JP2011172324A - Inverter controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise and loss due to superposition of harmonics according to the drive state of a motor, unlike conventional control where certain noise and loss occur at magnetic pole position detection by superposition of harmonics. <P>SOLUTION: This inverter controller is applicable to a hybrid electric car and an electric car, and it includes a unit which determines whether the rotational speed of the motor is lower than a specified velocity or not, and an estimation unit which estimates the magnetic pole position of the rotor by superposing the components of harmonics on a voltage applied to or a current supplied to the motor when determined that the rotational speed of the motor is lower than the specified velocity. This estimation unit reduces the amplitude of the components of the harmonics for estimation of the magnetic pole position according to a change in the drive state of the motor, thereby reducing the noise and loss due to superposition of harmonics. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hybrid electric vehicle and an inverter control device applied to an electric vehicle.

  Conventionally, when the output torque of a motor having electrical saliency on the rotor, for example, a permanent magnet motor, is controlled with high accuracy and high speed, it is necessary to attach a rotor position sensor in order to flow current based on the magnetic pole position of the rotor. was there. However, since the rotor position sensor is relatively large in volume, it induces restrictions on the arrangement, and increases in trouble factors such as troublesome routing of the control transmission line and disconnection for transmitting the sensor output to the control device. It becomes a problem.

  On the other hand, rotor position sensorless control is known in which the rotor position is indirectly estimated by detecting an induced voltage generated during rotation due to the magnetic flux of the permanent magnet. At low speeds where no induced voltage is generated in principle, the rotor position detection signal (harmonic component or alternating voltage) is applied using the motor's inductance characteristics, and the rotor position is known from the detected current. A rotor position sensorless control such as a method has been proposed (see Patent Document 1).

Japanese Patent No. 3312472

  In the case of the method using the inductance characteristic of the motor, the smaller the amplitude of the rotor position detection signal, the less noise and vibration are generated, and a comfortable riding comfort can be ensured. However, in order to prevent the vehicle from running backward due to a magnetic pole position estimation error, and to ensure stable magnetic pole position estimation accuracy and to drive the vehicle stably, a rotor position detection signal (harmonic) applied to the motor is required. The voltage amount or current amount of the wave component) cannot be reduced considering various driving conditions. Therefore, there is a problem that noise and loss are generated from the motor due to the harmonic component.

  Next, harmonic noise and loss generated from the motor will be described. Control of an inverter in an electric vehicle such as a hybrid vehicle requires rotor position information of the motor in order to control the rotation speed or output torque of the motor. The rotor position (magnetic pole position) can be estimated when the inverter superimposes a harmonic component on the applied voltage or supply current to the motor and detects the response current or voltage of the motor.

  However, noise due to harmonic components superimposed from the motor is generated. Furthermore, the energy of the harmonic component applied to the motor does not contribute to the motor torque, resulting in a heat loss, resulting in a problem that the motor efficiency is reduced.

  An object of the present invention is to reduce noise and loss due to harmonic superposition according to the driving state of the motor, unlike conventional control in which constant noise and loss occur when detecting the magnetic pole position by harmonic superposition. .

  An inverter control device according to an embodiment of the present invention includes a hybrid electric vehicle including an internal combustion engine, a motor having electrical saliency on a rotor, an inverter that drives the motor, and electrical saliency on the rotor. An inverter control device applied to an electric vehicle including a motor having a motor and an inverter that drives the motor, wherein the motor determines whether the rotational speed of the motor is lower than a predetermined speed, and the rotational speed of the motor When the low speed is determined to be low speed, the estimation means includes an estimation means for superimposing a harmonic component on the applied voltage or supply current to the motor to estimate the magnetic pole position of the rotor, and the estimation means The amplitude of the harmonic component for estimating the magnetic pole position is changed according to the driving state change.

  An inverter control apparatus according to another embodiment of the present invention is an inverter control apparatus applied to a hybrid electric vehicle including an internal combustion engine, a motor having an electric saliency in a rotor, and an inverter that drives the motor. The means for determining whether or not the rotational speed of the motor is lower than a predetermined speed, and when the rotational speed of the motor is determined to be the low speed, a harmonic component is applied to the applied voltage or supply current to the motor. And estimating means for estimating the magnetic pole position of the rotor by superimposing, wherein the estimating means has a smaller value of the amplitude of the harmonic component when the automobile is in an idling stop state than when the idling stop is not performed. Set to.

  Unlike conventional control in which constant noise and loss occur when detecting the magnetic pole position by harmonic superposition, noise and loss due to harmonic superposition can be reduced according to the driving state of the motor.

The block diagram which shows the structure of the hybrid electric vehicle in embodiment of this invention. The block diagram which shows the structure of the electric vehicle in embodiment of this invention. The flowchart which shows the 1st Example of this invention. The flowchart which shows the 2nd Example of this invention. The flowchart which shows the 3rd Example of this invention.

  Embodiments of an inverter control device according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration example of a hybrid electric vehicle system to which the present invention is applied. A clutch 2 is provided on the output side of the internal combustion engine (engine) 1, and a motor 3 having electric saliency is connected to the rotor. A motor having electrical saliency on the rotor refers to a motor having different inductance depending on the rotational position of the rotor when a predetermined voltage vector is applied. The connection of the clutch 2 is controlled by the transmission ECU 10 based on traveling conditions and the like. The motor 3 is provided with a transmission 4, and the output shaft of the transmission 4 is connected to drive wheels 13 via a differential gear 12. The clutch 2 may not be present and the internal combustion engine 1 and the motor 3 may be directly connected.

  The rotational speed of the internal combustion engine 1 is controlled by an internal combustion engine ECU (Electronic Control Unit) 7. Electric power from the battery 6 is supplied to the motor 3 after being converted into alternating current by the inverter 5, and the inverter 5 is controlled by the inverter ECU 9. The battery ECU 8 monitors the remaining amount and temperature of the battery 6.

  Information regarding the internal combustion engine ECU 7, the transmission ECU 10, the inverter ECU 9, and the battery ECU 8 is input to the hybrid ECU 11. The hybrid ECU 11 also receives a torque command or a speed command from the accelerator and brake device or other devices. Based on the torque command or the speed command, the hybrid ECU 11 comprehensively controls these ECUs so as to operate optimally in view of fuel consumption performance, power performance, and the like. Here, the inverter control device according to the present invention includes an inverter ECU 9 and a hybrid ECU 11.

  FIG. 2 is a block diagram showing a configuration example of an electric vehicle system to which the present invention is applied.

  The output shaft of the motor 3 is connected to the drive wheel 12. Electric power from the battery 6 is converted into alternating current by the inverter 5 and supplied to the motor 3, and the inverter 5 is controlled by the inverter ECU 9. The battery ECU 8 monitors the remaining amount and temperature of the battery 6.

  Information on the inverter ECU 9 and the battery ECU 8 is input to the electric vehicle ECU 14. The electric vehicle ECU 14 also receives a torque command or a speed command from the accelerator and brake device or other devices. Based on the torque command or the speed command, the electric vehicle ECU 14 comprehensively controls the inverter ECU 9 and the battery ECU 8 so as to achieve an optimum operation in view of efficiency performance, power performance, and the like. Here, the inverter control device according to the present invention includes an inverter ECU 9 and an electric vehicle ECU 11.

  FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention. In the present invention, the amplitude of the harmonic component for estimating the magnetic pole position is varied in accordance with a change in the vehicle state (motor driving state).

  First, the operation when idling is stopped, which is one of the vehicle states, will be described with reference to the configuration of the hybrid vehicle in FIG. 1 and the flowchart in FIG.

  When the inverter ECU 9 obtains a control command (acceleration / deceleration command or speed command or the like) from the hybrid ECU 11 (step S101), the motor ECU detects the motor speed and selects the magnetic pole position estimation by the harmonic superposition method if the speed is lower than the predetermined speed. (S102, S103). This predetermined speed is the maximum speed at which the magnetic position can be measured by the harmonic superposition method. There are two methods for estimating the magnetic position of the harmonic superposition method: a method of superimposing the harmonic voltage component for magnetic position detection from the voltage source to the inverter control signal, and a method of superimposing the harmonic current component from the current source to the inverter control signal. However, the present invention can be applied to any method.

  When the motor speed is higher than the predetermined speed (NO in S102), the inverter ECU 9 selects a magnetic pole position estimation method that does not superimpose harmonic components (S104), performs magnetic pole position estimation (S108), and controls the motor. (S109).

  The inverter ECU 9 superimposes the harmonic voltage component or the current component if the motor speed is low, but determines whether or not the idling stop state is present before that (S105). The idling stop state refers to a state in which the internal combustion engine 1 is stopped and the motor 3 is also stopped when the automobile stops due to a signal waiting or the like. In the idling stop state, since a large load fluctuation is not given to the motor from the internal combustion engine and the transmission, the harmonic amplitude to be applied can be made smaller than that in the normal operation without causing a magnetic pole position estimation error. (S106). Therefore, the noise and loss of the motor can be reduced. If it is not in the idling stop state (NO in S105), the inverter ECU 9 sets the harmonic amplitude to a larger amplitude during normal traveling than in step S106 (S107).

  As described above, after the harmonic amplitude is determined when the motor rotates at a low speed, the inverter ECU 9 superimposes the harmonic component on the inverter control command, and estimates the magnetic pole position of the rotor based on the response current (S108). The motor 3 is controlled (S109).

  Other vehicle states (motor drive states) include idling states of drive wheels, clutch engagement states, transmission states, and the like. First, regarding the state of the clutch and the state of the transmission, when the clutch is open and the transmission is neutral, the motor is not subjected to load fluctuations from the internal combustion engine and the transmission. Even when the amplitude of the wave component is reduced and the magnetic pole position estimation accuracy is low, the stability of the vehicle can be ensured.

  Next, since the motor speed can change suddenly when the driving wheel is idle, it is necessary to increase the amplitude of the superimposed harmonic component to ensure the stability of the vehicle. Therefore, the noise and loss of the motor can be reduced during normal running by increasing the amplitude of the harmonic component only when the idling state of the drive wheel is detected. The idling state of the drive wheel can be determined from the rotational speed of each axle.

  FIG. 4 is a flowchart showing the operation of the second embodiment of the present invention. The processing steps having the same contents as those in the first embodiment are given the same step numbers, and detailed descriptions thereof are omitted. This second embodiment can be applied to both the hybrid electric vehicle of FIG. 1 and the electric vehicle of FIG. Here, the case where the second embodiment is applied to the electric vehicle of FIG. 2 will be described, but the same operation is performed in the case of the hybrid electric vehicle of FIG.

  When the inverter ECU 9 obtains a control command (acceleration / deceleration command or speed command) from the electric vehicle ECU 14 (step S101), the motor ECU detects the motor speed and selects the magnetic pole position estimation by the harmonic superposition method if the motor speed is lower than the predetermined speed. (S102, S103).

  The inverter ECU 9 detects or estimates the motor load fluctuation that affects the estimation of the magnetic pole position of the motor. If the load fluctuation is smaller than the first predetermined value, the amplitude of the harmonic component applied to the motor is reduced to reduce the motor load. Noise and loss are reduced (S202). If the load fluctuation is larger than the second predetermined value larger than the first, the amplitude of the harmonic component applied to the motor is increased, and the magnetic position is reliably detected (S203). Further, the inverter ECU sets the amplitude of the harmonic component applied to the motor to medium (S404) when the fluctuation of the motor load is medium (other than steps S202 and S203).

  As a means for detecting fluctuations in the motor load, monitoring battery voltage, battery current, battery power, inverter output current, and inverter output power can be mentioned. When each change rate is large, the motor load varies, so the amplitude of the harmonic component is increased. For example, when the battery voltage increases significantly due to regenerative power during deceleration, the amplitude of the harmonic component is increased to reliably detect the magnetic position. When the rate of change of the motor load is small and substantially constant, the stability of the vehicle can be ensured even when the amplitude of the harmonic component is reduced and the magnetic pole position estimation accuracy is low.

  FIG. 5 is a flowchart showing a third embodiment to which the present invention is applied. The processing steps having the same contents as those in the first embodiment are given the same step numbers and will not be described in detail. This third embodiment is also applicable to both the hybrid electric vehicle of FIG. 1 and the electric vehicle of FIG.

  In this embodiment, two or more magnetic pole position estimation methods are switched according to the motor speed, and the amplitude of the harmonic component is changed based on a torque command value that is one of command values to the inverter. Hereinafter, a description will be given with reference to the flowchart of FIG.

  The inverter ECU 9 detects the motor speed, and if it is lower than the predetermined speed, selects a magnetic pole position estimation method that superimposes harmonic voltage or current, and selects a magnetic pole position estimation method that does not superimpose harmonic voltage or current at high speed. (S101 to S104).

  If the motor speed is low, the harmonic voltage or current is superimposed. However, if the torque command is smaller than the first predetermined value (including a small negative torque command), the speed change or Since the load fluctuation is small, the amplitude of the harmonic component applied to the motor can be reduced to reduce the noise and loss of the motor (S301, S302). When the torque command exceeds a second predetermined value that is larger than the first predetermined value (including a large negative torque command), the amplitude of the harmonic component applied to the motor is increased to reliably detect the magnetic position. (S303). Further, when the torque command is at a middle level as in normal driving (other than steps S302 and S303), the inverter ECU also sets the amplitude of the harmonic component applied to the motor to a medium level (S304).

  As a command value to the inverter other than the torque command, a speed command can be cited. When the difference between the speed command value to the inverter and the motor speed is large, the motor speed is suddenly changed by the output of the inverter, so the amplitude of the harmonic component for magnetic pole position estimation cannot be reduced. However, when the difference between the speed command value to the inverter and the motor speed is small, the motor speed does not change suddenly due to the output of the inverter. Therefore, the amplitude of the superimposed harmonic component is reduced while ensuring the stability of the vehicle. The noise and loss of the motor can be reduced.

  The above description is an embodiment of the present invention, and does not limit the apparatus and method of the present invention, and various modifications can be easily implemented.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Clutch, 3 ... Motor having electric saliency on rotor, 4 ... Transmission, 5 ... Inverter, 6 ... Battery, 7 ... Internal combustion engine ECU, 8 ... Battery ECU, 9 ... Inverter ECU DESCRIPTION OF SYMBOLS 10 ... Transmission ECU, 11 ... Hybrid ECU, 12 ... Differential gear, 13 ... Drive wheel, 14 ... Electric vehicle ECU.

Claims (7)

A hybrid electric vehicle including an internal combustion engine, a motor having electrical saliency on the rotor, an inverter that drives the motor, and a motor having electrical saliency on the rotor and an inverter that drives the motor An inverter control device applied to an electric vehicle,
Means for determining whether the rotational speed of the motor is lower than a predetermined speed;
When the rotational speed of the motor is determined to be the low speed, the estimation means for estimating the magnetic pole position of the rotor by superimposing a harmonic component on the applied voltage or supply current to the motor,
The said estimation means reduces the amplitude of the said harmonic component for magnetic pole position estimation according to the drive state change of the said motor, The inverter control apparatus characterized by the above-mentioned.   The inverter control apparatus according to claim 1, wherein the estimation unit reduces the amplitude of the harmonic component in accordance with a magnitude of fluctuation of a motor load.   3. The inverter according to claim 2, wherein the estimation unit detects the fluctuation of the motor load as at least one fluctuation of a battery voltage, a battery current, a battery power, an inverter output current, and an inverter output power of the automobile. Control device.   The inverter control apparatus according to claim 1, wherein the estimation unit reduces the amplitude of the harmonic component in accordance with a magnitude of a torque command value to the inverter. An inverter control device applied to a hybrid electric vehicle including an internal combustion engine, a motor having electrical saliency on a rotor, and an inverter that drives the motor,
Means for determining whether the rotation speed of the motor is low;
When the rotational speed of the motor is determined to be low, the estimation means for estimating the magnetic pole position of the rotor by superimposing a harmonic component on the applied voltage or supply current to the motor,
The estimation means sets the amplitude of the harmonic component to a smaller value when the automobile is in an idling stop state than when the automobile is not idling stop.   6. The inverter control device according to claim 5, wherein the estimation means sets the amplitude of the harmonic component to a value larger than a predetermined value when the driving wheel of the automobile is idling.   6. The inverter control apparatus according to claim 5, wherein the estimating means sets the amplitude of the harmonic component to a value smaller than a predetermined value when the clutch of the automobile is disengaged and transmission neutral.

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