Motor driving apparatus and electrified vehicle including same

Abstract

Disclosed is a motor driving apparatus including a motor, a first inverter connected with a first DC terminal and the motor, a second inverter connected with the motor and a second DC terminal, and a ground wire, and a ground line including a first node connected with the first DC terminal, a second node connected with the second DC terminal, a third node connected with ground between the first node and the second node, and at least one impedance element disposed on the ground line, and an electrified vehicle including the same.

Description

Technical Field

[0001] This invention relates to a grounding structure for an electric motor with dual voltage sources. Background Technology

[0002] With increasing public concern about the environment and the environmental impact of vehicles, more and more environmentally friendly vehicles are using electric motors as their power source. These environmentally friendly vehicles are also known as electrified vehicles, with representative examples including hybrid electric vehicles (HEVs) or electric vehicles (EVs).

[0003] For small or light-duty electric vehicles, cost competitiveness is crucial; therefore, it's essential to reduce not only the cost of the high-voltage battery but also the cost of the power electronic equipment (PE). The high-voltage battery is the most expensive component in the high-voltage power electronics. Reducing the cost of the PE requires decreasing the capacity of the high-voltage battery. However, when the capacity of the high-voltage battery is reduced, not only will the electric vehicle's driving range decrease, but the output of the motor and inverter will also decrease.

[0004] Therefore, a motor drive system using multiple independent batteries as voltage sources is proposed. This motor drive system has a different circuit structure than a motor drive system using a single battery as a voltage source.

[0005] Furthermore, even in motor drives that use multiple independent batteries as voltage sources, grounding is required to meet safety and environmental regulations. In particular, when multiple batteries are connected, it is necessary to ground each battery.

[0006] Therefore, a new grounding structure is needed for motor drive systems that include multiple independent batteries as voltage sources.

[0007] The above description of related technologies is only intended to enhance the understanding of the background of this disclosure and should not be construed as an endorsement that they are prior art known to those skilled in the art. Summary of the Invention

[0008] One aspect of this disclosure is to provide a motor drive device and an electrified vehicle including the motor drive device, the motor drive device having a grounding structure that blocks zero-sequence current leakage when driving a motor with dual voltage sources.

[0009] It should be noted that the aspects of this disclosure are not limited to those described above, and that other aspects of this disclosure will be apparent to those skilled in the art from the following description.

[0010] According to an embodiment of the present disclosure, a motor drive device includes: a motor including a plurality of windings; a first inverter including a first end connected to a first DC terminal and a second end connected to the first end of the plurality of windings; a second inverter including a first end connected to the second end of the plurality of windings and a second end connected to a second DC terminal; and a ground wire including a first node connected to the first DC terminal, a second node connected to the second DC terminal, a third node connected to ground between the first node and the second node, and at least one impedance element disposed on the ground wire.

[0011] For example, DC voltage can be applied to the first DC terminal and the second DC terminal respectively.

[0012] For example, the first node can be connected between the two poles of the first DC terminal, and at least one impedance element can be disposed between the first node and the two poles of the first DC terminal.

[0013] For example, the second node can be connected between the two poles of the second DC terminal, and at least one impedance element can be disposed between the second node and the two poles of the second DC terminal.

[0014] For example, at least one impedance element may be disposed between the first node and the third node, and between the second node and the third node.

[0015] For example, at least one impedance element can be placed between the third node and ground.

[0016] For example, a first node can be connected between the two poles of a first DC terminal, a second node can be connected between the two poles of a second DC terminal, and at least one impedance element can be disposed between the first node and the two poles of the first DC terminal, and between the second node and the two poles of the second DC terminal.

[0017] For example, at least one impedance element may be additionally provided in at least one of a first position and a second position, wherein the first position is between the first node and the third node and between the second node and the third node, and the second position is between the third node and ground.

[0018] For example, at least one impedance element can form a resonant point in the frequency avoidance region, where the zero-sequence voltage of the motor has a preset level or lower when the motor is operating.

[0019] For example, the avoidance frequency region may not overlap with the switching frequency region, which includes the switching frequency used for motor operation, or with the third harmonic frequency region, which includes the third harmonic frequency used for the electrical angular frequency of the motor.

[0020] For example, the avoidance frequency region may include a frequency region with frequencies higher than the switching frequency region.

[0021] For example, at least one impedance element may include a single capacitor or inductor element.

[0022] For example, at least one impedance element may include a combination of a capacitor and an inductor.

[0023] For example, at least one impedance element can generate a segment of increased impedance between multiple resonant points in the frequency domain when the motor is operating.

[0024] According to embodiments of the present disclosure, an electrified vehicle includes: an electric motor including a plurality of windings; a first inverter including a first end connected to a first DC terminal and a second end connected to the first end of the plurality of windings; a second inverter including a first end connected to the second end of the plurality of windings and a second end connected to a second DC terminal; a ground wire including a first node connected to the first DC terminal, a second node connected to the second DC terminal, a third node connected to ground between the first node and the second node, and at least one impedance element disposed on the ground wire; and a first battery and a second battery, respectively connected to the first DC terminal and the second DC terminal.

[0025] According to various embodiments of the present disclosure as described above, the grounding structure corresponding to the motor drive system with dual voltage sources is used to mitigate the leakage of the zero-sequence component while satisfying the grounding requirements of each of the dual voltage sources.

[0026] It should be noted that the effects of this disclosure are not limited to those described above, and other effects will be readily apparent to those skilled in the art from the following description. Attached Figure Description

[0027] Figure 1 The configuration of an electrified vehicle according to an embodiment of the present disclosure is shown.

[0028] Figure 2 The grounding structure of a motor drive device according to an embodiment of the present disclosure is shown.

[0029] Figure 3 The grounding structure of a motor drive device according to an embodiment of the present disclosure is shown.

[0030] Figure 4 The grounding structure of a motor drive device according to an embodiment of the present disclosure is shown.

[0031] Figure 5 An equivalent circuit of a grounding structure according to an embodiment of the present disclosure is shown.

[0032] Figure 6 Design criteria for impedance elements according to embodiments of this disclosure are described.

[0033] Figure 7Design criteria for impedance elements according to embodiments of this disclosure are described.

[0034] Figure 8 Design criteria for impedance elements according to embodiments of this disclosure are described. Detailed Implementation

[0035] The structural or functional descriptions herein are illustrative only and are intended to illustrate embodiments of the present disclosure with respect to the various implementations described herein. These various implementations may be carried out in various forms and should not be construed as limited to the implementations set forth herein.

[0036] The embodiments of this disclosure can be modified and have various implementations; therefore, specific embodiments will be shown and described in detail by way of example in the accompanying drawings. However, it should be understood that the drawings and description are not intended to limit this disclosure to the specific embodiments, but rather to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of this disclosure.

[0037] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should be further understood that terms defined in commonly used dictionaries shall be interpreted as having the same meaning as they have in the relevant technical context, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0038] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, wherein the same or similar elements are indicated by the same reference numerals, even if they are depicted in different drawings, and redundant descriptions will be avoided.

[0039] In the following description of the implementation, when a parameter is referred to as a "preset," it may be intended to mean that the value of the parameter is predetermined when it is used in a process or algorithm. The value of the parameter may be set at the start of the process or algorithm, or it may be set during a period of execution of the process or algorithm.

[0040] In the following description, the suffixes "module" and "unit" after "component" are given for ease of description only and have no distinguishing meaning or function.

[0041] In describing embodiments of this disclosure, detailed descriptions of related technologies will be omitted where such descriptions might make the subject matter of the embodiments of this disclosure quite unclear. Furthermore, the accompanying drawings are provided only for a better understanding of embodiments of this disclosure and are not intended to limit the technical concept of this disclosure. Therefore, it should be understood that the drawings include all modifications, equivalents, and substitutions within the scope and spirit of this disclosure.

[0042] Terms such as “first” and “second” may be used to describe various components, but components should not be limited by the terms mentioned above. Furthermore, the terms mentioned above are only used to distinguish one component from another.

[0043] When a component is described as being "connected" or "joined" to another component, it should be understood that a component may be directly connected or joined to another component, but there may be additional components in between. However, when a component is described as being "directly connected" or "directly coupled" to another component, it should be understood that there may be no additional components between the two components.

[0044] Unless the context clearly indicates otherwise, the singular form also includes the plural form.

[0045] In this disclosure, it should be understood that the terms "comprising" or "having" mean the presence of the features, numbers, steps, operations, elements, parts or combinations thereof described in the embodiments, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, elements, parts or combinations thereof.

[0046] First, refer to Figures 1 to 5 The configuration of an electrified vehicle according to an embodiment of the present disclosure will now be described.

[0047] Figure 1 The diagram illustrates the configuration of an electrified vehicle according to an embodiment of the present disclosure. Figures 2 to 4 The grounding structure of a motor drive device according to an embodiment of the present disclosure is shown. Figure 5 An equivalent circuit of a grounding mechanism according to an embodiment of the present disclosure is shown.

[0048] refer to Figures 1 to 5 An electrified vehicle according to an embodiment of this disclosure includes an electric motor drive unit 10, a first battery 21, and a second battery 22. However, Figure 1 The main illustration shows components related to the description of the implementation method; a real electrified vehicle can be implemented including more than [specific components]. Figure 1 The number of parts or the number of parts.

[0049] First, the motor drive device 10 includes a motor 100, a first inverter 210, a second inverter 220, and a ground wire GL.

[0050] The motor 100 includes multiple windings, each corresponding to a multiple phase. A first inverter 210 has a first end connected to first DC terminals D11 and D12, and a second end connected to the first ends of the multiple windings. A second inverter 220 has a first end connected to the second ends of the multiple windings, and a second end connected to second DC terminals D21 and D22. In other words, the motor drive device according to the embodiment has a dual-inverter structure, wherein multiple inverters are connected to both ends of the motor 100, and therefore the motor 100 is driven by the first inverter 210 and the second inverter 220.

[0051] DC voltages are applied to the first DC terminals D11 and D12 and the second DC terminals D21 and D22, respectively. The DC voltages can be provided by the first battery 21 and the second battery 22, respectively. For this purpose, the first battery 21 can be connected to the first DC terminals D11 and D12, and the second battery can be connected to the second DC terminals D21 and D22.

[0052] The ground wire GL includes a first node nd1 connected to the first DC terminals D11 and D12, a second node nd2 connected to the second DC terminals D21 and D22, and a third node nd3 connected to ground GND between the first node nd1 and the second node nd2. According to an embodiment, ground GND may be, for example, a vehicle chassis, but is not limited thereto.

[0053] Using this structure, the ground wire GL connects the first DC terminals D11 and D12 to the second DC terminals D21 and D22, allowing the first battery 21 connected to the first DC terminals D11 and D12 and the second battery 22 connected to the second DC terminals D21 and D22 to be connected to each other. Furthermore, the first battery 21 and the second battery 22 are immediately connected to ground GND via a third node nd3 located between the first node nd1 and the second node nd2.

[0054] Meanwhile, unlike the embodiments disclosed herein, the motor drive system based on a single voltage source allows zero-sequence current to flow through the interior of the motor and inverter, thus the grounding circuit has no effect on the flow of zero-sequence current. On the other hand, when both the first battery 21 and the second battery 22 are connected to ground as dual voltage sources, the grounding circuit of the dual-voltage-source-based motor drive system in the electrified vehicle according to the embodiment can affect the flow of zero-sequence current. In this case, a zero-sequence circuit can be formed through the ground GND, so zero-sequence current can leak to the ground GND. In particular, when the vehicle chassis is used as the ground GND, it is necessary to prevent zero-sequence current from flowing to the ground GND, because zero-sequence current can affect the safety of the vehicle and vehicle users.

[0055] To this end, at least one impedance element Z can be placed on the ground wire GL. This configuration and arrangement of the impedance element Z suppresses the zero-sequence current flowing to the ground GND. The detailed configuration of the ground wire GL with the impedance element Z will be described below.

[0056] According to the embodiment, the first node nd1 is connected between the two poles D11 and D12 of the first DC terminal, and at least one impedance element Z can be disposed between the first node nd1 and the two poles D11 and D12 of the first DC terminal. More specifically, as... Figures 2 to 4 As shown, the impedance element Z can be placed between the first pole D11 and the first node nd1 of the first DC terminal and between the second pole D12 and the first node nd1 of the first DC terminal, respectively.

[0057] Furthermore, the second node nd2 is connected between the two poles D21 and D22 of the second DC terminal, and at least one impedance element Z can be placed between the second node nd2 and the two poles D21 and D22 of the second DC terminal. More specifically, as... Figures 2 to 4 As shown, the impedance element Z can be placed between the first pole D21 and the second node nd2 of the second DC terminal, and between the second pole D22 and the second node nd2 of the second DC terminal, respectively.

[0058] Furthermore, at least one impedance element Z can be placed between the first node nd1 and the third node nd3, and between the second node nd2 and the third node nd3, such as Figure 3 As shown, it can be placed between the third node nd3 and ground GND, such as Figure 4 As shown.

[0059] Figure 2 The diagram shows the structure in which impedance element Z is positioned between the first node nd1 and the first DC terminals D11 and D12, and between the second node nd2 and the second DC terminals D21 and D22. Figure 3 Showing with Figure 2 In contrast, the impedance element Z is further positioned between the first node nd1 and the third node nd3, and between the second node nd2 and the third node nd3. Figure 4 Showing with Figure 2 In contrast, the impedance element Z is further positioned between the third node nd3 and ground GND. However, the grounding structure applicable to embodiments of this disclosure is not limited to these structures; for example, it can be achieved through... Figure 3 and Figure 4 The combination of structures shown is used to house the impedance element Z.

[0060] at the same time, Figure 5 The equivalent circuit of the above-described grounding structure of the motor drive device 10 and the electrified vehicle including it, according to an embodiment, is shown.

[0061] More specifically, Figure 5 Showing with Figure 1 The equivalent circuit corresponding to the grounding structure, and the zero-sequence voltage e of motor 100 on the equivalent circuit. n The zero-sequence voltage V of the first inverter 210 01 The zero-sequence voltage V of the second inverter 220 02 It can be used as a voltage source for a zero-sequence circuit. Furthermore, resonance may occur in this equivalent circuit due to the inductance of the multiple windings in the motor 100 and the inductance and capacitance of the impedance element Z.

[0062] Here, the level of the zero-sequence current flowing in ground GND can vary depending on the location and manner in which the resonant point is formed in the frequency domain, at which resonance occurs due to the minimum zero-sequence impedance when the maximum AC current flows in the circuit. The formation of the resonant point can be controlled based on the configuration of the impedance element Z. The following will refer to... Figures 6 to 8 Describe the impedance element Z used to suppress zero-sequence current.

[0063] Figures 6 to 8 The design criteria for impedance elements according to embodiments of this disclosure are described. Figure 6 It is a graph of frequency and zero-sequence voltage. Figure 7 and Figure 8 It is a graph of frequency and zero-sequence impedance.

[0064] According to the embodiment, at least one impedance element Z placed on the ground wire GL can be selected such that when the motor 100 is operating, the resonant point can be formed in the avoidance frequency region where the zero-sequence voltage of the motor 100 has a preset level or lower.

[0065] Here, the zero-sequence voltage generated when the motor 100 is operating can vary depending on the operating speed, output torque, switching frequency, etc. of the motor 100. Therefore, the preset level of the zero-sequence voltage can be based on the operating conditions of the motor 100 and the driving conditions of the first inverter 210 and the second inverter 220. For example, the preset level of the zero-sequence voltage can vary depending on the specifications of the motor 100, the first inverter 210, and the second inverter 220 applied to the vehicle model or vehicle.

[0066] Meanwhile, the avoidance frequency region can refer to regions a1, a2, and a3. The aforementioned avoidance frequency region does not overlap with the switching frequency region b, which includes the switching frequency nfsw used to drive the motor 100, and does not overlap with the third harmonic frequency region c, which includes the third harmonic frequency 3fr used for the electrical angular frequency of the motor 100.

[0067] Specifically, according to the implementation method, the avoided frequency region can be a frequency region a1 with a frequency higher than that of the switching frequency region b, such as... Figure 7 As shown. In this case, the resonant point r is formed in the frequency region where the zero-sequence voltage component is relatively small, thereby suppressing the level of the zero-sequence current.

[0068] Therefore, the impedance element Z can be configured as a single passive element, such as a capacitor or an inductor. In other words, according to the embodiment, the impedance element Z is configured as a single passive element such that the resonant point can be formed in the avoided frequency region, thereby taking into account the switching frequency region b and the third harmonic frequency region c to determine the capacitance of the element forming the impedance element Z.

[0069] Furthermore, the impedance element Z can be configured using a combination of capacitors and inductors. In this case, the combination of capacitors and inductors can be implemented in various ways based on series and parallel connections. In this way, when the impedance element Z is configured through a combination of multiple elements, the impedance at the resonant point can be controlled, as exemplified in... Figure 8 As shown in the image.

[0070] refer to Figure 8 The impedance element Z, through a combination of multiple elements, generates a segment u with increased impedance between multiple resonant points r1 and r2 when the motor 100 is operating. Here, the multiple resonant points r1 and r2 are not necessarily referred to as points where the impedance is exactly at its minimum, but can include points where the impedance is close to its minimum over the entire frequency range. By using the impedance element Z to form the segment u with increased impedance between resonant points r1 and r2, the impedance is relatively increased at resonant points r1 and r2, thereby correspondingly reducing the level of the zero-phase current.

[0071] By using the grounding structure corresponding to the motor drive system with dual voltage sources according to the various foregoing embodiments of this disclosure, the grounding requirements of each of the dual voltage sources are met, and the leakage of the zero-sequence component is reduced.

[0072] Although specific embodiments of this disclosure have been shown and described above, various modifications and alterations can be made by those skilled in the art without departing from the scope of the technical concept defined in the appended claims.

Claims

1. A motor drive device, comprising: An electric motor, the electric motor comprising multiple windings; A first inverter, the first inverter including a first end connected to a first DC terminal and a second end connected to the first end of the plurality of windings; The second inverter includes a first end connected to a second end of the plurality of windings and a second end connected to a second DC terminal; and The ground wire includes a first node connected to the first DC terminal, a second node connected to the second DC terminal, a third node connected to ground between the first node and the second node, and at least one impedance element disposed on the ground wire.

2. The motor drive device according to claim 1, wherein DC voltage is applied to the first DC terminal and the second DC terminal respectively.

3. The motor drive device according to claim 1, wherein... The first node is connected between the two poles of the first DC terminal, and The at least one impedance element is disposed between the two poles of the first node and the first DC terminal.

4. The motor drive device according to claim 1, wherein... The second node is connected between the two poles of the second DC terminal, and The at least one impedance element is disposed between the two poles of the second node and the second DC terminal.

5. The motor drive device according to claim 1, wherein the at least one impedance element is disposed between the first node and the third node, and between the second node and the third node.

6. The motor drive device according to claim 1, wherein the at least one impedance element is disposed between the third node and ground.

7. The motor drive device according to claim 1, wherein... The first node is connected between the two poles of the first DC terminal. The second node is connected between the two poles of the second DC terminal, and The at least one impedance element is disposed between the two poles of the first node and the first DC terminal, and between the two poles of the second node and the second DC terminal.

8. The motor drive device according to claim 7, wherein the at least one impedance element is additionally disposed in at least one of a first position and a second position, the first position being between the first node and the third node and between the second node and the third node, and the second position being between the third node and ground.

9. The motor drive device according to claim 1, wherein the at least one impedance element forms a resonant point in the avoidance frequency region, wherein the zero-sequence voltage of the motor has a preset level or lower when the motor is operating in the avoidance frequency region.

10. The motor drive device according to claim 9, wherein the avoidance frequency region does not overlap with the switching frequency region including the switching frequency of the motor operation, and does not overlap with the third harmonic frequency region including the third harmonic frequency of the electrical angular frequency used by the motor.

11. The motor drive device according to claim 10, wherein the avoidance frequency region is a frequency region having a higher frequency than the switching frequency region.

12. The motor drive device according to claim 9, wherein each of the at least one impedance element is a single capacitor or inductor element.

13. The motor drive device according to claim 9, wherein each of the at least one impedance element is a combination of a capacitor and an inductor.

14. The motor drive device according to claim 13, wherein the at least one impedance element generates a segment with increased impedance between a plurality of resonant points in the frequency domain when the motor is operating.

15. An electrified vehicle comprising: An electric motor, the electric motor comprising multiple windings; A first inverter, the first inverter including a first end connected to a first DC terminal and a second end connected to the first end of the plurality of windings; The second inverter includes a first end connected to a second end of the plurality of windings and a second end connected to a second DC terminal; The ground wire includes a first node connected to the first DC terminal, a second node connected to the second DC terminal, a third node connected to ground between the first node and the second node, and at least one impedance element disposed on the ground wire. and A first battery and a second battery are respectively connected to the first DC terminal and the second DC terminal.

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