Multi-input charging system and method using motor drive apparatuses

Abstract

Disclosed are a multiple-input charging system and method using a motor drive device. The system includes a motor having a plurality of windings; a first inverter including first switching elements, one end of which is connected to a power input terminal and the opposite end is connected to a first terminal of each of the plurality of windings; a second inverter including second switching elements, one end of which is connected to a battery and the other end is connected to a second terminal of each of the plurality of windings, the battery being connected to the power input terminal or one end of the second inverter; and a controller configured to directly charge the battery via the power input terminal or charge the battery using a voltage of a step-down charging power source.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a multi-input charging system and method using a motor driving device, and more particularly, to a system and method of charging a battery using an external charging power source. BACKGROUND

[0002] Generally, an electric vehicle or a plug-in hybrid vehicle performs battery charging by converting power supplied from an external charging facility into a state suitable for charging a battery in the vehicle and supplying the converted power to the battery.

[0003] Conventionally, a charging facility for fast charging has been manufactured as a single voltage standard of 500V, but there is a tendency to design a battery used in a vehicle to have a voltage of 800V or more to improve efficiency and driving distance.

[0004] Therefore, some fast charging facilities have a voltage standard of 1000V, and a 1000V fast charging facility can be stepped down to a voltage suitable for a battery. Accordingly, an 800V battery can be charged. However, in order to charge an 800V battery using a charging facility having a 500V voltage standard, a step-up converter for stepping up the voltage supplied from the external charging facility is required.

[0005] However, a high-capacity step-up converter for stepping up a 500V voltage to at least 800V has a very large weight and volume and is expensive, so it is difficult to provide in a vehicle and can increase the price of the vehicle.

[0006] A vehicle uses a coil of a motor and a power conversion switch of an inverter as a step-up converter to step up. In order to control the voltage of the fast charger output, the output voltage of the battery and the fast charger is monitored, the duty ratio is calculated, and then the three-phase top and bottom switches of the inverter are switched at a ratio corresponding to the duty ratio.

[0007] However, according to the conventional art, in the case of charging a 400V battery using a 1000V fast charging facility, the battery is charged at a stepped-down voltage, so the fast charger voltage specification can not be fully utilized. Therefore, the charging speed becomes the same as that of a 500V fast charging facility. Therefore, there is a problem that the charging speed is slow even when a 1000V fast charging facility is used.

[0008] The subject matter described as the related art is only for the enhancement of the understanding of the background of the disclosure, and should not be considered as acknowledging that the subject matter corresponds to the related art known to those of ordinary skill in the art. SUMMARY

[0009] Therefore, the present disclosure has been made in consideration of the above-mentioned problems occurring in the prior art. The present disclosure aims to provide a battery charging technology for directly charging a battery using a charging power source or a voltage of a charging power source reduced by using a motor and an inverter, according to a voltage level of an external charging power source.

[0010] To achieve the above-mentioned object, according to the present disclosure, a multi-input charging system using a motor driving device can be provided. The system can include a motor having a plurality of windings corresponding to a plurality of phases, respectively. The system can further include a first inverter including a plurality of first switching elements, one end of which is connected to a power input terminal into which a charging power source is externally input, and the other end of which is connected to a first terminal of each of the plurality of windings. The system can further include a second inverter including a plurality of second switching elements, one end of which is connected to a battery, and the other end of which is connected to a second terminal of each of the plurality of windings. The system can further include a battery connected to the power input terminal or one end of the second inverter. The system can further include a controller configured to, when a charging mode for charging the battery is initiated, directly charge the battery via the power input terminal according to a voltage level of the charging power source input to the power input terminal, or charge the battery using a voltage of the charging power source reduced by the first inverter and the second inverter.

[0011] The system can further include a charging relay provided between the power input terminal and the battery. The controller can be configured to control whether the charging relay is short-circuited, thereby charging the battery directly via the power input terminal or using the voltage of the charging power source reduced by the first inverter and the second inverter.

[0012] When the charging mode is initiated, the controller can be configured to charge the battery by the first inverter and the second inverter when the voltage level of the charging power source is not less than a reference voltage preset as a level capable of charging.

[0013] The controller can be configured to control pulse width modulation such that the plurality of first switching elements included in the first inverter are closed / shut off according to a duty ratio.

[0014] The controller can be configured to set a duty ratio of an upper switching element of the plurality of first switching elements to a ratio of a voltage of the battery to the voltage level of the charging power source.

[0015] The controller can be configured to control an upper switching element of the plurality of second switching elements included in the second inverter to be always closed.

[0016] The controller can be configured to diagnose whether the motor, the first inverter, or the second inverter is malfunctioning. When a malfunction is diagnosed, the controller can be configured to directly charge the battery via the power input terminal.

[0017] The system may further include current sensors configured to sense phase currents flowing in each of the multiple phases of the motor by means of a placement in each of the multiple windings of the motor. The controller may be configured to diagnose faults in the motor, the first inverter, or the second inverter based on the phase current sensed by the current sensors and the input current of the battery.

[0018] The system may further include temperature sensors configured to sense temperature by means of each of one or more second switching elements among a plurality of first switching elements. The controller may be configured to diagnose a fault in the motor, the first inverter, or the second inverter based on the temperature sensed by each of the temperature sensors.

[0019] To achieve the above objectives, according to this disclosure, a multi-input charging method using a motor drive device can be provided. Using a motor drive device, the method may include receiving a voltage level of a charging power supply input to a power input terminal. The method may further include determining, based on the received voltage level of the charging power supply, whether to charge the battery directly or using the voltage of a stepped-down charging power supply. The method may further include, based on the determination result, either directly charging the battery via the power input terminal or charging the battery using the voltage of a charging power supply stepped down by a first inverter and a second inverter.

[0020] During battery charging, the charging relay located between the power input terminal and the battery can be controlled to prevent short circuit, thereby charging the battery directly via the power input terminal or using the voltage of the charging power supply stepped down by the first inverter and the second inverter.

[0021] During battery charging, pulse width modulation can be controlled so that multiple first switching elements included in the first inverter can be closed / opened according to the duty cycle. The upper switching elements of multiple second switching elements included in the second inverter can be controlled to remain closed at all times.

[0022] The method may further include: after the battery is charged, diagnosing whether the motor, the first inverter, or the second inverter is faulty, and when a fault is diagnosed, charging the battery directly via the power input terminal.

[0023] When diagnosing a fault, the phase current flowing in multiple phases of the motor can be sensed by current sensors installed in multiple windings of the motor. Based on the sensed phase current and the battery input current, a fault in the motor, the first inverter, or the second inverter can be diagnosed. Alternatively, temperature can be sensed by temperature sensors installed in multiple first switching elements or multiple second switching elements. Based on the sensed temperature, a fault in the motor, the first inverter, or the second inverter can be diagnosed.

[0024] As described above, the multi-input charging system and method using an electric motor drive device disclosed herein, when using a high-voltage external charging power supply, has the effect of improving battery charging speed by using voltage reduction control of the electric motor and dual inverters.

[0025] Furthermore, by diagnosing whether there are faults in the motor, the first inverter, or the second inverter during battery charging, it can achieve stable charging of batteries using charging power supplies of various voltages. Attached Figure Description

[0026] The above and other objects, features and advantages of this disclosure should be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 This is a circuit diagram of a multi-input charging system using an electric motor drive device according to an embodiment of the present disclosure;

[0028] Figure 2 This is a schematic diagram of a multi-input charging system using an electric motor drive device according to an embodiment of the present disclosure;

[0029] Figures 3 to 6 This is a view illustrating the control of the first switching element according to an embodiment of the present disclosure;

[0030] Figure 7 This is a circuit diagram illustrating the control of the second switching element according to an embodiment of the present disclosure;

[0031] Figure 8 This is a circuit diagram showing the state of charging the battery by the voltage of a charging power supply stepped down by a first inverter and a second inverter according to an embodiment of the present disclosure.

[0032] Figure 9 This is a circuit diagram illustrating the state of directly charging the battery via the power input terminal according to an embodiment of the present disclosure; and

[0033] Figure 10 This is a flowchart of a multi-input charging method using an electric motor drive device according to an embodiment of the present disclosure. Detailed Implementation

[0034] The specific structural or functional descriptions of the embodiments of this disclosure disclosed in this specification or application are for illustrative purposes only. Therefore, embodiments of this disclosure can be implemented in various forms and should not be construed as limited to the embodiments described in this specification or application.

[0035] Because embodiments of this disclosure can be modified in various ways and take various forms, specific embodiments are shown in the accompanying drawings and described in detail in this specification or application. However, this is not intended to limit embodiments according to the concept of this disclosure to the specific forms of the disclosed embodiments, but should be understood to include all changes, equivalents, or substitutions included within the spirit and scope of this disclosure.

[0036] Terms such as “first” and / or “second” may be used to describe various elements, but these elements should not be limited by these terms. These terms are used only for the purpose of distinguishing one component from other components. For example, without departing from the scope of the conception according to this disclosure, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

[0037] When a component is described as being "coupled" or "connected" to another component, it should be understood that the component can be directly coupled or connected to the other component, although there may be other components in between. On the other hand, when a component is described as being "directly coupled" or "directly connected" to another component, it should be understood that there are no other components between the components. Other expressions describing the relationship between components, such as "between" and "just between" or "adjacent" and "directly adjacent," should also be interpreted in the same way.

[0038] The terminology used in this specification is for describing particular embodiments only and is not intended to limit this disclosure. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to specify the presence of a set of features, quantities, steps, actions, components, parts, or combinations thereof, and it should be understood that the presence or addition of at least one other feature or quantity, step, action, element, part, or combination thereof is not a preliminary exclusion.

[0039] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms such as those defined in common dictionaries should be interpreted as having a meaning consistent with that of the relevant art, and should not be construed as having an ideal or overly formal meaning unless expressly defined in this specification.

[0040] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The same reference numerals in each drawing denote the same or equivalent components.

[0041] Figure 1 This is a circuit diagram of a multi-input charging system using a motor 30 drive device according to an embodiment of the present disclosure. Figure 2 This is a schematic diagram of a multi-input charging system using a motor 30 drive device according to an embodiment of the present disclosure.

[0042] Reference Figure 1 and Figure 2 A multi-input charging system using a motor 30 drive device according to an embodiment of the present disclosure includes a motor 30 having a plurality of windings respectively corresponding to a plurality of phases. The system further includes a first inverter 10, which includes a plurality of first switching elements, one end of which is connected to a power input terminal for receiving charging power from an external source, and the opposite end of which is connected to a first terminal of each of the plurality of windings. The system further includes a second inverter 20, which includes a plurality of second switching elements, one end of which is connected to a battery, and the opposite end of which is connected to a second terminal of each of the plurality of windings. The system further includes a battery 40, which is connected to either the power input terminal or one end of the second inverter. The system further includes a controller 100 configured to charge the battery 40 directly via the power input terminal, or to charge the battery 40 using the voltage of a charging power supply stepped down by the first inverter 10 and the second inverter 20. When a charging mode for charging the battery 40 is activated, charging depends on the voltage level of the charging power supply input to the power input terminal.

[0043] The controller 100 according to embodiments of this disclosure can be implemented as follows: a non-volatile memory (not shown) configured to store an algorithm configured to control the operation of various components of the vehicle or data related to software commands for reproducing the algorithm; and a processor (not shown) configured to perform the operations described below using the data stored in the respective memory. Here, the memory and processor can be implemented as separate chips. Alternatively, the memory and processor can be integrated with each other and implemented as a single chip. Meanwhile, the processor can take the form of at least one processor.

[0044] Typically, one end of the winding of each phase included in the motor 30 is connected to an inverter, and the opposite end is connected to the opposite end of each winding of the other phase to form a Y connection.

[0045] When the motor 30 is driven, the switching elements in the inverter are controlled to close / close via pulse width modulation, allowing line voltage to be applied to the windings of the Y-connected motor 30 to generate AC current. Thus, torque can be generated. The inverter's AC output limiting voltage is proportional to the DC voltage level of the high-voltage battery 40.

[0046] The fuel economy (or electricity consumption) of eco-friendly vehicles, such as electric vehicles that use the torque generated by the electric motor 30 as power, is determined by the power conversion efficiency of the electric motor 30 inverter and the inverter. Therefore, in order to improve fuel economy, it is important to maximize the power conversion efficiency of the inverter and the efficiency of the electric motor 30.

[0047] In this disclosure, such as Figure 2 As shown, in order to improve the zero-return performance of the electric vehicle by increasing the output of the motor 30 with the same reference voltage, an open-winding motor and dual inverters sharing the same battery 40 are used.

[0048] When switching is performed using dual inverters, the phase voltage of motor 30 can be more than doubled compared to the existing SVPWM.

[0049] In the region above the base rpm where torque is limited, the available current of a dual inverter is greater than that of a single inverter, thus allowing for greater output. In the case of a dual inverter, the neutral terminal of the Y-connected motor 30 is connected to the three-phase input terminals of the inverter 2, and the motor 30 is referred to as an open-end winding motor 30.

[0050] The fast charging method for battery 40 involves converting externally input AC power to DC power via a fast charger E, and then directly charging battery 40 at high power by controlling the current. Currently, infrastructures with capacities of 50 kW, 100 kW, 200 kW, and 400 kW are available both domestically and internationally. In this implementation, the power input terminals of the infrastructure can have an output voltage of 500V or 1000V.

[0051] The method of rapidly charging infrastructure with output voltages of 500V and 1000V at power input terminals is called the multi-input charging method.

[0052] Specifically, the vehicle uses the coils of the electric motor 30 and the power conversion switch of the inverter as a boost converter or buck converter for voltage boosting. In this embodiment, in order to control the voltage at the power input terminals, after calculating the duty cycle by monitoring the output voltages of the battery 40 and the fast charger E, the up and down switches of the three-phase inverter can be switched at a ratio corresponding to the duty cycle.

[0053] Return to reference Figure 1 The first inverter 10 and the second inverter 20 can: convert DC power stored in the battery 40 into three-phase AC power and supply the AC power to the motor 30; or convert the regenerative braking energy generated by the regenerative braking torque of the motor 30 during regenerative braking into DC power and supply the DC power to the battery 40. This conversion between DC and AC power can be performed by controlling the pulse width modulation of a plurality of first switching elements (S11 to S16) and a plurality of second switching elements (S21 to S26) respectively disposed in the first inverter 10 and the second inverter 20.

[0054] The first inverter 10 may include a plurality of legs 11 to 13, to which a DC voltage formed in a DC link capacitor connected to the opposite end of the battery 40 is applied. Each of the legs 11 to 13 may correspond to each of the plurality of phases of the motor 30 to form an electrical connection.

[0055] More specifically, the first leg 11 includes two switching elements S11 and S12 connected in series between opposite ends of the DC capacitor 50. The connection node of the two switching elements S11 and S12 can be connected to one end of the winding C1, which is a phase of the motor 30, so as to allow the input / output to correspond to AC power of one phase among multiple phases.

[0056] Similarly, the second leg 12 includes two switching elements S13 and S14 connected in series between opposite ends of the DC capacitor 50. The connection point of the two switching elements S13 and S14 can be connected to one end of the winding C2, which is a phase of the motor 30, so as to allow the input / output to correspond to the AC power of one of the multiple phases.

[0057] Furthermore, the third leg 13 includes two switching elements S15 and S16 connected in series between opposite ends of the DC capacitor 50. The connection point of the two switching elements S15 and S16 can be connected to one end of the winding C3, which is a phase of the motor 30, so as to allow the input / output to correspond to the AC power of one of the multiple phases.

[0058] The second inverter 20 may also have a similar configuration to the first inverter 10. The second inverter 20 may include a plurality of legs 21 to 23, to which a DC voltage formed in a DC link capacitor connected to the opposite end of the battery 40 is applied. Each of the legs 21 to 23 may correspond to a plurality of phases of the motor 30 to form an electrical connection.

[0059] More specifically, the first leg 21 includes two switching elements S21 and S22 connected in series between opposite ends of the DC capacitor 50. The connection node of the two switching elements S21 and S22 can be connected to the opposite ends of the winding C1, which is a phase of the motor 30, so as to allow the input / output to correspond to AC power of one of the multiple phases.

[0060] Similarly, the second leg 22 includes two switching elements S23 and S24 connected in series between the opposite ends of the DC capacitor 50. The connection node of the two switching elements S23 and S24 can be connected to the opposite ends of the winding C2, which is a phase of the motor 30, so as to allow the input / output to correspond to the AC power of one of the multiple phases.

[0061] Furthermore, the third leg 23 includes two switching elements S25 and S26 connected in series between the opposite ends of the DC capacitor 50. The connection point of the two switching elements S25 and S26 can be connected to the opposite ends of the winding C3, which is a phase of the motor 30, so as to allow the input / output to correspond to the AC power of one of the multiple phases.

[0062] The first inverter 10 is connected to one end of each winding C1 to C3 of the motor 30, and the second inverter 20 is connected to the opposite ends of each winding C1 to C3 of the motor 30. In other words, an open winding type electrical connection can be formed, wherein the opposite ends of each winding C1 to C3 of the motor 30 are respectively connected to the first inverter 10 and the second inverter 20.

[0063] Battery 40 can be connected to the power input terminal simultaneously with DC capacitor 50, first inverter 10, and second inverter 20. When battery 40 is directly connected to the power input terminal, battery 40 can be directly charged from the power input terminal.

[0064] Alternatively, when the connection to the power input terminal is disconnected, the battery 40 can be charged using the voltage of a charging power supply that has been stepped down by the motor 30, the first inverter 10, and the second inverter 20. Here, the motor 30, the first inverter 10, and the second inverter 20 can be used as step-down converters.

[0065] The controller 100 can control the charging of the battery 40 directly via the power input terminal, or charge the battery 40 using the voltage of the charging power supply stepped down by the first inverter 10 and the second inverter 20.

[0066] More specifically, when the charging mode for charging battery 40 is activated, controller 100 can determine whether to charge battery 40 directly or to charge battery 40 using the voltage of a stepped-down charging power supply. When the charging mode for charging battery is activated, the charging depends on the voltage level of the charging power supply input to the power input terminal.

[0067] As an implementation, the charging system further includes a charging relay 90 disposed between the power input terminal and the battery 40, wherein the controller 100 can control the charging relay 90 to be short-circuited or not short-circuited. Therefore, the battery 40 can be charged directly via the power input terminal or using the voltage of the charging power supply stepped down by the first inverter 10 and the second inverter 20.

[0068] The charging relay 90 can be located between the power input terminal and the battery 40, allowing the power input terminal to connect to the battery 40 when short-circuited, and blocking power between the power input terminal and the battery 40 when disconnected.

[0069] Specifically, the power input terminal can be connected to the battery 40 via the charging relay 90, and simultaneously connected to the first inverter 10. The power input terminal is continuously connected to the first inverter 10.

[0070] When the charging mode is activated, if the voltage level of the charging power supply is not less than the reference voltage preset as a rechargeable level, the controller 100 can charge the battery 40 through the first inverter 10 and the second inverter 20.

[0071] As one implementation, the voltage of the charging power input to the power input terminal can be 500V or 1000V. On the other hand, the voltage of the battery 40 can be in the 400V range or the 800V range.

[0072] Here, when the voltage of battery 40 is 400V and the voltage of the charging power supply is 1000V, the controller 100 can charge battery 40 by reducing the voltage of the charging power supply. Alternatively, when the voltage of the charging power supply is 500V, battery 40 can be charged directly via the power input terminal.

[0073] For example, the preset reference voltage can be preset between 500V and 1000V. In other words, when the voltage level of the charging power supply is 1000V (not less than the preset reference voltage), the controller 100 can charge the battery 40 with the voltage stepped down by the first inverter 10 and the second inverter 20.

[0074] Figures 3 to 6 This is a view illustrating the control of a first switching element according to an embodiment of the present disclosure.

[0075] Reference Figures 3 to 6 The controller 100 can control pulse width modulation (PWM) so that a plurality of first switching elements included in the first inverter are closed / closed according to the duty cycle.

[0076] Here, among the multiple first switching elements included in the first inverter 10, IGBT 1 can be upper switching elements S11, S13 and S15, and IGBT 2 can be lower switching elements S12, S14 and S16.

[0077] The controller 100 can alternately switch IGBT 1 and IGBT 2 included in the first inverter 10, thereby reducing the charging voltage Vin at the power input terminal. Specifically, the controller 100 can switch IGBT 1 to closed and IGBT 2 to closed, or switch IGBT 1 to closed and IGBT 2 to closed.

[0078] like Figure 3As shown, when IGBT 1 is closed and IGBT 2 is off, energy can be stored in the inductor located in the winding of motor 30 through the charging voltage Vin at the power input terminal.

[0079] In addition, such as Figure 4 As shown, when IGBT 1 is turned off and IGBT 2 is turned on, the energy stored in the inductor can be released.

[0080] like Figure 5 As shown, the controller 100 can control the IGBT 1 (which is an upper switching element S11, S13, S15 among a plurality of first switching elements included in the first inverter 10) to close / close according to the duty cycle.

[0081] The phase currents (phase U, phase V and phase W) of motor 30 can increase when IGBT 1 is closed and decrease when IGBT 1 is turned off.

[0082] More specifically, the controller 100 can set the duty cycle of the upper switching element among a plurality of first switching elements to the ratio of the battery voltage to the voltage level of the charging power supply.

[0083] In one implementation, the controller 100 can set the duty cycle D of the closed IGBT 1 (which is an upper switching element S11, S13, and S15 included in a plurality of first switching elements) to be the ratio of the voltage Vbat of the battery 40 to the voltage level Vin of the charging power supply. Here, the duty cycle D can be the ratio of the closing time to the switching cycle (closing time + turning off time).

[0084] D = Vbat / Vin

[0085] In addition, such as Figure 5 As shown, the controller 100 can perform three-phase interleaved control of multiple first switching elements that are respectively connected to the three phases of the motor 30.

[0086] Specifically, the controller can perform three-phase interleaved control of upper switching elements S11, S13, S15 and lower switching elements S12, S14, S16 at 1 / 3-switch-cycle intervals, where each switching element is connected to a corresponding phase of the three phases (U phase, V phase, and W phase) of the motor 30. Therefore, it has the effect of minimizing the variation in the sum of the phase currents of the three phases of the motor 30 and minimizing the current ripple of the battery 40.

[0087] Figure 7 This is a circuit diagram illustrating the control of the second switching element according to an embodiment of the present disclosure.

[0088] Further reference Figure 7The controller 100 can control the upper switching element of the plurality of second switching elements included in the second inverter 20 to always be closed.

[0089] Here, among the multiple second switching elements included in the second inverter 20, IGBT 3 can be upper switching elements S21, S23 and S25, and IGBT 4 can be lower switching elements S22, S24 and S26.

[0090] The controller 100 can control the upper switching elements S21, S23 and S25 of the plurality of second switching elements included in the second inverter 20 to always be closed, and accordingly, the inductor energy of the motor 30 can be transferred to the battery 40.

[0091] In this case, the controller 100 can control the lower switching elements S22, S24 and S26 of the plurality of second switching elements to always be turned off.

[0092] The controller 100 can diagnose whether the motor 30, the first inverter 10 or the second inverter 20 is faulty, and when a fault is diagnosed, it can charge the battery 40 directly via the power input terminal.

[0093] Specifically, the controller 100 diagnoses whether the motor 30, the first inverter 10, or the second inverter 20 is faulty, and when no fault occurs, it allows the battery 40 to be charged by the charging voltage of the charging power supply stepped down through the motor 30, the first inverter 10, or the second inverter 20.

[0094] Conversely, when a fault is diagnosed in the motor 30, the first inverter 10, or the second inverter 20, the controller 100 may allow the battery 40 to be charged directly via the power input terminal.

[0095] Therefore, the controller 100 can continuously diagnose the status of the motor 30, the first inverter 10 or the second inverter 20, and simultaneously charge the battery 40 stably.

[0096] As one implementation, the charging system may further include a current sensor 60 configured to sense phase current flowing in each of the plurality of phases of the motor 30 by means of a portion disposed in each of the plurality of windings of the motor 30. The controller 100 may diagnose whether the motor 30, the first inverter 10, or the second inverter 20 is faulty based on each phase current sensed by the current sensor 60 and the input current of the battery 40.

[0097] The current sensor 60 is located on each of the multiple windings corresponding to the three phases (U phase, V phase, and W phase) of the motor 30, and can sense the phase current flowing through each of the multiple phases. The controller 100 can determine whether the sum of the phase currents (Iu+IV+Iw) flowing in the multiple phases sensed by the current sensor 60 is equal to the input current Ibat of the battery 40, and thus diagnose a fault in the current sensor 60.

[0098] In addition, a voltage sensor 70 configured to sense the voltage of the battery 40 may be provided.

[0099] In another embodiment, the charging system may further include a temperature sensor 80 configured to sense temperature by being disposed in each of one or more of the plurality of first switching elements. The controller 100 may diagnose whether the motor 30, the first inverter 10, or the second inverter 20 is faulty based on the temperature sensed by each of the temperature sensors 80.

[0100] Temperature sensors 80 can be respectively disposed in each of the plurality of first switching elements included in the first inverter 10 and in each of the plurality of second switching elements included in the second inverter 20. When the temperature sensed by temperature sensor 80 is not less than a preset limit temperature, controller 100 can diagnose that the first inverter 10 or the second inverter 20 has overheated.

[0101] Figure 8 This is a circuit diagram illustrating the state of battery charging by the voltage of a charging power supply stepped down by a first inverter and a second inverter according to an embodiment of the present disclosure. Figure 9 This is a circuit diagram illustrating a state in which the battery is directly charged via a power input terminal according to an embodiment of the present disclosure.

[0102] like Figure 8 As shown, when the controller 100 disconnects the charging relay 90, the voltage of the charging power input to the power input terminal can be stepped down while passing through the first inverter 10, the motor 30, and the second inverter 20 in sequence. Therefore, the battery 40 is charged.

[0103] As an example, when the battery 40 is charged using the voltage of a charging power supply that is stepped down simultaneously through the first inverter 10, the motor 30, and the second inverter 20, the power Pin of the fast charger E is the product of the charging voltage and the charging current (Pin = Vin × Iin), and the input power Pbat of the battery 40 is the product of the voltage and the input current of the battery 40 (Pbat = Vbat × Ibat). Here, the input power Pbat of the battery 40 can be a value obtained by multiplying the power of the fast charger E by the power conversion efficiency η of the motor 30, the first inverter 10, and the second inverter 20 (Pbat = Pin × η). Therefore, when the battery 40 is charged using the voltage of the stepped-down charging power supply, the input current Ibat of the battery 40 can be calculated as follows.

[0104] Ibat = (Vin × Iin × η) / Vbat

[0105] like Figure 9 As shown, when the controller 100 short-circuits the charging relay 90, the battery 40 can be charged directly via the power input terminal. In this case, the pulse width modulation control or the switch control can be turned off for the first inverter 10 and the second inverter 20.

[0106] For example, when battery 40 is charged directly via the power input terminal, the input current IBat' of battery 40 is the same as the charging current Iin. Therefore, the input power Pbat' of battery 40 can be calculated as the product of the charging voltage and the charging current Iin of battery 40 (Pbat' = Vbat × Ibat' = Vbat × Iin).

[0107] Therefore, the ratio between Pbat and Pbat', or the ratio between Ibat and Ibat', is as follows. Pbat and Ibat are the input power and input current of battery 40 when battery 40 is charged by a charging power supply whose voltage is stepped down through the first inverter, motor 30, and second inverter 20, respectively. Pbat' and Ibat' are the input power and input current of battery 40 when battery 40 is directly charged via the power input terminal, respectively.

[0108] Pbat / Pbat'=Ibat / Ibat'=Vin×η / Vbat

[0109] For example, assuming the charging voltage Vin is 800V, the battery voltage Vbat is 400V, and the power conversion efficiency η of the motor 30, the first inverter 10, and the second inverter 20 is 90%, then the ratio of the charging power supply to the battery 40 or the input current of the battery 40 is calculated to be 180%. In other words, when the battery 40 is charged with the voltage of the charging power supply stepped down by the motor 30, the first inverter 10, and the second inverter 20, the charging power and input current of the battery 40 can increase by 180% compared to charging the battery 40 directly via the power input terminal.

[0110] Figure 10 This is a flowchart of a multi-input charging method using a motor 30 drive device according to an embodiment of the present disclosure.

[0111] Further reference Figure 10 The multi-input charging method according to embodiments of the present disclosure is a charging method using a multi-input charging system utilizing a motor 30 drive device. The method includes, in step S100, receiving the voltage level of a charging power supply input to a power input terminal. The method further includes, in step S200, determining, based on the received voltage level of the charging power supply, whether to directly charge the battery 40 or charge it using the voltage of a stepped-down charging power supply. The method further includes, in step S300, based on the determination result, either directly charging the battery 40 via the power input terminal, or charging the battery 40 using the voltage of a charging power supply stepped down by the first inverter 10 and the second inverter 20.

[0112] In step S300, which involves charging the battery 40, the charging relay 90, located between the power input terminal and the battery 40, is controlled to prevent short circuit. Therefore, the battery 40 can be charged directly via the power input terminal or using the voltage of a charging power supply stepped down by the first inverter 10 and the second inverter 20.

[0113] In step S300, which charges battery 40, pulse width modulation can be controlled so that a plurality of first switching elements included in the first inverter 10 are closed / opened according to their duty cycles. The upper switching elements of a plurality of second switching elements included in the second inverter can be controlled to remain closed at all times.

[0114] The charging method may further include, after step S300 of charging the battery 40, step S400 of diagnosing whether the motor 30, the first inverter 10, or the second inverter 20 is faulty. The charging method may also include, when a fault is diagnosed, step S500 of directly charging the battery 40 via the power input terminal.

[0115] In step S400, which diagnoses whether a fault has occurred, phase currents flowing in multiple phases of the motor 30 are sensed by current sensors disposed in multiple windings of the motor 30. Based on the sensed phase currents and the input current of the battery 40, a fault can be diagnosed in the motor 30, the first inverter 10, or the second inverter 20. Alternatively, a temperature can be sensed by temperature sensors disposed in multiple first switching elements or multiple second switching elements. Based on the sensed temperature, a fault can be diagnosed in the motor 30, the first inverter 10, or the second inverter 20.

[0116] Although specific embodiments of this disclosure have been shown and described, it will be apparent to those skilled in the art that various modifications and alterations may be made to this disclosure within the limitations without departing from the technical spirit of the disclosure as set forth in the appended claims.

Claims

1. A multi-input charging system using an electric motor drive device, the multi-input charging system comprising: An electric motor has multiple windings, each corresponding to a different phase. A first inverter includes a plurality of first switching elements, and one end of the first inverter is connected to a power input terminal for receiving charging power from an external source, and the opposite end of the first inverter is connected to a first terminal of each of the plurality of windings. The second inverter includes a plurality of second switching elements, one end of the second inverter is connected to the battery, and the opposite end of the second inverter is connected to a second terminal of each of the plurality of windings; The battery is connected to the power input terminal or one end of the second inverter; as well as The controller is configured to, when activating a charging mode for charging the battery, charge the battery directly via the power input terminal according to the voltage level of the charging power supply input to the power input terminal, or charge the battery using the voltage of the charging power supply stepped down by the first inverter and the second inverter.

2. The multi-input charging system according to claim 1, further comprising: A charging relay is disposed between the power input terminal and the battery. The controller is configured to control whether the charging relay is short-circuited, thereby charging the battery directly via the power input terminal or charging the battery using the voltage of the charging power supply stepped down by the first inverter and the second inverter.

3. The multi-input charging system according to claim 1, wherein, When the charging mode is activated, the controller is configured to charge the battery through the first inverter and the second inverter when the voltage level of the charging power supply is not less than a reference voltage preset to a charging level.

4. The multi-input charging system according to claim 3, wherein, The controller is configured to control pulse width modulation such that the plurality of first switching elements included in the first inverter are closed or turned off according to the duty cycle.

5. The multi-input charging system according to claim 4, wherein, The controller is configured to set the duty cycle of the upper switching element among the plurality of first switching elements to the ratio of the battery voltage to the voltage level of the charging power supply.

6. The multi-input charging system according to claim 3, wherein, The controller is configured to keep the upper switching element of the plurality of second switching elements included in the second inverter always closed.

7. The multi-input charging system according to claim 1, wherein, The controller is configured to diagnose whether the motor, the first inverter, or the second inverter is faulty, and when the fault is diagnosed, the controller is configured to control the direct charging of the battery via the power input terminal.

8. The multi-input charging system according to claim 7, further comprising: A current sensor is configured to sense the phase current flowing in each of the plurality of phases of the motor by being disposed in each of the plurality of windings of the motor. The controller is configured to diagnose whether the motor, the first inverter, or the second inverter is faulty based on the phase current sensed by the current sensor and the input current of the battery.

9. The multi-input charging system according to claim 7, further comprising: A temperature sensor is configured to sense temperature by being disposed in each of the plurality of first switching elements or in each of the plurality of second switching elements. The controller is configured to diagnose whether the motor, the first inverter, or the second inverter is faulty based on the temperature sensed by each of the temperature sensors.

10. A multi-input charging method using a motor drive device, comprising the motor drive device according to claim 1, the multi-input charging method comprising: Receives the voltage level of the charging power input to the power input terminal; Based on the voltage level of the received charging power supply, determine whether to charge the battery directly or to charge the battery using the voltage of the charging power supply that has been stepped down; as well as Based on the determined results, the battery is charged directly via the power input terminal, or the battery is charged using the voltage of the charging power supply that is stepped down by the first inverter and the second inverter.

11. The multi-input charging method according to claim 10, wherein, During battery charging, the charging relay located between the power input terminal and the battery is controlled to prevent short circuit, thereby allowing the battery to be charged directly via the power input terminal or using the voltage of the charging power supply stepped down by the first inverter and the second inverter.

12. The multi-input charging method according to claim 10, wherein, During the charging of the battery, pulse width modulation is controlled such that the plurality of first switching elements included in the first inverter are closed / opened according to the duty cycle, and The upper switching element of the plurality of second switching elements included in the second inverter is always closed.

13. The multi-input charging method according to claim 10, further comprising: After the battery is charged, diagnose whether the motor, the first inverter, or the second inverter is faulty; as well as When the fault is diagnosed, the battery is charged directly via the power input terminal.

14. The multi-input charging method according to claim 13, wherein, When diagnosing whether the fault has occurred, current sensors disposed in the plurality of windings of the motor sense the phase current flowing in the plurality of phases of the motor, and based on the sensed phase current and the input current of the battery, diagnose whether the motor, the first inverter, or the second inverter is faulty, or Temperature is sensed by a temperature sensor disposed in the plurality of first switching elements or the plurality of second switching elements, and based on the sensed temperature, a fault is diagnosed in the motor, the first inverter or the second inverter.

Images