Electric vehicle

Abstract

The invention relates to an electric vehicle. The electric vehicle includes a controller configured to drive the motor according to a rotational speed of the motor when the motor is driven in a state in which the auxiliary battery is electrically connected to the motor through a node in which each second end of the plurality of windings is connected to each other. Pulse width modulation of the first inverter is controlled by at least one of a first pulse width modulation method and a second pulse width modulation method.

Description

Technical Field

[0001] This invention relates to an electric vehicle capable of installing a main battery and / or an auxiliary battery, and a control method thereof. Background Technology

[0002] Recently, with the global trend of carbon dioxide emission reduction, the demand for electric vehicles that generate power by using electricity stored in batteries to drive electric motors is increasing, in order to replace traditional internal combustion engine vehicles that generate power by burning fossil fuels.

[0003] The charging time for the batteries of electric vehicles may be longer than the refueling time for internal combustion engine vehicles, so it is important to consider (for example, the maximum driving range that an electric vehicle can travel on a single fully charged battery).

[0004] The maximum driving range of an electrified vehicle can vary depending on the battery voltage and capacity. Even with the same battery capacity, the voltage and charge level can differ depending on the combination of series / parallel connections between modules or cells. For example, the battery voltage can correspond to a value obtained by multiplying the voltage of a battery cell by the number of cells connected in series, and the battery charge level can correspond to a value obtained by multiplying the charge level of a battery cell by the number of cells connected in parallel.

[0005] Therefore, increasing the battery voltage can be considered to increase the driving range. However, increasing the battery voltage requires strengthening the voltage resistance design of the motor system, so a method that can increase the driving range without increasing the battery voltage is useful (e.g., necessary).

[0006] The above content is intended to help understand the background of this invention. Summary of the Invention

[0007] Therefore, the present invention aims to provide an electric vehicle capable of performing pulse width modulation control, which reduces harmonic effects when the motor is driven while the auxiliary battery and the motor are connected (e.g., connected to each other).

[0008] The present invention provides an electric vehicle capable of installing an auxiliary battery. The electric vehicle includes a motor, a first inverter, a main battery, and a controller. The motor includes multiple windings; the first inverter has a DC terminal and multiple branches connected to each first terminal of the multiple windings; the main battery is connected to the DC terminal; the controller is configured to perform pulse width modulation control of the first inverter, based on the motor's rotational speed, using either a first pulse width modulation method or a second pulse width modulation method, when driving the motor with the auxiliary battery installed and electrically connected to the motor via nodes where each second terminal of the multiple windings is interconnected (e.g., interconnected with each other), and the auxiliary battery is connected to the motor.

[0009] According to the present invention, the auxiliary battery can be used together with the main battery to drive the motor, thereby (e.g., effectively) increasing the driving range of the electrified vehicle.

[0010] In addition, when the motor is driven with the auxiliary battery electrically connected to the motor (e.g., electrically connected to each other), a pulse width modulation method less affected by harmonic effects is executed according to the motor speed, thereby improving the motor's drive efficiency without the need to add a separate device.

[0011] The present invention is not limited to the effects described above, and other effects not mentioned herein may be understood from the description herein. Attached Figure Description

[0012] The above and other objects and features of the present invention can be understood from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0013] Figure 1 This is a schematic diagram of the configuration of an electrified vehicle according to an embodiment of the present invention;

[0014] Figure 2 and Figure 3 This is a schematic diagram of an example of a motor system applicable to an embodiment of the present invention;

[0015] Figure 4 The graphs are of the first and second driving modes according to an embodiment of the present invention.

[0016] Figure 5 and Figure 6 This is a schematic diagram of a first pulse width modulation method according to an embodiment of the present invention;

[0017] Figure 7 This is a schematic diagram of a second pulse width modulation method according to an embodiment of the present invention;

[0018] Figure 8 and Figure 9 This is a schematic diagram of the determination criteria for the pulse width modulation method according to an embodiment of the present invention; and

[0019] Figure 10 This is a flowchart illustrating the process of controlling pulse width modulation according to an embodiment of the present invention. Detailed Implementation

[0020] The structural or functional description herein is intended to describe exemplary embodiments. However, the invention can be implemented in various ways and is not limited to the exemplary embodiments.

[0021] The embodiments described herein may be varied in manner and form, as the embodiments shown in the accompanying drawings and described herein are examples. Modifications, equivalents, and alternatives to exemplary embodiments of the invention may be included with reference to the accompanying drawings.

[0022] In the following description, exemplary embodiments disclosed herein will be described with reference to the accompanying drawings. In this specification, the same or similar components will be indicated by the same or similar reference numerals, and repeated descriptions may be omitted.

[0023] In the description of the embodiments herein, the term "preset" means (e.g., that the value of a parameter is predetermined when it is used in a process or algorithm). According to an exemplary embodiment, the value of a parameter may be set at the start of the process or algorithm, or may be set during the execution of the process or algorithm.

[0024] In this description, for convenience, the terms “module” and “part” included in the constituent elements may be used simultaneously, and it is stated that “module” and “part” do not have independent meanings or functions.

[0025] If a detailed description would obscure the embodiments described herein, such description may be omitted. Furthermore, the accompanying drawings are intended to illustrate embodiments of this specification, but this specification is not limited to the embodiments shown in the accompanying drawings. This specification may include modifications, equivalents, and alternatives contained in this invention.

[0026] The terms used herein, including ordinal numbers such as “first” or “second”, may be used to describe various elements, but these elements may not be limited by these terms. The terms may be used to distinguish one constituent element from another.

[0027] When a component is described as “connected,” “joined,” or “joined” to another component, that component may (for example, directly) be connected, joined, or joined to the other component. However, there may also be another component between the components. Conversely, when a component is described as “directly joined” or “directly connected” to another component, there may be no intermediate component.

[0028] Unless the context otherwise indicates, singular expressions include plural expressions.

[0029] Terms such as “comprising” and “having” are intended to specify the features, values, steps, operations, elements, components or combinations thereof disclosed in the specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, values, steps, operations, elements, components or combinations thereof.

[0030] Additionally, the word "unit" or "control unit" in the names of motor control unit (MCU) and hybrid power control unit (HCU) may (e.g., typically) refer to a controller that controls (e.g., a specific) function of the vehicle, and not (e.g., imply) a general-purpose functional unit.

[0031] Additionally, the "controller" may include a communication device, a memory, and at least one processor, the communication device being configured to communicate with another controller or sensor to control assigned functions, the memory being configured to store an operating system, logic instructions, and input and output information, and the at least one processor being configured to perform determinations, calculations, and decisions that can be used to control the assigned functions (e.g., as required).

[0032] Before describing pulse width modulation, we will refer to Figures 1 to 3 Describes (e.g., an embodiment of the invention) an electrified vehicle.

[0033] Figure 1 This is a schematic diagram of the configuration of an electric vehicle according to an embodiment of the present invention.

[0034] refer to Figure 1 The electric vehicle according to the embodiment includes a main battery 10, a motor system 30, and a controller 40. An auxiliary battery 20 may be installed in the electric vehicle. This document will describe the electric vehicle according to the embodiment with the auxiliary battery 20 installed.

[0035] The motor system 30 may include a motor as a power source for the electrified vehicle, and may include at least one inverter for driving the motor. The motor system 30 may be connected to the main battery 10 and the auxiliary battery 20 by being located between the main battery 10 and the auxiliary battery 20.

[0036] In an exemplary embodiment, the motor system 30 can drive the motor by operating the inverter based on the voltage of the main battery 10.

[0037] Additionally, in the electrified vehicle according to an exemplary embodiment, the auxiliary battery 20 may (e.g., optionally) be connected to the motor system 30. Furthermore, when the auxiliary battery 20 is connected to the motor system 30, the auxiliary battery 20 can supply power to the motor system 30. In an exemplary embodiment of the invention, the auxiliary battery 20 is different from the main battery 10. For example, the capacity or voltage of the auxiliary battery 20 may have a value equal to or less than the capacity or voltage of the main battery 10. Furthermore, since the auxiliary battery 20 can be used to drive the motor 31, the auxiliary battery 20 is different from the low-voltage (e.g., 12V) battery used to operate the electrical components. Moreover, the auxiliary battery 20 may have a larger capacity or a larger voltage than the low-voltage battery used to operate the electrical components.

[0038] In an exemplary embodiment, the auxiliary battery 20 can be used as a power source for driving the motor, or it can charge the main battery 10 by supplying power to the main battery 10 via the motor system 30. Alternatively, the auxiliary battery 20 can be charged by receiving power from the main battery 10 via the motor system 30.

[0039] Simultaneously, for example, controller 40 can control the switching state of the inverter included in motor system 30. Furthermore, controller 40 can control motor system 30 according to a first drive mode where auxiliary battery 20 is disconnected from the motor of motor system 30 (e.g., electrically disconnected) or a second drive mode where auxiliary battery 20 is connected to the motor of motor system 30 (e.g., electrically connected). Therefore, controller 40 can generate current commands for the motor of motor system 30 based on the voltage modulation index.

[0040] In an exemplary embodiment, controller 40 may be implemented as a single controller or as multiple controllers with distributed functionality. For example, controller 40 may be implemented as a combination of a motor control unit (MCU) configured to control the motor of motor system 30 and its superior control unit (e.g., a hybrid power control unit (HCU), a vehicle control unit (VCU), and a hydrogen fuel cell control unit (FCCU), etc.), but is not limited thereto. According to another exemplary embodiment, controller 40 may further include a charging controller.

[0041] As described herein, the motor system 30 can be (e.g., electrically) connected to the main battery 10 or to the auxiliary battery 20. Therefore, by utilizing the power of the auxiliary battery 20 to drive the motor, the driving range can be increased. Figure 2 and Figure 3 The diagram shows a structure, for example, for this purpose.

[0042] Figure 2 and Figure 3This is a schematic diagram of an example of a motor system applicable to an embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram illustrating an example of a motor system 30 implemented as a single inverter 32-1 structure. Figure 3 This is a schematic diagram of an example of a motor system 30 implemented as a dual inverter structure 32-1 and 32-2.

[0044] First, refer to Figure 2 According to an exemplary embodiment, the motor system 30 may include a motor 31, a first inverter 32-1, charging switches T1 and T2, and DC capacitors Cdc and Cn. Additionally, the motor system 30 may have DC terminals D1, D2, D3, and D4 connected to the main battery 10 and the auxiliary battery 20.

[0045] In an exemplary embodiment, the motor 31 may include a plurality of windings L1, L2, and L3 corresponding to a plurality of phases U, V, and W, respectively. The first inverter 32-1 has DC terminals D1 and D2 connected to the main battery 10 and may include a plurality of branches S1-S2, S3-S4, and S5-S6 connected to each first terminal of the plurality of windings L1, L2, and L3 included in the motor 31.

[0046] Charging switches T1 and T2 can be connected to the auxiliary battery 20 and each second terminal of the plurality of windings L1, L2, and L3 included in the motor 31 via a location between the auxiliary battery 20 and each second terminal of the windings L1, L2, and L3. In an exemplary embodiment, charging switches T1 and T2 can be connected to the node nd and the positive terminal of the auxiliary battery 20 via a location between the node nd and the positive terminal of the auxiliary battery 20, the node nd forming the neutral point of the motor 31 through the interconnection (e.g., interconnection) of the plurality of windings L1, L2, and L3. In an exemplary embodiment, charging switches T1 and T2 can be implemented as insulated gate bipolar transistors (IGBTs), but can also be implemented as another element capable of performing switching operations, such as metal-oxide-semiconductor field-effect transistors (MOSFETs), etc. Furthermore, although in Figure 2 and Figure 3 The charging switches T1 and T2 are connected in series, but the connection structure of the charging switches T1 and T2 is not limited to this.

[0047] The first drive mode or the second drive mode described herein can be executed based on the on / off state of charging switches T1 and T2. In an exemplary embodiment, in the first drive mode, charging switches T1 and T2 are off. In this exemplary embodiment, node nd and auxiliary battery 20 are disconnected (e.g., electrically disconnected from each other), and auxiliary battery 20 is disconnected from motor 31. Conversely, in the second drive mode, charging switches T1 and T2 are on. In this exemplary embodiment, node nd and auxiliary battery 20 are connected (e.g., electrically connected to each other), and auxiliary battery 20 and motor 31 are connected (e.g., connected to each other).

[0048] Meanwhile, the motor system 30 can be connected to the auxiliary battery 20 via relays RLY1 and RLY2. In this case, relay RLY1 can be connected to the positive terminal and DC terminal D3 of the auxiliary battery 20 by being located between the positive terminal and DC terminal D3, and relay RLY2 can be connected to the negative terminal and DC terminal D4 of the auxiliary battery 20 by being located between the negative terminal and DC terminal D4.

[0049] In an exemplary embodiment, the term "auxiliary battery 20 is installed" may refer to (e.g., meaning) the state in which the auxiliary battery 20 is connected to the motor system 30 when relays RLY1 and RLY2 are turned on. However, even if relays RLY1 and RLY2 are turned on and the auxiliary battery 20 is installed, the auxiliary battery 20 may be connected or disconnected from the motor 31 (e.g., electrically) depending on the on / off state of charging switches T1 and T2.

[0050] In an exemplary embodiment, the positive terminal of the auxiliary battery 20 can be connected to node nd at each of the second ends of the plurality of windings L1, L2 and L3 via charging switches T1 and T2 and relays RLY1 and RLY2, and the negative terminal of the auxiliary battery 20 can (e.g., optionally) be connected to DC terminal D4.

[0051] At the same time, such as Figure 2 As shown, no separate relay is provided between the main battery 10 and the motor system 30, but according to an exemplary embodiment, a relay may be provided between the main battery 10 and the motor system 30.

[0052] DC capacitors Cdc and Cn can be configured to reduce current ripple. In an exemplary embodiment, the current ripple of the main battery 10 can be reduced by the DC capacitor Cdc located between DC terminals D1 and D2 and connected to DC terminals D1 and D2, and the current ripple of the auxiliary battery 20 can be reduced by the DC capacitor Cn located between DC terminals D3 and D4 and connected to DC terminals D3 and D4.

[0053] In this article, we will use the following approach: Figure 2 The main difference in the motor system 30 shown is described below. Figure 3 The motor system 30 shown.

[0054] refer to Figure 3 In another exemplary implementation, with Figure 2 Compared to the motor system 30 in the middle, the motor system 30 may further include a second inverter 32-2 and multiple switching switches M1, M2 and M3.

[0055] The second inverter 32-2 may include multiple branches S1'-S2', S3'-S4' and S5'-S6' connected to each second end of multiple windings L1, L2 and L3.

[0056] Each first terminal of a plurality of switching switches M1, M2, and M3 can be connected to each second terminal of a plurality of windings L1, L2, and L3, and each second terminal of a plurality of switching switches M1, M2, and M3 can be interconnected (e.g., interconnected with each other) to form a node nd. The plurality of switching switches M1, M2, and M3 can, in a first drive mode, determine the specific drive mode through a first inverter 32-1 and a second inverter 32-2.

[0057] In an exemplary embodiment, the first drive mode may include a Closed Endwinding (CEW) mode and an Open End Winding (OEW) mode. First, in CEW mode, multiple switching switches M1, M2, and M3 are turned on. In an exemplary embodiment, node nd is the neutral point of motor 31, and motor 31 is driven (e.g., only) by the first inverter 32-1. Such a CEW mode can be implemented to drive motor 31 (e.g., effectively) in a low-power range.

[0058] In contrast, in the OEW mode of the first drive mode, multiple switching switches M1, M2, and M3 are turned off. In an exemplary embodiment, node nd does not become the neutral point of motor 31, and motor 31 can be driven by both the first inverter 32-1 and the second inverter 32-2. Such an OEW mode can be implemented to increase the driving force of motor 31 in the high-power range.

[0059] Meanwhile, in the dual inverter structures 32-1 and 32-2, the auxiliary battery 20 can be connected to the DC terminal D5 and each of the second terminals of the plurality of windings L1, L2, and L3 via a location between the DC terminal D5 and each of the second terminals of the plurality of windings L1, L2, and L3. In an exemplary embodiment, the positive terminal of the auxiliary battery 20 can be connected to a node nd formed at each of the second terminals of the plurality of switching switches M1, M2, and M3 via charging switches T1 and T2 and relays RLY1 and RLY2, and the negative terminal of the auxiliary battery 20 can be connected to the DC terminal D5.

[0060] In this article, reference will be made to Figure 4 (For example, briefly) describe each operating region of the first drive mode and the second drive mode.

[0061] Figure 4 This is a graph showing the first and second driving modes according to an embodiment of the present invention.

[0062] refer to Figure 4 Each operating region of the first drive mode and the second drive mode can provide (e.g., represented) a graph of the speed and torque of the motor 31.

[0063] First, CEW mode b1 can operate in a low-power range where the speed and torque are lower compared to OEW mode b2. Conversely, OEW mode b2 can operate in a high-power range where the speed and torque are higher compared to CEW mode b1.

[0064] The second drive mode a can be executed within the operating range of CEW mode b1, and can be executed in the lowest power range with relatively low speed and relatively low torque. In the lowest power range, the auxiliary battery 20, together with the main battery 10, is used to drive the motor 31, thereby increasing the driving range.

[0065] Meanwhile, in an electrified vehicle according to an exemplary embodiment, when the auxiliary battery 20 is installed and the motor 31 is driven (e.g., operating in a second drive mode) with the auxiliary battery 20 connected (e.g., electrically connected to each other) to the motor 31 via nodes nd where each second end of a plurality of windings is interconnected, pulse width modulation control can be performed on the first inverter 32-1 according to the rotational speed of the motor 31, using one of a first pulse width modulation method and a second pulse width modulation method (e.g., any one). Before describing the criteria for determining the pulse width modulation method herein, reference will be made to... Figures 5 to 7 Describe each of the first pulse width modulation method and the second pulse width modulation method.

[0066] first, Figure 5 and Figure 6This is a schematic diagram of a first pulse width modulation method according to an embodiment of the present invention.

[0067] refer to Figure 5 and Figure 6 The first pulse width modulation method according to the implementation scheme can be provided (e.g., defined) as a method in which: Figure 5 In the complex space provided (e.g., represented), three effective voltage vectors and a zero voltage vector with a phase difference of 120 degrees are synthesized (e.g., relative to each other), and then the neutral point voltage Vn applied to node nd of motor 31 is determined.

[0068] In this exemplary embodiment, the effective voltage vector can be set (e.g., represented as) as V1(1,0,0), V2(1,1,0), V3(0,1,0), V4(0,1,1), V5(0,0,1), V6(1,0,1), and V7(1,1,1) according to the switching state of each phase. Furthermore, based on the synthesis of this effective voltage vector, the neutral point voltage Vn of the motor 31 can be determined as any value among 0, Vdc / 3, 2Vdc / 3, and Vdc. Here, 1 represents the state where the upper switching elements S1, S3, and S5 of each phase are on, 0 represents the state where the lower switching elements S2, S4, and S6 are on, and Vdc corresponds to the voltage at DC terminals D1 and D2.

[0069] In an exemplary embodiment, the first pulse width modulation method can be performed using voltage vectors V1, V3, V5 or V2, V4, and V5 that have a phase difference of 120 degrees between them in the effective voltage vectors. In an exemplary embodiment, the neutral point voltage Vn can be controlled by including a zero voltage vector V0 between the effective voltage vectors.

[0070] For example, refer to Figure 6 The diagram illustrates a process of pulse width modulation using effective voltage vectors V1, V3, and V5 with a phase difference of 120 degrees from each other, and a zero voltage vector V0. During the entire switching cycle Tsw, branches S1-S2, S3-S4, and S5-S6, included in the first inverter 32-1 and corresponding to each phase, can be switched according to a vector sequence such as V5-V0-V1-V0-V3-V0-V5-V5-V0-V3-V0-V1-V0-V5. Thus, the neutral point voltage Vn can be controlled to Vdc / 3 or 0 during the entire switching cycle Tsw. Alternatively, the first pulse width modulation method can be performed using effective voltage vectors V2, V4, and V6 with a phase difference of 120 degrees from each other, and a zero voltage vector V0. In this exemplary embodiment, the neutral point voltage Vn can be determined to be 2Vdc / 3 or 0.

[0071] Because of the use of effective voltage vectors with a phase difference, this first pulse width modulation method can be configured (e.g., denoted) as odd-even vector modulation (Remote State PWM, RSPWM). However, in the first pulse width modulation method according to an exemplary embodiment, the effective voltage vectors (e.g., each other) can have a phase difference and can also have zero voltage vectors that can be used together.

[0072] Reference Figure 7 Describe a second pulse width modulation method performed in a different manner.

[0073] Figure 7 This is a schematic diagram of a second pulse width modulation method according to an embodiment of the present invention.

[0074] refer to Figure 7 According to the implementation scheme, the second pulse width modulation method can be set (e.g., defined) as a method to determine the switching states of multiple branches S1-S2, S3-S4 and S5-S6 in the first inverter by comparing the voltage commands Vun*, Vvn* and Vwn* of the first inverter with a predetermined triangular carrier Vc during the switching cycle Tsw.

[0075] In this exemplary embodiment, the peak-to-peak value of the triangular carrier Vc can be set to the voltage Vdc of the DC terminals D1 and D2, and the switching states of the corresponding branches S1-S2, S3-S4 and S5-S6 can be determined according to the magnitude relationship between the triangular carrier Vc and the voltage commands Vun*, Vvn* and Vwn*.

[0076] For example, when the values ​​of the voltage commands Vun*, Vvn*, and Vwn* for each phase exceed the value of the triangular carrier wave Vc, the upper switching elements S1, S3, and S5 of each of branches S1-S2, S3-S4, and S5-S6 can be turned on. Conversely, when the values ​​of the voltage commands Vun*, Vvn*, and Vwn* for each phase do not exceed the value of the triangular carrier wave Vc, the lower switching elements S2, S4, and S6 of each of branches S1-S2, S3-S4, and S5-S6 can be turned on.

[0077] At the same time, this article will refer to Figure 8 and Figure 9 The description refers to the reference for the controller 40 of the implementation scheme to determine whether to perform pulse width modulation using the first pulse width modulation method or the second pulse width modulation method.

[0078] Figure 8 and Figure 9 This is a schematic diagram of the determination criteria for the pulse width modulation method according to an embodiment of the present invention.

[0079] First, refer to Figure 8The controller 40 can perform pulse width modulation control on the first inverter 32-1 by utilizing one of the first pulse width modulation method PWM1 and the second pulse width modulation method PWM2 (e.g., any one) based on which of the multiple speed ranges (e.g., which are divided by predetermined reference speeds ref1 and ref2) the speed of the motor 31 is included in.

[0080] In this exemplary embodiment, the reference speeds ref1 and ref2 can be set to speed values ​​such that the difference between the frequency of the neutral point current of the motor 31 controlled by pulse width modulation according to the first pulse width modulation method PWM1 and the frequency of the neutral point current of the motor 31 controlled by pulse width modulation according to the second pulse width modulation method PWM2 is included within a predetermined error range.

[0081] Additionally, the reference speed may include a first reference speed ref1 and a second reference speed ref2, where the value of the second reference speed ref2 is equal to or greater than the value of the first reference speed ref1, thereby dividing the speed range into at least three speed ranges. For example, the first reference speed ref1 may be a range division reference for a relatively low speed range such as 1krpm to 5krpm, and the second reference speed ref2 may be a range division reference for a relatively high speed range exceeding 5krpm.

[0082] This is because the harmonic effects when executing the first pulse width modulation method PWM1 and the second pulse width modulation method PWM2 will change according to the speed range of the motor 31, and the pulse width modulation control is performed by a pulse width modulation method with relatively low harmonic effects for each speed range.

[0083] In an exemplary embodiment, in the controller 40, the first pulse width modulation method PWM1 is more susceptible to harmonic effects than the second pulse width modulation method PWM2 in the low-speed and high-speed regions, so pulse width modulation is performed for each speed range to (e.g., to) reduce harmonic effects.

[0084] For example, when the speed of motor 31 falls within the range between a first reference speed ref1 and a second reference speed ref2, controller 40 can perform pulse width modulation control using a first pulse width modulation method PWM1, which is advantageous for reducing harmonic effects in the mid-speed region. Additionally, when the speed of motor 31 falls within at least one range between a range below the first reference speed (i.e., the low-speed region) and a range above the second reference speed (i.e., the high-speed region), pulse width modulation control can be performed using a second pulse width modulation method PWM2, which is advantageous for reducing harmonic effects in both the low-speed and high-speed regions.

[0085] Simultaneously, the controller 40 can determine the method for controlling the pulse width modulation by further considering the voltage applied to the motor 31 through the first inverter 32-1. In an exemplary embodiment, the controller 40 can determine the pulse width modulation method based on the reverse magnetic flux determined by the ratio of the rotational speed of the motor 31 to the input voltage (e.g., Vdc) of the first inverter 32-1. Regarding this, reference will be made herein to... Figure 9 Describe it.

[0086] refer to Figure 9 The controller 40 can perform pulse width modulation control on the first inverter 32-1 by utilizing either the first pulse width modulation method PWM1 or the second pulse width modulation method PWM2, depending on which of the multiple reverse magnetic flux intervals (e.g., divided by predetermined reference reverse magnetic flux ref1' and ref2') the reverse magnetic flux (e.g., the reverse magnetic flux based on the ratio of speed to voltage) is included in.

[0087] In this exemplary embodiment, the reference reverse magnetic fluxes ref1' and ref2' can be set to such reverse magnetic flux values ​​that the difference between the frequency of the neutral point current of the motor 31 controlled by pulse width modulation according to the first pulse width modulation method PWM1 and the frequency of the neutral point current of the motor 31 controlled by pulse width modulation according to the second pulse width modulation method PWM2 is included within a predetermined error range.

[0088] In addition, the reference reverse magnetic flux may include a first reference reverse magnetic flux ref1' and a second reference reverse magnetic flux ref2', the value of the second reference reverse magnetic flux ref2' being equal to or greater than the value of the first reference reverse magnetic flux ref1', thereby dividing the reverse magnetic flux interval into at least three reverse magnetic flux intervals. For example, the first reference reverse magnetic flux ref1' can be the interval division reference for an interval with relatively low reverse magnetic flux, and the second reference reverse magnetic flux ref2' can be the interval division reference for an interval with relatively high reverse magnetic flux.

[0089] This is because the harmonic effects when executing the first pulse width modulation method PWM1 and the second pulse width modulation method PWM2 will change according to the reverse magnetic flux interval, and pulse width modulation control is performed by a pulse width modulation method with relatively low harmonic effects for each reverse magnetic flux interval.

[0090] For example, when the reverse magnetic flux is included in the interval between the first reference reverse magnetic flux ref1' and the second reference reverse magnetic flux ref2', the controller 40 can perform pulse width modulation control using a first pulse width modulation method PWM1 for (e.g., advantageously) reducing harmonic effects in the corresponding region. For example, when the reverse magnetic flux is included in at least one interval below the first reference reverse magnetic flux ref1' and above the second reference reverse magnetic flux ref2', pulse width modulation control can be performed using a second pulse width modulation method PWM2 for (e.g., advantageously) reducing harmonic effects in the corresponding region.

[0091] Meanwhile, the determination of this pulse width modulation method can be performed by referring to a predetermined table. For example, the controller 40 can perform pulse width modulation control on the first inverter 32-1 based on the output value of the predetermined table, in which the speed of the motor 31 and the voltage applied to the motor 31 are used as input values, and at least one (e.g., either one) of the first pulse width modulation method PWM1 and the second pulse width modulation method PWM2 is used as the output value.

[0092] In this article, reference will be made to Figure 10 Describe the process of controlling pulse width modulation as described so far.

[0093] Figure 10 This is a flowchart illustrating the process of controlling pulse width modulation according to an embodiment of the present invention.

[0094] refer to Figure 10 During the execution of the CEW mode in the first driving mode (step S1001 is "yes"), when the switching conditions of the second driving mode are met (step S1002 is "yes"), the controller 40 can determine the pulse width modulation method by determining whether the preset interval conditions are met (step S1003) (steps S1004 and S1005).

[0095] In this case, the interval condition can be determined based on the speed and voltage of the motor 31 described herein. For example, the interval condition can be set to be satisfied when the speed of the motor 31 is included in the interval between the first reference speed ref1 and the second reference speed ref2, or when the reverse magnetic flux is included in the interval between the first reference reverse magnetic flux ref1' and the second reference reverse magnetic flux ref2'.

[0096] When the pulse width modulation method is determined through this process, the controller 40 performs pulse width control and drives the motor 31 according to the determined method (step S1008).

[0097] Simultaneously, even if the CEW mode of the first drive mode is not executed (step S1001 is "No"), the CEW mode can be executed when the switching condition of the CEW mode is met (step S1006 is "Yes") (step S1007). In this exemplary embodiment, the above process can be executed when the switching condition of the second drive mode is met (S1002 is "Yes"). However, when the switching condition of the second drive mode is not met (step S1002 is "No"), the motor 31 is driven by the first drive mode (step S1008).

[0098] According to an exemplary embodiment of the invention described herein, an auxiliary battery can be used together with the main battery to drive a motor, thereby (e.g., effectively) increasing the driving range of an electrified vehicle.

[0099] In addition, when the motor is driven with the auxiliary battery connected to the motor (e.g., electrically connected to each other), a pulse width modulation method less affected by harmonic effects is executed according to the motor speed, thereby improving the motor's drive efficiency without the need to add a separate device.

[0100] Although exemplary embodiments of the invention have been described herein, the invention should not be limited to these exemplary embodiments, and modifications and changes can be made to the invention within the scope of the invention.

Claims

1. An electric vehicle capable of installing an auxiliary battery, the electric vehicle comprising: An electric motor, which includes multiple windings; A first inverter includes a DC terminal and multiple branches connected to each first terminal of the plurality of windings; The main battery is connected to the DC terminal; as well as The controller is configured to control the pulse width modulation of the first inverter based on the motor speed when the motor is driven with the auxiliary battery installed and the auxiliary battery electrically connected to the motor through a node where each of the second ends of the plurality of windings is interconnected.

2. The electrified vehicle of claim 1, wherein, The controller is configured to control the pulse width modulation of the first inverter by at least one of a first pulse width modulation method and a second pulse width modulation method, based on which of a plurality of speed ranges the motor's speed falls within, wherein the plurality of speed ranges are divided by a predetermined reference speed.

3. The electrified vehicle of claim 2, wherein, The reference speed is such that the difference between the frequency of the neutral point current of the motor controlled by pulse width modulation according to the first pulse width modulation method and the frequency of the neutral point current of the motor controlled by pulse width modulation according to the second pulse width modulation method is included within a predetermined error range.

4. The electrified vehicle according to claim 2, wherein, The reference speed includes a first reference speed and a second reference speed, wherein the value of the second reference speed is equal to or greater than the value of the first reference speed.

5. The electrified vehicle according to claim 4, wherein, When the motor speed is within the range between the first reference speed and the second reference speed, the controller performs pulse width modulation control through the first pulse width modulation method.

6. The electrified vehicle according to claim 5, wherein, The first pulse width modulation method is a method for determining the neutral point voltage of the motor by synthesizing three effective voltage vectors and a zero voltage vector, wherein the three effective voltage vectors have a phase difference of 120 degrees in complex space.

7. The electrified vehicle according to claim 4, wherein, When the motor speed is within at least one range that is below the first reference speed and above the second reference speed, the controller performs pulse width modulation control using the second pulse width modulation method.

8. The electrified vehicle according to claim 7, wherein, The second pulse width modulation method is a method of determining the switching state of multiple branches by comparing the voltage command of the first inverter with a predetermined triangular carrier wave.

9. The electrified vehicle according to claim 1, wherein, The controller is configured to perform pulse width modulation control of the first inverter by taking into account the input voltage of the first inverter, using at least one of a first pulse width modulation method and a second pulse width modulation method.

10. The electrified vehicle according to claim 9, wherein, The controller is configured to perform pulse width modulation control of the first inverter based on the reverse magnetic flux determined by the ratio between the motor speed and the input voltage of the first inverter, using at least one of a first pulse width modulation method and a second pulse width modulation method.

11. The electrified vehicle according to claim 10, wherein, The controller is configured to perform pulse width modulation control of the first inverter by at least one of a first pulse width modulation method and a second pulse width modulation method, depending on which of a plurality of reverse magnetic flux intervals the reverse magnetic flux is included in, wherein the plurality of reverse magnetic flux intervals are divided by a predetermined reference reverse magnetic flux.

12. The electrified vehicle according to claim 11, wherein, The reference reverse magnetic flux is a reverse magnetic flux such that the difference between the frequency of the neutral point current of the motor controlled by pulse width modulation according to the first pulse width modulation method and the frequency of the neutral point current of the motor controlled by pulse width modulation according to the second pulse width modulation method is included within a predetermined error range.

13. The electrified vehicle according to claim 12, wherein, The reference reverse magnetic flux includes a first reference reverse magnetic flux and a second reference reverse magnetic flux, wherein the value of the second reference reverse magnetic flux is equal to or greater than the value of the first reference reverse magnetic flux.

14. The electrified vehicle according to claim 13, wherein, When the reverse magnetic flux is included in the interval between the first reference reverse magnetic flux and the second reference reverse magnetic flux, the controller performs pulse width modulation control by the first pulse width modulation method.

15. The electrified vehicle according to claim 14, wherein, The first pulse width modulation method is a method for determining the neutral point voltage of the motor by synthesizing three effective voltage vectors and a zero voltage vector, wherein the three effective voltage vectors have a phase difference of 120 degrees in complex space.

16. The electrified vehicle according to claim 13, wherein, When the reverse magnetic flux is included in at least one interval between the interval below the first reference reverse magnetic flux and the interval above the second reference reverse magnetic flux, the controller performs pulse width modulation control by the second pulse width modulation method.

17. The electrified vehicle according to claim 16, wherein, The second pulse width modulation method is a method of determining the switching state of multiple branches by comparing the voltage command of the first inverter with a predetermined triangular carrier wave.

18. The electrified vehicle according to claim 9, wherein, The controller is configured to control the pulse width modulation of the first inverter based on the output values ​​of a predetermined table, wherein the motor speed and the input voltage of the first inverter are used as input values, and at least one of a first pulse width modulation method and a second pulse width modulation method is used as the output value.

19. The electrified vehicle according to claim 1, further comprising: The second inverter includes multiple branches connected to each second end of the plurality of windings. When the auxiliary battery is installed but the motor is driven while the auxiliary battery is electrically disconnected from the motor, the controller is configured to execute at least one of the closed-end winding mode of driving the motor through the first inverter and the open-end winding mode of driving the motor through the first inverter and the second inverter.

20. The electrified vehicle according to claim 19, further comprising: Multiple switching switches, each with a first terminal connected to a second terminal of multiple windings, wherein each second terminal of the multiple switching switches is interconnected to form a node. The controller is configured to control the winding in either a closed end winding mode or an open end winding mode by controlling the on / off state of the plurality of switching switches.

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