Apparatus and method for controlling motor for vehicle

A motor control apparatus for a vehicle includes a data detector detecting driving data and a vehicle controller controlling a drive motor according to the driving data. The vehicle controller includes an acceleration generator determining a request torque and a request speed using the driving data and generating a request acceleration using the request torque and the request speed; a driving point determinator selecting an inductance control current map or a motor efficiency control current map according to the request acceleration and determining a current driving point according to the request torque and the request speed using the selected current map; and a motor controller controlling the drive motor using the current driving point.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Korean Patent Application No. 10-2016-0043178, filed on Apr. 8, 2016 in the Korean Intellectual Property Office, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a motor control apparatus for a vehicle. More particularly, the present disclosure relates to an apparatus and method for controlling a motor for a vehicle that can control a drive motor in consideration of a rotor inductance.

BACKGROUND

Currently, as environment pollution has become a more serious problem, use of pollution-free energy has become more important. In particular, air pollution in large cities has gradually become more serious, and vehicle exhaust gas is one of the major sources thereof.

Accordingly, in order to reduce the amount of exhaust gas and to provide more efficient fuel consumption, environmentally-friendly vehicles including hybrid vehicles and electric vehicles have been developed and driven.

An environmentally-friendly vehicle may be a vehicle that does not discharge an exhaust gas. Such an environmentally-friendly vehicle may include a pure electric vehicle that drives using the power of a motor, a hybrid electric vehicle that combines and drives using the power of a motor and an engine, and a fuel cell vehicle that drives using the power of a motor driven by electricity that is generated in a fuel cell.

Such an environmentally-friendly vehicle mounts a high voltage battery as an electric power source that drives a drive motor and a converter.

Currently, a drive motor uses a field coil motor rather than a permanent magnet motor.

Here, because the field coil motor may be formed without a rare earth metal and has a wide driving area, the field coil motor may be a representative motor that can replace a permanent magnet motor. By winding a coil to an iron core of each of a stator and a rotor and by applying a current thereto, the field coil motor generates a torque.

Because such a field coil motor may replace a permanent magnet for generating a field magnet magnetic flux with a coil, the field coil motor has different electrical response characteristics according to a field magnet current. In particular, when a drive motor drives with a maximum efficiency control that minimizes a loss, it is advantageous in efficiency, but a dynamic response performance thereof may be deteriorated due to an increase in rotor inductance.

SUMMARY

The present disclosure has been made in an effort to provide an apparatus and method for controlling a motor for a vehicle that is capable of controlling a drive motor in consideration of a rotor inductance.

The present disclosure has been made in an effort to further provide an apparatus and method for controlling a motor for a vehicle that is capable of controlling a drive motor by minimizing a rotor inductance based on acceleration.

An exemplary embodiment in the present disclosure provides a motor control apparatus for a vehicle including: a data detector detecting driving data and a vehicle controller controlling a drive motor according to the driving data. The vehicle controller includes an acceleration generator determining a request torque and a request speed using the driving data and generating a request acceleration using the request torque and the request speed; a driving point determinator selecting an inductance control current map or a motor efficiency control current map according to the request acceleration and determining a current driving point according to the request torque and the request speed using the selected current map; and a motor controller controlling the drive motor using the current driving point.

The driving point determinator may determine a current driving point according to the request torque and the request speed using the inductance control current map, if the request acceleration is equal to or larger than a reference value.

The driving point determinator may determine a plurality of current driving points according to the request torque and the request speed, if the request acceleration is equal to or larger than the reference value, extract a rotor inductance according to each of the plurality of current driving points from the inductance control current map, and determine a current driving point according to a minimum rotor inductance among the extracted rotor inductances.

The motor controller may control a drive motor using a current and a current phase angle of the current driving point.

The vehicle controller may further include a current map generator that generates at least one of the inductance control current map and the motor efficiency control current map.

The current map generator may extract a basic rotor inductance according to a basic current driving point through finite element analysis, determine at least one current driving point according to a motor torque and a motor speed within a predetermined range, generate a rotor inductance according to at least one current driving point using the basic rotor inductance, and generate an inductance control current map by matching a rotor inductance to the at least one current driving point.

The driving point determinator may determine a current driving point according to a request torque and a request speed using the motor efficiency control current map, if the request acceleration is less than the reference value.

Another embodiment of the present invention provides a method in which a motor control apparatus for a vehicle controls a drive motor including: determining a request torque and a request speed using driving data; generating request acceleration using the request torque and the request speed; determining whether the request acceleration is equal to or larger than a reference value; determining a current driving point using an inductance control current map when the request acceleration is equal to or larger than the reference value; and controlling the drive motor using the current driving point.

According to an exemplary embodiment, because a drive motor can be controlled in consideration of a rotor inductance, fuel consumption can be improved and driving satisfaction can be enhanced.

Further, by minimizing a rotor inductance based on acceleration, the drive motor can be controlled and thus responsiveness can be improved.

In addition, an effect that may be obtained or estimated due to an exemplary embodiment of the present invention is directly or implicitly described in a detailed description of an exemplary embodiment in the present disclosure.

That is, various effects that are estimated according to an exemplary embodiment in the present disclosure will be described within a detailed description to be described later.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, an operation principle of an apparatus and method for controlling a motor for a vehicle according to an exemplary embodiment in the present disclosure will be described in detail with reference to the accompanying drawings and description. However, drawings shown hereinafter and a detailed description to be described later relate to an exemplary embodiment among several exemplary embodiments for effectively describing a characteristic of the present disclosure. Therefore, the present disclosure is not limited to only the following drawing and description.

Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present disclosure. The terms used herein are defined in consideration of functions in the present invention and may vary depending on a user's or an operator's intension and usage. Therefore, the terms used herein should be understood based on the descriptions made herein.

Further, the following exemplary embodiment may use terms by appropriately changing, integrating, or separating to be clearly understood by a person of ordinary skill in the art in order to efficiently describe a core technical characteristic of the present invention, but the present invention is not limited thereto.

Hereinafter, an exemplary embodiment in the present disclosure will be described in detail with reference to the accompanying drawings.

FIG. 1is a diagram illustrating an environmentally-friendly vehicle including a motor control apparatus according to an exemplary embodiment in the present disclosure.

That is, for better comprehension and ease of description,FIG. 1illustrates a hybrid electric vehicle as an example of an environmentally-friendly vehicle as an exemplary embodiment. Therefore, a method of controlling a motor for a vehicle according to an exemplary embodiment may be applied to other environmentally-friendly vehicles as well as the hybrid electric vehicle ofFIG. 1.

Referring toFIG. 1, an environmentally-friendly vehicle includes an engine110, an engine clutch120, a drive motor130, a battery140, a transmission150, an engine controller160(hereinafter, referred to as an ‘EC’), a motor controller (hereinafter, referred to as an ‘MC’)170, a transmission controller (hereinafter, referred to as a ‘TC’)180, a traction control system (hereinafter, referred to as a ‘TCS’)190, and a hybrid controller (hereinafter, referred to as an ‘HO’)200.

A thrust of the engine110is controlled by the control of the EC160, and driving thereof is controlled to an optimal driving point according to the control of the EC160.

The engine clutch120is disposed between the engine110and the drive motor130and operates according to the control of the HC200to connect or disconnect power delivery between the engine110and the drive motor130. That is, the engine clutch120connects or disconnects power between the engine110and the drive motor130according to a switch between an Electric Vehicle (EV) mode and a Hybrid Electric Vehicle (HEV) mode.

When the engine clutch120is opened, the environmentally-friendly vehicle may be driven only by the drive motor130, and when the engine clutch120is locked, the environmentally-friendly vehicle may be driven by only the engine110or by the engine110and the drive motor130.

The drive motor130is operated by a three phase AC voltage that is applied from the MC170to generate a torque. The drive motor130is operated as a generator upon coasting or regenerative braking to supply a voltage to the battery140.

The battery140is formed of a plurality of unit cells, and at the battery140, a high voltage for providing a driving voltage to the drive motor130is stored. The battery140supplies a driving voltage to the drive motor130in an EV mode or an HEV mode and is charged with a voltage that is generated in the motor upon regenerative braking.

When a commercial power source is plug-in connected, the battery140may be charged by a voltage and a current that are supplied through a charging device.

The transmission150adjusts a shift ratio according to the control of the TC180, distributes an output torque that is added and applied through the engine clutch120with a shift ratio according to a driving mode to transfer the distributed output torque to a driving wheel, thereby enabling the environmentally-friendly vehicle to be driven.

The EC160is connected with the HC200through a network and is interlocked with the HC200to control general operations of the engine110according to an engine operation state such as a driver's demand torque signal, a coolant temperature, an engine speed, a throttle valve opening level, an intake amount, an oxygen amount, and an engine torque. The EC160provides an operation state of the engine110to the HC200.

The MC170controls driving and torque of the drive motor130according to the control of the HC200and stores a voltage that is generated in the drive motor130upon regenerative braking at the battery140.

The TC180controls a shift ratio according to each output torque of the EC160and the MC170and controls general operations of the transmission150such as determination of a regenerative braking amount. The TC180provides an operation state of the transmission150to the HC200.

The TCS190is a safety system that controls a driving torque of the environmentally-friendly vehicle in order to prevent a tire from slipping with an excessive driving torque upon starting or accelerating on a snowy road, an icy road, or an uneven road.

The TC180and the TCS190may cooperate to adjust a fuel injection amount, ignition timing, and a throttle valve to control an output torque of the engine110and to simultaneously control an output torque of the drive motor130through power distribution.

The HC200is an uppermost control unit that controls hybrid driving mode setting and general operations of the environmentally-friendly vehicle. The HC200integrally controls subordinate control units that are connected through a network, collects and analyzes information of each subordinate control unit, executes a cooperation control, and controls an output torque of the engine110and the drive motor130.

In an environmentally-friendly vehicle according to the present exemplary embodiment, common operations are executed equally to or similarly to that of a conventional environmentally-friendly vehicle and therefore a detailed description thereof will be omitted.

FIG. 2is a block diagram illustrating a configuration of a motor control apparatus according to an exemplary embodiment in the present disclosure. In a method of controlling a motor for a vehicle according to an exemplary embodiment to be described later, some processes may be performed by the MC170and some other processes may be performed by the EC160or the HC200. Therefore, the EC160, the MC170, the TC180, the TCS190, and the HC200according to an exemplary embodiment in the present disclosure are referred to as a vehicle controller, and for convenience of description, in this specification and claims, unless stated otherwise, the EC160, the MC170, the TC180, the TCS190, and the HC200are referred to as a vehicle controller.

Referring toFIG. 2, a motor control apparatus100includes a data detector210, a vehicle controller220, and a storage240.

The data detector210detects driving data for controlling the drive motor130. That is, when the vehicle drives, the data detector210detects general driving data including a vehicle speed, a gear shift stage, a displacement of an accelerator pedal, and a displacement of a brake pedal. The data detector210provides the detected driving data to the vehicle controller220.

The vehicle controller220controls the drive motor130based on driving data. For this reason, the vehicle controller220includes an acceleration generator231, a current map generator233, a driving point determinator235, and a motor controller237.

The acceleration generator231determines a request torque and a request speed and generates request acceleration using the request torque and the request speed. In other words, the acceleration generator231determines a request torque and a request speed based on driving data that are detected in the data detector210. The acceleration generator231generates request acceleration using the request torque and the request speed.

The current map generator233generates at least one of an inductance control current map and a motor efficiency control current map for extracting a current driving point for controlling the drive motor130. In this case, the inductance control current map may represent a map in which a rotor inductance is matched to each of a plurality of current driving points, and the motor efficiency control current map may represent a map in which motor efficiency is matched to each of a plurality of current driving points.

In other words, the current map generator233extracts magnetic flux interlinkage according to a motor speed and a current driving point through finite element analysis and a basic rotor inductance according to an iron loss and a basic current driving point. Technology that is related to a finite element analysis method is well-known technology that is presently widely known in the art and therefore a detailed description thereof will be omitted.

The current map generator233determines at least one current driving point according to a motor torque and a motor speed within a predetermined range. The current map generator233generates a rotor inductance according to at least one current driving point using the basic rotor inductance and matches the rotor inductance to each of at least one current driving point to generate an inductance control current map.

The current map generator233generates motor loss data according to a motor torque and a motor speed within a predetermined range. Here, motor loss data may represent the total sum of an iron loss, a copper loss, and a mechanical loss. The current map generator233generates a motor parameter according to a motor torque and a motor speed using motor loss data. In this case, the motor parameter may include at least one of motor efficiency, a voltage, and a power factor. By matching motor efficiency to each of at least one current driving point, the current map generator233generates a motor efficiency control current map.

Here, finite element analysis is exemplified, but the present invention is not limited thereto, and any analysis method that can extract a magnetic flux, an iron loss, and a rotor inductance may be used.

The driving point determinator235selects an inductance control current map or a motor efficiency control current map based on request acceleration. That is, if request acceleration is equal to or larger than a reference value, the driving point determinator235selects an inductance control current map and determines a current driving point according to a request torque and a request speed using the inductance control current map.

If request acceleration is less than a reference value, the driving point determinator235selects a motor efficiency control current map and determines a current driving point according to a request torque and a request speed using the motor efficiency control current map.

The motor controller237controls the drive motor130using the current driving point. That is, the motor controller237receives a current driving point from the driving point determinator235and controls the drive motor130using a current and a current phase angle of the received current driving point.

For such an object, the vehicle controller220may be implemented into at least one processor operating by a predetermined program, and the predetermined program may be programmed to perform each step of the vehicle motor control apparatus100according to an exemplary embodiment in the present disclosure.

The storage240stores necessary data in constituent elements of the motor control apparatus100and data that are generated in the motor control apparatus100. For example, the storage240may store driving data that are detected in the data detector210and may store an inductance control current map and a motor efficiency control current map that are generated in the vehicle controller220. The storage240may store a request speed and a request torque that are determined in the vehicle controller220and request acceleration that is generated in the vehicle controller220and may store a current driving point that is extracted from the inductance control current map or the motor control current map.

Further, the storage240may store various programs for controlling general operations of the motor control apparatus100.

The storage240may provide necessary data according to a request of the data detector210and the vehicle controller220. The storage240may be formed with an integrated memory or may be divided into a plurality of memories. For example, the storage240may be formed with a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash memory.

Hereinafter, a method of controlling a motor for a vehicle according to an exemplary embodiment in the present disclosure will be described with reference toFIGS. 3 and 4. Constituent elements of the vehicle controller220according to an exemplary embodiment that is described with reference toFIG. 2may be integrated or subdivided, and constituent elements of the vehicle controllers220that perform the above-described function regardless of a corresponding name may be constituent elements of the vehicle controller220according to the exemplary embodiment. Hereinafter, when describing a method of controlling a motor in a vehicle motor control apparatus100according to an exemplary embodiment, a subject of each step is the vehicle controller220instead of corresponding constituent elements and the vehicle controller220will be mainly described.

FIG. 3is a flowchart illustrating a method of controlling a motor according to an exemplary embodiment in the present disclosure.

Referring toFIG. 3, when a vehicle is being driven, the vehicle controller220determines driving data (S300). That is, the data detector210detects driving data including a displacement of a vehicle speed and an accelerator pedal and provides the detected driving data to the vehicle controller220. The vehicle controller220receives and determines driving data from the data detector210.

The vehicle controller220determines a request torque and a request speed based on the driving data (S310). That is, when a driver requests a sports mode, the vehicle controller220may generate a request torque and a request speed using the driving data. For example, the driver may request a sports mode through an input device such as a button within the vehicle.

The vehicle controller220generates request acceleration using a request torque and a request speed (S320).

The vehicle controller220determines whether request acceleration is equal to or larger than a reference value (S330). Here, a reference value may be a value to be a reference for selecting a current map based on request acceleration. The reference value may be set through a predetermined algorithm (e.g., program and probability model).

If the request acceleration is equal to or larger than a reference value, the vehicle controller220selects an inductance control current map (S340).

The vehicle controller220determines a current driving point according to a request torque and a request speed using the inductance control current map (S350). In other words, the vehicle controller220determines a plurality of current driving points according to a request torque and a request speed and extracts a rotor inductance according to each of a plurality of current points from an inductance control current map to generate an inductance candidate group. The vehicle controller220determines a minimum rotor inductance in the inductance candidate group. The vehicle controller220determines a current driving point according to the minimum rotor inductance. The current driving point is determined according to a minimum rotor inductance because an acceleration performance of the drive motor130can be improved when controlling the drive motor130by minimizing a rotor inductance.

The vehicle controller220controls the drive motor130using the current driving point (S360). That is, the vehicle controller220controls the drive motor130using a current and a current phase angle of the current driving point that is determined at step S350.

If request acceleration is less than a reference value, the vehicle controller220selects a motor efficiency control current map (S370).

The vehicle controller220determines a current driving point according to a request torque and a request speed using the motor efficiency control current map (S380). Specifically, the vehicle controller220determines a plurality of current driving points according to a request torque and a request speed. The vehicle controller220determines motor efficiency according to each of a plurality of current driving points in the motor efficiency control current map. The vehicle controller220determines highest motor efficiency of a plurality of motor efficiency and determines a current driving point according to the highest motor efficiency.

The vehicle controller220controls the drive motor130using a current and a current phase angle of the current driving point that is determined at step S380(S390).

As described above, in a method of controlling a motor according to an exemplary embodiment in the present disclosure, because the drive motor130may be controlled by minimizing a rotor inductance based on an inductance control current map, an acceleration performance of the drive motor130can be improved, fuel consumption can be improved, and a driver's driving satisfaction can be enhanced.

FIG. 4is a flowchart illustrating a method of generating a current map according to an exemplary embodiment in the present disclosure.

Referring toFIG. 4, the vehicle controller220extracts a basic rotor inductance through finite element analysis (S410). In other words, the vehicle controller220extracts a magnetic flux, an iron loss, and a basic rotor inductance according to a speed, a current, and a current phase angle through finite element analysis.

The vehicle controller220determines a predetermined range (S420). That is, the vehicle controller220may determine a predetermined range of a motor torque and determine a predetermined range of a motor speed.

Here, a predetermined range may represent a range of a motor torque and a range of a motor speed for generating a current map. The predetermined range may be set by an operator or may be set through a predetermined algorithm (e.g., program and probability model).

For example, a predetermined range of a motor torque may be 10 Nm to 150 Nm, and a predetermined range of a motor speed may be 1000 rpm to 6000 rpm.

The vehicle controller220determines at least one current driving point according to a motor torque and a motor speed within a predetermined range (S430). That is, when starting generation of a current map, the vehicle controller220may determine at least one current driving point according to a start motor torque and a start motor speed in a predetermined range. For example, the start motor torque may be 10 Nm, and the start motor speed may be 1000 rpm.

The vehicle controller220generates a rotor inductance according to at least one current driving point (S440). In other words, the vehicle controller220generates a rotor inductance according to each of at least one current driving point using the basic rotor inductance that is determined at the step S410.

The vehicle controller220generates a rotor inductance according to at least one current driving point (S440). In other words, the vehicle controller220generates a rotor inductance according to each of at least one current driving point using the basic rotor inductance that is determined at the step S420.

The vehicle controller220determines whether a motor torque is less than a final torque (S450). Here, the final torque may represent a final motor torque in a predetermined range. For example, the final torque may be 150 Nm.

If a motor torque is less than a final torque, the vehicle controller220increases the motor torque by a predetermined unit (S460). Here, the predetermined unit may represent a torque amount for increasing a motor torque and may be set by an operator or may be set through a predetermined algorithm (e.g., program and probability model). For example, a predetermined unit of the motor torque may be 10 Nm. The vehicle controller220may increase the motor torque by a predetermined unit and repeat a process after step S430.

If a motor torque corresponds with a final torque, the vehicle controller220determines whether a motor speed is less than a final speed (S470). Here, the final speed may represent a final motor speed in a predetermined range. For example, the final speed may be 6000 rpm.

If a motor speed is less than a final speed, the vehicle controller220increases the motor speed by a predetermined unit (S480). In this case, the predetermined unit may represent a magnitude of the motor speed for increasing the motor speed and may be set by an operator or may be set through a predetermined algorithm (e.g., program and probability model). A predetermined unit of the motor speed may be 1000 rpm. The vehicle controller220may increase the motor speed by a predetermined unit and repeat a process after step S430.

If a motor speed corresponds with a final speed, the vehicle controller220matches a rotor inductance to a plurality of current driving points to generate an inductance control current map (S490). That is, by matching a rotor inductance to a plurality of current driving points that are determined by repeating steps S430to S480, the vehicle controller220generates an inductance control current map.