JP2015023611A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric vehicle that can correct an electric angle of a motor by detecting a detection error of the electric angle by means of a technique with less restriction on motor driving condition and constitution.SOLUTION: The electric vehicle 1 comprises: an electrification control section 10, which makes an electrification control on an angular error detection mode that uses a d-axis current command value Id_c as a command value Id_a for angular error detection under a dq vector control with an electric angle θs detected by a resolver 30 when a motor 5 rotates at a constant rotational speed with a torque command value Trc of null, and nullifies the q-axis current command value Iq_c to control current supply to the motor 5; and an angle correction part 32 that calculates an offset angle θoff to compensate a detection error factor of the resolver 30 on the basis of a fluctuation degree of the vehicle speed when the electrification control of the motor 5 is executed with the angular error detection mode.

Description

  The present invention relates to an electric vehicle that travels by a driving force of a motor.

  Conventionally, there has been proposed a motor control device having a function of correcting a detection error of a rotation angle (motor electrical angle) of a motor rotor by an angle sensor such as a resolver (see, for example, Patent Documents 1 and 2). The motor control device described in Patent Documents 1 and 2 is used by being mounted on an electric vehicle, and performs energization control of the motor by so-called dq vector control.

  In the motor control device described in Patent Literature 1, when the ignition of the electric vehicle is turned off, only the d-axis current (field current) is generated by the discharge power from the capacitor connected between the output terminals of the DC power source. To supply. In this state, a process for correcting the detected value of the electric angle of the motor is performed so that the rotational speed of the motor converges to 0, and the correction value at this time is obtained as an error in detecting the electric angle.

  In the motor control device described in Patent Document 2, when the motor rotor is connected to the output shaft of the engine and the motor is rotating at a constant speed by idling operation of the engine, the d-axis current and q The d-axis voltage and the q-axis voltage are feedback-controlled so that both the axis currents are zero. Then, a detection error of the motor electrical angle is obtained from the d-axis voltage and the q-axis voltage at this time.

  In the motor control devices described in Patent Documents 1 and 2, the motor operation is performed using the electrical angle obtained by correcting the detection value of the angle sensor by the motor electrical angle detection error obtained as described above. Is controlling.

JP 2007-228700 A JP 2004-129359 A

  The calculation of the electrical angle detection error in the motor control device described in Patent Document 1 is performed using the discharge power of the capacitor when the electric vehicle is turned off, that is, when the electric vehicle is stopped. For this reason, it is impossible to calculate an electrical angle detection error when the electric vehicle is traveling.

  Furthermore, when only the d-axis current is supplied to the motor when the vehicle is stopped, it is necessary to provide a mechanism for separating the rotor of the motor from the wheels in order to enable rotation of the motor due to an electrical angle detection error.

  On the other hand, the calculation of the electrical angle detection error in the motor control device described in the cited document 2 is performed by rotating the motor at a constant speed during idling (when the electric vehicle is stopped), so the motor is driven by the engine. It cannot be applied to an electric vehicle or a fuel cell vehicle that does not have a configuration to do so.

  Further, since it is necessary to detect the d-axis and q-axis voltages in a state where the command values of the d-axis and q-axis currents are 0, the motor needs to generate a counter electromotive voltage. Furthermore, it is necessary that the command values of the d-axis current and the q-axis current can be set to 0 (the modulation factor is equal to or less than a predetermined value and no field weakening current flows).

  As described above, in the conventional motor control device, there are many restrictions on the operating condition of the motor that can obtain the detection error of the electrical angle of the rotor. Moreover, it is difficult to apply to an electric vehicle in which the motor is frequently controlled by the field-weakening magnetic field as in the case where the motor is driven by a low-voltage power source.

  The present invention has been made in view of such a background, and an electric vehicle capable of detecting an electric angle detection error of a motor and correcting the electric angle by using a method with less motor operating conditions and configuration restrictions. The purpose is to provide.

The present invention has been made to achieve the above object, and the electric vehicle of the present invention includes:
A motor connected to the drive wheels;
An electrical angle detector for detecting an electrical angle of the motor;
A vehicle speed detector for detecting the vehicle speed;
A torque command unit for setting a torque command value for the motor;
The dq vector control based on the corrected electrical angle obtained by correcting the electrical angle detected by the electrical angle detection unit with an offset angle for compensating for the detection error of the electrical angle detection unit is used to change the torque command value from the motor. The torque control mode for controlling the current supply to the motor by determining the d-axis current command value and the q-axis current command value so that the corresponding torque is output, and the vehicle speed detected by the vehicle speed detection unit are constant. When the torque command value is zero, the dq vector command control based on the electrical angle detected by the electrical angle detection unit sets the d-axis current command value as a predetermined error detection command value and q An energization control unit that controls the energization of the motor by switching the angle error detection mode for controlling the current supply to the motor by setting the shaft current command value to zero;
An offset angle calculation unit that calculates the offset angle based on a variation degree of the vehicle speed detected by the vehicle speed detection unit when the energization control of the motor is performed in the angle error detection mode. .

  According to the present invention, the energization control unit causes the electric vehicle to travel at a constant vehicle speed (in this case, the rotational speed of the motor connected to the drive wheels is also constant), and the torque command value is zero. When it is, the energization control of the motor by the angle error detection mode is executed. Here, if there is no error in the electric angle (rotor angle) of the motor detected by the electric angle detector, only the d-axis current corresponding to the error detection command value is supplied to the motor. Since no q-axis current is supplied, no torque is generated in the motor. Therefore, the vehicle speed of the electric vehicle does not change.

  On the other hand, when there is an error in the electrical angle of the motor detected by the electrical angle detection unit due to a shift in the mounting position of the electrical angle detection unit with respect to the rotor of the motor, When dq vector control based on the electrical angle of the motor detected by the electrical angle detector is performed, q-axis current is also supplied to generate torque in the motor. As a result, the vehicle speed of the electric vehicle changes.

  Therefore, the offset angle calculation unit can calculate the offset angle based on the variation degree of the vehicle speed detected by the vehicle speed detection unit when executing the energization control of the motor in the angle error detection mode.

  In the energization control of the motor in the angle error detection mode, if the condition that the motor rotates at a constant rotational speed and the torque command is zero is satisfied, the electric vehicle travels. Therefore, the process of calculating the offset angle and determining the corrected electrical angle can be executed by a method with few motor operating conditions and configuration restrictions.

  The vehicle speed detection unit may detect the vehicle speed based on a change amount per predetermined time of the electrical angle of the motor detected by the electrical angle detection unit.

  According to this configuration, it is not necessary to provide a speed detection element such as a rotation speed sensor separately from the electrical angle detection unit, and thus the configuration of the electric vehicle can be simplified.

  In addition, when the energization control unit starts energization control of the motor in the angle error detection mode, the d-axis current command value is changed from a level smaller than the error detection command value to the error detection command value. It is characterized by being gradually increased.

  According to this configuration, by suddenly switching the d-axis current command value to the error detection command value, the rotational speed of the motor changes suddenly, and the passenger of the electric vehicle feels a sudden acceleration or a sudden deceleration. It can be prevented from receiving.

  Further, when the energization control unit ends the energization control of the motor in the angle error detection mode, the d-axis current command value is changed from the error detection command value to a level smaller than the error detection command value. It is characterized by being gradually reduced.

  According to this configuration, when the d-axis current command value is suddenly decreased from the error detection command value, the rotation speed of the motor changes suddenly, and the passenger of the electric vehicle feels sudden acceleration or sudden deceleration. Can be prevented.

In addition, a slope detection unit that detects the slope of the road that is running
The offset angle calculation unit calculates the offset angle when the degree of change in gradient detected by the gradient detection unit exceeds a predetermined threshold level during execution of energization control of the motor in the angle error detection mode. It is characterized by canceling.

  According to this configuration, when the gradient of the road on which the electric vehicle is traveling exceeds the threshold level, and the rotational speed of the motor is in a situation that can be changed by a gradient that is a factor other than the torque of the motor, By stopping the calculation of the offset angle, it is possible to prevent the accuracy of the offset angle from being lowered.

  The offset angle calculation unit is detected by the vehicle speed detection unit when the d-axis current is kept constant at the error detection command value by energization control of the motor in the angle error detection mode. It is characterized by detecting the degree of variation in vehicle speed.

  According to this configuration, the fluctuation degree of the vehicle speed detected by the vehicle speed detection unit is accurately detected in a state where the d-axis current is maintained at the error detection command value and the torque of the motor is stable. be able to.

The control block diagram of an electric vehicle. The flowchart of the calculation process of an offset angle. Explanatory drawing of the relationship between the electrical angle detection error and torque. Torque / angle error amount correlation map. Explanatory drawing of the driving | running | working condition of the electric vehicle at the time of calculating an offset angle.

  An example of an embodiment of an electric vehicle according to the present invention will be described with reference to FIGS. Referring to FIG. 1, an electric vehicle 1 of the present embodiment is an electric vehicle that travels by driving drive wheels (not shown) by a motor 5.

  The electric vehicle 1 includes a motor 5 connected to drive wheels, an energization control unit 10 that controls energization of the motor 5, and a resolver 30 that detects an electrical angle of the rotor 6 of the motor 5 (corresponding to an electrical angle detection unit of the present invention). ), A rotational speed calculation unit 31 for calculating the rotational speed ω of the motor 5 from the amount of change of the electrical angle θs detected by the resolver 30 per predetermined time, and an offset angle θost for correcting an electrical angle detection error by the resolver 30 And a torque command value Tr_c for the motor 5 according to an operation of an accelerator pedal (not shown), etc., for an angle correction unit 32 (including the function of the offset angle calculation unit of the present invention) that corrects a detection angle by the resolver 30. Is provided with a torque command unit 33 for setting the gradient and a gradient detection unit 34 for detecting the gradient of the road on which the electric vehicle 1 is traveling.

  Note that an inclination angle sensor can be used as the gradient detector 34. Further, the gradient detection unit 34 may be configured by obtaining the inclination angle of the road on which the electric vehicle 1 is traveling from the map information of the navigation device mounted on the electric vehicle 1. In addition to the resolver, another type of position detection sensor such as a Hall element may be used as the electrical angle detection unit.

  Further, since the motor 5 is connected to the drive wheels, the rotational speed of the motor 5 is linked to the vehicle speed of the electric vehicle 1. In the present embodiment, the rotational speed of the motor 5 is used as the vehicle speed of the electric vehicle 1. In this case, the rotation speed calculation unit 31 corresponds to a vehicle speed detection unit of the present invention.

  The motor 5 is a three-phase DC brushless motor, and the energization control unit 10 converts the motor 5 into an equivalent circuit of a rotational coordinate system in which the field direction of the rotor 6 is d-axis and the direction orthogonal to the d-axis is q-axis. The energization control of the motor 5 is performed by dq vector control which is converted and handled.

  The energization control unit 10 controls the energization of the motor 5 so that the torque (drive torque, regenerative torque) of the motor 5 corresponds to the torque command value Tr_c input from the torque command unit 33. ”And the“ angle error calculation mode ”for controlling the energization of the motor 5 so that the energization amount of the motor 5 becomes the current command value input from the angle correction unit 32, and the energization control of the motor 5 is performed. .

  The energization control unit 10 includes a current command determination unit 11, a subtraction unit 12, a PI (proportional integration) calculation unit 13, a subtraction unit 14, a PI calculation unit 15, a dq / 3-phase conversion unit 16, a PWM conversion unit 17, an inverter 18, A V-phase current sensor 20, a W-phase current sensor 21, and a three-phase / dq converter 22 are provided.

  The current command determination unit 11, the subtraction unit 12, the PI calculation unit 13, the subtraction unit 14, the PI calculation unit 15, the dq / 3 phase conversion unit 16, the PWM conversion unit 17, and the three phase / dq conversion unit 22 of the energization control unit 10. The rotation speed calculation unit 31, the angle correction unit 32, and the torque command unit 33 are executed by a CPU (not shown) executing a control program for the electric vehicle 1 held in a memory (not shown). Composed.

  In the “torque control mode”, the current command determining unit 11 is a d-axis that is a command value of a d-axis current (current flowing through the d-axis armature) in accordance with the torque command value Tr_c input from the torque command unit 33. A current command value Id_c and a q-axis current command value Iq_c which is a command value of a q-axis current (current flowing through the q-axis armature) are determined. In the “angle error detection mode”, the current command determination unit 11 uses the current command value (Id_c = Id_a, Iq = 0) for angle error detection input from the angle correction unit 32 as the d-axis current command value. Let Id_c and q-axis current command value Iq_c.

  The three-phase / dq converter 22 detects the detected value Iv_s of the V-phase current (current flowing through the V-phase armature) detected by the V-phase current sensor 20 and the W-phase current (W The detected value Iw_s of the current flowing through the armature of the phase is converted into a d-axis current detection value Id_s and a q-axis current detection value Iq_s by coordinate conversion using the corrected electrical angle θa calculated by the angle correction unit 32.

  The subtraction unit 12 calculates a difference ΔId between the d-axis current command value Id_c and the d-axis current detection value Id_s and inputs the difference ΔId to the PI calculation unit 13. The PI calculation unit 13 calculates a d-axis voltage command value Vd_c by performing PI calculation on ΔId, and inputs it to the dq / 3-phase conversion unit 16.

  The subtraction unit 14 calculates a difference ΔIq between the q-axis current command value Iq_c and the q-axis current detection value Iq_s and inputs the difference ΔIq to the PI calculation unit 15. The PI calculation unit 15 calculates a q-axis voltage command value Vq_c by performing a PI calculation on ΔIq and inputs it to the dq / 3-phase conversion unit 16.

  The dq / 3-phase conversion unit 16 converts the d-axis voltage command value Vd_c and the q-axis voltage command value Vq_c to 3 of U, V, and W by coordinate conversion using the corrected electrical angle θa calculated by the angle correction unit 32. Phase drive voltage command values Vu_c, Vv_c, and Vw_c are converted.

  The PWM converter 17 compares the drive voltage command values Vu_c, Vv_c, and Vw_c with a triangular wave voltage having a predetermined frequency and determines the duty ratio of the PWM control signal, thereby converting the PWM signals of the U, V, and W phases. Generated and input to the inverter 18.

  The inverter 18 converts DC power supplied from a battery (not shown) into three-phase AC power, and an arm in which two switching elements are connected in series is connected to a positive line and a negative line of the battery. Three (U-phase, W-phase, and V-phase) are connected in between, and the middle point of each arm is a three-phase output.

  Then, the two switching elements of each arm are complementarily turned ON (conducting state) by the PWM control signal of each phase, whereby a drive current is supplied to the motor 5 from the middle point of each arm. With this drive current, the motor 5 is rotationally driven with an output corresponding to the torque command value Tr_c (“torque control mode”) or the current command value for angle error detection (“angle error detection mode”).

  Here, the energization control of the motor 5 by the dq vector control of the energization control unit 10 involves coordinate conversion using an electrical angle (position of the rotor 6) detected by the resolver 30. Therefore, if the detection error of the electrical angle by the resolver 30 is large, the energization control of the motor 5 cannot be performed with high accuracy.

  Therefore, the angle correction unit 32 detects an error of the detected value θs of the electrical angle of the rotor 6 by the resolver 30, calculates an offset angle θoft for compensating for the detected error, and detects the detected value θs based on the offset angle θoft. A corrected electrical angle θa is calculated by correcting the above. The offset angle θoft calculation process will be described below with reference to the flowchart shown in FIG.

  STEP 1 to STEP 2 and STEP 10 in FIG. 2 are processes by the energization control unit 10. In STEP 1, the energization control unit 10 has a torque command value Tr_c output from the torque command unit 33 of zero, and the rotation speed ω of the motor 5 calculated by the rotation speed calculation unit 31 (the vehicle speed of the present invention). It is determined whether or not (corresponding) is constant.

  In the present embodiment, the rotational speed ω of the motor 5 obtained by the resolver 30 and the rotational speed calculation unit 31 is the vehicle speed of the electric vehicle 1, but the vehicle speed of the electric vehicle 1 is determined by a vehicle speed sensor provided separately from the resolver 30. It may be detected. In addition, the fact that the rotational speed of the motor 5 is constant does not require strictness in a strict sense, but factors other than the d-axis current for angle error detection when calculating the electrical angle detection error described later. This means that the change in rotational speed due to is negligible.

  In STEP1, when the torque command value Tr_c is zero and the rotation speed ω of the motor 5 is constant, the process proceeds to STEP2. Further, when the torque command value Tr_c is not zero or the rotational speed ω of the motor 5 is changing, the process proceeds to STEP 10 and the energization control unit 10 performs energization control of the motor 5 in the “torque control mode” and proceeds to STEP 1. Return.

  In STEP 2, the energization control unit 10 sets the current command values for detecting the angle error (Id_c = Id_a, Iq_c = 0) to the d-axis current command Id_c and the q-axis current command value Iq_c by the current command determination unit 11. Then, energization control of the motor 5 by the “angle error detection mode” is executed.

  Subsequent STEP 3 to STEP 5 are processes by the angle correction unit 32. The angle correction unit 32 outputs the electrical angle θs detected by the resolver 30 as it is (without adding the offset angle θoft) to the dq / 3-phase conversion unit 16 and the 3-phase / dq conversion unit 22 as the corrected electrical angle θa. To do.

  In this case, in the energization control unit 10, the dq / 3-phase conversion unit 16 and the 3-phase / dq conversion unit 22 perform coordinate conversion using the electrical angle θs detected by the resolver 30, and the d-axis current is The current supply to the motor 5 is controlled so that Id_a and the q-axis current become zero.

  Here, FIG. 3 is a diagram showing the relationship between the deviation of the electrical angle θs detected by the resolver 30 with respect to the actual motor electrical angle and the torque generated in the motor 5 when only the d-axis current is supplied. is there.

  When the actual motor electrical angle matches the electrical angle θs detected by the resolver 30 (in the case of 50 in FIG. 3), only the d-axis current flows and the q-axis current does not flow. Torque is not generated. On the other hand, when the electrical angle θs detected by the resolver 30 is deviated from the actual motor electrical angle θs, the q-axis current also flows in accordance with the deviation, so that torque is generated in the motor 5.

  For example, when the deviation of the electrical angle θs detected by the resolver 30 is 90 degrees <θs <180 degrees (range Wtr in the figure), a drive torque is generated in the motor 5. When the deviation of the electrical angle θs detected by the resolver 30 is 180 degrees <θs <270 degrees (range Wre in the figure), regenerative torque is generated in the motor 5.

  When the drive torque is generated in the motor 5, the rotational speed ω of the motor 5 is increased, and when the regenerative torque is generated in the motor 5, the rotational speed ω of the motor 5 is decreased. Therefore, there is a correlation between the rotational acceleration (degree of change in the rotational speed of the motor 5) α, the torque generated in the motor 5, and the detection error of the electrical angle θs by the resolver 30.

  Therefore, the angle correction unit 32 calculates the amount of change per unit time of the rotational speed ω of the motor 5 calculated by the rotational speed calculation unit 31 in STEP 3 as the rotational acceleration α (degree of variation in rotational speed) of the motor 5. To do. In subsequent STEP 4, the angle correction unit 32 calculates the torque Tr generated in the motor 5 from the rotational acceleration α of the motor 5 by the following formula (1).

  However, Tr: Torque generated in the motor 5, α: Rotational acceleration of the motor 5, Kc: Constant of inertia of the electric vehicle 1, etc.

  In the next STEP 5, the angle correction unit 32 applies the torque Tr calculated in STEP 4 to the torque / angle error amount map shown in FIG. 4 to obtain the corresponding angle error amount (phase current advance angle). When the phase current advance angle (advance angle of the d-axis with respect to the q-axis) is 90 degrees, the angle error amount is zero. In this case, no q-axis current flows, so torque is generated in the motor 5. do not do.

  On the other hand, drive torque is generated when an angle error amount is generated on the plus side, and regenerative torque is generated when an angle error is generated on the minus (−) side. Then, the angle correction unit 32 sets the angle error amount thus obtained as the offset angle θoft.

  After calculating the offset angle θoft, the angle correction unit 32 calculates the corrected electrical angle θa obtained by correcting the electrical angle θs detected by the resolver 30 with the offset angle θoft according to the following equation (2) as needed. To the three-phase converter 16 and the three-phase / dq converter 22.

  Where θa: corrected electrical angle, θs: electrical angle detected by the resolver 30, and θoft: offset angle.

  As a result, in the energization control unit 10, dq vector control based on the corrected electrical angle θ is performed, so that the detection error of the electrical angle by the resolver 30 can be compensated and dq vector control accuracy can be improved.

  Further, the angle correction unit 32 monitors the road slope slps detected by the slope detection unit 34 when the energization control in the “angle error detection mode” is being executed. When the gradient change degree exceeds a predetermined threshold level, the offset angle θoft calculation process is stopped.

  Next, FIG. 5 shows the vehicle speed of the electric vehicle 1, the gradient of the road on which the electric vehicle 1 is traveling, and the output from the torque command unit 33 under the situation where the energization control is performed in the “angle error detection mode”. It is explanatory drawing which illustrated transition of torque command value Tr_c and d-axis current command value for error detection illustrated on a common time axis (t).

  As for the torque command value Tr_c, the torque command value Tr_c on the driving side is output during the period from t0 to t2, and the torque command value Tr_c is zero after t2. As for the road gradient, the gradient is zero between t0 and t3, and a constant downward gradient after t3.

  As a result, the vehicle speed of the electric vehicle 1 increases from t0 to t1, reaches a constant speed from t1 to t2, and decreases from t2 to t3. And between t3-t4, the vehicle speed of the electric vehicle 1 is constant.

  Between t3 and t4, the vehicle speed of the electric vehicle 1 is constant and the torque command value Tr_c is zero. Therefore, the condition of STEP 1 in the flowchart of FIG. 2 described above is satisfied, the process proceeds from STEP 1 to STEP 2, and the d-axis command current Id_a for error detection is input from the angle correction unit 32 to the current command determination unit 11.

  Here, as shown in the figure, the input and stop of the error detection d-axis current command value Id_a is zero during the period from t4 to t5 (corresponding to a level smaller than the error detection command value of the present invention). The driving torque that can be generated by the detection error of the electrical angle by gradually increasing from the point of time and by stopping the input gradually to zero (corresponding to the error detection command value of the present invention) during the period of t6 to t7. Alternatively, sudden acceleration / deceleration of the electric vehicle 1 due to the regenerative torque can be prevented from causing discomfort to the passenger of the electric vehicle 1.

  When a drive torque is generated in the motor 5 due to an electrical angle detection error caused by the resolver 30, the vehicle speed of the electric vehicle 1 gradually increases (slow acceleration state a in the figure). Further, when the regenerative torque is generated in the motor 5 due to the detection error of the electrical angle by the resolver 30, the vehicle speed of the electric vehicle 1 gradually decreases (slow deceleration state in b in the figure).

  When there is no electrical angle detection error by the resolver 30, no torque is generated in the motor 5 even if the error detection d-axis current command value Id_a is input to the current command determination unit 11. The vehicle speed is constant (no acceleration / deceleration state c in the figure).

  In the present embodiment, as shown in FIG. 5, a process of gradually increasing the d-axis current command value to the command value Id_a for angle detection and a process of gradually decreasing the d-axis current command value from Id_a to zero are performed. However, the effect of the present invention can be obtained when either one of these processes is performed or when these processes are not performed.

  In the present embodiment, the angle correction unit 32 stops the calculation of the offset angle when the degree of change in the road gradient exceeds the threshold level during the energization control in the “angle error detection mode”. Even if this cancellation is not performed, the effect of the present invention can be obtained.

  Further, when the rotational acceleration α of the motor 5 is calculated in STEP 3 in FIG. 2, it is required that the d-axis current detection value Id_s be kept constant at the error detection command value Id_a. The rotational acceleration α can be calculated in a state where the torque is stable.

  Further, in the present embodiment, a DC brushless motor is shown as the motor of the present invention, but the present invention can be applied to other types of motors as long as the motor is controlled by detecting the electrical angle of the rotor. The invention can be applied.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 5 ... Motor, 6 ... Rotor, 10 ... Energization control part, 11 ... Current command determination part, 16 ... dq / 3 phase conversion part, 17 ... PWM conversion part, 18 ... Inverter, 22 ... 3 phase / dq Conversion unit, 30 ... resolver (electrical angle detection unit), 31 ... rotational speed calculation unit, 32 ... angle correction unit, 33 ... torque command unit, 34 ... gradient detection unit.

Claims (6)

A motor connected to the drive wheels;
An electrical angle detector for detecting an electrical angle of the motor;
A vehicle speed detector for detecting the vehicle speed;
A torque command unit for setting a torque command value for the motor;
The dq vector control based on the corrected electrical angle obtained by correcting the electrical angle detected by the electrical angle detection unit with an offset angle for compensating for the detection error of the electrical angle detection unit is used to change the torque command value from the motor. The torque control mode for controlling the current supply to the motor by determining the d-axis current command value and the q-axis current command value so that the corresponding torque is output, and the vehicle speed detected by the vehicle speed detection unit are constant. When the torque command value is zero, the dq vector command control based on the electrical angle detected by the electrical angle detection unit sets the d-axis current command value as a predetermined error detection command value and q An energization control unit that controls the energization of the motor by switching the angle error detection mode for controlling the current supply to the motor by setting the shaft current command value to zero;
An offset angle calculation unit that calculates the offset angle based on a variation degree of the vehicle speed detected by the vehicle speed detection unit when the energization control of the motor is performed in the angle error detection mode. Electric vehicle. The electric vehicle according to claim 1,
The vehicle speed detection unit detects a vehicle speed based on a change amount per predetermined time of an electrical angle of the motor detected by the electrical angle detection unit. In the electric vehicle according to claim 1 or 2,
The energization control unit gradually increases the d-axis current command value from a level smaller than the error detection command value to the error detection command value when starting the energization control of the motor in the angle error detection mode. The electric vehicle characterized by the above-mentioned. The electric vehicle according to any one of claims 1 to 3,
The energization control unit gradually decreases the d-axis current command value from the error detection command value to a level smaller than the error detection command value when the motor energization control in the angle error detection mode is finished. The electric vehicle characterized by the above-mentioned. The electric vehicle according to any one of claims 1 to 4,
It has a slope detector that detects the slope of the road that is running,
The offset angle calculation unit calculates the offset angle when the degree of change in gradient detected by the gradient detection unit exceeds a predetermined threshold level during execution of energization control of the motor in the angle error detection mode. An electric vehicle characterized by stopping the operation. In the electric vehicle according to any one of claims 1 to 5,
The offset angle calculation unit is configured to detect a vehicle speed detected by the vehicle speed detection unit when the d-axis current is kept constant at the error detection command value by energization control of the motor in the angle error detection mode. An electric vehicle characterized by detecting a degree of fluctuation.