Motor control device and vehicle

Abstract

To provide a motor control unit and a vehicle that can provide a stable motor output during low-speed rotation.SOLUTION: A motor control unit 10 comprises: a drive section 11 that can selectively drive a motor 20 with rectangular wave voltage driving and vector control driving; a detection section 12 that can selectively detect a rotational position of a rotor 23 by first position detecting and second position detecting; and a switching section 14 that when the rotational speed of the motor 20 is lower than a low-rotational-speed threshold value, brings the drive section 11 switching the driving of the motor 20 to the rectangular wave voltage driving, when the rotational speed is equal to or higher than the low-rotational-speed threshold value, brings the drive section 11 switching the driving of the motor 20 to the vector control driving, and when the rotational speed is lower than a high-rotational-speed threshold value set to be higher than the low-rotational-speed threshold value, brings the detection section 12 switching detection of the rotor rotational position set for the motor 20 to the first position detecting, and when the rotational speed is equal to or higher than the high-rotational-speed threshold value, brings the detection section 12 switching the detection of the rotor rotational position to the second position detecting.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor control device and a vehicle. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have been intensified, and research and development into electrification technologies has been conducted in order to reduce CO2 emissions and improve energy efficiency in vehicles. One of these electrification technologies is known to be a technology in which a drive voltage having a specific voltage waveform is applied to drive a motor installed in a vehicle.

[0003] Patent Document 1 discloses a technique for driving a DC motor with rectangular wave energization when the rotation speed of the DC motor is below a threshold value, and for driving the DC motor with sine wave energization when the rotation speed of the DC motor is equal to or higher than the threshold value. The technique disclosed in Patent Document 1 makes it possible to avoid braking operation at the time of phase switching when starting the motor, and to suppress a reduction in starting torque.

[0004] Patent Document 2 discloses a technique for calculating the rotation speed of a permanent magnet rotor provided in a brushless motor based on the time interval of a half cycle or one cycle, which is the interval between the rising or falling edges of a pulsed position sensor signal detected by each Hall sensor provided in the brushless motor. The technique disclosed in Patent Document 2 can reduce calculation errors in the rotation speed caused by variations in the mounting position of each Hall sensor, achieving a brushless motor that rotates smoothly and produces little noise. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-242432 A [Patent Document 2] JP 2003-264990 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in motor drive technology, which is one of the technologies related to electrification technology, there is an issue that the resolution for detecting the magnetic pole position of the rotor installed in the motor decreases when the motor is rotating at low speeds, resulting in unstable motor output at low speeds.

[0007] The present invention aims to achieve stabilization of motor output at low rotation speeds in order to solve the above problems, and thereby contribute to improving energy efficiency. [Means for solving the problem]

[0008] One aspect for achieving the above object is a motor drive system including a drive unit capable of selectively driving the motor by a rectangular wave voltage drive that applies a rectangular wave voltage to a stator winding provided in the motor to drive the motor, and a vector control drive that applies a sinusoidal wave voltage to the stator winding to drive the motor, and a plurality of vector control signals that indicate a rotational position of a rotor provided in the motor. Hall detection output from the hall sensor a first position detection based on a combination of signal levels; Hall Sensor Any one of from of Hole Detection a detection unit capable of selectively detecting the rotational position by detecting a first position based on a change in a signal level and a second position based on a change in a signal level; and a switching unit that causes the drive unit to switch the drive of the motor to the rectangular wave voltage drive or the vector control drive based on a rotational speed of the motor, and causes the detection unit to switch the detection of the rotational position to the first position detection or the second position detection, At a rotation speed equal to or lower than a low rotation speed threshold, the operation is switched to a first operation region operated with the square wave voltage drive and the first position detection, at a rotation speed equal to or higher than a high rotation speed threshold above the low rotation speed threshold, the operation is switched to a third operation region operated with the vector control drive and the second position detection, and at a rotation speed between the low rotation speed threshold and the high rotation speed threshold, the operation is switched to a second operation region operated with the vector control drive and the first position detection. A motor control device.

[0009] In another aspect for achieving the above object, the motor control device includes the motor, and the plurality of Hall Sensor A vehicle equipped with the above. Effect of the Invention

[0010] According to the above aspect, it is possible to achieve stabilization of motor output during low rotation. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an example of a schematic configuration of a motor control device and a vehicle according to an embodiment of the present disclosure. [Diagram 2] 1 is a diagram illustrating an example of a circuit configuration of an inverter unit provided in a motor control device according to an embodiment of the present disclosure. [Diagram 3] FIG. 2 is a diagram illustrating an operating region in a motor control device according to an embodiment of the present disclosure. [Figure 4] 5A to 5C are diagrams illustrating an example of a voltage waveform and a signal waveform of a Hall detection signal when driven by a square wave voltage in a motor control device according to an embodiment of the present disclosure. [Diagram 5] 4A and 4B are diagrams illustrating a first position detection in a motor control device according to an embodiment of the present disclosure. [Figure 6] 5A to 5C are diagrams illustrating an example of voltage waveforms and signal waveforms of Hall detection signals during vector control driving in a motor control device according to an embodiment of the present disclosure. [Figure 7] 11A and 11B are diagrams illustrating second position detection in a motor control device according to an embodiment of the present disclosure. [Figure 8] 5 is a flowchart illustrating an example of a switching operation between a drive unit and a detection unit in a motor control device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [1. Configuration of the motor control device and vehicle] 1 is a block diagram showing an example of a schematic configuration of a motor control device 10 and a vehicle 1 according to an embodiment of the present disclosure. The vehicle 1 includes the motor control device 10, a motor 20 controlled by the motor control device 10, and a plurality of hall sensors (examples of a position detection unit) 22u, 22v, and 22w that are provided in the motor 20 and output a plurality of hall detection signals (examples of position signals) Hu, Hv, and Hw. Examples of the vehicle 1 include an automobile and a motor-driven bicycle.

[0013] The motor 20 is, for example, a brushless motor. The motor 20 includes a rotor 23 provided with a permanent magnet (not shown) and a stator (not shown) provided with a U-phase winding 21u, a V-phase winding 21v, and a W-phase winding 21w (each of which is an example of a stator winding). The U-phase winding 21u, the V-phase winding 21v, and the W-phase winding 21w are arranged at intervals of 120°. The hall sensors 22u, 22v, and 22w are arranged at intervals of 120° and shifted from the U-phase winding 21u, the V-phase winding 21v, and the W-phase winding 21w by 60°. In this embodiment, the hall sensor 22u is arranged between the U-phase winding 21u and the W-phase winding 21w, the hall sensor 22v is arranged between the U-phase winding 21u and the V-phase winding 21v, and the hall sensor 22w is arranged between the V-phase winding 21v and the W-phase winding 21w.

[0014] Next, the configuration of the motor control device 10 will be described with reference to FIGS. 1, the motor control device 10 includes a drive unit 11 connected to a U-phase winding 21u, a V-phase winding 21v, and a W-phase winding 21w provided on a motor 20. The motor control device 10 includes a detection unit 12 connected to Hall sensors 22u, 22v, and 22w provided on the motor 20, and a rotation speed calculation unit 13 connected to the Hall sensor 22u. The motor control device 10 includes a switching unit 14 connected to the drive unit 11, the detection unit 12, and the rotation speed calculation unit 13, and a command unit 15 connected to the switching unit 14.

[0015] The driving unit 11 is configured to selectively drive the motor 20 by a rectangular wave voltage driving in which a rectangular wave voltage is applied to the U-phase winding 21u, the V-phase winding 21v, and the W-phase winding 21w provided in the motor 20 to drive the motor 20, and a vector control driving in which a sinusoidal wave voltage is applied to the U-phase winding 21u, the V-phase winding 21v, and the W-phase winding 21w to drive the motor 20. The driving unit 11 has a rectangular wave voltage driving unit 111, a vector control driving unit 112, and an inverter unit 113. The rectangular wave voltage driving unit 111 is switched between a state in which the output is electrically connected to the inverter unit 113 and a state in which the output is electrically disconnected from the inverter unit 113 by a drive switching signal Scd1 input from the switching unit 14. The vector control driving unit 112 is switched between a state in which the output is electrically connected to the inverter unit 113 and a state in which the output is electrically disconnected from the inverter unit 113 by a drive switching signal Scd2 input from the switching unit 14. The rectangular wave voltage driver 111 and the vector control driver 112 are electrically disconnected from the input of the inverter unit 113 by putting the outputs into a high impedance state, for example.

[0016] When the switching unit 14 switches the drive unit 11 to operate using the square wave voltage drive unit 111, the drive unit 11 drives the motor 20 with square wave voltage drive using the square wave voltage drive unit 111 and the inverter unit 113. On the other hand, when the switching unit 14 switches the drive unit 11 to operate using the vector control drive unit 112, the drive unit 11 drives the motor 20 with vector control drive using the vector control drive unit 112 and the inverter unit 113.

[0017] The rectangular wave voltage driver 111 drives the q-axis current command value Iq * The detector 12 generates pulse signals Pau, Pav, Paw, Pax, Pay, and Paz for driving the inverter unit 113, using a U-phase current Iu, a V-phase current Iv, and a W-phase current Iw input from the inverter unit 113, and a rotation angle signal Sθ of the motor 20 input from the detector 12. Hereinafter, the "pulse signals Pau, Pav, Paw, Pax, Pay, and Paz" may be abbreviated as "pulse signals Pau to Paz".

[0018] The vector control driver 112 controls the d-axis current command value Id * and q-axis current command value Iq * The detection unit 12 generates pulse signals Pbu, Pbv, Pbw, Pbx, Pby, and Pbz for driving the inverter unit 113 using a U-phase current Iu, a V-phase current Iv, and a W-phase current Iw input from the inverter unit 113, and a rotation angle signal Sθ input from the detection unit 12. Hereinafter, the "pulse signals Pbu, Pbv, Pbw, Pbx, Pby, and Pbz" may be abbreviated as "pulse signals Pbu to Pbz".

[0019] When the switching unit 14 switches the drive of the motor 20 to square wave voltage drive, the drive unit 11 inputs the pulse signals Pau, Pav, Paw, Pax, Pay, and Paz as pulse signals Pu, Pv, Pw, Px, Py, and Pz to the inverter unit 113. When the switching unit 14 switches the drive of the motor 20 to vector control drive, the drive unit 11 inputs the pulse signals Pbu, Pbv, Pbw, Pbx, Pby, and Pbz as pulse signals Pu, Pv, Pw, Px, Py, and Pz to the inverter unit 113. Hereinafter, "pulse signals Pu, Pv, Pw, Px, Py, and Pz" may be abbreviated as "pulse signals Pu to Pz".

[0020] FIG. 2 shows an example of a circuit configuration of the inverter unit 113. As shown in FIG. 2, the inverter unit 113 is configured by connecting six semiconductor elements Qu, Qv, Qw, Qx, Qy, and Qz in a full bridge configuration between a positive line Lp to which a positive DC voltage is applied and a negative line Ln to which a negative DC voltage is applied. Hereinafter, the "semiconductor elements Qu, Qv, Qw, Qx, Qy, and Qz" may be abbreviated as "semiconductor elements Qu to Qz." The semiconductor elements Qu and Qx are connected in series between the positive line Lp and the negative line Ln to configure a U-phase arm 113u. The semiconductor elements Qv and Qy are connected in series between the positive line Lp and the negative line Ln to configure a V-phase arm 113v. The semiconductor elements Qw and Qz are connected in series between the positive line Lp and the negative line Ln to configure a W-phase arm 113w. The semiconductor elements Qu to Qz each include a power semiconductor element and a free wheel diode connected in anti-parallel to the power semiconductor element.

[0021] A pulse signal Pu is input to the gate of the power semiconductor element provided in the semiconductor element Qu, and a pulse signal Px is input to the gate of the power semiconductor element provided in the semiconductor element Qx. A pulse signal Pv is input to the gate of the power semiconductor element provided in the semiconductor element Qv, and a pulse signal Py is input to the gate of the power semiconductor element provided in the semiconductor element Qy. A pulse signal Pw is input to the gate of the power semiconductor element provided in the semiconductor element Qw, and a pulse signal Pz is input to the gate of the power semiconductor element provided in the semiconductor element Qz. The semiconductor elements Qu to Qz are on / off controlled at a predetermined timing and in a predetermined order by the pulse signals Pu to Pz. As a result, the U-phase arm 113u outputs a U-phase AC voltage Vu from the connection part of the semiconductor elements Qu and Qx to the U-phase winding 21u provided in the motor 20 (see FIG. 1). The V-phase arm 113v outputs a V-phase AC voltage Vv from the connection portion of the semiconductor elements Qv, Qy to a V-phase winding 21v provided in the motor 20. The W-phase arm 113w outputs a W-phase AC voltage Vw from the connection portion of the semiconductor elements Qw, Qz to a W-phase winding 21w provided in the motor 20.

[0022] When the inverter unit 113 operates, an AC U-phase current Iu flowing between the inverter unit 113 and the motor 20 is output from the U-phase arm 113u to the drive unit 11, an AC V-phase current Iv flowing between the inverter unit 113 and the motor 20 is output from the V-phase arm 113v to the drive unit 11, and an AC W-phase current Iw flowing between the inverter unit 113 and the motor 20 is output from the W-phase arm 113w to the drive unit 11.

[0023] The detection unit 12 is configured to be able to selectively detect the rotational position of the rotor 23 provided in the motor 20 by a first position detection based on a combination of signal levels of a plurality of Hall detection signals Hu, Hv, Hw indicating the rotational position of the rotor 23 provided in the motor 20, and a second position detection based on a change in the signal level of any one of the plurality of Hall detection signals Hu, Hv, Hw. As shown in Fig. 1, the detection unit 12 has a first position detection unit 121 that performs the first position detection, and a second position detection unit 122 that performs the second position detection.

[0024] The first position detection unit 121 receives a Hall detection signal Hu output from a Hall sensor 22u provided in the motor 20, a Hall detection signal Hv output from a Hall sensor 22v provided in the motor 20, and a Hall detection signal Hw output from a Hall sensor 22w provided in the motor 20. As will be described in detail later, the first position detection unit 121 determines the angle (electrical angle) of the rotating magnetic field in the motor 20 based on a combination of voltage levels of the Hall detection signals Hu, Hv, and Hw input from the motor 20. The second position detection unit 122 receives, for example, the Hall detection signal Hu. As will be described in detail later, the second position detection unit 122 determines the electrical angle based on the rising edge and falling edge (i.e., the timing at which the signal level changes) of the Hall detection signal Hu.

[0025] Based on the determined electrical angle, the first position detection unit 121 and the second position detection unit 122 detect the rotational position (i.e., the rotational angle) of the rotor 23 provided in the motor 20. If the number of magnetic poles of the permanent magnet provided in the rotor 23 is p, the first position detection unit 121 and the second position detection unit 122 detect the rotational angle of the rotor 23 by the following formula (1). Rotation angle = electrical angle × 2 / p (1)

[0026] The first position detection unit 121 detects a rotation angle θ1 of the rotor 23 based on equation (1) and outputs a rotation angle signal Sθ1 including information on the rotation angle θ1 to the drive unit 11. The second position detection unit 122 detects a rotation angle θ2 of the rotor 23 based on equation (1) and outputs a rotation angle signal Sθ2 including information on the rotation angle θ2 to the drive unit 11. In this embodiment, the second position detection unit 122 detects the rotation angle θ2 using the Hall detection signal Hu, but may also detect the rotation angle θ2 using the Hall detection signal Hv or Hall detection signal Hw.

[0027] The first position detection unit 121 is switched between a state in which the output is electrically connected to the drive unit 11 and a state in which the output is electrically disconnected from the drive unit 11 by a detection switching signal Scp1 input from the switching unit 14. The second position detection unit 122 is switched between a state in which the output is electrically connected to the drive unit 11 and a state in which the output is electrically disconnected from the drive unit 11 by a detection switching signal Scp2 input from the switching unit 14. The first position detection unit 121 and the second position detection unit 122 are electrically disconnected from the input of the drive unit 11 by, for example, putting the outputs into a high impedance state.

[0028] The switching unit 14 is configured to cause the drive unit 11 to switch the drive of the motor 20 to square wave voltage drive or vector control drive based on the rotational speed of the motor 20, and to cause the detection unit 12 to switch the detection of the rotational position of the rotor 23 to first position detection or second position detection.

[0029] When the motor 20 is driven by the square wave voltage drive, the switching unit 14 electrically connects the output of the square wave voltage drive unit 111 to the inverter unit 113 and electrically disconnects the output of the vector control drive unit 112 from the inverter unit 113. On the other hand, when the motor 20 is driven by the vector control drive, the switching unit 14 electrically disconnects the output of the square wave voltage drive unit 111 from the inverter unit 113 and electrically connects the output of the vector control drive unit 112 to the inverter unit 113. Therefore, even if the drive unit 11 has a configuration in which the output of the square wave voltage drive unit 111 and the output of the vector control drive unit 112 are connected to each other and connected to the input of the inverter unit 113, it is possible to input only one of the pulse signals Pau to Paw and the pulse signals Pbu to Pbw to the inverter unit 113 as the pulse signals Pu to Pw without causing interference between the pulse signals Pau to Paw and the pulse signals Pbu to Pbw.

[0030] When the switching unit 14 electrically connects the output of the first position detection unit 121 to the drive unit 11, the switching unit 14 electrically disconnects the output of the second position detection unit 122 from the drive unit 11. On the other hand, when the switching unit 14 electrically connects the output of the second position detection unit 122 to the drive unit 11, the switching unit 14 electrically disconnects the output of the first position detection unit 121 from the drive unit 11. Therefore, even if the detection unit 12 has a configuration in which the output of the first position detection unit 121 and the output of the second position detection unit 122 are connected to each other and connected to the input of the drive unit 11, it is possible to input only one of the rotation angle signals Sθ1 and Sθ2 to the drive unit 11 as the rotation angle signal Sθ without interference between the rotation angle signals Sθ1 and Sθ2.

[0031] The rotation speed calculation unit (an example of a calculation unit) 13 calculates the rotation speed ω of the motor 20 based on any one of the multiple Hall detection signals Hu, Hv, and Hw. In this embodiment, the rotation speed calculation unit 13 calculates the rotation speed ω of the motor 20 (more specifically, the rotation angular speed of the rotor 23) using, for example, the Hall detection signal Hu. However, the rotation speed calculation unit 13 may calculate the rotation speed ω of the motor 20 using the Hall detection signal Hv or the Hall detection signal Hw. If the number of magnetic poles of the permanent magnet provided in the rotor 23 is p and the frequency of the Hall detection signal Hu is f, the rotation speed calculation unit 13 calculates the rotation speed ω of the motor 20 by the following formula (2). ω=2×π×f / (p / 2) = 2 × π × 2 × f / p (2)

[0032] The rotation speed calculation unit 13 outputs a rotation speed signal Sω including information on the calculated rotation speed ω to the switching unit 14. The switching unit 14 is set with a low rotation speed threshold and a high rotation speed threshold (details will be described later) for comparison with the rotation speed ω included in the rotation speed signal Sω input from the rotation speed calculation unit 13. The switching unit 14 causes the drive unit 11 to switch the drive of the motor 20 to square wave voltage drive when the rotation speed ω of the motor 20 is lower than the low rotation speed threshold, and to switch to vector control drive when the rotation speed ω is equal to or higher than the low rotation speed threshold. Furthermore, the switching unit 14 causes the detection unit 12 to detect the rotation position of the rotor 23 to switch to square wave voltage drive when the rotation speed ω of the motor 20 is lower than the low rotation speed threshold, and to vector control drive when the rotation speed ω is equal to or higher than the low rotation speed threshold. Threshold When the rotation speed ω is lower than a high rotation speed threshold value that is set to a higher value, the detection mode is switched to the first position detection, and when the rotation speed ω is equal to or higher than the high rotation speed threshold value, the detection mode is switched to the second position detection. As will be described in detail later, the motor control device 10 determines the driving method and load of the motor 20 according to the rotation speed ω of the motor 20. Ta By switching the method of detecting the rotational position of 23, it is possible to prevent the noise and vibration generated by the motor 20 from increasing, and to stabilize the output of the motor 20.

[0033] The command unit 15 determines a d-axis current command value Id based on, for example, an accelerator opening degree input from the outside. * and q-axis current command value Iq *The command unit 15 generates the q-axis current command value Iq * The command unit 15 outputs the generated d-axis current command value Id * and q-axis current command value Iq * is output to the vector control driver 112.

[0034] [2. Motor operating range in motor control device] The operating range of the motor in the motor control device 10 according to this embodiment will be described using Figures 3 to 7 while also referring to Figures 1 and 2. Figure 3 is a diagram explaining the operating range of the motor 20 in the motor control device 10. Figure 3 shows that the rotation speed of the motor increases from left to right.

[0035] 3, the operating range of the motor in the motor control device 10 is divided into a first operating range in which the motor is driven by a square wave voltage and operated by first position detection, a second operating range in which the motor is driven by vector control and operated by first position detection, and a third operating range in which the motor is driven by vector control and operated by second position detection, in correspondence with low rotation speed thresholds Lth1, Lth2 and high rotation speed thresholds Hth1, Hth2. The switching unit 14 (see FIG. 1) switches the operating range of the motor 20 among the first operating range, the second operating range, and the third operating range according to the rotation speed ω.

[0036] The low rotation speed thresholds Lth1, Lth2 and the high rotation speed thresholds Hth1, Hth2 are set to different values ​​when the rotation speed ω increases and when the rotation speed ω decreases. In this embodiment, the low rotation speed thresholds Lth1, Lth2 and the high rotation speed thresholds Hth1, Hth2 are set to lower values ​​when the rotation speed ω decreases than when the rotation speed ω increases.

[0037] Specifically, the low rotation speed threshold Lth1, which is compared with the rotation speed ω when the rotation speed of the motor 20 increases, is set to a value greater than the low rotation speed threshold Lth2, which is compared with the rotation speed ω when the rotation speed of the motor 20 decreases. The high rotation speed threshold Hth1, which is compared with the rotation speed ω when the rotation speed of the motor 20 increases, is set to a value greater than the high rotation speed threshold Hth2, which is compared with the rotation speed ω when the rotation speed of the motor 20 decreases. Each of the low rotation speed thresholds Lth1, Lth2 and the high rotation speed thresholds Hth1, Hth2 is set to a rotation speed in an extremely low rotation region. For example, the low rotation speed thresholds Lth1, Lth2 are set to a value between 1 and 10 [rad / min], and the high rotation speed thresholds Hth1, Hth2 are set to a value between 100 and 1000 [rad / min].

[0038] When the low rotation speed threshold Lth1 and the low rotation speed threshold Lth2 are set to the same value, if the rotation speed ω of the motor 20 increases or decreases in a short time while straddling the low rotation speed thresholds Lth1 and Lth2, the voltage waveforms of the U-phase AC voltage Vu applied to the U-phase winding 21u of the motor 20, the V-phase AC voltage Vv applied to the V-phase winding 21v, and the W-phase AC voltage Vw applied to the W-phase winding 21w of the motor 20 are repeatedly switched between a sine wave and a rectangular wave. This causes the U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw applied to the motor 20 to become disturbed, and the phase currents flowing through the U-phase winding 21u, the V-phase winding 21v, and the W-phase winding 21w of the motor 20 to also become disturbed. As a result, the noise and vibration generated by the motor 20 increase.

[0039] Furthermore, when the high rotational speed threshold Hth1 and the high rotational speed threshold Hth2 are set to the same value, if the rotational speed ω of the motor 20 increases or decreases in a short period of time while straddling the high rotational speed thresholds Hth1, Hth2, the noise and vibration generated by the motor 20 will increase for the same reasons as the low rotational speed thresholds Lth1, Lth2.

[0040] In the motor control device 10, the low rotation speed thresholds Lth1, Lth2 are set to different values ​​so that the rotation speed ω of the motor 20 does not cross the low rotation speed thresholds Lth1, Lth2 even if the rotation speed ω of the motor 20 increases or decreases in a short period of time. Similarly, in the motor control device 10, the high rotation speed thresholds Hth1, Hth2 are set to different values ​​so that the rotation speed ω of the motor 20 does not cross the high rotation speed thresholds Hth1, Hth2 even if the rotation speed ω of the motor 20 increases or decreases in a short period of time. This allows the motor control device 10 to prevent an increase in noise and vibration generated by the motor 20.

[0041] The square wave voltage drive is a control that switches the energization pattern based on the change in the Hall detection signal, and therefore has the advantage that it is possible to control energization even in a region where the rotation speed cannot be calculated based on the pulse interval at very low rotation speeds. On the other hand, the square wave voltage drive has the disadvantage that it is difficult to achieve high efficiency.

[0042] Vector control drive has the advantage that it theoretically eliminates torque pulsation of the motor and is superior to square wave voltage drive in terms of noise, vibration, efficiency, torque accuracy, and transient characteristics. On the other hand, vector control drive has the disadvantage that it requires a controller with high computing power because it uses pulse width modulation (PWM) control to generate sinusoidal U-phase current, V-phase current, and W-phase current with little distortion. Also, vector control drive has the disadvantage that it requires more accurate detection of the magnetic pole position of the rotor provided in the motor.

[0043] The first position detection using six-step angle calculation has the advantage that the rotor position of the motor can be precisely observed, so that the rotor position can be detected with high accuracy even when the motor is rotating at low speed. On the other hand, the first position detection has the disadvantage that the intervals between the edges of the Hall detection signal vary due to an error in the mounting position of the three Hall sensors, resulting in an error in the detected position of the rotor. This error becomes particularly large when the motor is rotating at high speed.

[0044] The second position detection using the change in the signal level of one Hall detection signal has the advantage of being able to reduce the processing load of motor position detection because the observation frequency can be suppressed when the motor is rotating at high speed. On the other hand, the second position detection has the disadvantage that the resolution for calculating the rotor position is low, so the accuracy of position detection is particularly reduced when the motor is rotating at low speed.

[0045] Thus, the square wave voltage drive, the vector control drive, the first position detection, and the second position detection each have advantages and disadvantages. Therefore, the motor control device 10 divides the operating region of the motor 20 according to the rotation speed of the motor 20, and controls the motor 20 by utilizing the respective advantages of the square wave voltage drive, the vector control drive, the first position detection, and the second position detection.

[0046] 3, in the first operating region, the motor 20 is driven by square wave voltage drive, and the rotational position (i.e., rotation angle) of the rotor 23 is detected by first position detection. In the second operating region, the motor 20 is driven by vector control drive, and the rotational position of the rotor 23 is detected by first position detection. In the third operating region, the motor 20 is driven by vector control drive, and the rotational position of the rotor 23 is detected by second position detection.

[0047] As a result, in a first operating region where the rotation speed of the motor 20 is low, the motor control device 10 drives the motor 20 by square wave voltage drive that can obtain high output even at low rotation speeds, and can detect the rotation position (rotation angle) of the rotor 23 by first position detection that can detect the rotation position of the rotor 23 with high accuracy even at low rotation speeds of the motor. In a second operating region where the rotation speed of the motor 20 is faster than that of the first operating region, the motor control device 10 drives the motor 20 by vector control drive that is superior to square wave voltage drive in terms of sound, vibration, efficiency, torque accuracy, and transient characteristics, and can detect the rotation position (rotation angle) of the rotor 23 by first position detection. In a third operating region where the rotation speed of the motor 20 is high, the motor control device 10 drives the motor 20 by vector control drive, and can detect the rotation position (rotation angle) of the rotor 23 by second position detection that has a lower processing load than the first position detection unit.

[0048] Next, the square wave voltage driving and the first position detection executed in the first operation region will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a diagram showing an example of the voltage waveforms of the U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw output to the motor 20 by the driving unit 11 (see Fig. 1) in which the driving of the motor 20 is switched to the square wave voltage driving by the switching unit 14, and an example of the voltage waveforms of the Hall detection signals Hu, Hv, and Hw output from the Hall sensors 22u, 22v, and 22w (see Fig. 1) provided in the motor 20. Fig. 5 is a diagram showing an example of the voltage waveforms of the Hall detection signals Hu, Hv, and Hw shown in Fig. 4, and a diagram showing an example of the relationship between the combination of the Hall detection signals Hu, Hv, and Hw in the first position detection using the 6-step angle calculation and the rotation angle θ1 of the motor 20.

[0049] A square-wave voltage driver 111 (see FIG. 1) that performs square-wave voltage driving generates pulse signals Pau-Paz (see FIG. 1) that are input to an inverter unit 113 as pulse signals Pu-Pz (see FIG. 1). The pulse signals Pau-Paz are signals for outputting, from the inverter unit 113 (see FIG. 2), to the motor 20, a U-phase AC voltage Vu, a V-phase AC voltage Vv, and a W-phase AC voltage Vw that correspond to the excitation patterns of the U-phase winding 21u, the V-phase winding 21v, and the W-phase winding 21w that correspond to the rotation angle θ of the motor 20. In square-wave voltage driving, the pulse signals Pau-Paz input from the square-wave voltage driver 111 control switching of six semiconductor elements Qu-Qz (see FIG. 2) provided in the inverter unit 113 in a control pattern in which the high side of one phase is turned on, the low side of another phase is turned on, and both sides of the remaining phases are turned off. 4, the U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw are positive pulse signals for a 120° period during a period in which the electrical angle rotates 360° (i.e., one cycle of the electrical angle), are constant 0 V signals for the next 60° period, are negative pulse signals for the next 120° period, and are constant 0 V signals for the final 60° period. The U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw are signals whose electrical angles are shifted by 120° from each other.

[0050] The pulse signals Pau to Paz generated by the rectangular wave voltage driver 111 are generated by multiplying the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw input from the inverter 113 by the q-axis current command value Iq * These pulse signals Pau to Paz cause the inverter unit 113 to repeatedly operate, thereby changing the duty ratios of the rectangular pulse-shaped U-phase AC voltage Vu, V-phase AC voltage Vv, and W-phase AC voltage Vw. As a result, the rotation speed of the motor 20 approaches a desired value.

[0051] The Hall sensors 22u, 22v, and 22w provided in the motor 20 are arranged at 120° intervals and shifted by 60° from the U-phase winding 21u, the V-phase winding 21v, and the W-phase winding 21w (see FIG. 1). Therefore, as shown in FIG. 4 and FIG. 5, the Hall detection signal Hu output from the Hall sensor 22u, the Hall detection signal Hv output from the Hall sensor 22v, and the Hall detection signal Hw output from the Hall sensor 22w have signal waveforms whose phases are shifted by 120° from each other. Moreover, one cycle of the Hall detection signals Hu, Hv, and Hw coincides with one cycle of the electrical angle of the motor 20.

[0052] As shown in Fig. 5, the first position detection unit 121 (see Fig. 1) determines the electrical angle, for example, in a stepped manner, according to a combination of the voltage levels of the Hall detection signals Hu, Hv, and Hw. For example, when the voltage level of the Hall detection signal Hu is high, the voltage level of the Hall detection signal Hv is low, and the voltage level of the Hall detection signal Hw is high, the first position detection unit 121 determines the electrical angle to be 0° (360°). Also, for example, when the voltage level of the Hall detection signal Hu is high, the voltage level of the Hall detection signal Hv is low, and the voltage level of the Hall detection signal Hw is low, the first position detection unit 121 determines the electrical angle to be 60°.

[0053] Based on the electrical angle thus determined, the first position detection unit 121 detects the rotation angle θ1 of the rotor 23 in a stepped manner from 0° to 360° (0°). The first position detection unit 121 detects the rotation angle θ1 of the motor 20 by using the above-mentioned equation (1).

[0054] In the first operating region, the switching unit 14 switches the drive of the motor 20 to square wave voltage drive, and switches the position detection of the rotor 23 to the first position detection. Therefore, the output of the first position detection unit 121 is electrically connected to the input of the drive unit 11, and a rotation angle signal Sθ1 including information on the rotation angle θ1 detected by the first position detection unit 121 is input to the drive unit 11 as the rotation angle signal Sθ. As a result, the square wave voltage drive unit 111 generates pulse signals Pau to Paz for making the U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw conform to the excitation pattern corresponding to the rotation angle θ1 of the motor 20 detected by the first position detection unit 121.

[0055] Next, the vector control driving and the first position detection executed in the second operating region will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of voltage waveforms of the U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw output to the motor 20 by the driving unit 11 in which the driving of the motor 20 has been switched to the vector control driving by the switching unit 14, and an example of voltage waveforms of the Hall detection signals Hu, Hv, and Hw output from the Hall sensors 22u, 22v, and 22w provided in the motor 20.

[0056] A vector control driving unit 112 (see FIG. 1) that performs vector control driving is a unit that converts a U-phase current Iu, a V-phase current Iv, and a W-phase current Iw input from an inverter unit 113 into a d-axis current command value Id * and q-axis current command value Iq * The inverter unit 113 generates pulse signals Pbu-Pbz for making the semiconductor elements Qu-Qz follow the pulse signals Pbu-Pbz input from the vector control drive unit 112 as the pulse signals Pu-Pz, and outputs them to the inverter unit 113. In the vector control drive, the switching of the six semiconductor elements Qu-Qz provided in the inverter unit 113 is controlled by the pulse signals Pbu-Pbz input from the vector control drive unit 112 as the pulse signals Pu-Pz, in the same manner as in the square wave voltage drive. As a result, as shown in Fig. 6, the U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw become sinusoidal signals whose one cycle coincides with the period of a 360° electrical angle rotation. The U-phase AC voltage Vu, the V-phase AC voltage Vv, and the W-phase AC voltage Vw become signals whose electrical angles are shifted from each other by 120°.

[0057] The U-phase current Iu, the V-phase current Iv, and the W-phase current Iw input from the inverter unit 113 are converted into the d-axis current command value Id * and q-axis current command value Iq * By the drive unit 11 repeatedly executing vector control drive so as to follow the rotation speed of the motor 20, the rotation speed of the motor 20 approaches a desired value.

[0058] As shown in FIG. 6, the Hall detection signal Hu output from the Hall sensor 22u has a period that matches the period of the U-phase AC voltage Vu, and is a square wave signal that is positive when the U-phase AC voltage Vu is positive and 0 V when the U-phase AC voltage Vu is negative. The Hall detection signal Hv output from the Hall sensor 22v has a period that matches the period of the V-phase AC voltage Vv, and is a square wave signal that is positive when the V-phase AC voltage Vv is positive and 0 V when the V-phase AC voltage Vv is negative. The Hall detection signal Hw output from the Hall sensor 22w has a period that matches the period of the W-phase AC voltage Vw, and is a square wave signal that is positive when the W-phase AC voltage Vw is positive and 0 V when the W-phase AC voltage Vw is negative. The Hall detection signals Hu, Hv, and Hw have signal waveforms that are out of phase with each other by 120°, and one period of the Hall detection signals Hu, Hv, and Hw matches one period of the electrical angle of the motor 20.

[0059] 4 and 6, the Hall detection signals Hu, Hv, and Hw in the vector control drive have the same signal waveforms as the Hall detection signals Hu, Hv, and Hw in the square wave voltage drive. Therefore, the first position detector 121 can detect the rotational position (i.e., rotational angle) of the rotor 23 in the second operation region in which the motor 20 is driven by the vector control drive in the same manner as in the first operation region in which the motor 20 is driven by the square wave voltage drive.

[0060] In the second operating region, the switching unit 14 switches the driving of the motor 20 to vector control driving, and switches the position detection of the rotor 23 to first position detection. Therefore, the output of the first position detection unit 121 is electrically connected to the input of the driving unit 11, and a rotation angle signal Sθ1 including information on the rotation angle θ1 detected by the first position detection unit 121 is input as the rotation angle signal Sθ to the driving unit 11. As a result, the vector control driving unit 112 uses the rotation angle θ1 of the motor 20 detected by the first position detection unit 121 as the rotation angle of the motor 20 for executing vector control driving.

[0061] Next, the vector control driving and the second position detection executed in the third operating region will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of the voltage waveforms of the Hall detection signals Hu, Hv, and Hw output from the Hall sensors 22u, 22v, and 22w provided in the motor 20 in the third operating region, and an example of the relationship between the Hall detection signal Hu and the rotation angle θ2 of the motor 20 in the second position detection.

[0062] In the third operating region, the drive unit 11 performs vector control driving by the same operation as in the second operating region, and therefore a description of the vector control driving in the third operating region will be omitted.

[0063] As shown in FIG. 7, the Hall detection signal Hu output from the Hall sensor 22u in the third operating region has the same signal waveform (see FIG. 6) as the Hall detection signal Hu output from the Hall sensor 22u in the second operating region. The second position detection unit 122 (see FIG. 1) determines the electrical angle, for example, linearly, based on the rising edge and falling edge (i.e., the timing at which the signal level changes) of the Hall detection signal Hu. For example, the second position detection unit 122 determines the rising edge of the Hall detection signal Hu as an electrical angle of 0° (360°) and the falling edge of the Hall detection signal Hu as an electrical angle of 180°. Furthermore, the second position detection unit 122 determines the electrical angle between 0° and 180° and between 180° and 0° (360°) on the assumption that the electrical angle increases monotonically linearly between the rising edge and the falling edge of the Hall detection signal Hu.

[0064] The second position detection unit 122 linearly detects the rotation angle of the rotor 23 from 0° to 360° (0°) based on the electrical angle determined in this manner. The second position detection unit 122 detects the rotation angle θ2 of the rotor 23 using the above-mentioned equation (1). In this embodiment, the second position detection unit 122 detects the rotation angle θ2 using the Hall detection signal Hu, but may also detect the rotation angle θ2 using the Hall detection signal Hv or the Hall detection signal Hw.

[0065] In the third operating region, the switching unit 14 switches the driving of the motor 20 to vector control driving, and switches the position detection of the rotor 23 to the second position detection. Therefore, the output of the second position detection unit 122 is electrically connected to the input of the driving unit 11, and a rotation angle signal Sθ2 including information on the rotation angle θ2 detected by the second position detection unit 122 is input to the driving unit 11 as the rotation angle signal Sθ. As a result, the vector control driving unit 112 uses the rotation angle θ2 of the motor 20 detected by the second position detection unit 122 as the rotation angle of the motor 20 for executing the vector control driving.

[0066] [3. Operation of the motor control device] The operation of the motor control device 10 according to this embodiment will be described using Fig. 8 with reference to Fig. 1 and Fig. 3. Fig. 8 is a flowchart showing an example of the flow of operation of the motor control device 10. The process shown in Fig. 8 is started, for example, when power is applied to the motor control device 10 (i.e., the power is turned on).

[0067] When the motor control device 10 (see FIG. 1) starts controlling the motor 20 (see FIG. 1), in step S11, the switching unit 14 (see FIG. 1) determines whether or not the rotation speed of the motor 20 is increasing. The switching unit 14 time-differentiates the rotation speed signal Sω input from the rotation speed calculation unit 13 (see FIG. 1), and if the result of the time differentiation is positive, it determines that the rotation speed of the motor 20 is increasing (step S11: YES), and proceeds to processing of step S12. On the other hand, if the result is negative or zero, the switching unit 14 determines that the rotation speed of the motor 20 is not increasing (step S11: NO), and proceeds to processing of step S23.

[0068] In step S12, the switching unit 14 determines whether the rotation speed ω included in the rotation speed signal Sω input from the rotation speed calculation unit 13 is lower than the low rotation speed threshold Lth1. If the switching unit 14 determines that the rotation speed ω is lower than the low rotation speed threshold Lth1 (step S12: YES), the switching unit 14 proceeds to processing in step S13. On the other hand, if the switching unit 14 determines that the rotation speed ω is equal to or higher than the low rotation speed threshold Lth1 (step S12: NO), the switching unit 14 proceeds to processing in step S16.

[0069] In step S13, the switching unit 14 switches the operation region of the motor 20 to the first operation region (see FIG. 3), and in the next step S14 after step S13, the driving of the motor 20 is switched to square wave voltage driving. S15 In step S36, the position detection of rotor 23 is switched to the first position detection. When the process of step S15 in switching unit 14 ends, motor control device 10 proceeds to the process of step S36.

[0070] In step S16, the switching unit 14 determines whether the rotation speed ω included in the rotation speed signal Sω input from the rotation speed calculation unit 13 is within a range equal to or greater than the low rotation speed threshold Lth1 and lower than the high rotation speed threshold Hth1. If the switching unit 14 determines that the rotation speed ω is within this range (step S16: YES), the switching unit 14 proceeds to processing in step S17. On the other hand, if the switching unit 14 determines that the rotation speed ω is not within this range (step S16: NO), the switching unit 14 proceeds to processing in step S20.

[0071] In step S17, switching unit 14 switches the operating region of motor 20 to the second operating region (see FIG. 3), and in step S18, the next step after step S17, switches the drive of motor 20 to vector control drive, and in step S19, the next step after step S18, switches the position detection of rotor 23 to first position detection. When the process of step S19 in switching unit 14 is completed, motor control device 10 proceeds to the process of step S36. Note that if the position detection of rotor 23 has already been switched to first position detection, switching unit 14 may proceed to the process of step S36 without performing any special process in step S19.

[0072] In step S20, the switching unit 14 switches the operating region of the motor 20 to the third operating region (see FIG. 3), and in the next step S21 after step S20, the driving of the motor 20 is switched to vector control driving, and in the next step S22 after step S21, the position detection of the rotor 23 is switched to the second position detection. Note that if the driving of the motor 20 has already been switched to vector control driving, the switching unit 14 may proceed to the process of step S22 without performing any special process in step S21. When the process of step S22 in the switching unit 14 ends, the motor control device 10 proceeds to the process of step S36.

[0073] In step S23, the switching unit 14 determines whether or not the rotation speed of the motor 20 is decreasing. If the result of the time differentiation of the rotation speed signal Sω acquired in step S11 is negative, the switching unit 14 determines that the rotation speed of the motor 20 is decreasing (step S23: YES), and proceeds to processing in step S24. On the other hand, if the result is zero, the switching unit 14 determines that the rotation speed of the motor 20 is not decreasing (step S23: NO), and proceeds to processing in step S35.

[0074] In step S24, the switching unit 14 determines whether the rotation speed ω included in the rotation speed signal Sω input from the rotation speed calculation unit 13 is equal to or greater than the high rotation speed threshold Hth2. If the switching unit 14 determines that the rotation speed ω is equal to or greater than the high rotation speed threshold Hth2 (step S24: YES), the switching unit 14 proceeds to processing in step S25. On the other hand, if the switching unit 14 determines that the rotation speed ω is not equal to or greater than the high rotation speed threshold Hth2 (step S24: NO), the switching unit 14 proceeds to processing in step S28.

[0075] In step S25, switching unit 14 switches the operating region of motor 20 to the third operating region (see FIG. 3), and in the next step S26 after step S25, switches the drive of motor 20 to vector control drive, and in the next step S27 after step S26, switches the position detection of rotor 23 to the second position detection. When the process of step S27 in switching unit 14 ends, motor control device 10 proceeds to the process of step S36.

[0076] In step S28, the switching unit 14 determines whether the rotation speed ω included in the rotation speed signal Sω input from the rotation speed calculation unit 13 is within a range equal to or higher than the low rotation speed threshold Lth2 and lower than the high rotation speed threshold Hth2. If the switching unit 14 determines that the rotation speed ω is within this range (step S28: YES), the switching unit 14 proceeds to processing in step S29. On the other hand, if the switching unit 14 determines that the rotation speed ω is not within this range (step S28: NO), the switching unit 14 proceeds to processing in step S32.

[0077] In step S29, the switching unit 14 switches the operating region of the motor 20 to the second operating region (see FIG. 3), and in the next step S30 after step S29, switches the driving of the motor 20 to vector control driving, and in the next step S31 after step S30, switches the position detection of the rotor 23 to the first position detection. Note that if the driving of the motor 20 has already been switched to vector control driving, the switching unit 14 may proceed to the processing of step S31 without performing any special processing in step S30. When the processing of step S31 in the switching unit 14 ends, the motor control device 10 proceeds to the processing of step S36.

[0078] In step S32, switching unit 14 switches the operating region of motor 20 to the first operating region (see FIG. 3), and in the next step S33 after step S32, switches the drive of motor 20 to square wave voltage drive, and in the next step S34 after step S33, switches the position detection of rotor 23 to first position detection. When the processing of step S34 in switching unit 14 is completed, motor control device 10 proceeds to processing of step S36. Note that if the position detection of rotor 23 has already been switched to first position detection, switching unit 14 may proceed to processing of step S36 without performing any special processing in step S34.

[0079] In step S35, the switching unit 14 maintains the control of the drive of the motor 20 and the position detection of the rotor 23 in the current state. When the processing of step S35 in the switching unit 14 ends, the motor control device 10 proceeds to processing of step S36. The processing of step S35 is executed when it is determined in step S11 that the rotation speed of the motor 20 is not increasing and when it is determined in step S23 that the rotation speed of the motor 20 is not decreasing, that is, when it is determined that the rotation speed of the motor 20 is constant. For this reason, there is no need to change the operating range of the motor 20 in step S35, so the switching unit 14 maintains the current control state.

[0080] In step S36, it is determined whether the power supply for operating the motor control device 10 is off. If the voltage value of the power supply input to the motor control device 10 is lower than a predetermined value (step S36: YES), the motor control device 10 determines that the power supply is off and ends operation. On the other hand, if the voltage value of the power supply input to the motor control device 10 is equal to or higher than the predetermined value (step S36: NO), the motor control device 10 determines that the power supply is not off and returns to the processing of step S11.

[0081] [4. Other embodiments] The driving unit 11 may be configured to stop the operation of the non-selected one of the rectangular wave voltage driving unit 111 and the vector control driving unit 112, and the detection unit 12 may be configured to stop the operation of the non-selected one of the first position detection unit 121 and the second position detection unit 122. This allows the motor control device 10 to reduce the processing load.

[0082] In the operation of the motor control device 10 according to the above embodiment, if it is determined in the process of step S16 that the rotation speed ω is not included in the range equal to or greater than the low rotation speed threshold Lth1 and lower than the high rotation speed threshold Hth1, the operation region is switched to the third operation region in the process of the next step S20, but this is not limited thereto. For example, between the process of step S16 and the process of step S20, a process of determining whether the rotation speed ω is equal to or greater than the high rotation speed threshold Hth1 may be executed. In this process, if it is determined that the rotation speed ω is equal to or greater than the high rotation speed threshold Hth1, the process may proceed to the process of step S20, and if it is determined that the rotation speed ω is not equal to or greater than the high rotation speed threshold Hth1, the process may proceed to the process of step S36. This makes it possible to prevent the motor 20 from operating in an operation region different from the operation region in which it should originally operate, even if a determination error occurs in the processes of steps S12 and S16.

[0083] In the operation of the motor control device 10 according to the above embodiment, if it is determined in the process of step S28 that the rotation speed ω is not within a range equal to or greater than the low rotation speed threshold Lth2 and lower than the high rotation speed threshold Hth2, the operation range is switched to the first operation range in the process of the next step S32, but this is not limited to this. For example, if the rotation speed ω is greater than or equal to the low rotation speed threshold Lth2 between the processes of steps S28 and S32, 2 In the process, if it is determined that the rotation speed ω is lower than the low rotation speed threshold Lth2, the process may proceed to step S32, and if it is determined that the rotation speed ω is not lower than the low rotation speed threshold Lth2, the process may proceed to step S36. This makes it possible to prevent the motor 20 from operating in an operating range different from the operating range in which it should originally operate, even if a determination error occurs in the processes of steps S24 and S28.

[0084] In the above embodiment, the second position detection unit 122 determines the electrical angle based on the rising edge and the falling edge of the Hall detection signal Hu, but this is not limited to the above. The second position detection unit 122 may determine the electrical angle, for example, linearly, based only on the rising edge of the Hall detection signal Hu. In this case, the second position detection unit 122 determines, for example, the rising edge of the Hall detection signal Hu as an electrical angle of 0°, and determines the next rising edge of the Hall detection signal Hu as an electrical angle of 360° (0°). Furthermore, the second position detection unit 122 determines the electrical angle between 0° and 360° (0°) on the assumption that the electrical angle increases monotonically linearly between the rising edge and the next rising edge of the Hall detection signal Hu.

[0085] [5. Configuration supported by the above embodiment] The above embodiment is a specific example of the following configuration.

[0086] (Configuration 1) A motor drive unit capable of selectively driving the motor by rectangular wave voltage driving, which applies a rectangular wave voltage to a stator winding provided in the motor to drive the motor, and vector control driving, which applies a sine wave voltage to the stator winding to drive the motor; a detection unit capable of selectively detecting the rotational position by first position detection based on a combination of signal levels of a plurality of position signals indicating a rotational position of a rotor provided in the motor, and second position detection based on a change in the signal level of any one of the plurality of position signals; and a switching unit that causes the drive unit to switch the drive of the motor to the rectangular wave voltage driving or the vector control driving, based on a rotational speed of the motor, and causes the detection unit to switch the detection of the rotational position to the first position detection or the second position detection, Threshold A motor control device that switches to the first position detection when the rotational speed is lower than a high rotational speed threshold that is set to a higher value, and switches to the second position detection when the rotational speed is equal to or greater than the high rotational speed threshold. According to the motor control device of configuration 1, when the rotation speed of the motor is low, the rotation angle of the motor can be calculated with high resolution by the first position detection, and high-output drive is possible by square wave voltage drive. Also, according to the motor control device of configuration 1, when the rotation speed of the motor is high, the rotation angle of the motor is calculated by the second position detection, so that the processing load is reduced by lowering the resolution of the rotation angle of the motor at high rotation speeds, and drive with less vibration of the motor is possible by vector control drive. Therefore, efficient drive with less vibration can be performed in all rotation speed ranges. As a result, according to the motor control device of configuration 1, stabilization of the motor output at low rotation speeds can be achieved, which in turn contributes to improving energy efficiency.

[0087] (Configuration 2) The motor control device described in Configuration 1 has an operating region of the motor divided into a first operating region in which the motor is operated with the rectangular wave voltage drive and the first position detection, a second operating region in which the motor is operated with the vector control drive and the first position detection, and a third operating region in which the motor is operated with the vector control drive and the second position detection, corresponding to the low rotational speed threshold and the high rotational speed threshold, and the switching unit switches the operating region among the first operating region, the second operating region, and the third operating region depending on the rotational speed. According to the motor control device of configuration 2, it is possible to drive the motor more efficiently according to the rotation speed of the motor.

[0088] (Configuration 3) The motor control device according to configuration 1 or 2, wherein the low rotational speed threshold and the high rotational speed threshold are set to different values ​​when the rotational speed increases and when the rotational speed decreases. According to the motor control device of configuration 3, when the rotation speed of the motor increases or decreases in a short time so as to cross a rotation speed threshold for switching the motor drive method and the rotor rotation position calculation method, frequent changes in the voltage applied to the motor and the current flowing through the motor can be prevented, and as a result, the noise and vibration of the motor can be reduced.

[0089] (Configuration 4) The motor control device according to configuration 3, wherein the low rotation speed threshold and the high rotation speed threshold are each set to a lower value when the rotation speed is decreasing than when the rotation speed is increasing. According to the motor control device of configuration 4, the noise and vibration of the motor can be reduced.

[0090] (Configuration 5) The motor control device according to any one of configurations 1 to 4, further comprising a calculation unit that calculates the rotation speed based on any one of the plurality of position signals. According to the motor control device of configuration 5, the detection of the rotational position of the rotor and the calculation of the rotational speed can be performed using the same signal.

[0091] (Configuration 6) A vehicle comprising: the motor control device according to any one of configurations 1 to 5; the motor; and a plurality of position detectors provided in the motor and outputting the plurality of position signals. According to the vehicle of configuration 6, the same effects as those of the motor control device of configurations 1 to 5 can be obtained. [Explanation of symbols]

[0092] 1...vehicle, 10...motor control device, 11...drive unit, 12...detection unit, 13...rotation speed calculation unit, 14...switching unit, 15...command unit, 20...motor, 21u...U-phase winding, 21v...V-phase winding, 21w...W-phase winding, 22u, 22v, 22w...Hall sensor, 23...rotor, 111...rectangular wave voltage drive unit, 112...vector control drive unit, 113...inverter unit, 113u...U-phase arm, 113v...V-phase arm, 113w...W-phase arm, 121...first position detection unit, 122...second position detection unit, Hth1, Hth2...high rotation speed threshold, Hu, Hv, Hw...Hall detection signal, Id * …d-axis current command value, Iq * ...q-axis current command value, Iu...U-phase current, Iv...V-phase current, Iw...W-phase current, Ln...positive line, Lp...negative line, Lth1, Lth2...rotation speed threshold, Pau~Paz, Pbu~Pbz, Pu~Pz...pulse signal, Qu~Qz...semiconductor element, Scd1, Scd2...drive switching signal, Scp1, Scp2...detection switching signal, Sθ, Sθ1, Sθ2...rotation angle signal, Sω...rotation speed signal, Vu...U-phase AC voltage, Vv...V-phase AC voltage, Vw...W-phase AC voltage, θ, θ1, θ2...rotation angle, ω...rotation speed

Claims

1. a drive unit capable of selectively driving the motor by a rectangular wave voltage drive that applies a rectangular wave voltage to a stator winding provided in the motor to drive the motor, and a vector control drive that applies a sinusoidal wave voltage to the stator winding to drive the motor; a detection unit capable of selectively detecting the rotational position by a first position detection based on a combination of Hall detection signal levels output from a plurality of Hall sensors indicating a rotational position of a rotor provided in the motor, and a second position detection based on a change in Hall detection signal level from any one of the plurality of Hall sensors; a switching unit that causes the drive unit to switch the drive of the motor to the rectangular wave voltage drive or the vector control drive based on a rotation speed of the motor, and causes the detection unit to switch detection of the rotation position to the first position detection or the second position detection; Equipped with The switching unit is Switching to a first operating region in which the rotational speed is equal to or lower than a low rotational speed threshold and the rotational speed is driven by the rectangular wave voltage and the first position detection; Switching to a third operating region in which the rotational speed is operated with the vector control drive and the second position detection at a rotational speed equal to or higher than a high rotational speed threshold value that is higher than the low rotational speed threshold value; switching to a second operating region in which the vector control drive and the first position detection are performed at a rotation speed between the low rotation speed threshold value and the high rotation speed threshold value; Motor control device.

2. The range of rotational speeds in the second operating region is greater than the range of rotational speeds in the first operating region, The motor control device according to claim 1 .

3. The low rotation speed threshold and the high rotation speed threshold are set to different values ​​when the rotation speed increases and when the rotation speed decreases. The motor control device according to claim 1 .

4. The low rotation speed threshold and the high rotation speed threshold are each set to a lower value when the rotation speed is decreasing than when the rotation speed is increasing. The motor control device according to claim 3.

5. a calculation unit that calculates the rotation speed based on any one of the Hall detection signals output from the plurality of Hall sensors; The motor control device according to claim 1 .

6. A motor control device according to any one of claims 1 to 5, The motor; The plurality of Hall sensors provided on the motor; A vehicle equipped with.

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