Motor driving device, electrified vehicle, and method for controlling motor driving system

Abstract

Disclosed are a motor driving device, an electrified vehicle, and a method for controlling a motor driving system. The motor driving device comprises: a multi-phase motor having a plurality of windings corresponding to each of a plurality of phases; an inverter controlling a phase current flowing in the multi-phase motor; and a controller which performs heat generation control by receiving a first motor angle which is an electrical angle of the multi-phase motor.

Description

Control method for motor drive device, electric vehicle and motor drive system

[0001] The present disclosure relates to a motor drive device capable of controlling heat generation of a motor, an electric vehicle, and a control method for a motor drive system.

[0002] Electric vehicles utilize heat pump systems for efficient heating. These systems transfer external heat energy to the vehicle interior through a refrigeration cycle consisting of a compressor, evaporator, condenser, and expansion valve. The electric compressor is a core component of the heat pump system. It compresses the refrigerant, creating the high-temperature, high-pressure refrigerant required for heating, and then releases the heat from the condenser.

[0003] Heat pump systems play a crucial role in improving the energy efficiency of electric vehicles, providing effective heating with lower power consumption compared to conventional PTC (Positive Temperature Coefficient) heaters. In particular, advancements in motor control technology and the continuous optimization of electric compressor performance are becoming a key factor in improving the efficiency of electric vehicle heating systems.

[0004] However, in situations where heat sources are limited, such as in extremely low-temperature environments or during the initial startup of a heat pump system, it may be difficult for a heat pump system alone to provide sufficient thermal energy. In these cases, PTC heaters can be used to compensate for the insufficient heat output, but this increases the power consumption of the high-voltage battery, potentially reducing the driving range of electric vehicles.

[0005] Therefore, there is a need for a technology that can improve heating performance by providing additional heat to a heat pump system without using a PTC heater.

[0006] The matters described as background technology above are only intended to enhance understanding of the background of the present disclosure, and should not be taken as an admission that they correspond to prior art already known to a person of ordinary skill in the art.

[0007] The purpose of the present disclosure is to ensure stable heating performance in a heat pump system of an electric vehicle even in situations where heat source availability is limited, such as in an extremely low temperature environment or at the beginning of a start-up.

[0008] The problems to be solved through the embodiments of the present disclosure are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0009] In order to achieve the above object, a motor driving device according to the present disclosure may include a multi-phase motor having a plurality of windings corresponding to each of a plurality of phases, an inverter controlling a phase current flowing in the multi-phase motor, and a controller that receives a first motor angle, which is an electrical angle of the multi-phase motor, and controls the inverter based on the first motor angle to drive the multi-phase motor, or performs heat generation control to increase the heat generation amount of the multi-phase motor based on a second motor angle obtained by adding a compensation angle to the first motor angle.

[0010] For example, the controller may determine the second motor angle by adding a compensation angle set to increase the size of each of the plurality of phase currents according to the heat generation control to the first motor angle.

[0011] For example, when the controller performs the heat generation control, it can convert the phase current on the abc coordinate system into a current on the dq rotational coordinate system based on the second motor angle, and perform feedback control by comparing the current on the dq rotational coordinate system with a current command.

[0012] For example, the controller may determine the compensation angle to be a value less than 0.

[0013] For example, the controller can determine the compensation angle so that the q-axis current command has a value greater than 0.

[0014] For example, the controller may perform the heating control based on the speed of the motor being less than a preset base speed.

[0015] For example, the multi-phase motor may be an Interior Permanent Magnet Synchronous Motor (IPMSM).

[0016] In order to achieve the above object, an electric vehicle according to the present disclosure may include a multi-phase motor having a plurality of windings corresponding to each of a plurality of phases, an inverter controlling a phase current flowing in the multi-phase motor, and a controller performing heat generation control that receives a first motor angle, which is an electrical angle of the multi-phase motor, and controls the inverter based on the first motor angle to drive the multi-phase motor, or drives the multi-phase motor based on a second motor angle obtained by adding a compensation angle to the first motor angle to increase the heat generation amount of the multi-phase motor.

[0017] For example, the controller may determine the second motor angle by adding a compensation angle set to increase the size of each of the plurality of phase currents according to the heat generation control to the first motor angle.

[0018] For example, when the controller performs the heat generation control, it can convert the phase current on the abc coordinate system into a current on the dq rotational coordinate system based on the second motor angle, and perform feedback control by comparing the current on the dq rotational coordinate system with a current command.

[0019] For example, the controller may determine the compensation angle to be a value less than 0.

[0020] For example, the controller can determine the compensation angle so that the q-axis current command has a value greater than 0.

[0021] For example, the controller may perform the heating control based on the speed of the motor being less than a preset base speed.

[0022] For example, the multi-phase motor may comprise a compressor of a heat pump system.

[0023] For example, the multi-phase motor may be an Interior Permanent Magnet Synchronous Motor (IPMSM).

[0024] In order to achieve the above object, a control method of a motor drive system according to the present disclosure is a control method of a motor drive system including a multi-phase motor having a plurality of windings corresponding to each of a plurality of phases, and an inverter for controlling a phase current flowing in the multi-phase motor, the control method may include receiving a first motor angle, which is an electrical angle of the multi-phase motor, determining a second motor angle by adding a compensation angle to the motor angle, and determining a driving mode as a first mode for driving the multi-phase motor by controlling the inverter based on the first motor angle or a second mode for driving the multi-phase motor based on the second motor angle to increase the heat generation amount of the multi-phase motor, and driving the multi-phase motor according to the determined driving mode.

[0025] For example, determining the second motor angle may include determining the second motor angle by adding a compensation angle set to increase the magnitude of each of the plurality of phase currents according to the second mode to the first motor angle.

[0026] For example, determining the second motor angle may include determining the compensation angle to be a value less than 0.

[0027] For example, determining the second motor angle may include determining a compensation angle such that the q-axis current command has a value greater than 0.

[0028] According to the motor drive device, electric vehicle, and motor drive system control method of the present disclosure, effective heating is possible without a PTC heater by controlling the heat generation amount of the motor equipped in the electric compressor to increase the temperature of the refrigerant in the heat pump system. In addition, heating performance in extremely low-temperature environments and at the initial start-up can be improved by controlling heat generation through phase compensation of the electric compressor.

[0029] The effects that can be obtained through the embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art from the description below.

[0030] Figure 1 is a drawing showing the operating principle of a heat pump system equipped in an electric vehicle (1).

[0031] Fig. 2 is a circuit diagram showing a motor driving system according to the present disclosure.

[0032] FIG. 3 is a block diagram showing a process in which a controller (250) according to the present disclosure controls an inverter (230) and a motor (240).

[0033] Figure 4 is a diagram for comparing the results of performing MTPA control based on the first motor angle and the results of performing heat generation control based on the second motor angle.

[0034] FIG. 5 is a first drawing for explaining the range of compensation angle according to the present disclosure.

[0035] Figure 6 is a second drawing for explaining the range of compensation angle according to the present disclosure.

[0036] Figure 7 is the third drawing for explaining the range of compensation angle.

[0037] Fig. 8 is a flowchart showing an example of a heat generation control method of a motor drive system according to the present disclosure.

[0038] In describing the embodiments disclosed in this specification, if it is determined that a detailed description of related known technology may obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present disclosure. The following disclosure is not intended to limit the present disclosure to the described form or a specific field, and it is contemplated that various alternative embodiments and modifications of the present disclosure are possible, whether explicitly described or implied herein. A person of ordinary skill in the art to which the present disclosure pertains will recognize that the form and details of the contents of the present disclosure may be changed.

[0039] The present disclosure has been described with reference to specific embodiments. However, as will be appreciated by those skilled in the art, the various embodiments disclosed herein may be modified or implemented in various other ways without departing from the spirit and scope of the present disclosure. Accordingly, the following description is to be considered illustrative and is intended to teach those skilled in the art how to make and use various embodiments. It is to be understood that the forms of the disclosure shown and described herein are to be taken as representative embodiments. Equivalent elements, materials, processes, or steps may be substituted for those exemplified and described herein. The terms "including," "comprising," "incorporating," "consisting of," "have," "is," and the like, used in describing the present disclosure, are to be construed in a non-exclusive manner, that is, to allow for the identification of items, components, or elements that are not explicitly listed. Also, references to the singular should be understood to include references to the plural.

[0040] Furthermore, the various embodiments disclosed herein are to be taken in an illustrative and explanatory sense and should not be construed as limiting the scope of the present disclosure. Any references to joining (e.g., attached, affixed, coupled, connected, etc.) are used solely to aid understanding of the present disclosure and do not limit the location, orientation, or use of any component or method disclosed herein. Accordingly, any references to joining, if any, should be interpreted broadly. Moreover, such references to joining do not imply that two or more elements are directly connected to each other. Additionally, any numeric terms, such as "first," "second," "third," "primary," "secondary," "main," or any other generic or numerical terms, are to be taken only as identifiers to aid in understanding the various components, forms, variations, or modifications of the present disclosure, and do not imply any limitation on any component, form, variation, or modification, or any order or preference therefor. That is, while such expressions may be used to describe various components, the components are not limited by such expressions. Such expressions are used only to distinguish one component from another.

[0041] The suffixes "module" and "part" used for components in the following description are given or used interchangeably only for the convenience of writing specifications, and do not have distinct meanings or roles in themselves.

[0042] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0043] Additionally, the terms “Unit” or “Control Unit” included in the name are terms widely used to name a control device (Controller) that controls a specific function of a vehicle, and do not mean a generic function unit.

[0044] The controller may include a communication device that communicates with other controllers or sensors to control the function in charge, a memory that stores operating system or logic commands and input / output information, and one or more processors that perform judgments, calculations, decisions, etc. necessary for controlling the function in charge.

[0045] Any number of components or a variety of components in any of the configurations described herein may be incorporated into the disclosure described herein. The components may include any combination of the features described herein and may be arranged in any of the various configurations described herein. The concepts relating to the structure and arrangement of the components of the present disclosure, as well as their use and operation, may be applied to any number of embodiments in any combination, as well as to the specific embodiments discussed herein. Embodiments that include those having various features in various arrangements are described below with reference to the drawings.

[0046] Hereinafter, various embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components are given the same reference numbers and redundant descriptions thereof will be omitted.

[0047] A motor driving device according to the present disclosure may include a multi-phase motor having a plurality of windings corresponding to each of a plurality of phases, an inverter controlling phase currents flowing in the multi-phase motor, and a controller performing heat generation control that receives a first motor angle, which is an electrical angle of the multi-phase motor, and controls the inverter based on the first motor angle to drive the multi-phase motor, or drives the multi-phase motor based on a second motor angle obtained by adding a compensation angle to the motor angle, thereby increasing the heat generation amount of the multi-phase motor. Through this, intentional motor heat generation can be induced in an electric compressor of a heat pump system, thereby achieving effective heating performance even without a PTC heater.

[0048] First, the operating principle of the heat pump system to which the present disclosure is applied will be described with reference to FIG. 1.

[0049] Figure 1 is a drawing showing the operating principle of a heat pump system equipped in an electric vehicle (1).

[0050] Referring to Fig. 1, a heat pump system can form a cycle in which an evaporator (100), a compressor (200), a condenser (300), and an expansion valve (400) are connected by a refrigerant pipe. The heat pump system for an electric vehicle can play a significant role in improving the energy efficiency of an electric vehicle by enabling effective heating with lower power consumption compared to conventional PTC heaters.

[0051] The evaporator (100) can perform the function of absorbing heat energy from the outside air and evaporating the refrigerant, and the compressor (200) can perform the function of compressing the low-temperature, low-pressure refrigerant vaporized in the evaporator (100) and converting it into a high-temperature, high-pressure refrigerant.

[0052] The condenser (300) can perform the function of releasing heat energy into the vehicle interior as the high-temperature, high-pressure refrigerant compressed in the compressor (200) condenses through heat exchange with indoor air. The expansion valve (400) can perform the function of expanding the high-pressure liquid refrigerant condensed in the condenser (300) to a low pressure, thereby creating a low-temperature, low-pressure state.

[0053] In such a heat pump system, the compressor (200) may be configured as an electric compressor, and the electric compressor may include a multi-phase motor (240) therein to perform refrigerant compression. Since the electric motor of the compressor (200) may have a structure in which the motor case and the refrigerant may physically contact each other, the heat generated by the motor may be directly transferred to the refrigerant, thereby achieving a refrigerant temperature raising effect.

[0054] Next, a specific configuration of a motor driving system according to the present disclosure will be described with reference to FIG. 2.

[0055] Fig. 2 is a circuit diagram showing a motor driving system according to the present disclosure.

[0056] Referring to FIG. 2, a motor driving device equipped in a compressor (200) of an electric vehicle (1) may include a high-voltage battery (210), a direct current capacitor (or DC-Link capacitor, 220), an inverter (230), a motor (240) having a plurality of windings (C1, C2, C3) corresponding to a plurality of phases, and a controller (250).

[0057] A high-voltage battery (210) may serve as a main power source for an electric vehicle (1) and may supply direct current power to an inverter (230). A direct current capacitor (220) may be connected between both terminals of the high-voltage battery (210) to stabilize the direct current voltage and minimize voltage ripple resulting from the switching operation of the inverter (230).

[0058] The inverter (230) may include a plurality of switching elements (S1, S2, S3, S4, S5, S6) connected to one end of each of the plurality of windings (C1, C2, C3) of the motor (240). The inverter (230) may include a plurality of legs (31, 32, 33) to which a DC voltage formed in a DC capacitor (220) connected between both ends of a high-voltage battery (210) is applied. Each leg (31, 32, 33) may be electrically connected to a plurality of phases of the motor (240), respectively.

[0059] More specifically, the first leg (31) includes two switching elements (S1, S2) that are mutually connected in series between both ends of a DC capacitor (220), and the connection node of the two switching elements (S1, S2) can be connected to one end of a winding (C1) of one phase within the motor (240) so that AC power corresponding to one phase among the plurality of phases is input and output. Similarly, the second leg (32) includes two switching elements (S3, S4) that are mutually connected in series between both ends of a DC capacitor (220), and the connection node of the two switching elements (S3, S4) can be connected to one end of a winding (C2) of one phase within the motor (240) so that AC power corresponding to one phase among the plurality of phases is input and output. In addition, the third leg (33) includes two switching elements (S5, S6) that are connected in series with each other between both ends of a DC capacitor (220), and the connection node of the two switching elements (S5, S6) can be connected to one end of a winding (C3) of one phase in the motor (240) so that AC power corresponding to one phase among the plurality of phases is input and output.

[0060] The motor (240) is a multi-phase motor for driving the compressor (200) of the heat pump system, and in one embodiment, may be an Interior Permanent Magnet Synchronous Motor (IPMSM). The motor (240) includes a plurality of windings (C1, C2, C3) corresponding to each of a plurality of phases, and a rotating magnetic field is formed by three-phase AC power supplied from an inverter (230), thereby generating a rotational torque. Through this, mechanical power for driving the refrigerant compression operation of the compressor (200) can be provided.

[0061] The controller (250) can control the motor (240) to be driven by switching the switching elements (S1, S2, S3, S4, S5, S6) included in the inverter (230) through pulse width modulation control based on the torque command for the motor (240). In addition, the controller (250) can control the on / off states of a plurality of switching elements (S1, S2, S3, S4, S5, S6) based on the torque command for the motor (240), the DC link voltage of the inverter (230), the phase current of the motor, and the motor angle.

[0062] Although not shown in FIG. 2, the motor drive device may further include a so-called Y-capacitor (Y-Cap) which connects two capacitors in series with each other between the positive (+) DC terminal and the negative (-) DC terminal and grounds the connection node between the capacitors.

[0063] Next, the detailed configuration and control process of the controller (250) will be described with reference to FIG. 3.

[0064] FIG. 3 is a block diagram showing a process in which a controller (250) according to the present disclosure controls an inverter (230) and a motor (240).

[0065] Referring to FIG. 3, the controller (250) may include a speed control unit (251), a current map (252), a phase compensation unit (253), a stationary-rotating coordinate system conversion unit (254), a current control unit (255), a rotating-stationary coordinate system conversion unit (256), and a voltage modulation unit (257).

[0066] The speed control unit (251) compensates for the difference between the speed (ω) of the motor (240) and the speed command to obtain the torque command (T * ) can be generated. For example, the speed control unit (251) can be implemented as a PI (Proportional-Integral controller) controller, through which the speed of the motor (240) can be precisely controlled. The generated torque command (T * ) can be converted into d-axis and q-axis current commands through current map (252) query.

[0067] The current map (252) may mean a map in which the output torque of the multi-phase motor (240) is predefined according to the size of the d-axis current and the size of the q-axis current, and by referring to this, the current command (i) on the dq-rotational coordinate system r dq * ) can be generated. The current map (252) can store the optimal current combination for MTPA (Maximun Torque Per Ampere) control and the current combination for MTPV (Maximun Torque Per Voltage) control, and the controller (250) can select an appropriate current command according to the operating conditions of the motor (240). The phase compensation unit (253) is a key component of the present disclosure, and is configured to control the electrical angle (or first motor angle, θ) of the motor. r ) and can be responsible for the function of receiving and performing phase compensation. The phase compensation unit (253) is based on the motor driving system entering the heat generation control, and the first motor angle (θ r ) at the compensation angle (θ) err ) and add the second motor angle (θ') r) can be generated. This causes the heat generation of the motor (240) to increase, and a detailed explanation related to this will be described later with reference to FIG. 4.

[0068] The stationary-rotating coordinate system conversion unit (254) is a first motor angle (θ r ) or the second motor angle (θ' r ) receives information and the phase current (i) flowing in each winding of the motor (240) abc ) can be expressed in the dq-rotation coordinate system (i r dq ) First motor angle (θ r ) information can be obtained from sensors such as encoders, resolvers, and hall sensors, or through back EMF-based estimation of the motor (240), sliding mode observers, high-frequency injection methods, and magnetic flux-based sensorless methods.

[0069] In particular, in relation to the disclosed embodiment, the stationary-rotating coordinate system conversion unit (254) converts the second motor angle (θ') as the motor drive system enters heat generation control. r ) can be used to perform coordinate transformation to induce additional heat generation of the motor (240).

[0070] The current control unit (255) provides a current command (i r dq * ) and the current flowing in the motor winding (i r dq ) based on the current command (i r dq * ) and motor current (i r dq ) voltage reference (v) that compensates for the difference between r dq *) can be generated. For example, the current control unit (254) may be configured as a PI controller that performs feedback control, but is not limited thereto. In addition, the current control unit (255) may have independent PI controllers for the d-axis and the q-axis. The rotation-stationary coordinate system conversion unit (256) may generate a first motor angle (θ r ) or the second motor angle (θ' r ) based on the voltage reference (v) expressed in the dq-rotational coordinate system r dq * ) is the voltage reference (v) on the dq-stationary coordinate system s dq * ) can be converted to .

[0071] Converted voltage reference (v s dq * ) can be transmitted to the voltage modulation unit (256) and converted into an actual switching signal.

[0072] The voltage modulation unit (257) can generate a control signal for each switching element (S1, S2, S3, S4, S5, S6) of the inverter (230) according to the SVPWM (Space Vector Pulse Width Modulation) technique. Since the control method of the inverter (230) and the motor (240) according to the SVPWM technique is widely known to those skilled in the art, a detailed description thereof will be omitted. The voltage modulation unit (257) can convert the voltage command of the stationary coordinate system into a three-phase PWM signal, through which the switching elements of the inverter (230) can operate at an appropriate duty ratio to supply the desired voltage and current to the motor (240).

[0073] Next, the heat generation control effect according to the phase compensation of the controller will be described with reference to Fig. 4.

[0074] Figure 4 is a diagram for comparing the results of performing MTPA control based on the first motor angle and the results of performing heat generation control based on the second motor angle.

[0075] I shown in Fig. 4 q Axis and I d The axes correspond to the d-axis current and the q-axis current on the dq-rotational coordinate system based on the first motor angle, respectively, and the I'q axis and the I'd axis correspond to the second motor angle (θ' r ) is the axis corresponding to the d-axis current and q-axis current on the dq-rotational coordinate system based on the compensation angle (θ) of the Iq and Id axes. err ) is an expression of a coordinate system rotated by that amount.

[0076] When the controller (250) controls the inverter (230) based on the first motor angle, a phase current of I flows through the motor (240) to satisfy the output torque, and the operating point at this time may be located at P. This is the point where the MTPA curve (G401) and the isotorque curve (G402) for the output torque intersect, and may mean an efficient operating point that achieves the output torque corresponding to the torque command with the minimum current.

[0077] On the other hand, if the controller (250) controls the inverter (230) based on the second motor angle, the operating point is the MTPA curve (G401) at the compensation angle (θ err ) moves to P', which is the point where the heat control curve (G401') and the torque curve (G402), which are curves that have rotated by the amount of torque, meet, and the phase current flowing in the motor (240) may increase to I'. This means that the motor (240) requires a larger current to output torque corresponding to the torque command, and as the phase current of the motor (240) increases, the heat generation of the motor (240) winding may increase.

[0078] In more detail, in normal operation without performing heat control, when the controller (250) receives a torque command, the current map (252) can output a current command corresponding to the driving point determined according to the MTPA curve (G401). However, in case phase compensation is performed according to heat control, the current control unit (255) outputs a second motor angle (θ') according to the phase compensation. r) receives the current value of the motor converted by the torque command, and as a result, a voltage command corresponding to a lower torque output than the torque command can be generated. Accordingly, the speed control unit (251) increases the torque command to compensate for the low output torque, and as a result, the size of the current flowing to the motor (240) increases, which may also increase the heat generation of the motor winding.

[0079] Next, the setting range of the compensation angle (θerr) will be described with reference to FIGS. 5 to 7.

[0080] FIG. 5 is a first drawing for explaining the range of compensation angle according to the present disclosure.

[0081] Referring to Fig. 5, when the compensation angle θ1 is positive, the operating point according to the heat generation control curve (G401') is located on the curve between the origin (O) and P5, so that the d-axis current can have a positive direction. Since these operating points are outside the normal driving range of the motor (240), the compensation angle may be a preset value that has a negative value for stable heat generation control of the motor (240).

[0082] Figure 6 is a second drawing for explaining the range of compensation angle according to the present disclosure.

[0083] Referring to Fig. 6, it shows a case where a point (P6) where the heat generation control curve (G401') meets the Id axis occurs due to a negative absolute value. In this case, the q-axis current value may have a negative angular point, which means reverse rotation, and thus normal operation control of the motor (240) may be impossible. Therefore, the compensation angle of the motor (240) may be a preset negative value in consideration of the shape of the MTPA curve determined by the motor's (240) q-axis inductance, d-axis inductance, and permanent magnetic flux.

[0084] Figure 7 is the third drawing for explaining the range of compensation angle.

[0085] Referring to Fig. 7, compared to Figs. 5 and 6, an appropriate compensation angle (θ err ) is set. The preset compensation angle (θ) err ) range, the q-axis current is always positive and the d-axis current is always negative, so the motor (240) can always be in a driving state. This can mean that the motor (240) operates in a normal forward rotation driving range, not in a reverse rotation or regenerative state. Furthermore, the compensation angle (θ err ) may be a preset value considering the heat generation or power consumption of the motor (240). Through this, effective heat generation control can be achieved while maintaining stable operation of the motor (240).

[0086] The controller (250) can determine a second motor angle by adding a compensation angle set to increase the size of each of a plurality of phase currents according to heat generation control to the first motor angle. The controller (250) can determine the compensation angle to be a value less than 0 and determine the compensation angle so that the q-axis current command has a value greater than 0. Through such compensation angle setting, the motor (240) can increase the amount of heat generation while operating stably in the forward rotation driving range.

[0087] When performing heat generation control, the controller (250) can convert the phase current on the abc coordinate system into the current on the dq rotational coordinate system based on the second motor angle, and perform feedback control by comparing the current on the dq rotational coordinate system with the current command. Through this, precise current control can be realized in the phase-compensated coordinate system, thereby simultaneously achieving heat generation effect and control stability.

[0088] Additionally, the controller (250) can perform heat control based on the speed of the motor (240) being lower than a preset base speed. This is because the effect of heat control is large in the low-speed range and motor stability can be secured.

[0089] Next, a method for controlling heat generation of a motor drive system will be described with reference to Fig. 8.

[0090] Fig. 8 is a flowchart showing an example of a heat generation control method of a motor drive system according to the present disclosure.

[0091] Referring to FIG. 8, the controller (250) can receive a heat control request from an external device (S801). For example, the controller (250) can receive a heat control request from a higher-level controller or a separately provided HVAC (Heating, Ventilating, and Air Conditioning) controller.

[0092] Upon entering the heat control, the controller (250) can determine the second motor angle (S802). The controller (250) can receive the first motor angle, which is the electrical angle of the motor (240), and determine the second motor angle by adding a compensation angle of a preset size to the motor angle. The compensation angle is determined as a negative value set to increase the size of each of the plurality of phase currents, and can be set within an appropriate range so that the q-axis current command has a value greater than 0.

[0093] The controller (250) can perform heat generation control based on the determined second motor angle (S803). The controller (250) can increase the heat generation amount of the multi-phase motor (240) by driving the multi-phase motor (240) based on the second motor angle. In the heat generation control process, the phase current on the abc coordinate system is converted into current on the dq rotational coordinate system, and feedback control can be performed by comparing the current on the dq rotational coordinate system with a current command.

[0094] Depending on the heat generation control, the motor (240) generates additional heat, thereby increasing the temperature of the refrigerant flowing in the heat pump (S804). Since the structure of the electric compressor (200) allows the case of the motor (240) and the refrigerant to physically contact each other, the heat generated by the motor (240) can be transferred to the refrigerant. This additional heat generation can contribute to improving the heating performance when the heat pump operates in a heating cycle (i.e., a reverse refrigeration cycle). This allows for an additional heating effect to be obtained without the intervention of a PTC heater.

[0095] The multi-phase motor (240) can be applied to all synchronous motors requiring synchronous electrical angle, such as an Interior Permanent Magnet Synchronous Motor (IPMSM), a Surface Permanent Magnet Synchronous Motor (SPMSM), and a Synchronous Reluctance Motor (SynRM). This allows the heating performance of a heat pump system to be improved by applying the same heat generation control principle to various types of synchronous motors.

[0096] Furthermore, the heat generation control method of the present disclosure can generate heat energy in the motor windings by increasing the phase current by adjusting motor angle information during the operation of the electric compressor. This can provide the effect of simultaneously improving the efficiency and economy of the heating system of an electric vehicle.

[0097] Although the present disclosure has been illustrated and described with respect to specific embodiments thereof, it will be apparent to those skilled in the art that the present disclosure may be variously improved and modified without departing from the technical spirit of the present disclosure as defined by the following claims.

Claims

1. A multi-phase motor having multiple windings corresponding to each of the multiple phases; An inverter that controls the phase current flowing in the multi-phase motor; and A motor driving device including a controller that receives a first motor angle, which is an electrical angle of the multi-phase motor, and controls the inverter based on the first motor angle to drive the multi-phase motor, or performs heat generation control to increase the heat generation amount of the multi-phase motor by driving the multi-phase motor based on a second motor angle obtained by adding a compensation angle to the first motor angle.

2. In claim 1, The above controller, A motor driving device that determines the second motor angle by adding a compensation angle set to increase the size of each of a plurality of phase currents according to the above heat generation control to the first motor angle.

3. In claim 2, The above controller, When performing the above fever control, Based on the second motor angle above, the phase current on the abc coordinate system is converted into the current on the dq rotational coordinate system, A motor driving device that performs feedback control by comparing the current on the above dq rotational coordinate system with a current command.

4. In claim 1, The above controller, A motor driving device that determines the above compensation angle as a value less than 0.

5. In claim 1, The above controller, A motor driving device that determines the compensation angle so that the q-axis current command has a value greater than 0.

6. In claim 3, The above controller, A motor driving device that performs the heat generation control based on the speed of the motor being less than a preset base speed.

7. A compressor comprising a motor drive device as described in claim 1.

8. In claim 1, The above multi-phase motor is a motor drive device that is an IPMSM (Interior Permanent Magnet Synchronous Motor).

9. A multi-phase motor having multiple windings corresponding to each of the multiple phases; An inverter that controls the phase current flowing in the multi-phase motor; and An electric vehicle including a controller that receives a first motor angle, which is an electrical angle of the multi-phase motor, and controls the inverter based on the first motor angle to drive the multi-phase motor, or performs heat generation control to increase the heat generation amount of the multi-phase motor by driving the multi-phase motor based on a second motor angle obtained by adding a compensation angle to the first motor angle.

10. In claim 9, The above controller, An electric vehicle that determines the second motor angle by adding a compensation angle set to increase the size of each of a plurality of phase currents according to the above heat generation control to the first motor angle.

11. In claim 10, The above controller, When performing the above fever control, Based on the second motor angle above, the phase current on the abc coordinate system is converted into the current on the dq rotational coordinate system, An electric vehicle that performs feedback control by comparing the current on the above dq rotational coordinate system with a current command.

12. In claim 9, The above controller, An electric vehicle in which the above compensation angle is determined to a value less than 0.

13. In claim 9, The above controller, An electric vehicle that determines the compensation angle so that the q-axis current command has a value greater than 0.

14. In claim 11, The above controller, An electric vehicle that performs the heat generation control based on the speed of the motor being less than a preset base speed.

15. In claim 9, The above multi-phase motor is an electric vehicle including a compressor of a heat pump system.

16. In claim 9, The above multi-phase motor is an IPMSM (Interior Permanent Magnet Synchronous Motor) for an electric vehicle.

17. A control method for a motor drive system including a multi-phase motor having multiple windings corresponding to each of multiple phases and an inverter that controls phase current flowing in the multi-phase motor, Receive the first motor angle, which is the electrical angle of the above multi-phase motor, The second motor angle is determined by adding a compensation angle to the above motor angle, The driving mode is determined as a first mode for driving the multi-phase motor by controlling the inverter based on the first motor angle or a second mode for driving the multi-phase motor based on the second motor angle to increase the heat generation amount of the multi-phase motor. A control method for a motor drive system including driving the multi-phase motor according to the determined driving mode.

18. In claim 17, Determining the second motor angle is as follows: A control method for a motor drive system, comprising determining the second motor angle by adding a compensation angle set to increase the size of each of a plurality of phase currents according to the second mode to the first motor angle.

19. In claim 17, Determining the second motor angle is as follows: A control method for a motor drive system, comprising determining the above compensation angle to a value less than 0.

20. In claim 17, Determining the above second motor angle is: A control method for a motor drive system, comprising determining a compensation angle such that the q-axis current command has a value greater than 0.

Images