Motor driving device and electrified vehicle including the same

Abstract

Disclosed are a motor driving device and an electrified vehicle including the same, the motor driving device including: a motor; a first inverter connected to the first DC terminal and the motor; a second inverter connected to the motor and the second DC terminal; a ground line including at least one first impedance element disposed thereon; and a connection line connecting the first DC terminal and the second DC terminal and including at least one second impedance element disposed thereon.

Description

Technical Field

[0001] This disclosure relates to the grounding structure of an electric motor with dual voltage sources. Background Technology

[0002] With increasing environmental concerns, there is a growing number of environmentally friendly vehicles using electric motors as their power source. These environmentally friendly vehicles are also known as electrified vehicles, and representative examples include hybrid electric vehicles (HEVs) or electric vehicles (EVs).

[0003] For small or light-duty electric vehicles, cost competitiveness is paramount; therefore, reducing not only the cost of the high-voltage battery but also the cost of the power electronic equipment (PE) is crucial. Furthermore, the high-voltage battery is the most expensive component in the high-voltage power electronic system. Reducing the cost of the power electronic equipment necessitates reducing the capacity of the high-voltage battery. However, when the capacity of the high-voltage battery is reduced, not only does the driving range of the electric vehicle decrease, but the output of the motor and inverter also decreases.

[0004] Therefore, motor drive systems using multiple independent batteries as voltage sources have been proposed. These motor drive systems have a different circuit structure than those using a single battery as a voltage source.

[0005] Furthermore, even in motor drives that use multiple independent batteries as voltage sources, grounding must meet safety and environmental regulations. Specifically, when multiple batteries are connected, each battery must be grounded.

[0006] 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 admission that they are prior art known to those skilled in the art. Summary of the Invention

[0007] One aspect of this disclosure is to provide a motor driving apparatus and an electrified vehicle including the motor driving apparatus, the motor driving apparatus having a grounding structure that interrupts the leakage of zero-sequence current when driving a motor having dual voltage sources.

[0008] It should be noted that the aspects of this disclosure are not limited to those described above, and other aspects of this disclosure will be apparent to those skilled in the art from the following description.

[0009] According to one embodiment of this 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; 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 first impedance element disposed thereon; and at least one connecting line connecting the first DC terminal and the second DC terminal, and including at least one second impedance element disposed thereon.

[0010] For example, DC voltage can be applied to the first DC terminal and the second DC terminal respectively.

[0011] For example, a first node may be connected between the two poles of a first DC terminal, and at least one first impedance element may be disposed between the first node and the two poles of the first DC terminal.

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

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

[0014] For example, at least one connection line may include a fourth node connected between the two poles of the first DC terminal, and at least one second impedance element may be disposed between the first DC terminal and the fourth node.

[0015] For example, at least one connection line may include a fifth node connected between the two poles of the second DC terminal, and at least one second impedance element may be disposed between the second DC terminal and the fifth node.

[0016] For example, at least one connection line may include a fourth node connected between the two poles of the first DC terminal and a fifth node connected between the two poles of the second DC terminal, and at least one second impedance element may be disposed between the fourth node and the two poles of the first DC terminal and between the fifth node and the two poles of the second DC terminal.

[0017] For example, at least one connection line may include a first connection line that connects to a first pole of a first DC terminal and a corresponding first pole of a second DC terminal; and a second connection line that connects to a second pole of a first DC terminal and a corresponding second pole of a second DC terminal.

[0018] For example, both the first connecting line and the second connecting line may include at least one second impedance element disposed thereon.

[0019] For example, at least one first impedance element and at least one second impedance element can form a resonant point in a frequency avoidance region, in which the zero-sequence voltage of the motor has a preset level or lower when the motor is operated.

[0020] For example, the avoidance frequency region may not overlap with the switching frequency region, which includes the switching frequency used to operate the motor, and the third harmonic frequency region, which includes the third harmonic frequency of the motor's electrical angular frequency.

[0021] For example, the frequency avoidance region may include a frequency region that includes the frequency between the switching frequency region and the third harmonic frequency region.

[0022] Each of at least one first impedance element and at least one second impedance element may include at least one of a capacitor and an inductor.

[0023] According to one embodiment 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 ends of the plurality of windings; a second inverter including a first end connected to the second ends of the plurality of windings and a second end connected to a second DC terminal; a grounding 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 first impedance element disposed thereon; a connecting wire connecting the first DC terminal and the second DC terminal, and including at least one second impedance element disposed thereon; and a first battery and a second battery, the first battery and the second battery being respectively connected to the first DC terminal and the second DC terminal.

[0024] According to the various embodiments of this disclosure described above, the grounding structure corresponding to the motor drive system with dual voltage sources is used to reduce the leakage of the zero-sequence component while meeting the grounding requirements of each dual voltage source.

[0025] It should be noted that the effects of this disclosure are not limited to those described above, and those skilled in the art can understand other effects of this disclosure from the following description. Attached Figure Description

[0026] Figure 1 The configuration of an electrified vehicle according to an embodiment of the present disclosure is shown.

[0027] Figure 2 The grounding structure of a motor drive device according to an embodiment of the present disclosure is shown.

[0028] Figure 3 The grounding structure of a motor drive device according to an embodiment of the present disclosure is shown.

[0029] Figure 4 An equivalent circuit of a grounding structure according to an embodiment of the present disclosure is shown.

[0030] Figure 5 Design criteria for impedance elements according to embodiments of this disclosure are shown.

[0031] Figure 6 Design criteria for impedance elements according to embodiments of this disclosure are shown. Detailed Implementation

[0032] The specific structural or functional descriptions are merely illustrative and are intended to describe the various embodiments of this disclosure disclosed herein. These various embodiments may be implemented in various forms and are not to be construed as limited to the embodiments set forth herein.

[0033] The embodiments of this disclosure can be modified in various ways and have various implementations. Therefore, specific embodiments will be described and described in detail with reference to examples in the accompanying drawings. However, it should be understood that the drawings and description are not intended to limit this disclosure to specific embodiments, but rather to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of this disclosure.

[0034] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms defined in common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted as having an idealized or overly formal meaning unless explicitly defined herein.

[0035] 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.

[0036] 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 parameter value 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.

[0037] In the following description, the suffixes “module” and “unit” placed after the component are for ease of description only and do not have a distinguishing meaning or function.

[0038] In describing embodiments of this disclosure, detailed descriptions of related technologies will be omitted where such descriptions would obscure the subject matter of the embodiments. Furthermore, the accompanying drawings are provided merely for a better understanding of the embodiments of this disclosure and not for limiting the technical concept of this disclosure. Therefore, it should be understood that the drawings include all modifications, equivalents, and alternatives within the scope and spirit of this disclosure.

[0039] Terms such as "first" and "second" can be used to describe various components, but components should not be limited by these terms. Furthermore, these terms are used only for the purpose of distinguishing one component from another.

[0040] When a component is described as "connected" or "joined" to another component, it should be understood that a component can be directly connected or joined to another component, but additional components may be present in between. However, when a component is described as "directly connected" or "directly coupled" to another component, it should be understood that no additional components may exist between the two components.

[0041] Unless the context clearly indicates otherwise, the singular form also includes the plural form.

[0042] In this disclosure, the terms “include” or “have” should be understood to indicate the presence of features, numbers, steps, operations, elements, components 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, components or combinations thereof.

[0043] The embodiments of this disclosure fulfill the need for a novel grounding structure suitable for a motor drive system comprising multiple independent batteries as voltage sources.

[0044] First, refer to Figures 1 to 4 The configuration of an electrified vehicle according to an embodiment of the present disclosure will be described below.

[0045] Figure 1 The configuration of an electrified vehicle according to an embodiment of the present disclosure is shown. Figure 2 and Figure 3 The grounding structure of a motor drive device according to an embodiment of the present disclosure is shown. Figure 4 An equivalent circuit of a grounding structure according to an embodiment of the present disclosure is shown.

[0046] refer to Figures 1 to 4 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 illustrations are the components associated with the description of the implementation methods, and the actual electrified vehicle may be implemented to include more than [other components]. Figure 1 The number of components, whether more or fewer.

[0047] First, the motor drive device 10 includes a motor 100, a first inverter 210, a second inverter 220, a grounding wire GL, and at least one connecting wire CL.

[0048] The motor 100 includes multiple windings, each corresponding to a multiple phase. A first inverter 210 has a first terminal connected to first DC terminals D11, D12, D11', and D12', and a second terminal connected to the first terminals of the multiple windings. A second inverter 220 has a first terminal connected to the second terminals of the multiple windings, and a second terminal connected to second DC terminals D21, D22, D21', and D22'. In other words, the motor drive 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.

[0049] A DC voltage is applied to the first DC terminals D11, D12, D11', and D12' and the second DC terminals D21, D22, D21', and D22'. The DC voltage 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, D12, D11', and D12', and the second battery can be connected to the second DC terminals D21, D22, D21', and D22'.

[0050] The ground wire GL includes a first node nd1 connected to the first DC terminals D11, D12, D11', and D12', a second node nd2 connected to the second DC terminals D21, D22, D21', and D22', and a third node nd3 connected to the ground GND between the first node nd1 and the second node nd2. According to one embodiment, the ground GND may be, for example, a vehicle chassis, but is not limited thereto.

[0051] Using this structure, the ground wire GL connects the first DC terminals D11, D12, D11', and D12' and the second DC terminals D21, D22, D21', and D22', thereby allowing the first battery 21 connected to the first DC terminals D11, D12, D11', and D12' and the second battery 22 connected to the second DC terminals D21, D22, D21', and D22' to be interconnected. Furthermore, the first battery 21 and the second battery 22 are simultaneously connected to ground GND via a third node nd3 located between the first node nd1 and the second node nd2.

[0052] Meanwhile, unlike the embodiments disclosed herein, the single-voltage-source-based motor drive system allows zero-sequence current to flow through 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 grounded as dual-voltage-source systems, the grounding circuit of the dual-voltage-source-based motor drive system in an electrified vehicle according to one embodiment can affect the flow of zero-sequence current. In this case, the zero-sequence circuit can be formed through the ground GND, thus allowing zero-sequence current to 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, as zero-sequence current can affect the safety of the vehicle and its occupants.

[0053] For this purpose, at least one first impedance element Z can be arranged on the grounding wire GL, and such configuration and arrangement of the first impedance element Z suppresses the zero-sequence current flowing to the ground GND.

[0054] Furthermore, according to one embodiment, the motor drive device 10 includes a connecting line CL, separate from the grounding line GL, for connecting the first DC terminals D11, D12, D11', and D12' to the second DC terminals D21, D22, D21', and D22', and at least one second impedance element Z' disposed on the connecting line CL. Separated from the first impedance element Z' placed on the grounding line GL, the second impedance element Z' is placed on the connecting line CL, thereby allowing for different designs of the zero-sequence impedance frequency in the grounding configuration.

[0055] The following section describes the detailed configuration of a grounding structure with a grounding wire GL and a connecting wire CL.

[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 first impedance element Z can be placed between the first node nd1 and the two poles D11 and D12 of the first DC terminal. More specifically, as... Figure 2 and Figure 3As shown, the first impedance element Z can be placed between the first pole D11 of the first DC terminal and the first node nd1, and between the second pole D12 of the first DC terminal and the first node nd1, 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 first 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... Figure 2 and Figure 3 As shown, the first 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] At the same time, such as Figure 2 As shown, the connecting line CL may include a fourth node nd4 connected between the two poles D11' and D12' of the first DC terminal, in which case at least one second impedance element Z' may be placed between the fourth node nd4 and the first DC terminals D11' and D12'. Furthermore, the connecting line CL may include a fifth node nd5 connected between the two poles D21' and D22' of the second DC terminal. In this case, at least one second impedance element Z' may be placed between the fifth node nd5 and the second DC terminals D21' and D22'.

[0059] Alternative locations, such as Figure 3 As shown, at least one connecting line CL may include a first connecting line CL1 for connecting the first pole D11 of the first DC terminal and the corresponding first pole D21 of the second DC terminal, and a second connecting line CL2 for connecting the second pole D12 of the first DC terminal and the corresponding second pole D22 of the second DC terminal. In this case, at least one second impedance element Z' may be placed on each of the first connecting line CL1 and the second connecting line CL2.

[0060] Figure 4 The equivalent circuit of the aforementioned grounding structure of the motor drive unit 10 and the electrified vehicle including the motor drive unit 10 is shown.

[0061] More specifically, Figure 4 The zero-sequence voltage e of motor 100 shown in 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, due to the inductance of the multiple windings in the motor 100, as well as the inductance and capacitance of the first impedance element Z and the second impedance element Z', resonance can occur in this equivalent circuit.

[0062] Here, the level of the zero-sequence current flowing into ground (GND) can vary depending on the location and manner in which the resonant point is formed in the frequency domain. When the maximum alternating current flows in the circuit, resonance occurs at the resonant point due to the minimum zero-sequence impedance. The formation of the resonant point can be controlled based on the configuration of the first impedance element Z and the second impedance element Z'. The following will refer to... Figure 5 and 6 Describe the configuration of the first impedance element Z and the second impedance element Z' used to suppress zero-sequence current.

[0063] Figure 5 and Figure 6 Design criteria for impedance elements according to embodiments of this disclosure are described. Figure 5 It is a graph of frequency and zero-sequence voltage, and Figure 6 It is a graph of frequency and zero-sequence impedance.

[0064] According to one embodiment, the first impedance element Z and the second impedance element Z' placed on the grounding wire GL and the connecting wire CL can be selected such that the resonant point can be formed in the avoidance frequency region, in which the zero-sequence voltage of the motor 100 has a preset level or lower when the motor 100 is operating.

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

[0066] Meanwhile, the avoided frequency regions may refer to regions a1, a2, and a3, which do not overlap with the switching frequency region b, which includes the switching frequency used to drive the motor 100, and the third harmonic frequency region c, which includes the third harmonic frequency 3fr, which includes the electrical angular frequency of the motor 100.

[0067] Specifically, according to one implementation, the avoided frequency region can be frequency region a2 between the switching frequency region b and the third harmonic frequency region c. In this case, the resonant point r is formed in a frequency region where the zero-sequence voltage component is relatively small, thereby suppressing the level of the zero-sequence current.

[0068] Therefore, the first impedance element Z' can form a grounding circuit together with the second impedance element Z, wherein the first impedance element Z is selected for the high-frequency region, and the second impedance element Z' is used to adjust the total zero-sequence impedance to the low-frequency region. Simultaneously, each of the first impedance element Z and the second impedance element Z' may include at least one of a capacitor and an inductor, and in this case, the combination of capacitor and inductor may be implemented differently depending on whether they are connected in series or in parallel. Furthermore, the capacitance of the elements forming the first impedance element Z and the second impedance element Z' can be determined by considering the switching frequency region b and the third harmonic frequency region c.

[0069] By using the grounding structure corresponding to the motor drive system with dual voltage sources according to the foregoing various 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.

[0070] Although specific embodiments of this disclosure have been described and illustrated above, those skilled in the art can make various modifications and alterations without departing from the technical concept defined by 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 a 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; A grounding wire, the grounding 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 the ground between the first node and the second node, and at least one first impedance element disposed thereon; and At least one connecting line connects the first DC terminal and the second DC terminal, and includes at least one second impedance element disposed thereon.

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 first 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 first 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 first node is connected between the two poles of the first DC terminal, and the second node is connected between the two poles of the second DC terminal. The at least one first impedance element is 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.

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

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

8. The motor drive device according to claim 1, wherein... The at least one connection line includes a fourth node connected between the two poles of the first DC terminal and a fifth node connected between the two poles of the second DC terminal, and The at least one second impedance element is disposed between the fourth node and the two poles of the first DC terminal, and between the fifth node and the two poles of the second DC terminal.

9. The motor drive device according to claim 1, wherein... The at least one connecting line includes A first connecting line connects the first terminal of the first DC terminal to the corresponding first terminal of the second DC terminal; and The second connecting line connects the second pole of the first DC terminal to the corresponding second pole of the second DC terminal.

10. The motor drive device according to claim 9, wherein each of the first connecting line and the second connecting line includes the at least one second impedance element disposed thereon.

11. The motor drive device according to claim 1, wherein The at least one first impedance element and the at least one second impedance element form a resonant point in the avoidance frequency region, in which the zero-sequence voltage of the motor has a preset level or lower when the motor is operated.

12. The motor drive device according to claim 11, wherein the avoidance frequency region does not overlap with the switching frequency region including the switching frequency of operating the motor and the third harmonic frequency region including the third harmonic frequency of the electrical angular frequency of the motor.

13. The motor drive device according to claim 12, wherein the avoidance frequency region includes a frequency region, the frequency region including the frequency between the switching frequency region and the third harmonic frequency region.

14. The motor drive device according to claim 11, wherein each of the at least one first impedance element and the at least one second impedance element comprises at least one of a capacitor and an inductor.

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 a 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; A grounding wire, the grounding 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 the ground between the first node and the second node, and at least one first impedance element disposed thereon; A connecting line that connects the first DC terminal and the second DC terminal, and includes at least one second impedance element disposed thereon; as well as A first battery and a second battery are respectively connected to the first DC terminal and the second DC terminal.

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