provided by any one of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily drawn to scale, and components with similar related properties or features may have the same or similar reference numerals.

[0020] Figure 1 A schematic diagram of a topological circuit of a charging and driving module of an existing electric vehicle is shown;

[0021] Figure 2A schematic diagram of a topological circuit of an electric drive system provided according to some embodiments of the present invention is shown;

[0022] Figure 3A to Figure 3B A schematic diagram of a current loop of the electric drive system 200 in a boost charging mode is shown;

[0023] Figure 4 A schematic diagram showing a current loop of the electric drive system 200 in the motor drive mode;

[0024] Figure 5 A schematic diagram of a topological circuit of an electric drive system provided according to some embodiments of the present invention is shown;

[0025] Figure 6 A schematic diagram showing a current loop of the electric drive system 500 in a direct charging mode;

[0026] Figure 7 A schematic diagram of a topological circuit of an electric drive system provided according to some embodiments of the present invention is shown;

[0027] Figure 8A to Figure 8B A schematic diagram showing a current loop of the electric drive system 700 in a buck-current boost mode; and

[0028] Figures 9A to 9C A schematic diagram of the current loop of the electric drive system 700 in the boost charging mode, the motor driving mode, and the direct charging mode is shown.

[0029] Reference numerals:

[0030] 200, 500, 700: Electric drive system;

[0031] 201, 501, 701: branch roads;

[0032] 202, 502, 702: branch roads;

[0033] 203, 503, 703: branch roads;

[0034] 504, 704: First branch road;

[0035] 210, 510, 710: Motor;

[0036] 211, 511, 711: first end of the motor winding;

[0037] 212, 512, 712: second end of the motor winding;

[0038] 220, 520, 720: filter and voltage stabilizing capacitors;

[0039] 230: Integrated filter;

[0040] 240: DC bus capacitor;

[0041] 310, 610, 810: Vehicle batteries;

[0042] 311, 611, 811: negative pole of vehicle battery;

[0043] 312, 612, 812: positive pole of vehicle battery;

[0044] 320, 620, 820: Charging device;

[0045] 321, 621, 821: negative pole of charging device;

[0046] 322, 622, 822: positive pole of charging device;

[0047] 705: Second branch road;

[0048] 721: the first terminal of the filter stabilizing capacitor;

[0049] 722: the second terminal of the filtering and stabilizing capacitor;

[0050] P1: first end;

[0051] P2: second end;

[0052] P3: third terminal;

[0053] a1, A: endpoint;

[0054] b1, B: first connection point;

[0055] c1, C: second connection point;

[0056] D: third connection point;

[0057] E: fourth connection point;

[0058] F: fifth connection point;

[0059] G: sixth connection point;

[0060] U: first winding;

[0061] V: Second winding;

[0062] W: tertiary winding;

[0063] K1: first switch;

[0064] K2: Second switch;

[0065] K3: The third switch;

[0066] K4: the fourth switch;

[0067] K5: The fifth switch;

[0068] U1, V1, W1: switching devices; and

[0069] U2, V2, W2: switching devices. DETAILED DESCRIPTION

[0070] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are only exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0071] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal" and "vertical" used in the following description should be understood as the directions shown in the paragraph and the related drawings. Such relative terms are only used for the convenience of description and do not mean that the device described therein must be manufactured or operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0073] It is understood that although the terms "first", "second", "third", etc. may be used herein to describe various components, regions, layers and / or parts, these components, regions, layers and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers and / or parts. Therefore, the first component, region, layer and / or part discussed below may be referred to as a second component, region, layer and / or part without departing from some embodiments of the present invention.

[0074] As mentioned above, existing electric vehicles achieve boost charging and motor drive through two power units: the electric drive unit and the boost auxiliary module unit. The three-phase motor of the electric drive unit adopts a Y-type connection, with the neutral point drawn out and connected to the boost auxiliary module unit external to the electric drive unit. The capacitor in the boost auxiliary module unit can provide additional inductance for the entire charging circuit after pre-charging. Through the boost auxiliary module unit, electric vehicles can achieve the boost function and charge the battery with a voltage significantly higher than the charging device.

[0075] However, the space occupied by the above-mentioned electric drive unit and boost auxiliary module unit is relatively large, and it is difficult to realize the integration scheme of the same shell. Therefore, the existing electric drive unit and boost auxiliary module unit adopt a split solution, that is, the electric drive unit and the boost auxiliary module unit are in separate shells, and the interaction of power and control signals is realized by power linearity and low-voltage control linearity. The split solution has low integration, large space occupation, and high cost, and cannot meet the existing vehicle's requirements for high integration and low cost of power conversion units. In addition, since the existing charging circuit requires multiple electrical system components to cooperate with each other, the control difficulty is high and the risk of failure is high; the electric vehicle also needs to arrange a complex high-voltage wiring harness circuit, which is difficult to design.

[0076] In order to overcome the above-mentioned defects in the prior art, the present invention provides a highly integrated electric drive system and an electric vehicle, which can reduce the occupied space and reduce the cost while realizing the vehicle driving and boost charging functions.

[0077] Please refer to Figure 2 , Figure 2 A schematic diagram of a topological circuit of an electric drive system provided according to some embodiments of the present invention is shown.

[0078] like Figure 2 As shown, in addition to the electric drive system 200, the electric vehicle may also include a vehicle battery 310, which can supply power to the electric drive system 200. The electric vehicle may also be connected to an external charging device 320. The electric drive system 200 may include a first terminal P1, a second terminal P2, and a third terminal P3. The first terminal P1 of the electric drive system 200 is connected to the positive electrode 312 of the vehicle battery, the third terminal P3 is connected to the positive electrode 322 of the charging device, and the negative electrode 321 of the charging device is connected to the negative electrode 311 of the vehicle battery, and the second terminal P2 is connected.

[0079] The electric drive system 200 may include a motor 210 and a filtering and stabilizing capacitor 220. The motor 210 may include a first end 211 of a motor winding and a second end 212 of the motor winding. The first end 211 of the motor winding is connected to the inverter circuit of the motor 210, and the neutral point Y of the motor 210 is located at the second end 212 of the motor winding. Preferably, the motor 210 may be a three-phase motor, and the three-phase motor may include a first winding U, a second winding V, and a third winding W. Accordingly, the upper bridge of the inverter circuit may include a switching device U1, a switching device V1, and a switching device W1, and the lower bridge of the inverter circuit may include a switching device U2, a switching device V2, and a switching device W2. The switching device U1, the switching device V1, and the switching device W1 may be connected to the first winding U, the second winding V, and the third winding W of the three-phase motor, respectively, with the switching device U2, the switching device V2, and the switching device W2.

[0080] Here, the switches and switching devices mentioned in the present invention may include but are not limited to relays, power SIC (silicon carbide), IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), etc.

[0081] The first end P1 is connected to the motor 210 via the upper bridge of the motor inverter circuit, and the second end P2 is connected to the motor 210 via the lower bridge of the motor inverter circuit. Figure 2 As shown, a branch 201 is formed between the upper bridge of the inverter circuit and the positive electrode 312 of the vehicle battery, and a branch 202 is formed between the lower bridge of the inverter circuit and the negative electrode 311 of the vehicle battery.

[0082] Specifically, the negative electrode 321 of the charging device and the negative electrode 311 of the vehicle battery can be connected to the terminal a1, and the lower bridge of the inverter circuit can be directly connected to the terminal a1 via the second terminal P2. Optionally, the terminal a1 can be located outside the electric drive system 200 and inside the electric vehicle, so that the negative electrode 311 of the vehicle battery and the negative electrode 321 of the charging device share the second terminal P2 of the electric drive system 200, and the branch 202 can extend to the inside of the electric drive system 200 via the second terminal P2. By connecting the lower bridge of the inverter circuit of the motor to the terminal a1, the motor can be connected to the negative electrode 311 of the vehicle battery and the negative electrode 321 of the charging device at the same time. Optionally, the terminal a1 can also be located inside the electric drive system 200.

[0083] The third terminal P3 is connected to the neutral point Y of the motor 210, and thus the positive electrode 322 of the charging device is connected to the neutral point Y of the motor 210. Figure 2 In the illustrated embodiment, the positive electrode 322 of the charging device may be connected to the second end 212 of the motor winding via the branch 203 .

[0084] The two ends of the filter and voltage stabilizing capacitor 220 are connected between the second end P2 and the third end P3, so that the two ends of the filter and voltage stabilizing capacitor 220 can be connected between the positive electrode 322 of the charging device and the negative electrode 321 of the charging device. Figure 2 As shown, two ends of the filtering and stabilizing capacitor 220 can be connected to the first connection point b1 of the branch 202 with the second end P2 and connected to the second connection point c1 of the branch 203 with the third end P3 respectively.

[0085] Therefore, the filter and voltage-stabilizing capacitor 220 is integrated inside the electric drive system 200 , and the motor 210 is used as an equivalent inductor. The electric drive system 200 can realize the boost charging function of the electric vehicle by relying on the internal components of the motor 210 and the filter and voltage-stabilizing capacitor 220 .

[0086] An integrated filter 230 may also be provided inside the electric drive system 200, and the integrated filter 230 may be an electromagnetic compatibility filter (EMC Filter). The integrated filter 230 is respectively connected to the first end P1, the second end P2, and the third end P3 of the electric drive system 200. Through the integrated filter 230, the electric drive system 200 can filter out unnecessary signals, thereby keeping the signal clean and the internal stability of the electric drive system 200.

[0087] In addition, the electric drive system 200 may further include a DC bus capacitor 240 , and two ends of the DC bus capacitor 240 may be bridged between the first end P1 and the second end P2 .

[0088] In some non-limiting embodiments, the electric vehicle provided by the present invention may also be equipped with a control device, and the electric drive system is controlled by the configured control device. The specific scheme of the control device does not involve the technical improvement of the present invention and will not be elaborated here.

[0089] When the voltage of the charging device is lower than the voltage of the vehicle battery, the electric vehicle can use the boost charging mode to boost the voltage, thereby charging the vehicle's high-voltage battery.

[0090] Please refer to Figure 3A to Figure 3B , Figure 3A to Figure 3B A schematic diagram of a current loop of the electric drive system 200 in a boost charging mode is shown.

[0091] In the boost charging mode, the electric vehicle is connected to an external charging device 320, and the positive and negative switches of the charging device 320 are closed, so that current can flow into the filter stabilizing capacitor 220 across the charging device 320 to achieve pre-charging of the filter stabilizing capacitor 220. The current can also continue to flow from the branch 203 to the neutral point Y of the motor 210. Afterwards, the control device can charge and store energy for the motor 210 and boost the vehicle battery 310 by controlling the inverter circuit of the motor.

[0092] First, if Figure 3A As shown, the control device can disconnect the upper bridge of the inverter circuit, that is, disconnect the switch device U1, the switch device V1, and the switch device W1, so as to disconnect the motor 210 from the positive electrode 312 of the vehicle battery; and close the lower bridge of the inverter circuit, that is, close the switch device U2, the switch device V2, and the switch device W2, so as to conduct the motor 210 and the terminal a1, so as to connect the motor 210 to the negative electrode 321 of the charging device. Thus, the electric drive system 200 uses the motor 210 as an equivalent inductor, and the current flowing to the neutral point Y of the motor flows to the lower bridge of the inverter circuit through the first end 211 of the motor winding and then flows back to the negative electrode 321 of the charging device, so as to realize the charging and energy storage of the motor 210.

[0093] After the motor 210 is charged and stored, Figure 3B As shown, the control device can disconnect the motor 210 from the terminal a1, and connect the motor 210 to the positive electrode 312 of the vehicle battery. Specifically, the control device can disconnect the lower bridge of the inverter circuit, that is, disconnect the switching device U2, the switching device V2, and the switching device W2, and close the upper bridge of the inverter circuit, that is, close the switching device U1, the switching device V1, and the switching device W1.

[0094] The current flows through the positive electrode 322 of the charging device to the neutral point Y of the motor, and then flows through the first end 211 of the motor winding and the upper bridge of the inverter circuit to the positive electrode 312 of the vehicle battery, and then flows from the negative electrode 311 of the vehicle battery to the negative electrode 321 of the charging device to form a current loop in the boost charging mode. Here, the voltage output by the electric drive system 200 is equal to the voltage of the charging device 320 (for example, 400V) plus the voltage across the inductance of the motor 210, thereby boosting the lower voltage of the charging device 320 and converting it into an output charging voltage that exceeds the voltage of the vehicle battery 310 (for example, 800V), so as to achieve boost charging of the vehicle battery 310.

[0095] The electric drive system 200 can achieve the boost charging function through internal devices and is compatible with lower voltage charging piles on the market. There is no need to configure additional boost auxiliary equipment on the electric vehicle, which can save more vehicle space and cost.

[0096] In addition, under normal circumstances, the control device can control the working mode of the electric drive system 200 to be in the motor drive mode. In the motor drive mode, the electric energy applied to the motor 210 can be converted into the kinetic energy of the motor 210, thereby driving the electric vehicle to travel.

[0097] Please refer to Figure 4 , Figure 4 A schematic diagram of a current loop of the electric drive system 200 in a motor drive mode is shown.

[0098] exist Figure 4 In the embodiment shown, in the motor drive mode, the charging device 320 is not connected to the electric vehicle, and the control device can realize the motor drive by closing the switch device U1 and the switch device V1 in the upper bridge of the inverter circuit, disconnecting the switch device W1, and disconnecting the switch device U2 and the switch device V2 in the lower bridge of the inverter circuit, and closing the switch device W2. The current flows from the positive electrode 312 of the vehicle battery into the first winding U and the second winding V through the switch device U1 and the switch device V1, and then flows to the third winding W through the neutral point Y; and then flows back to the negative electrode 311 of the vehicle battery through the switch device W2.

[0099] exist Figure 2In the preferred embodiment shown, a first switch K1 may be provided between the first connection point b1 between the filter and voltage-stabilizing capacitor 220 of the electric drive system 200 and the second terminal P2 and the neutral point Y of the motor 210. When the electric drive system 200 is in the boost charging mode, the first switch K1 may be closed; when the electric drive system 200 is in the motor driving mode, the first switch K1 may be opened to prevent the filter and voltage-stabilizing capacitor 220 from failing. Preferably, Figure 2 As shown, the first switch K1 may be disposed between the second connection point c1 between the filtering and stabilizing capacitor 220 and the third terminal P3 and the neutral point Y of the motor 210 .

[0100] When the maximum charging voltage of the charging device (for example, 750V, 1000V) is slightly higher than the voltage of the vehicle battery (for example, 800V), the electric drive system can be adjusted to the direct charging mode, thereby enabling the charging device to directly charge the vehicle battery.

[0101] Please refer to Figure 5 , Figure 5 A schematic diagram of a topological circuit of an electric drive system provided according to some embodiments of the present invention is shown.

[0102] exist Figure 5 In the preferred embodiment shown, compared with the electric drive system 200, the first terminal P1 and the third terminal P3 of the electric drive system 500 are connected through the first branch 504, thereby connecting the positive electrode 622 of the charging device and the positive electrode 612 of the vehicle battery. A second switch K2 may be provided on the first branch 504. The two ends of the first branch 504 may be connected to the branch 501 and the branch 503 respectively.

[0103] Please refer to Figure 6 , Figure 6 A schematic diagram of a current loop of the electric drive system 500 in a direct charging mode is shown.

[0104] like Figure 6 As shown, the control device can close the second switch K2, thereby conducting the connection between the positive electrode 622 of the charging device and the positive electrode 612 of the vehicle battery, so as to realize the direct charging of the vehicle battery 610 by the charging device 620. The control device can also disconnect the second switch K2, thereby disconnecting the connection between the positive electrode 622 of the charging device and the positive electrode 612 of the vehicle battery, and conducting the connection between the third terminal P3 and the neutral point Y of the motor 510, so as to realize the boost charging mode and the motor driving mode of the electric drive system 500. Preferably, a first switch can also be provided on the branch 503, and in the motor driving mode, the first switch can be configured to be in an open state.

[0105] In the direct charging mode, the current flows from the positive electrode 622 of the charging device through the second switch K2 and then flows into the positive electrode 612 of the vehicle battery to directly charge the vehicle battery 610 without conversion through other devices. Afterwards, the current flows from the negative electrode 611 of the vehicle battery back to the negative electrode 621 of the charging device to form a closed loop.

[0106] In direct charging mode, the charging power is related to the maximum current of the charging device. By setting the second switch K2 inside the electric drive system 500 and the copper busbar wiring harness of the first branch 504, the number of high-voltage wiring harnesses of the electric vehicle during direct charging can be reduced, the difficulty of wiring harness arrangement of the whole vehicle can be reduced, and the spatial structure can be optimized.

[0107] Here, the switch integrated in the electric drive system can be powered directly by the vehicle battery for diagnostics without the need for an additional power supply.

[0108] Please continue to refer to Figure 7 , Figure 7 A schematic diagram of a topological circuit of an electric drive system provided according to some embodiments of the present invention is shown.

[0109] Compared with the electric drive system 200, Figure 7 In the preferred embodiment shown, the electric drive system 700 may further include a first branch 704 and a second branch 705. The upper bridge of the inverter circuit of the motor 710 and the positive electrode 812 of the vehicle battery are branch 701, the lower bridge of the inverter circuit and the negative electrode 811 of the vehicle battery are branch 702, and the positive electrode 822 of the charging device and the neutral point Y of the motor 710 are branch 703. The first branch 704 is between the first terminal P1 and the third terminal P3, and the second branch 705 is between the neutral point Y of the motor 710 and the first terminal P1.

[0110] The negative electrode 821 of the charging device and the negative electrode 811 of the vehicle battery can be connected to the terminal A on the branch 702, so that the negative electrode 821 of the charging device and the negative electrode 811 of the vehicle battery are commonly connected to the first end 711 of the motor winding through the second end P2.

[0111] The positive electrode 822 of the charging device can be connected to the second end 712 of the motor winding, that is, the neutral point Y of the motor 710, through the branch 703. The filter stabilizing capacitor 720 includes a first end 721 of the filter stabilizing capacitor close to the second end P2 and a second end 722 of the filter stabilizing capacitor close to the third end P3. Figure 7 As shown, the first end 721 of the filtering and stabilizing capacitor can be connected to the first connection point B of the branch 702 with the second end P2, and the second end 722 of the filtering and stabilizing capacitor can be connected to the second connection point C of the branch 703 with the third end P3.

[0112] The electric drive system 700 may further include a first branch 704 connecting the first end P1 and the third end P3, a third connection point D of the first branch 704 connected to the third end P3 at the branch 703, and a fourth connection point E connected to the first end P1 at the branch 701. Here, the first branch 704 may be a wire.

[0113] In addition, the electric drive system 700 further includes a second branch 705 for connecting the second end 712 of the motor winding and the positive electrode 812 of the vehicle battery. The second branch 705 can be connected to the first end P1 at the fifth connection point F of the branch 701, and connected to the second end 712 of the motor winding at the sixth connection point G of the branch 703.

[0114] exist Figure 7 In the embodiment shown, by controlling the connection between the electric drive system 700 and the vehicle battery 810 and the charging device 820, charging devices with different voltages can be adapted. Figure 7 As shown, the electric drive system 700 can be provided with a third switch K3, which is located between the second connection point C and the third connection point D; the electric drive system 700 can also be provided with a fourth switch K4, which is located between the fourth connection point E and the fifth connection point F; more preferably, the electric drive system 700 can also be provided with a fifth switch K5 located in the second branch 704, a second switch K2 located in the first branch 704 and / or a first switch K1 between the neutral point Y of the motor 710 and the second connection point C.

[0115] Those skilled in the art should understand that Figure 7 The positions of the switches shown are only a non-limiting embodiment of the present invention, which is intended to clearly illustrate the main concept of the present invention and provide a specific solution that is convenient for the public to implement, rather than to limit the scope of protection of the present invention. Figure 7 The first switch K1 , the second switch K2 , and the fifth switch K5 shown in FIG. 1 can be replaced by wires.

[0116] When faced with a charging device with a higher voltage than the vehicle battery, the electric drive system cannot fully utilize the capacity of the charging device by relying solely on the boost charging function. For example, when the charging pile voltage (e.g., 1000V, 1250V) is much higher than the vehicle battery voltage (e.g., 650V), if the electric vehicle is charged directly, due to the limitation of the maximum output current of the charging device (e.g., 250A), the charging power of the charging pile is small when the vehicle battery voltage is low. The Buck circuit formed by the topological structure of the electric drive system can achieve voltage reduction and current increase, thereby increasing the charging power (e.g., the output power of the charging device changes from 650V*250A to 1000V*250A).

[0117] Please refer to Figure 8A to Figure 8B , Figure 8A to Figure 8B A schematic diagram of a current loop of the electric drive system 700 in a voltage-reducing and current-increasing mode is shown.

[0118] The electric drive system 700 can close the first switch K1, the second switch K2 and the fifth switch K5 and open the third switch K3 and the fourth switch K4 to form a Buck loop, thereby realizing the buck-boost mode of the electric drive system 700. Here, the filter stabilizing capacitor 720 can be an output capacitor to make the output voltage smoother.

[0119] like Fig. 8A As shown, the control device can close the upper bridge of the inverter circuit and disconnect the lower bridge of the inverter circuit to connect the motor 710 of the electric drive system 700 with the positive electrode 822 of the charging device, and disconnect the motor 710 from the first end 721 of the filtering and stabilizing capacitor.

[0120] The current flows from the positive electrode 822 of the charging device through the branch 703 and the third branch 705 to the motor 710, and uses the winding of the motor 710 as the equivalent inductance to charge and store energy for the motor 710. The current is separated at the sixth connection point G and flows to the second end 722 of the filter and voltage stabilizing capacitor to charge and store energy for the filter and voltage stabilizing capacitor 720; at the same time, the current flows from the second branch 704 to the positive electrode 812 of the vehicle battery to charge the vehicle battery 810. Thus, in Fig. 8A In the current loop shown, the charging device 820 can simultaneously charge the motor 710, the filter and voltage stabilization capacitor 720, and the vehicle battery 810, and convert the higher voltage of the charging device 820 into a lower output voltage of the electric drive system 700.

[0121] like Figure 8B As shown, the control device can disconnect the upper bridge of the inverter circuit and close the lower bridge of the inverter circuit to disconnect the connection between the motor 710 and the positive electrode 822 of the charging device, and connect the connection between the motor 710 and the first end 721 of the filtering and stabilizing capacitor.

[0122] The motor 710 and the filtering and stabilizing capacitor 720 release current. The current released by the motor 710 flows from the first end 711 of the motor winding through the second end 712 of the motor winding to the sixth connection point G. The current of the filtering and stabilizing capacitor 720 flows from the second end 722 of the filtering and stabilizing capacitor to the sixth connection point G. After the current released by the motor 710 and the current released by the filtering and stabilizing capacitor 720 merge at the sixth connection point G, they flow from the second branch 704 into the positive electrode 812 of the vehicle battery to realize the freewheeling charging of the vehicle battery 810.

[0123] The maximum output current (for example, 250A) output by the charging device external to the electric vehicle usually remains unchanged, and those skilled in the art can increase the charging power of the charging device by increasing the charging voltage of the charging device as much as possible. The electric drive system 700 provided by the present invention can reduce the charging voltage of the charging device through the formed Buck circuit, and at the same time, the current output by the electric drive system 700 is increased when the input charging power remains unchanged. As a result, the electric drive system 700 decouples the maximum output voltage and the maximum output current of the charging device, and makes full use of the capacity of the charging device as much as possible, thereby outputting higher power at a higher voltage of the charging device to charge the entire vehicle, reducing the charging time, and achieving the charging effect of voltage reduction and current increase, rather than being limited to the single capacity of the maximum output current of the charging device.

[0124] In addition, please refer to Figures 9A to 9C , Figures 9A to 9C A schematic diagram of the current loop of the electric drive system 700 in the boost charging mode, the motor driving mode, and the direct charging mode is shown.

[0125] like Fig.9A As shown, the control device can close the third switch K3, the fourth switch K4 and the first switch K1 of the electric drive system 700, disconnect the fifth switch K5 and the second switch K2, and then continue to control the inverter circuit of the motor 710 to realize the boost charging mode of the electric drive system 700. Those skilled in the art can understand that when the electric drive system only includes the buck-boost mode and the boost charging mode, the first switch K1 can be replaced by a wire.

[0126] like Fig. 9B As shown, the control device can realize the motor driving mode of the electric drive system 700 by closing the fourth switch K4 of the electric drive system 700, disconnecting the third switch K3, the fifth switch K5, the first switch K1 and the second switch K2, and then continuing to control the inverter circuit of the motor 710.

[0127] like Fig. 9C As shown, the control device can realize the direct charging mode of the electric drive system 700 by closing the fourth switch K4 and the second switch K2 of the electric drive system 700 and opening the third switch K3, the fifth switch K5 and the first switch K1.

[0128] The electric drive system 700 does not need to add an additional external boost auxiliary module, which reduces the complexity of the vehicle electrical architecture and avoids the extra space occupied by the vehicle. In addition, since each device is arranged inside the electric drive system 700, the difficulty of device coordination and control is relatively low, reducing the risk of failure.

[0129] In addition, the electric drive system 700 can also adapt to charging devices with a charging voltage higher than the vehicle battery voltage. In conjunction with the control strategy of the control device, the electric drive system 700 can switch between different working modes and adapt to charging devices with multiple charging voltage levels to avoid the situation where there is a charging pile but it cannot be used.

[0130] To sum up, the highly integrated electric drive system provided by the present invention can be compatible with charging devices with lower charging voltages during charging, so as to adapt to charging piles with various charging voltage levels. The boost charging function can be realized without adding an external boost auxiliary module, thereby reducing the complexity of the vehicle's electrical architecture and avoiding additional space occupation of the vehicle.

[0131] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions from those illustrated and described herein or not illustrated and described herein but understandable to those skilled in the art.

[0132] Those skilled in the art will appreciate that information, signals, and data may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips cited throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0133] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0134] The control device in the above embodiment may include a controller, although the controller can be implemented by a combination of software and hardware. However, it is understood that the controller can also be implemented in software and hardware. For hardware implementation, the controller can be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, other electronic devices for performing the above functions, or a selection combination of the above devices. For software implementation, the controller can be implemented by independent software modules such as procedures and functions running on a general-purpose chip, each of which performs one or more functions and operations described herein.

[0135] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in cooperation with a DSP core, or any other such configuration.

[0136] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in a user terminal as discrete components.

[0137] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented as a computer program product in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, a server, or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0138] The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electric drive system, comprising a motor and a filter stabilizing capacitor, characterized in that: The electric drive system includes a first end connected to the positive electrode of a vehicle battery, a second end connected to the negative electrode of a charging device and the negative electrode of the vehicle battery, and a third end connected to the positive electrode of the charging device, wherein the first end is connected to the motor via an upper bridge of an inverter circuit of the motor, The second end is connected to the motor via the lower bridge of the inverter circuit of the motor, The third terminal is connected to the neutral point of the motor, and Two ends of the filtering and stabilizing capacitor are connected between the second end and the third end.

2. The electric drive system according to claim 1, characterized in that: A first switch is provided between a first connection point between the filtering and stabilizing capacitor and the second end and a neutral point of the motor; In the boost charging mode, the first switch is configured to be in a closed state; as well as In the motor driving mode, the first switch is configured to be in an off state to prevent the filtering and stabilizing capacitor from failing.

3. The electric drive system according to claim 2, characterized in that: The first switch is provided between the second connection point between the filtering and stabilizing capacitor and the third end and the neutral point of the motor.

4. The electric drive system according to claim 1, characterized in that: A first branch is connected between the first end and the third end, and a second switch is provided on the first branch; In the direct charging mode, the second switch is configured to be in a closed state; as well as In the boost charging mode, the second switch is configured to be in an off state.

5. The electric drive system according to claim 1, characterized in that: A first branch is connected between the first end and the third end, a second branch is connected between the neutral point of the motor and the first end, a third switch is provided between the second connection point between the filtering and stabilizing capacitor and the third end and the third connection point between the first branch and the third end, a fourth switch is provided between the fourth connection point between the first branch and the first end and the fifth connection point between the second branch and the first end, and the third switch and the fourth switch realize a step-down and step-up current mode in the disconnected state.

6. The electric drive system according to claim 5, characterized in that: The second branch is provided with a fifth switch, and the first branch is provided with a second switch; In the boost charging mode, the third switch and the fourth switch are configured to be in a closed state, and the fifth switch and the second switch are configured to be in an open state.

7. The electric drive system according to claim 6, characterized in that: A first switch is provided between the second connection point and the neutral point of the motor, In the motor driving mode, the third switch, the fifth switch, the second switch and the first switch are configured to be in an open state, and the fourth switch is configured to be in a closed state; as well as In the direct charging mode, the third switch, the fifth switch and the first switch are configured to be in an open state, and the fourth switch and the second switch are configured to be in a closed state.

8. The electric drive system according to claim 1, characterized in that: The electric drive system further includes a DC bus capacitor, and two ends of the DC bus capacitor are connected between the first end and the second end.

9. The electric drive system according to claim 1, characterized in that: The electric drive system also includes an integrated filter, which is respectively connected to the first end, the second end and the third end.

10. An electric vehicle, characterized in that: The invention comprises a vehicle battery and an electric drive system as claimed in any one of claims 1 to 9.

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