CN113872474A - Sensorless control device, electric oil pump device, and sensorless control method - Google Patents

Abstract

A sensorless control apparatus, an electric oil pump apparatus, and a sensorless control method. The sensorless control device includes: a motor drive circuit; a phase detection unit that outputs a phase detection signal based on a back electromotive force of the motor; a storage section that stores a voltage control pattern and a speed control pattern; a voltage control section that outputs a control voltage according to the voltage control pattern; and an energization control section that controls the driving voltage and the energization switching speed according to the control voltage and the speed control pattern. When starting the motor, the voltage control part changes the control voltage with time according to the voltage control pattern, and the conduction control part performs the following forced commutation control: the energizing switching speed is changed with time according to the speed control pattern while the driving voltage is changed with time in synchronization with the control voltage. During the forced commutation control, the combination of the drive voltage and the energization switching speed at an arbitrary timing always satisfies a linear function having the drive voltage and the energization switching speed as variables and having a negative slope.

Description

Sensorless control device, electric oil pump device, and sensorless control method

Technical Field

The invention relates to a sensorless control device, an electric oil pump device, and a sensorless control method.

Background

A hybrid vehicle includes a mechanical oil pump driven by a driving force of an engine and an electric oil pump driven by a motor as a hydraulic pressure supply device for supplying hydraulic pressure to a transmission. In such a hybrid vehicle, the hydraulic pressure required for the transmission can be supplied by the electric oil pump by controlling the motor when the engine in which the mechanical oil pump is not operable is stopped.

As a motor control method, the following sensorless control is known: the phase of the motor is detected by the back electromotive force of the motor without using a position sensor such as a hall sensor, and the energization control of the motor is performed based on the detection result of the phase. In the sensorless control, in order to detect the phase of the motor, it is necessary to detect a zero cross point, which is a point where the neutral point voltage of the motor crosses the counter electromotive force, but if the rotation speed of the motor is not equal to or higher than a predetermined speed, the counter electromotive force capable of detecting the zero cross point is not generated. Therefore, when the motor is started by the sensorless control, the energization control of the motor is generally performed in a predetermined starting order before the rotation speed of the motor reaches a speed at which the zero-cross point can be detected.

As an example of the start-up sequence, the following start-up sequence is known: after the phase of the motor is fixed to a specific phase by performing dc excitation for a predetermined time, forced commutation control is performed in which the energized phase is forcibly switched at a constant energization switching speed while applying a constant drive voltage to the energized phase. When the rotation speed of the motor reaches a speed at which a zero-crossing point can be detected by this starting sequence, the forced commutation control is terminated, and then the sensorless control of the motor is performed based on a phase detection result of the motor obtained by the detection of the zero-crossing point.

Patent document 1 describes a method of starting a sensorless motor, in which when a detection pattern of a zero-crossing point captured during forced commutation control matches a regular change pattern stored in advance, the forced commutation control is shifted to the sensorless control. In this startup method, when the pattern switching timing time in the forced commutation control is shorter than a predetermined time, the delay angle control is performed and the process shifts to the sensorless control.

Patent document 1: japanese laid-open patent publication No. 2008-271727

However, in order to rotate the motor appropriately, it is necessary to control the driving voltage V applied to the motor to an appropriate value according to the rotation speed F in accordance with the F-V characteristic depending on the specification of the motor. Since the rotation speed F is proportional to the drive voltage V, the F-V characteristic can be expressed by a linear function having a positive slope. The more the combination of the rotation speed F and the drive voltage V deviates from the F-V characteristic, the more unstable the rotation of the motor, and the more difficult it is to appropriately control the motor.

In addition, when the motor is connected to a load such as an oil pump, energy required to rotate the motor increases, and therefore, a driving voltage required to rotate the motor connected to the load at the same rotation speed as in the case of no load increases. That is, even with the same motor, the F-V characteristic of the motor varies depending on the magnitude of the load.

When the motor is started by the sensorless control as described above, the forced commutation control is performed in accordance with a combination of the drive voltage and the energization switching speed that are determined in advance, but the actual rotation speed of the motor does not necessarily coincide with the energization switching speed, and depends on the magnitude of the drive voltage and the magnitude of the load. Therefore, it is preferable to experimentally acquire the F-V characteristics under various load conditions in advance, and to perform forced commutation control in accordance with a combination of a drive voltage and an energization switching speed suitable for the F-V characteristics according to the actual load size when the motor is started by sensorless control.

Therefore, as a practical method, the following methods are often used: the combination of the drive voltage and the conduction switching speed at which the motor can be rotated to a speed at which the zero-cross point can be detected is determined in advance through experiments by performing forced commutation control while adjusting the drive voltage and the conduction switching speed based on the F-V characteristic obtained under a specific load condition. In this case, when the motor is started, the forced commutation control is performed in accordance with the combination of the drive voltage and the energization switching speed determined by the above method, but when the actual load condition greatly deviates from the load condition used in the experiment, the forced commutation control is performed in accordance with the combination of the drive voltage and the energization switching speed which is not suitable for the actual load condition. As a result, the motor may not be rotated to a speed at which the zero-cross point can be detected when the motor is started, and the starter motor may fail.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a sensorless control device, an electric oil pump device, and a sensorless control method that can successfully start a motor regardless of the magnitude of a load when the motor is started by sensorless control.

A sensorless control device according to an aspect of the present invention controls a motor without a position sensor, and includes: a motor drive circuit including a plurality of phase switching elements and configured to supply electric power to each phase of the motor; and a phase detection unit that detects a phase of the motor based on a counter electromotive force of the motor and outputs a phase detection signal indicating a detection result of the phase. The sensorless control device according to one aspect of the present invention includes a storage unit that stores a voltage control pattern indicating a control pattern of a drive voltage applied to an energization phase of the motor and a speed control pattern indicating a control pattern of an energization switching speed that is a speed at which the energization phase is switched. In addition, the sensorless control device according to one aspect of the present invention includes a voltage control unit that outputs a control voltage based on a control command signal input from a host control device, the phase detection signal, and the voltage control pattern. The sensorless control device according to one aspect of the present invention further includes an energization control unit that controls the driving voltage and the energization switching speed by controlling the switching element of the motor driving circuit based on the control voltage, the phase detection signal, and the speed control pattern. In the sensorless control device according to one aspect of the present invention, when the phase cannot be identified from the phase detection signal at the time of starting the motor, the voltage control unit changes the control voltage over time in accordance with the voltage control pattern, and the energization control unit controls the switching element in accordance with the control voltage and the speed control pattern, thereby performing forced commutation control as follows: the energization switching speed is varied with time in accordance with the speed control pattern while varying the drive voltage with time in synchronization with the control voltage. The combination of the drive voltage and the energization switching speed at any time during the forced commutation control always satisfies a linear function having the drive voltage and the energization switching speed as variables and having a negative slope.

An electric oil pump device according to an aspect of the present invention includes: a motor having a shaft; a pump located on one axial side of the shaft and driven by the motor via the shaft to discharge oil; and a sensorless control device of the above-described aspect that controls the motor without a position sensor.

A sensorless control method according to an aspect of the present invention controls a motor without a position sensor, and performs forced commutation control as follows when a phase of the motor cannot be recognized when the motor is started: while changing a drive voltage applied to an energized phase of the motor with time in accordance with a predetermined voltage control pattern, changing an energization switching speed, which is a switching speed of the energized phase, with time in accordance with a predetermined speed control pattern, a combination of the drive voltage and the energization switching speed at an arbitrary timing during the period in which the forced commutation control is performed always satisfies a linear function having the drive voltage and the energization switching speed as variables and having a negative slope.

According to the above aspect of the present invention, it is possible to provide the sensorless control device, the electric oil pump device, and the sensorless control method that can successfully start the motor regardless of the magnitude of the load when the motor is started by the sensorless control.

Drawings

Fig. 1 is a block diagram schematically showing an electric oil pump device having a sensorless control device of the present embodiment.

Fig. 2 is a diagram showing an example of the energization pattern and the phase pattern used in the sensorless 120 ° energization system according to the present embodiment.

Fig. 3 is a timing chart showing a basic principle of the sensorless 120 ° power-on mode of the present embodiment.

Fig. 4 is a diagram showing a relationship between the F-V characteristic and the load of the motor according to the present embodiment.

Fig. 5 is a diagram showing an example of the voltage control pattern and the speed control pattern stored in the storage unit in the present embodiment.

Fig. 6 is a diagram showing another example of the voltage control pattern and the speed control pattern stored in the storage unit in the present embodiment.

Fig. 7 is a diagram showing another example of the voltage control pattern and the speed control pattern stored in the storage unit in the present embodiment.

Fig. 8 is a diagram showing another example of the voltage control pattern and the speed control pattern stored in the storage unit in the present embodiment.

Fig. 9 is a timing chart showing the operation of the sensorless control apparatus according to the present embodiment.

Description of the reference symbols

10: a sensorless control device; 11: a motor drive circuit; 12: a phase detection unit; 12 a: a zero-crossing detection circuit; 12 b: a signal delay circuit; 13: a storage unit; 14: a voltage control unit; 15: an energization control unit; 20: a motor; 30: a pump; 40: an electric oil pump; 100: an electric oil pump device; 200: an oil; 300: a vehicle-mounted battery; 400: and a host control device.

Detailed Description

Hereinafter, the configuration of an embodiment of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a circuit block diagram schematically showing an electric oil pump device 100 having a sensorless control device 10 of the present embodiment. As shown in fig. 1, the electric oil pump device 100 has a sensorless control device 10 and an electric oil pump 40. The electric oil pump 40 has a motor 20 and a pump 30. The electric oil pump device 100 is a device that supplies oil to a transmission mounted on a hybrid vehicle, for example.

The sensorless control device 10 is a device that controls the motor 20 of the electric oil pump 40 without a position sensor such as a hall sensor. That is, the sensorless control device 10 detects the phase of the motor 20 using the back electromotive force of the motor 20, and performs energization control of the motor 20 based on the detection result of the phase. The details of the vehicle control device 200 will be described later.

The motor 20 is, for example, an inner rotor type three-phase brushless DC motor, and is a sensorless motor having no position sensor such as a hall sensor. Motor 20 includes shaft 21, U-phase terminal 22U, V-phase terminal 22V, W-phase terminal 22W, U-phase coil 23U, V-phase coil 23V, and W-phase coil 23W.

Although not shown in fig. 1, the motor 20 includes a motor case, and a rotor and a stator housed in the motor case. The rotor is a rotating body rotatably supported by a bearing member inside the motor case. The stator is fixed inside the motor case in a state of surrounding the outer peripheral surface of the rotor, and generates electromagnetic force necessary for rotating the rotor.

The shaft 21 is a shaft-like body that is coaxially joined to the rotor in a state of penetrating the rotor radially inward in the axial direction. U-phase terminal 22U, V-phase terminal 22V, and W-phase terminal 22W are metal terminals exposed from the surface of the motor case. The U-phase terminal 22U, the V-phase terminal 22V, and the W-phase terminal 22W are electrically connected to the motor drive circuit 11 of the sensorless control device 10, respectively, and will be described in detail later. The U-phase coil 23U, the V-phase coil 23V, and the W-phase coil 23W are excitation coils provided in the stator, respectively. U-phase terminal 22U, V-phase terminal 22V, and W-phase terminal 22W are star-connected inside motor 20.

U-phase coil 23U is electrically connected between U-phase terminal 22U and neutral point N. V-phase coil 23V is electrically connected between V-phase terminal 22V and neutral point N. W-phase coil 23W is electrically connected between W-phase terminal 22W and neutral point N. By controlling the energization state of U-phase terminal 22U, V-phase terminal 22V, and W-phase terminal 22W by sensorless control device 10, electromagnetic force necessary for rotating the rotor is generated. By the rotation of the rotor, the shaft 21 also rotates in synchronization with the rotor.

The pump 30 is located on one axial side of the shaft 21 of the motor 20, and the pump 30 is driven by the motor 20 via the shaft 21 to discharge the oil 200. The pump 30 has an oil suction port 31 and an oil discharge port 32. The oil 200 is sucked into the pump 30 through the oil inlet port 31 and then discharged to a transformer, not shown, through the oil discharge port 32. Thus, the pump 30 and the motor 20 are connected adjacently in the axial direction of the shaft 21, thereby constituting the electric oil pump 40.

The sensorless control device 10 includes a motor drive circuit 11, a phase detection unit 12, a storage unit 13, a voltage control unit 14, and an energization control unit 15. The sensorless control device 10 is electrically connected to the motor 20, the in-vehicle battery 300, and the host control device 400, respectively. The in-vehicle battery 300 and the host control device 400 are not components of the sensorless control device 10 and the electric oil pump device 100.

The in-vehicle battery 300 is one of a plurality of batteries mounted on the hybrid vehicle, and supplies a power supply voltage V of 12V to an in-vehicle system of a 12V system, for example_M. The host Control device 400 is one of a plurality of ECUs (Electric Control units) mounted on a hybrid vehicle, for example, and outputs a Control command signal CS for controlling a hydraulic pressure supply operation of the Electric oil pump device 100 to the transformer to the sensorless Control device 10.

The motor drive circuit 11 is composed of switching elements of plural phases, and is a circuit for supplying electric power to each phase of the motor 20. Specifically, the motor drive circuit 11 includes a U-phase upper arm switch Q_UHV-phase upper side arm switch Q_VHW-phase upper side arm switch Q_WHU-phase lower side arm switch Q_ULV-phase lower side arm switch Q_VLAnd W-phase lower arm switch Q_WL. In the present embodiment, each arm switch is, for example, an N-channel MOS-FET.

U-phase upper side arm switch Q_UHDrain terminal of (1), V-phase upper arm switch Q_VHDrain terminal of (1) and W-phase upper arm switch Q_WHAre electrically connected to the positive electrode terminals of the vehicle-mounted battery 300, respectively. U-phase lower side arm switch Q_ULSource terminal of (1), V-phase lower arm switch Q_VLSource terminal of (1) and W-phase lower arm switch Q_WLAnd the source terminals of the same are respectively connected to the negative terminals of the on-vehicle battery 300The sub-electrical connections. The negative terminal of the in-vehicle battery 300 is electrically connected to the in-vehicle ground terminal.

U-phase upper side arm switch Q_UHAnd the U-phase terminal 22U of the motor 20 and the U-phase lower arm switch Q_ULAre electrically connected to each other. V-phase upper side arm switch Q_VHAnd the V-phase terminal 22V of the motor 20 and the V-phase lower arm switch Q_VLAre electrically connected to each other. W-phase upper side arm switch Q_WHAnd W-phase terminal 22W and W-phase lower arm switch Q of motor 20_WLAre electrically connected to each other.

U-phase upper side arm switch Q_UHGate terminal of (1), V-phase upper arm switch Q_VHGate terminal of (1) and W-phase upper arm switch Q_WHThe gate terminals of the gate lines are electrically connected to the energization control unit 15. In addition, a U-phase lower arm switch Q_ULGate terminal of (1), and V-phase lower arm switch Q_VLGate terminal of (1) and W-phase lower arm switch Q_WLThe gate terminals of the respective transistors are also electrically connected to the energization control unit 15.

As described above, the motor drive circuit 11 is an inverter constituted by a 3-phase full bridge circuit having 3 upper arm switches and 3 lower arm switches. The motor drive circuit 11 configured as described above performs switching control of the arm switches by the energization control unit 15, and converts dc power supplied from the in-vehicle battery 300 into three-phase power and outputs the three-phase power to the motor 20.

In the present embodiment, a case in which a sensorless 120 ° energization system is used as an energization system of the motor 20 is exemplified. For convenience of explanation, the basic principle of the sensorless 120 ° conduction method will be explained below, and the configurations of the phase detection unit 12, the storage unit 13, the voltage control unit 14, and the conduction control unit 15 will be explained. The basic principle of the sensorless 120 ° conduction method described below is only an example, and the present invention is not limited to this.

In the case of using the sensorless 120 ° conduction pattern, the arm switches are on-off controlled in accordance with the conduction pattern shown in fig. 2. As shown in fig. 2, the energization pattern of the 120 ° energization pattern includes 6 energization patterns PA1, PA2, PA3, PA4, PA5, and PA 6.In FIG. 2, at slave "Q_UHTo Q_WL"1" in "1" and "0" arranged in the column means that the corresponding arm switch is controlled to be on, and "0" means that the corresponding arm switch is controlled to be off.

In fig. 3, an energization period P1 from time t10 to time t11 indicates a period during which each arm switch is subjected to switching control in accordance with an energization pattern PA 1. During this energization period P1, the U-phase arm switch Q_UHAnd W-phase lower arm switch Q_WLOn and the remaining arm switches off. During the power-on period P1, only the U-phase upper arm switch Q_UHIs switched at a prescribed switching duty ratio. The switching duty is controlled by a control voltage VC output from a voltage control unit 14 described later. In the energization period P1, a drive current flows through the U-phase coil 23U and the W-phase coil 23W from the U-phase terminal 22U toward the W-phase terminal 22W. That is, the current-carrying phases in the current-carrying period P1 are U-phase and W-phase.

In fig. 3, an energization period P2 from time t11 to time t12 indicates a period during which each arm switch is subjected to switching control in accordance with an energization pattern PA 2. During this energization period P2, the U-phase arm switch Q_UHAnd V-phase lower arm switch Q_VLOn and the remaining arm switches off. During the energization period P2, the U-phase-only upper arm switch Q_UHIs switched at a prescribed switching duty ratio. In the energization period P2, a drive current flows through the U-phase coil 23U and the V-phase coil 23V from the U-phase terminal 22U toward the V-phase terminal 22V. That is, the current-carrying phases in the current-carrying period P2 are U-phase and V-phase.

In fig. 3, an energization period P3 from time t12 to time t13 indicates a period during which each arm switch is subjected to switching control in accordance with an energization pattern PA 3. In the conduction period P3, the W-phase upper arm switch Q_WHAnd V-phase lower arm switch Q_VLOn and the remaining arm switches off. In the energization period P3, only the W-phase upper arm switch Q_WHIs switched at a prescribed switching duty ratio. In the energization period P3, a drive current flows through the W-phase coil 23W and the V-phase coil 23V from the W-phase terminal 22W toward the V-phase terminal 22V. That is, the conduction phases in the conduction period P3 are the W phase and the V phase.

In the figureIn fig. 3, an energization period P4 from time t13 to time t14 indicates a period during which each arm switch is subjected to switching control in accordance with an energization pattern PA 4. In the conduction period P4, the W-phase upper arm switch Q_WHAnd U-phase lower arm switch Q_ULOn and the remaining arm switches off. In the energization period P4, only the W-phase upper arm switch Q_WHIs also switched at a prescribed switching duty cycle. In the energization period P4, a drive current flows through the W-phase coil 23W and the U-phase coil 23U from the W-phase terminal 22W toward the U-phase terminal 22U. That is, the conduction phases in the conduction period P4 are the W phase and the U phase.

In fig. 3, an energization period P5 from time t14 to time t15 indicates a period during which each arm switch is subjected to switching control in accordance with an energization pattern PA 5. In the current-carrying period P5, the V-phase upper arm switch Q_VHAnd U-phase lower arm switch Q_ULOn and the remaining arm switches off. In the power-on period P5, the side arm switch Q is on the V phase only_VHIs switched at a prescribed switching duty ratio. In the energization period P5, a drive current flows through the V-phase coil 23V and the U-phase coil 23U from the V-phase terminal 22V toward the U-phase terminal 22U. That is, the energized phases in the energization period P5 are the V-phase and the U-phase.

In fig. 3, an energization period P6 from time t15 to time t16 indicates a period during which each arm switch is subjected to switching control in accordance with an energization pattern PA 6. In the current-carrying period P6, the V-phase upper arm switch Q_VHAnd W-phase lower arm switch Q_WLOn and the remaining arm switches off. In the energization period P6, the upper arm switch Q is on the V-phase only_VHIs switched at a prescribed switching duty ratio. In the energization period P6, a drive current flows through the V-phase coil 23V and the W-phase coil 23W from the V-phase terminal 22V toward the W-phase terminal 22W. That is, the energized phases in the energization period P6 are the V-phase and the W-phase.

By performing switching control of the arm switches in accordance with the 6 energization patterns described above, a rotating magnetic field is generated to rotate the shaft 21 of the motor 20 in a certain direction by 360 °. As a result, the shaft 21 of the motor 20 rotates 360 ° in a constant direction during a period from time t10 to time t 16. In other words, the shaft 21 of the motor 20 rotates 60 ° in a certain direction during each period from the energization period P1 to the energization period P6.

The speed at which the energization pattern is switched, that is, the speed at which the energization phases are switched is the energization switching speed F. The unit of the energization switching speed F is [ Hz ]. When a period during which switching control is performed in accordance with one energization pattern is P (seconds), the energization switching speed Fs is represented by [ Fs ═ 1/P ]. The energization switching speed F is also sometimes referred to as a commutation frequency.

Fig. 3 shows waveforms of voltages appearing at U-phase terminal 22U, V-phase terminal 22V, and W-phase terminal 22W of motor 20, respectively. In fig. 3, "Vu" is a U-phase terminal voltage appearing in the U-phase terminal 22U. "Vv" is a V-phase terminal voltage appearing in the V-phase terminal 22V. "Vw" is a W-phase terminal voltage appearing in the W-phase terminal 22W. Note that, although the waveforms of the actual U-phase terminal voltage Vu, V-phase terminal voltage Vv, and W-phase terminal voltage Vw have the same duty ratio as the switching duty ratio, fig. 3 shows only the envelope of the voltage waveform for convenience.

The U-phase terminal voltage Vu has an effective voltage value determined by the switching duty ratio in the conduction periods P1 and P2, and has a ground terminal level value of 0V in the conduction periods P4 and P5. The V-phase terminal voltage Vv is an effective voltage value determined by the switching duty ratio in the energization periods P5 and P6, and is 0V in the energization periods P2 and P3. The W-phase terminal voltage Vw has an effective voltage value determined by the switching duty ratio in the conduction periods P3 and P4, and is 0V in the conduction periods P1 and P6. In this way, in the sensorless 120 ° energization mode, the phase to which the driving voltage required for driving the motor 20 is applied is switched every 120 °.

In the energization period P3, although the drive current does not flow to the U-phase coil 23U, the energy accumulated in the U-phase coil 23U passes through the U-phase lower arm switch Q_ULThe free-wheeling current flows for a certain time through the U-phase coil 23U. As a result, ringing occurs in which the U-phase terminal voltage Vu becomes 0V only for a certain time from the start time of the period P3. Thereafter, the U-phase terminal voltage Vu coincides with the back electromotive force generated in the U-phase coil 23U. In the energization period P3, the counter electromotive force is increased from a high value at the middle of the energization period P3, that is, at a timing when the motor 20 rotates by 30 ° from the start time of the energization period P3Neutral point voltage V which is the voltage between the neutral point N and the ground with the voltage side facing the low voltage side_NAnd (4) intersection.

Similarly, in the energization period P6, although the drive current does not flow to the U-phase coil 23U, the energy accumulated in the U-phase coil 23U passes through the U-phase upper arm switch Q_UHThe free-wheeling current flows for a certain time through the U-phase coil 23U. As a result, the U-phase terminal voltage Vu is generated to be the power supply voltage V for a certain time from the start time of the energization period P6_MThe ringing phenomenon of (1). Thereafter, the U-phase terminal voltage Vu coincides with the back electromotive force generated in the U-phase coil 23U. In the energization period P6, the counter electromotive force is generated from the low voltage side toward the high voltage side at the timing when the motor 20 rotates by 30 ° in the middle of the energization period P6, that is, at the timing when the energization period P6 starts, and the neutral point voltage V_NAnd (4) intersection.

As described above, during the rotation of the motor 20 by 360 °, the back electromotive force is exposed in the U-phase terminal 22U only during the energization periods P3 and P6. Based on the same principle, during the rotation of the motor 20 by 360 °, the counter electromotive force is exposed in the V-phase terminal 22V only during the energization periods P1 and P4, and the counter electromotive force is exposed in the W-phase terminal 22W only during the energization periods P2 and P5. In the sensorless 120 ° conduction system, the neutral point voltage V needs to be detected in order to detect the phase of the motor 20_NThe point of intersection with the back emf is the zero crossing point.

In fig. 3, "Zu" indicates that the back electromotive force exposed to U-phase terminal 22U becomes neutral point voltage V_NThe following timing becomes low level, and the back electromotive force exposed to U-phase terminal 22U becomes lower than neutral point voltage V_NThe high timing becomes a high-level U-phase zero-crossing point detection signal. "Zv" is a neutral point voltage V at the back electromotive force exposed to the V-phase terminal 22V_NThe following timing becomes low, and the counter electromotive force exposed to the V-phase terminal 22V becomes lower than the neutral point voltage V_NThe high timing becomes a high-level V-phase zero-crossing point detection signal. "Zw" is a neutral point voltage V when the back electromotive force exposed to W-phase terminal 22W becomes a neutral point_NThe timing is low, and the back electromotive force exposed to W-phase terminal 22W becomes lower than neutral point voltage V_NHigh isThe timing becomes a high-level W-phase zero-crossing point detection signal.

In addition, only by inputting the U-phase terminal voltage Vu and the neutral point voltage V to the comparator, for example_NThe U-phase zero cross detection signal Zu shown in fig. 3 cannot be obtained. In practice, the output voltage of the comparator is subjected to a predetermined waveform processing to generate a voltage V only at the neutral point_NAnd a U-phase zero-crossing point detection signal Zu in which an edge appears at a zero-crossing point crossing the counter electromotive force. The V-phase zero-cross point detection signal Zv and the W-phase zero-cross point detection signal Zw are also generated by the same method.

In fig. 3, "Hu" is a U-phase detection signal having a phase delay of 30 ° with respect to the U-phase zero-crossing detection signal Zu. "Hv" is a V-phase detection signal having a phase delay of 30 ° with respect to the V-phase zero-cross point detection signal Zv. "Hw" is a W-phase detection signal having a phase delay of 30 ° with respect to the W-phase zero-crossing point detection signal Zw.

In addition, the motor 20 rotates by 60 ° in the time between 2 zero-crossings adjacent on the time axis. Therefore, by measuring the time between 2 zero-crossing points adjacent on the time axis and delaying the U-phase zero-crossing detection signal Zu by half the time of the measurement result, it is possible to generate the U-phase detection signal Hu having a phase delay of 30 ° with respect to the U-phase zero-crossing detection signal Zu. The V-phase detection signal Hv and the W-phase detection signal Hw are also generated by the same method.

As shown in fig. 3, it can be seen that: the voltage levels of the U-phase detection signal Hu, the V-phase detection signal Hv, and the W-phase detection signal Hw regularly change depending on the 6 energization patterns. Hereinafter, a pattern in which the voltage levels of the U-phase detection signal Hu, the V-phase detection signal Hv, and the W-phase detection signal Hw change depending on the energization pattern is referred to as a phase pattern. As shown in fig. 2, the phase pattern of the sensorless 120 ° energization pattern includes 6 phase patterns PB1, PB2, PB3, PB4, PB5, and PB 6. In FIG. 2, at "H_U”、“H_VAnd H_WIn the "1" and "0" arranged in the column, "1" means that the corresponding phase detection signal is at a high level, and "0" means that the corresponding phase detection signal is at a high levelThe test signal is low.

In the sensorless 120 ° conduction pattern, a phase pattern is recognized for each conduction period from the 3 phase detection signals Hu, Hv, and Hw, and a conduction pattern used in the next conduction period is determined based on the recognition result of the phase pattern. And, at the timing when the phase pattern changes, the energization pattern is switched to the next energization pattern.

As shown in fig. 3, for example, in the energization period P1, it is recognized from the phase detection signals Hu, Hv and Hw that the phase pattern of the energization period P1 is the phase pattern PB 1. Since the phase pattern of the energization period P1 is the phase pattern PB1, the energization pattern PA2 is determined as the energization pattern used in the next energization period P2. Then, the energization pattern is switched from the energization pattern PA1 to the energization pattern PA2 at a timing at which the phase pattern PB1 changes, that is, at a timing at which a falling edge occurs in the V-phase detection signal Hv.

In the sensorless 120 ° energization system, the identification of the phase pattern, the determination of the energization pattern, and the switching of the energization pattern as described above are performed in synchronization with the phase detection signals Hu, Hv, and Hw generated by the counter electromotive force generated in the motor 20, thereby enabling energization control of the motor 20 without using a position sensor such as a hall sensor. Hereinafter, the case where the energization control of the motor 20 is performed in synchronization with the phase detection signals Hu, Hv, and Hw generated by the counter electromotive force generated in the motor 20 is referred to as "sensorless synchronization control".

The above is the basic principle of the sensorless 120 ° power-on mode. In the sensorless 120 ° conduction method, it is necessary to detect the neutral point voltage V of the motor 20 in order to generate the phase detection signals Hu, Hv, and Hw_NThe zero-crossing point is a point crossing the counter electromotive force, but if the rotational speed of the motor 20 is not equal to or higher than a predetermined speed, the counter electromotive force capable of detecting the zero-crossing point is not generated. Therefore, when the motor 20 is started by the sensorless 120 ° energization system, the phase pattern cannot be recognized from the phase detection signals Hu, Hv, and Hw, that is, the phase of the motor 20 cannot be recognized until the rotation speed of the motor 20 reaches a speed at which the counter electromotive force capable of detecting the zero cross point is generated, and thus the phase pattern cannot be recognizedAnd carrying out sensorless synchronous control. Therefore, when the motor 20 is started by the sensorless 120 ° energization system, the energization control of the motor 20 needs to be performed in accordance with a predetermined starting procedure until the rotation speed of the motor 20 reaches a speed at which a counter electromotive force that can detect a zero cross point is generated.

As an example of the start-up sequence, the following start-up sequence is known: after the phase of the motor is fixed to a specific phase by performing dc excitation for a predetermined time, forced commutation control is performed in which the energized phase is forcibly switched at a constant energization switching speed while applying a constant drive voltage to the energized phase.

As shown in fig. 4, in order to rotate the motor 20 appropriately, the driving voltage V applied to the motor 20 needs to be controlled to an appropriate value according to the rotation speed F according to the F-V characteristic depending on the specification of the motor 20. Since the rotation speed F is proportional to the drive voltage V, the F-V characteristic can be expressed by a linear function having a positive slope. The more the combination of the rotation speed F and the drive voltage V deviates from the F-V characteristic, the more unstable the rotation of the motor 20 becomes, and the more difficult it becomes to appropriately control the motor 20.

When the motor 20 is connected to a load such as the pump 30, energy required to rotate the motor 20 increases, and therefore, a driving voltage required to rotate the motor 20 connected to the load at the same rotation speed as that in the case of no load increases. That is, the F-V characteristic of the motor 20 varies depending on the load size. In fig. 4, a linear function LF0 having a positive slope represents the F-V characteristic of the load T0. In fig. 4, a linear function LF1 having a positive slope represents the F-V characteristic of the load T1 smaller than the load T0. In fig. 4, a linear function LF4 having a positive slope represents the F-V characteristic of the load T4 larger than the load T0. As shown in fig. 4, the slope of the linear function representing the F-V characteristic is constant regardless of the load, but the intercept of the linear function representing the F-V characteristic varies depending on the load. That is, the smaller the load, the larger the intercept of the linear function representing the F-V characteristic, and the larger the load, the smaller the intercept of the linear function representing the F-V characteristic.

When the motor 20 is started by the forced commutation control as described above, the forced commutation control is performed in accordance with a combination of a predetermined drive voltage and an energization switching speed, but the actual rotation speed of the motor 20 does not necessarily coincide with the energization switching speed and depends on the magnitude of the drive voltage and the magnitude of the load. Therefore, as shown in fig. 4, it is preferable to experimentally acquire the F-V characteristics under various load conditions in advance, and to perform forced commutation control in accordance with a combination of a drive voltage and an energization switching speed that satisfy the F-V characteristics corresponding to the actual load size when the motor 20 is started by sensorless control, but this method is difficult to be implemented in reality.

Therefore, as a practical method, the following methods are often used: forced commutation control is performed while adjusting the drive voltage and the energization switching speed in accordance with the F-V characteristic obtained under a specific load condition, and thus a combination of the drive voltage and the energization switching speed, which can rotate the motor to a speed at which the zero-crossing point can be detected, is determined in advance through experiments. In this case, when the motor is started, the forced commutation control is performed in accordance with the combination of the drive voltage and the energization switching speed determined by the above method, but when the actual load condition greatly deviates from the load condition used in the experiment, the forced commutation control is performed in accordance with the combination of the drive voltage and the energization switching speed which do not suit the actual load condition. As a result, the motor may not be rotated to a speed at which the zero-cross point can be detected when the motor is started, and the starter motor may fail.

For example, in fig. 4, it is assumed that the drive voltage V0 and the energization switching speed F0 used in forced commutation control are determined in accordance with the F-V characteristic of the load T0. When a load T4 larger than the load T0 is connected to the motor 20, the drive voltage V0 determined based on the F-V characteristic of the load T0 greatly deviates from the F-V characteristic of the load T4 toward the low-voltage side, and the energization switching speed F0 determined based on the F-V characteristic of the load T0 greatly deviates from the F-V characteristic of the load T4 toward the high-speed side. As a result, the motor 20 is applied with the drive voltage V0 that is much lower than the drive voltage V4 suitable for the F-V characteristic of the load T4, and the energization phase (energization pattern) is switched at the energization switching speed F0 that is much higher than the energization switching speed F4 suitable for the F-V characteristic of the load T4, whereby the motor 20 is restricted by the load and does not rotate.

On the other hand, when the load T1 smaller than the load T0 is connected to the motor 20, the drive voltage V0 determined from the F-V characteristic of the load T0 greatly deviates from the F-V characteristic of the load T1 toward the high-speed side, and the energization switching speed F0 determined from the F-V characteristic of the load T0 greatly deviates from the F-V characteristic of the load T1 toward the low-speed side. As a result, the motor 20 is applied with the driving voltage V0 that is much higher than the driving voltage V1 suitable for the F-V characteristic of the load T1, and the energization phase is switched at the energization switching speed F0 that is much lower than the energization switching speed F1 suitable for the F-V characteristic of the load T1, and thus the motor 20 may generate large vibration and cannot be controlled.

In order to solve such a problem, in the present embodiment, when the phase of the motor 20 cannot be recognized at the time of starting the motor 20, the following forced commutation control is performed: the energization switching speed is changed with time based on a predetermined speed control pattern while changing the drive voltage applied to the energization phase of the motor 20 with time based on a predetermined voltage control pattern. However, the drive voltage and the conduction switching speed are not changed without limitation during the period in which the forced commutation control is performed, but the drive voltage and the conduction switching speed are changed while satisfying the condition that "the combination of the drive voltage and the conduction switching speed at an arbitrary timing during the period in which the forced commutation control is performed always satisfies a linear function having the drive voltage and the conduction switching speed as variables and having a negative slope".

Specifically, in the forced commutation control of the present embodiment, for example, as shown in fig. 4, while the drive voltage V is varied with time in the range from the drive voltage V1 suitable for the F-V characteristic of the load T1 to the drive voltage V4 suitable for the F-V characteristic of the load T4, the energization switching speed F is varied in the range from the energization switching speed F1 suitable for the F-V characteristic of the load T1 to the energization switching speed F4 suitable for the F-V characteristic of the load T4. During the forced commutation control, the combination of the drive voltage V and the conduction switching speed F at an arbitrary timing always satisfies a linear function LF having the drive voltage V and the conduction switching speed F as variables and having a negative slope. In other words, while the forced commutation control is performed, in a 2-axis coordinate plane having the driving voltage V as the horizontal axis and the conduction switching speed F as the vertical axis, the intersection of the driving voltage V and the conduction switching speed F at any time is always located on the straight line represented by the linear function LF.

By performing the forced commutation control as described above at the time of starting the motor 20, the F-V characteristic suitable for the combination of the drive voltage V and the energization switching speed F changes with time in the range from the F-V characteristic of the load T1 to the F-V characteristic of the load T4. That is, the range of the F-V characteristic of the motor 20 that can be stably controlled can be widened, and as a result, the motor 20 can be stably rotated to a rotation speed at which a counter electromotive force that can detect a zero cross point is generated regardless of the magnitude of the load when the motor 20 is started, and the motor 20 can be successfully started.

In a 2-axis coordinate plane having the driving voltage V as the horizontal axis and the conduction switching speed F as the vertical axis, the linear function LF having a negative slope preferably intersects at right angles with, for example, the linear function LF0 having a positive slope that represents the F-V characteristic of the load T0.

Hereinafter, the phase detection unit 12, the storage unit 13, the voltage control unit 14, and the energization control unit 15 included in the sensorless control device 10 according to the present embodiment will be described based on the description of the basic principle of the sensorless 120 ° energization system and the description of the forced commutation control performed when the motor 20 is started in the present embodiment.

The phase detection unit 12 detects the phase of the motor 20 from the counter electromotive force of the motor 20, and outputs phase detection signals Hu, Hv, and Hw indicating the detection result of the phase to the voltage control unit 14 and the energization control unit 15. Phase detector 12 is electrically connected to U-phase terminal 22U, V-phase terminal 22V, and W-phase terminal 22W of motor 20, respectively. In addition, the phase detection unit 12 and the W-phase upper arm switch Q_WHIs electrically connected. The phase detection unit 12 receives a U-phase terminal voltage Vu, a V-phase terminal voltage Vv, a W-phase terminal voltage Vw, and a power supply voltage V_M。

The phase detector 12 includes a zero-cross point detection circuit 12a and a signal delay circuit 12 b. The zero-crossing point detection circuit 12a detects the zero-crossing point based on the power supply voltage V_MGenerating a neutral point voltage V_N(＝V_M/2). In addition, it hasThe zero point detection circuit 12a detects the zero point based on the U-phase terminal voltage Vu and the neutral point voltage V_NAnd generates a U-phase zero-crossing detection signal Zu and outputs it to the signal delay circuit 12 b. The back electromotive force of U-phase zero-crossing detection signal Zu exposed to U-phase terminal 22U becomes neutral point voltage V_NThe following timing becomes low level, and the back electromotive force exposed to U-phase terminal 22U becomes lower than neutral point voltage V_NThe high timing becomes the high level.

As described above, only by inputting the U-phase terminal voltage Vu and the neutral point voltage V to the comparator, for example_NThe U-phase zero cross detection signal Zu shown in fig. 3 cannot be obtained. Therefore, the zero-cross point detection circuit 12a inputs the U-phase terminal voltage Vu and the neutral point voltage V to the input terminal_NThe output voltage of the comparator of (3) is subjected to a predetermined waveform processing to generate a voltage V only at the neutral point_NAnd a U-phase zero-crossing detection signal Zu whose edge appears at a zero-crossing point crossed with the back electromotive force exposed to the U-phase terminal 22U.

The zero-cross point detection circuit 12a detects the zero-cross point based on the V-phase terminal voltage Vv and the neutral point voltage V_NAnd generates a V-phase zero-crossing detection signal Zv and outputs it to the signal delay circuit 12 b. When the V-phase zero-cross detection signal Zv is exposed to the back electromotive force of the V-phase terminal 22V, the back electromotive force becomes a neutral point voltage V_NThe following timing becomes low, and the counter electromotive force exposed to the V-phase terminal 22V becomes lower than the neutral point voltage V_NThe high timing becomes the high level. The zero-crossing point detection circuit 12a detects the input V-phase terminal voltage Vv and the neutral point voltage V_NThe output voltage of the comparator of (3) is subjected to a predetermined waveform processing to generate a voltage V only at the neutral point_NAnd a V-phase zero-crossing point detection signal Zv whose edge appears at a zero-crossing point crossing the counter electromotive force exposed to the V-phase terminal 22V.

The zero-cross point detection circuit 12a detects the zero-cross point based on the W-phase terminal voltage Vw and the neutral point voltage V_NAnd generates W-phase zero-crossing detection signal Zw and outputs it to signal delay circuit 12 b. When the back electromotive force of W-phase zero-crossing detection signal Zw exposed to W-phase terminal 22W becomes neutral point voltage V_NThe timing is low, and the back electromotive force exposed to W-phase terminal 22W becomes lower than neutral point voltage V_NThe high timing becomes the high level. For treatingThe zero point detection circuit 12a inputs the W-phase terminal voltage Vw and the neutral point voltage V_NThe output voltage of the comparator of (3) is subjected to a predetermined waveform processing to generate a voltage V only at the neutral point_NA W-phase zero-crossing detection signal Zw that appears edged with a zero-crossing exposed to the counter electromotive force of the W-phase terminal 22W.

The signal delay circuit 12b generates a U-phase detection signal Hu having a phase delay of 30 ° with respect to the U-phase zero-crossing detection signal Zu, and outputs the signal Hu to the voltage control unit 14 and the energization control unit 15. The signal delay circuit 12b generates a V-phase detection signal Hv having a phase delay of 30 ° with respect to the V-phase zero-cross point detection signal Zv, and outputs the signal to the voltage control unit 14 and the energization control unit 15. The signal delay circuit 12b generates a W-phase detection signal Hw having a phase delay of 30 ° with respect to the W-phase zero-crossing detection signal Zw, and outputs the W-phase detection signal Hw to the voltage control unit 14 and the energization control unit 15. In this way, the signal delay circuit 12b outputs the 3 phase detection signals Hu, Hv, and Hw to the voltage control unit 14 and the conduction control unit 15.

As described above, the motor 20 rotates by 60 ° in the time between two zero-crossing points adjacent on the time axis. The signal delay circuit 12b measures the time between two zero-crossing points adjacent on the time axis and delays the U-phase zero-crossing detection signal Zu by half the time of the measurement result, thereby generating a U-phase detection signal Hu having a phase delay of 30 ° with respect to the U-phase zero-crossing detection signal Zu. The signal delay circuit 12b generates the V-phase detection signal Hv and the W-phase detection signal Hw by the same method.

The storage unit 13 stores various data necessary for controlling the motor 20 by the sensorless 120 ° energization system. The storage unit 13 includes a nonvolatile memory such as an EEPROM and a volatile memory such as a RAM. The storage unit 13 stores the energization pattern and the phase pattern shown in fig. 2 in advance. The storage unit 13 stores dc excitation conditions under which the phase of the motor 20 is fixed to a specific phase in advance. The storage unit 13 stores in advance a voltage control pattern indicating a control pattern of the drive voltage V and a speed control pattern indicating a control pattern of the energization switching speed F.

For example, as shown in fig. 5, the voltage control pattern is a pattern in which the driving voltage V increases from the driving voltage V1 to the driving voltage V4 with a constant slope over time t. The drive voltage V1 is a value of the drive voltage V suitable for the F-V characteristic of the load T1, and the drive voltage V4 is a value of the drive voltage V suitable for the F-V characteristic of the load T4. The driving voltage V1 is lower than the driving voltage V4. Further, as shown in fig. 5, the speed control pattern is a pattern in which the energization switching speed F decreases from the energization switching speed F1 to the energization switching speed F4 with a constant slope over time t. The energization switching speed F1 is a value of the energization switching speed F suitable for the F-V characteristic of the load T1, and the energization switching speed F4 is a value of the energization switching speed F suitable for the F-V characteristic of the load T4. The energization switching speed F1 is higher than the energization switching speed F4.

In fig. 5, for example, the combination "V1, F1" of the driving voltage V and the energization switching speed F at time t0 satisfies the linear function LF. Further, the combination "V0, F0" of the driving voltage V and the energization switching speed F at the time t100 also satisfies the linear function LF. Further, the combination "V4, F4" of the driving voltage V and the energization switching speed F at the time t200 also satisfies the linear function LF. In this way, in the present embodiment, the voltage control pattern and the speed control pattern satisfy the condition that "the combination of the drive voltage V and the energization switching speed F at an arbitrary timing always satisfies the linear function LF having the drive voltage V and the energization switching speed F as variables and having a negative slope".

As another example of the voltage control pattern, as shown in fig. 6, the voltage control pattern in which the driving voltage V decreases from the driving voltage V4 to the driving voltage V1 with a constant slope over time t may be stored in the storage unit 13. As another example of the speed control pattern, as shown in fig. 6, a speed control pattern in which the energization switching speed F is increased from the energization switching speed F4 to the energization switching speed F1 at a constant slope with time t may be stored in the storage unit 13. The voltage control pattern and the speed control pattern shown in fig. 6 also satisfy the condition that "the combination of the driving voltage V and the energization switching speed F at any time always satisfies the linear function LF having the driving voltage V and the energization switching speed F as variables and having a negative slope".

As another example of the voltage control pattern, as shown in fig. 7, the storage unit 13 may store a voltage control pattern in which the driving voltage V is increased from the driving voltage V1 to the driving voltage V4 in a stepwise manner with time t. As another example of the speed control pattern, as shown in fig. 7, a speed control pattern in which the energization switching speed F is gradually decreased from the energization switching speed F1 to the energization switching speed F4 with time t may be stored in the storage unit 13. The voltage control pattern and the speed control pattern shown in fig. 7 also satisfy the condition that "the combination of the driving voltage V and the energization switching speed F at any time always satisfies the linear function LF having the driving voltage V and the energization switching speed F as variables and having a negative slope".

As another example of the voltage control pattern, as shown in fig. 8, the memory unit 13 may store a voltage control pattern in which the driving voltage V decreases from the driving voltage V4 to the driving voltage V1 in a stepwise manner with time t. As another example of the speed control pattern, as shown in fig. 8, a speed control pattern in which the energization switching speed F is increased from the energization switching speed F4 to the energization switching speed F1 in a stepwise manner with time t may be stored in the storage unit 13. The voltage control pattern and the speed control pattern shown in fig. 8 also satisfy the condition that "the combination of the driving voltage V and the energization switching speed F at any time always satisfies the linear function LF having the driving voltage V and the energization switching speed F as variables and having a negative slope".

The voltage control unit 14 outputs the control voltage VC to the energization control unit 15 based on various data including the control command signal CS input from the host control device 400, the phase detection signals Hu, Hv, and Hw input from the phase detection unit 12, and the voltage control pattern stored in the storage unit 13. The control voltage VC determines the switching duty, and the value of the drive voltage V applied to the energized phase, that is, the effective voltage value, is determined by the switching duty.

The energization control unit 15 controls the arm switches of the motor drive circuit 11 based on various data including the control voltage VC input from the voltage control unit 14, the phase detection signals Hu, Hv, and Hw input from the phase detection unit 12, and the speed control pattern stored in the storage unit 13, thereby controlling the drive voltage V and the energization switching speed F.

When the phase pattern, which is the phase of the motor 20, cannot be recognized from the phase detection signals Hu, Hv, and Hw at the time of starting the motor 20, the voltage control unit 14 and the energization control unit 15 are set to a forced commutation mode in which forced commutation control is performed. In the forced commutation mode, the voltage control unit 14 changes the control voltage VC with time in accordance with the voltage control pattern stored in the storage unit 13, and the energization control unit 15 controls the arm switches in accordance with the control voltage VC input from the voltage control unit 14 and the speed control pattern stored in the storage unit 13, thereby performing the following forced commutation control: the energization switching speed F is varied with time according to a speed control pattern while varying the drive voltage V with time in synchronization with the control voltage VC. During the forced commutation control, the combination of the drive voltage V and the conduction switching speed F at an arbitrary timing always satisfies a linear function LF having the drive voltage V and the conduction switching speed F as variables and having a negative slope. When the phase pattern cannot be recognized from the phase detection signals Hu, Hv, and Hw at the time of starting the motor 20, the voltage control unit 14 and the energization control unit 15 enter the dc excitation mode in which dc excitation control is performed before the forced commutation mode is entered. In the dc excitation mode, the voltage control unit 14 outputs the control voltage VC according to the dc excitation condition stored in the storage unit 13 before outputting the control voltage VC according to the voltage control pattern, and the energization control unit 15 controls the arm switches according to the control voltage VC and the dc excitation condition input from the voltage control unit 14, thereby applying a dc drive voltage for a certain period of time to a specific energization phase.

In the operation in the forced commutation mode, when the phase pattern is successfully recognized from the phase detection signals Hu, Hv, and Hw, the voltage control unit 14 and the energization control unit 15 are in the sensorless synchronous control mode in which sensorless synchronous control is performed. In the sensorless synchronous control mode, the voltage control unit 14 outputs the control voltage VC based on the control command signal CS and the phase detection signals Hu, Hv, and Hw input from the upper control device 400, and the energization control unit 15 controls the arm switches based on the control voltage VC and the phase detection signals Hu, Hv, and Hw input from the voltage control unit 14, thereby switching the energization phases at the energization switching speed F determined by the phase detection signals Hu, Hv, and Hw while applying the drive voltage V corresponding to the control command signal CS to the energization phases.

The operation of the sensorless control apparatus 10 configured as described above will be described below with reference to a timing chart shown in fig. 9.

In fig. 9, at time t1, the control command signal CS is input from the host control device 400 to the voltage control unit 14. For example, the control command signal CS is an analog voltage signal having a voltage value indicating the target rotation speed. When the control command signal CS is input at time t1, the voltage control unit 14 determines whether or not a phase pattern that matches the state of the phase detection signals Hu, Hv, and Hw exists among the 6 phase patterns stored in the storage unit 13.

At time t1, motor 20 is in a stopped state, and therefore no back electromotive force is generated. In this case, since the zero-cross point detection circuit 12a cannot detect a zero-cross point, all of the zero-cross point detection signals Zu, Zv, Zw output from the zero-cross point detection circuit 12a are at a low level as shown in fig. 9. As a result, all of the phase detection signals Hu, Hv, and Hw output from the signal delay circuit 12b are low. In this case, the phase pattern of the motor 20 cannot be recognized from the phase detection signals Hu, Hv, and Hw. Therefore, at time t1, voltage control unit 14 determines that there is no phase pattern that matches the state of phase detection signals Hu, Hv, and Hw, and shifts to the dc excitation mode.

After shifting to the dc excitation mode at time t1, voltage control unit 14 outputs control voltage VC having a voltage value indicating, for example, a switching duty of 15% to 25% to energization control unit 15 in accordance with the dc excitation condition stored in storage unit 13. Further, the voltage control unit 14 starts a timer operation from time t1 when shifting to the dc excitation mode.

When control voltage VC having a voltage value indicating, for example, a switching duty ratio of 15% to 25% is input at time t1, energization control unit 15 determines whether or not there is a phase pattern that matches the state of phase detection signals Hu, Hv, and Hw among the 6 phase patterns stored in storage unit 13. As described above, at time t1, all of phase detection signals Hu, Hv, and Hw are at low level. Therefore, at time t1, energization control unit 15 determines that there is no phase pattern that matches the state of phase detection signals Hu, Hv, and Hw. When control voltage VC having a voltage value indicating a switching duty ratio of, for example, 15% to 25% is input, energization control unit 15 shifts to the dc excitation mode when there is no phase pattern that matches the state of phase detection signals Hu, Hv, and Hw.

When the dc excitation mode is switched to at time t1, the energization control unit 15 starts switching control of the arm switches based on the control voltage VC input from the voltage control unit 14 and the dc excitation condition stored in the storage unit 13. Specifically, for example, as shown in fig. 9, the energization control unit 15 switches the U-phase upper arm Q_UHW-phase upper side arm switch Q_WHAnd a V-phase lower arm switch Q_VLThe control is on, and the other arm switches are off. At this time, the energization control unit 15 controls the U-phase upper arm switch Q at a switching duty determined by the control voltage VC, that is, for example, a switching duty of 15% to 25%_UHAnd W-phase upper arm switch Q_WH。

As a result of the operations of the voltage control unit 14 and the energization control unit 15 in the dc excitation mode as described above, the U-phase terminal voltage Vu and the W-phase terminal voltage Vw have voltage values corresponding to, for example, a switching duty of 15% to 25% and the V-phase terminal voltage Vv becomes 0V after time t1, as shown in fig. 9. As a result, in the dc excitation mode, the dc drive voltage is applied to the specific energized phase. By such dc excitation control, the shaft 21 of the motor 20 is rotated to a specific phase and stopped. That is, the phase of the motor 20 is fixed to a specific phase by the dc excitation control. When it is detected that the time required to fix the shaft 21 of the motor 20 to the specific phase has elapsed at time t2 by the timer operation started at time t1, for example, the voltage control unit 14 shifts to the forced commutation mode.

Note that, although the waveforms of the actual U-phase terminal voltage Vu, V-phase terminal voltage Vv, and W-phase terminal voltage Vw have the same duty ratio as the switching duty ratio, fig. 9 shows only the envelope of the voltage waveform for convenience.

When the forced commutation mode is shifted to at time t2, the voltage controller 14 outputs the control voltage VC to the energization controller 15 in accordance with the voltage control pattern stored in the storage 13. For example, as shown in fig. 5, when the voltage control pattern in which the drive voltage V increases at a constant slope with time t is stored in the storage unit 13, the voltage control unit 14 outputs the control voltage VC increasing at a constant slope with time t from time t 2.

As another example, as shown in fig. 6, when the voltage control pattern in which the drive voltage V decreases with a constant slope over time t is stored in the storage unit 13, the voltage control unit 14 outputs the control voltage VC decreasing with a constant slope over time t from time t 2. As another example, as shown in fig. 7, when the voltage control pattern in which the drive voltage V increases stepwise with time t is stored in the storage unit 13, the voltage control unit 14 outputs the control voltage VC that increases stepwise with time t from time t 2. As another example, as shown in fig. 8, when a voltage control pattern in which the drive voltage V decreases stepwise with time t is stored in the storage unit 13, the voltage control unit 14 outputs the control voltage VC that decreases stepwise with time t from time t 2.

When the control voltage VC in accordance with the voltage control pattern is input at time t2, the energization control unit 15 shifts to the forced commutation mode if there is no phase pattern that matches the state of the phase detection signals Hu, Hv, and Hw. When the forced commutation mode is switched to at time t2, the energization control unit 15 starts switching control of the arm switches based on the control voltage VC input from the voltage control unit 14 and the speed control pattern and energization pattern stored in the storage unit 13.

Specifically, as shown in fig. 9, the energization control unit 15 generates the energization switching timing signal ST which is a pulse signal having the same frequency as the energization switching speed F determined in accordance with the speed control pattern after time t 2. When the speed control pattern stored in the storage unit 13 is a pattern in which the energization switching speed F decreases with a constant slope as time t elapses, as shown in fig. 5, for example, the frequency of the energization switching timing signal ST decreases with a constant slope as time t elapses from time t 2.

As another example, as shown in fig. 6, when the speed control pattern in which the energization switching speed F increases at a constant slope with time t is stored in the storage unit 13, the frequency of the energization switching timing signal ST increases at a constant slope with time t from time t 2. As another example, as shown in fig. 7, when a speed control pattern in which the communication switching speed F decreases stepwise with time t is stored in the storage unit 13, the frequency of the energization switching timing signal ST decreases stepwise with time t from time t 2. As another example, as shown in fig. 8, when a speed control pattern in which the energization switching speed F increases stepwise with time t is stored in the storage unit 13, the frequency of the energization switching timing signal ST increases stepwise with time t from time t 2.

The energization control section 15 switches the energization pattern in synchronization with the rising edge of the energization switching timing signal ST. For example, as shown in fig. 9, when a rising edge occurs in the energization switching timing signal ST at time t2, the energization control unit 15 first starts switching control of the arm switches in accordance with an energization pattern PA4 that generates a rotating magnetic field appropriate for the phase of the motor 20 fixed by the dc excitation control. That is, the W-phase upper arm switch Q is turned on during the conduction period from the time t2 to the time t3 when the next rising edge occurs in the conduction switching timing signal ST_WHAnd U-phase lower arm switch Q_ULOn and the remaining arm switches off. In the current-carrying period, W-phase upper arm switch Q_WHIs switched at a switching duty ratio determined by a control voltage VC that varies in accordance with a voltage control pattern. Therefore, the effective voltage value of the W-phase terminal voltage Vw, which is the drive voltage V applied to the energized phase during this energization period, changes in accordance with the voltage control pattern.

As shown in fig. 9, when the next rising edge occurs in the energization switching timing signal ST at time t3, the energization controller 15 switches the energization pattern PA4 to the energization pattern PA5 and turns on the energization pattern PA5The on-off control of the switches of the arms is started. That is, the V-phase upper arm switch Q is turned on during the energization period from the time t3 to the time t4 when the next rising edge occurs in the energization switching timing signal ST_VHAnd U-phase lower arm switch Q_ULOn and the remaining arm switches off. In the current-carrying period, the V-phase upper arm switch Q_VHIs switched at a switching duty ratio determined by a control voltage VC that varies in accordance with a voltage control pattern. Therefore, the effective voltage value of the V-phase terminal voltage Vv, which is the drive voltage V applied to the energized phase during this energization period, changes in accordance with the voltage control pattern.

As shown in fig. 9, when the next rising edge occurs in the energization switching timing signal ST at time t4, the energization controller 15 switches the energization pattern PA5 to the energization pattern PA6, and starts the switching control of the arm switches in accordance with the energization pattern PA 6. That is, the V-phase upper arm switch Q is turned on during the energization period from the time t4 to the time t5 when the next rising edge occurs in the energization switching timing signal ST_VHAnd W-phase lower arm switch Q_WLOn and the remaining arm switches off. In the current-carrying period, the V-phase upper arm switch Q_VHIs switched at a switching duty ratio determined by a control voltage VC that varies in accordance with a voltage control pattern. Therefore, the effective voltage value of the V-phase terminal voltage Vv, which is the drive voltage V applied to the energized phase during this energization period, changes in accordance with the voltage control pattern.

As shown in fig. 9, when the next rising edge occurs in the energization switching timing signal ST at time t5, the energization controller 15 switches the energization pattern PA6 to the energization pattern PA1, and starts the switching control of the arm switches in accordance with the energization pattern PA 1. That is, the U-phase upper arm switch Q is turned on during the energization period from the time t5 to the time t6 when the next rising edge occurs in the energization switching timing signal ST_UHAnd W-phase lower arm switch Q_WLOn and the remaining arm switches off. During this energization period, the side arm switch Q is on the U phase_UHIs switched at a switching duty ratio determined by a control voltage VC that varies in accordance with a voltage control pattern. Therefore, the effective voltage value of the U-phase terminal voltage Vu, which is the drive voltage V applied to the energized phase during this energization period, is controlled in accordance with the voltageThe pattern varies.

As shown in fig. 9, when the next rising edge occurs in the energization switching timing signal ST at time t6, the energization controller 15 switches the energization pattern PA1 to the energization pattern PA2, and starts the switching control of the arm switches in accordance with the energization pattern PA 2. That is, the U-phase upper arm switch Q is turned on during the energization period from the time t6 to the time t7 when the next rising edge occurs in the energization switching timing signal ST_UHAnd V-phase lower arm switch Q_VLOn and the remaining arm switches off. During this energization period, the side arm switch Q is on the U phase_UHIs switched at a switching duty ratio determined by a control voltage VC that varies in accordance with a voltage control pattern. Therefore, the effective voltage value of the U-phase terminal voltage Vu, which is the drive voltage V applied to the energized phase during this energization period, changes in accordance with the voltage control pattern.

As shown in fig. 9, when the next rising edge occurs in the energization switching timing signal ST at time t7, the energization controller 15 switches the energization pattern PA2 to the energization pattern PA3, and starts the switching control of the arm switches in accordance with the energization pattern PA 3. That is, the W-phase upper arm switch Q is turned on during the conduction period from the time t7 to the time t8 when the next rising edge occurs in the conduction switching timing signal ST_WHAnd V-phase lower arm switch Q_VLOn and the remaining arm switches off. In the current-carrying period, W-phase upper arm switch Q_WHIs switched at a switching duty ratio determined by a control voltage VC that varies in accordance with a voltage control pattern. Therefore, the effective voltage value of the W-phase terminal voltage Vw, which is the drive voltage V applied to the energized phase during this energization period, changes in accordance with the voltage control pattern.

As described above, when the sensorless control device 10 operates in the forced commutation mode, the following forced commutation control is performed: the energization switching speed F is changed according to a predetermined speed control pattern while changing the drive voltage V applied to the energization phase of the motor 20 with time according to a predetermined voltage control pattern. During the forced commutation control, the combination of the drive voltage V and the conduction switching speed F at an arbitrary timing always satisfies a linear function LF having the drive voltage V and the conduction switching speed F as variables and having a negative slope.

For example, as shown in fig. 5, when a voltage control pattern in which the drive voltage V increases at a constant slope with time t and a speed control pattern in which the energization switching speed F decreases at a constant slope with time t are stored in the storage unit 13, the drive voltage V applied to the energized phase of the motor 20 increases at a constant slope with time t in accordance with the voltage control pattern and the energization switching speed F, which is the frequency of the energization switching timing signal ST, decreases at a constant slope with time t in accordance with the speed control pattern from time t2 when the forced commutation control is started.

As another example, as shown in fig. 6, when a voltage control pattern in which the drive voltage V decreases at a constant slope with time t and a speed control pattern in which the energization switching speed F increases at a constant slope with time t are stored in the storage unit 13, the drive voltage V applied to the energized phase of the motor 20 decreases at a constant slope with time t in accordance with the voltage control pattern and the energization switching speed F, which is the frequency of the energization switching timing signal ST, increases at a constant slope with time t in accordance with the speed control pattern from time t2 when the forced commutation control is started.

As another example, as shown in fig. 7, when a voltage control pattern in which the drive voltage V increases in a stepwise manner with time t and a speed control pattern in which the energization switching speed F decreases in a stepwise manner with time t are stored in the storage unit 13, the drive voltage V applied to the energized phase of the motor 20 increases in a stepwise manner with time t in accordance with the voltage control pattern and the energization switching speed F, which is the frequency of the energization switching timing signal ST, decreases in a stepwise manner with time t in accordance with the speed control pattern from time t2 at which the forced commutation control is started.

As another example, as shown in fig. 8, when a voltage control pattern in which the drive voltage V decreases stepwise with time t and a speed control pattern in which the energization switching speed F increases stepwise with time t are stored in the storage unit 13, the drive voltage V applied to the energized phase of the motor 20 decreases stepwise with time t in accordance with the voltage control pattern and the energization switching speed F, which is the frequency of the energization switching timing signal ST, increases stepwise with time t in accordance with the speed control pattern from time t2 at which the forced commutation control starts.

In any of the examples of fig. 5 to 8, the combination of the drive voltage V and the conduction switching speed F at any time always satisfies the linear function LF having the drive voltage V and the conduction switching speed F as variables and having a negative slope from the time t2 at which the forced commutation control is started.

By performing the forced commutation control described above at the time of starting the motor 20, the F-V characteristic suitable for the combination of the drive voltage V and the energization switching speed F changes with time in the range from the F-V characteristic of the load T1 to the F-V characteristic of the load T4. That is, the range of the F-V characteristic of the motor 20 that can be stably controlled can be widened, and as a result, the motor 20 can be stably rotated to the rotation speed at which the counter electromotive force that can detect the zero cross point is generated regardless of the magnitude of the load at the time of starting the motor 20.

As shown in fig. 9, before the rotation speed of the motor 20 reaches a speed at which the counter electromotive force capable of detecting the zero-crossing point is generated, all of the zero-crossing point detection signals Zu, Zv, Zw are at a low level, and all of the phase detection signals Hu, Hv, Hw are also at a low level. Here, it is assumed that at time t12, the rotation speed of motor 20 reaches a speed at which a counter electromotive force that can detect a zero-crossing point is generated.

When the rotation speed of the motor 20 reaches a speed at which a counter electromotive force capable of detecting a zero cross point is generated at time t12, the zero cross point detection signals Zu, Zv, Zw generate rising edges or falling edges in synchronization with the timing at which the zero cross point is generated in the terminal voltages Vu, Vv, Vw after time t 12. As a result, after time t12, phase detection signals Hu, Hv, Hw generate rising edges or falling edges with a phase delay of 30 ° with respect to zero cross point detection signals Zu, Zv, Zw.

As shown in fig. 9, the phase pattern identified from the phase detection signals Hu, Hv, and Hw changes in the order of PB4, PB5, PB6, PB1, PB2, and PB3 during the period from time t14 to time t 20. When the state of the phase detection signals Hu, Hv, and Hw is monitored in the forced commutation mode and it is detected that the phase patterns identified from the phase detection signals Hu, Hv, and Hw appear in the same order of the rule as the 6 phase patterns stored in the storage unit 13 as described above, the voltage control unit 14 and the energization control unit 15 determine that the phases have been successfully identified from the phase detection signals Hu, Hv, and Hw, and shift to the sensorless synchronization control mode. Voltage control unit 14 and energization control unit 15 shift to the sensorless synchronization control mode in synchronization with the falling edge generated in phase detection signal Hu at time t 20.

After shifting to the sensorless synchronous control mode at time t20, voltage control unit 14 calculates the rotation speed of motor 20 from phase detection signals Hu, Hv, and Hw. For example, the voltage control unit 14 measures the time between the falling edge generated in the phase detection signal Hu at time t20 and the rising edge generated in the phase detection signal Hw at time t19, that is, the time during which the motor 20 rotates by 60 °, to thereby calculate the rotation speed of the motor 20. The voltage control unit 14 determines a control voltage VC that makes a deviation between the calculation result of the rotation speed and the target rotation speed indicated by the control command signal CS zero by PI operation, and outputs the determined control voltage VC to the energization control unit 15.

When the sensorless synchronous control mode is switched to at time t20, the energization control unit 15 stops generating the energization switching timing signal ST and switches the energization pattern in synchronization with the edges generated in the phase detection signals Hu, Hv, and Hw. For example, in synchronization with the falling edge generated in phase detection signal Hu at time t20, energization control unit 15 switches the energization pattern to energization pattern PA4, and starts switching control of the arm switches in accordance with energization pattern PA 4.

That is, the W-phase upper arm switch Q is turned on during the conduction period from the time t20 to the time t21 at which the phase detection signal Hv has a rising edge_WHAnd U-phase lower arm switch Q_ULOn and the remaining arm switches off. In the current-carrying period, W-phase upper arm switch Q_WHIs switched at a switching duty ratio determined by the control voltage VC. Therefore, the drive voltage V applied to the energized phase in this energization period has a voltage value such that the deviation between the calculation result of the rotation speed and the target rotation speed is zero. The energization control unit 15 detects the phase of the signals Hu, Hv, and HwAnd it is recognized that the phase pattern in the energization period is the phase pattern PB 4. The energization control section 15 determines the energization pattern PA5 as an energization pattern to be used in the next energization period based on the recognized phase pattern PB 4.

As shown in fig. 9, when a rising edge occurs in phase detection signal Hv at time t21, voltage control unit 14 measures the time between the rising edge and a falling edge that occurs in phase detection signal Hu at time t20, thereby calculating the rotation speed of motor 20. The voltage control unit 14 determines a control voltage VC that makes a deviation between the calculation result of the rotation speed and the target rotation speed indicated by the control command signal CS zero by PI operation, and outputs the determined control voltage VC to the energization control unit 15.

When a rising edge occurs in the phase detection signal Hv at time t21, the energization controller 15 switches the energization pattern to the energization pattern PA5 in synchronization with the rising edge, and starts switching control of the arm switches in accordance with the energization pattern PA 5. That is, the V-phase upper arm switch Q is turned on during the energization period from the time t21 to the time t22 at which the falling edge occurs in the phase detection signal Hw_VHAnd U-phase lower arm switch Q_ULOn and the remaining arm switches off. In the current-carrying period, the V-phase upper arm switch Q_VHIs switched at a switching duty ratio determined by the control voltage VC. Therefore, the drive voltage V applied to the energized phase during this energization period has a voltage value such that the deviation between the calculation result of the rotation speed and the target rotation speed is zero. The energization control unit 15 recognizes that the phase pattern in the energization period is the phase pattern PB5 from the states of the phase detection signals Hu, Hv, and Hw. The energization control section 15 determines the energization pattern PA6 as an energization pattern to be used in the next energization period based on the recognized phase pattern PB 5.

As described above, when the sensorless control device 10 operates in the sensorless synchronous control mode, the phase pattern recognition, the determination of the energization pattern, and the switching of the energization pattern are performed in synchronization with the phase detection signals Hu, Hv, and Hw generated by the counter electromotive force generated in the motor 20, and thereby the energization control of the motor 20 is performed without using a position sensor such as a hall sensor. By performing such sensorless synchronous control, the rotation speed of the motor 20 is maintained at the target rotation speed indicated by the control command signal CS. The energization switching speed F in the sensorless synchronous control is automatically controlled in accordance with the timing at which edges occur in the phase detection signals Hu, Hv, and Hw.

As described above, in the present embodiment, when the phase of the motor 20 cannot be recognized at the time of starting the motor 20, the forced commutation control is performed in which the energization switching speed F is changed in accordance with the predetermined speed control pattern while changing the drive voltage V applied to the energized phase of the motor 20 in accordance with the predetermined voltage control pattern over time. During the forced commutation control, the combination of the drive voltage V and the conduction switching speed F at an arbitrary timing always satisfies a linear function LF having the drive voltage V and the conduction switching speed F as variables and having a negative slope.

By performing the forced commutation control described above when starting the motor 20, the range of the F-V characteristic of the motor 20 that can be stably controlled can be expanded, and as a result, the motor 20 can be stably rotated to a rotation speed at which a counter electromotive force that can detect a zero cross point is generated regardless of the magnitude of the load when starting the motor 20. Therefore, according to the present embodiment, the motor 20 can be successfully started by the sensorless control regardless of the load size at the time of starting the motor 20.

In the present embodiment, as an example of the forced commutation control, the energization switching speed F is decreased at a constant slope with time based on a predetermined speed control pattern while the driving voltage V applied to the energized phase of the motor 20 is increased at a constant slope with time based on a predetermined voltage control pattern.

In the present embodiment, as another example of the forced commutation control, the energization switching speed F is increased with time at a constant slope according to a predetermined speed control pattern while the driving voltage V applied to the energized phase of the motor 20 is decreased with time at a constant slope according to a predetermined voltage control pattern.

By performing forced commutation control according to these two examples, the range of the F-V characteristic of the stably controllable motor 20 linearly changes. As a result, the possibility of driving the motor 20 according to the combination of the driving voltage V and the energization switching speed F that are actually suitable for the F-V characteristic of the load connected to the motor 20 is increased, and the motor 20 can be rotated more stably to the rotation speed at which the counter electromotive force capable of detecting the zero cross point is generated when the motor 20 is started.

In the present embodiment, as another example of the forced commutation control, the energization switching speed F is decreased in a stepwise manner with time in accordance with a predetermined speed control pattern while the drive voltage V applied to the energized phase of the motor 20 is increased in a stepwise manner with time in accordance with a predetermined voltage control pattern.

In the present embodiment, as another example of the forced commutation control, the energization switching speed F is increased in a stepwise manner with time according to a predetermined speed control pattern while the drive voltage V applied to the energized phase of the motor 20 is decreased in a stepwise manner with time according to a predetermined voltage control pattern.

By performing forced commutation control in accordance with these two examples, the range of the F-V characteristic of the stably controlled motor 20 can be changed stepwise. As a result, although the possibility of driving the motor 20 according to the combination of the driving voltage V and the energization switching speed F that are actually suitable for the F-V characteristic of the load connected to the motor 20 becomes lower than the above two examples in which the range of the F-V characteristic linearly changes, the processing load of the energization control can be reduced.

In the present embodiment, the dc excitation control is performed before the forced commutation control is performed when the motor 20 is started. Thus, since the phase of the motor 20 is fixed to a specific phase before the forced commutation control is performed, the motor 20 can be smoothly started to rotate when the forced commutation control is started.

In the present embodiment, the sensorless synchronous control is performed after the rotation speed of the motor 20 reaches a speed at which a counter electromotive force capable of detecting a zero cross point is generated in the forced commutation control. Thus, the rotation speed of the motor 20 can be controlled to the target rotation speed indicated by the control command signal CS input from the host control device 400 without using a position sensor such as a hall sensor.

[ modified examples ]

The present invention is not limited to the above-described embodiments, and the respective structures described in this specification can be appropriately combined within a range not inconsistent with each other.

For example, in the above-described embodiment, as examples of the voltage control pattern, a pattern in which the driving voltage increases with time at a constant slope, a pattern in which the driving voltage decreases with time at a constant slope, a pattern in which the driving voltage increases stepwise with time, and a pattern in which the driving voltage decreases stepwise with time are shown. Further, in the above-described embodiment, as examples of the speed control pattern, a pattern in which the energization switching speed increases with time at a constant slope, a pattern in which the energization switching speed decreases with time at a constant slope, a pattern in which the energization switching speed increases in a stepwise manner with time, and a pattern in which the energization switching speed decreases in a stepwise manner with time are shown. The voltage control pattern and the speed control pattern of the present invention are not limited thereto, and other patterns may be used as long as a condition that "a combination of the driving voltage V and the energization switching speed F at an arbitrary timing always satisfies a linear function having the driving voltage V and the energization switching speed F as variables and having a negative slope" is satisfied.

In the above-described embodiment, the case of using the sensorless 120 ° conduction scheme has been exemplified as the sensorless control scheme, but the sensorless control scheme in the present invention is not limited to the sensorless 120 ° conduction scheme. As long as the control method does not use a position sensor, other methods such as a 180 ° conduction method may be used.

In the above embodiment, the case where the dc excitation control is performed before the forced commutation control is performed when the motor 20 is started is exemplified, but the dc excitation control is not necessarily performed.

Claims (11)

1. A sensorless control apparatus that controls a motor without a position sensor, wherein,

the sensorless control device includes:

a motor drive circuit including a plurality of phase switching elements and configured to supply electric power to each phase of the motor;

a phase detection unit that detects a phase of the motor from a counter electromotive force of the motor and outputs a phase detection signal indicating a detection result of the phase;

a storage unit that stores a voltage control pattern indicating a control pattern of a drive voltage applied to an energization phase of the motor and a speed control pattern indicating a control pattern of an energization switching speed that is a speed at which the energization phase is switched;

a voltage control unit that outputs a control voltage based on a control command signal input from a host control device, the phase detection signal, and the voltage control pattern; and

an energization control section that controls the switching element of the motor drive circuit in accordance with the control voltage, the phase detection signal, and the speed control pattern, thereby controlling the drive voltage and the energization switching speed,

when the phase cannot be identified from the phase detection signal at the time of starting the motor, the voltage control unit changes the control voltage over time according to the voltage control pattern, and the energization control unit controls the switching element according to the control voltage and the speed control pattern, thereby performing forced commutation control as follows: changing the energization switching speed with time based on the speed control pattern while changing the driving voltage with time in synchronization with the control voltage,

the combination of the drive voltage and the energization switching speed at any time during the forced commutation control always satisfies a linear function having the drive voltage and the energization switching speed as variables and having a negative slope.

2. The sensorless control apparatus according to claim 1,

the voltage control section increases the control voltage with time according to the voltage control pattern,

the energization control unit controls the switching element in accordance with the control voltage and the speed control pattern, thereby performing forced commutation control as follows: the energization switching speed is decreased with time based on the speed control pattern while increasing the driving voltage with time in synchronization with the control voltage.

3. The sensorless control apparatus according to claim 2,

the voltage control section increases the control voltage according to a constant slope with time based on the voltage control pattern,

the energization control unit controls the switching element in accordance with the control voltage and the speed control pattern, thereby performing forced commutation control as follows: the energization switching speed is decreased with a constant slope with time based on the speed control pattern while increasing the driving voltage with a constant slope with time in synchronization with the control voltage.

4. The sensorless control apparatus according to claim 2,

the voltage control section increases the control voltage in stages over time according to the voltage control pattern,

the energization control unit controls the switching element in accordance with the control voltage and the speed control pattern, thereby performing forced commutation control as follows: while the drive voltage is increased in a stepwise manner with time in synchronization with the control voltage, the energization switching speed is decreased in a stepwise manner with time in accordance with the speed control pattern.

5. The sensorless control apparatus according to claim 1,

the voltage control section decreases the control voltage with time according to the voltage control pattern,

the energization control unit controls the switching element in accordance with the control voltage and the speed control pattern, thereby performing forced commutation control as follows: the energization switching speed is increased with time based on the speed control pattern while the drive voltage is decreased with time in synchronization with the control voltage.

6. The sensorless control apparatus of claim 5 wherein,

the voltage control section decreases the control voltage according to a constant slope with time based on the voltage control pattern,

the energization control unit controls the switching element in accordance with the control voltage and the speed control pattern, thereby performing forced commutation control as follows: the energization switching speed is increased with a constant slope with time based on the speed control pattern while the driving voltage is decreased with a constant slope with time in synchronization with the control voltage.

7. The sensorless control apparatus of claim 5 wherein,

the voltage control section decreases the control voltage in stages over time according to the voltage control pattern,

the energization control unit controls the switching element in accordance with the control voltage and the speed control pattern, thereby performing forced commutation control as follows: while the drive voltage is decreased in a stepwise manner with time in synchronization with the control voltage, the energization switching speed is increased in a stepwise manner with time in accordance with the speed control pattern.

8. The sensorless control apparatus according to any one of claims 1 to 7,

the storage unit stores in advance a dc excitation condition in which the phase of the motor is fixed to a specific phase,

when the phase cannot be identified from the phase detection signal at the time of starting the motor, the voltage control unit outputs the control voltage in accordance with the dc excitation condition before outputting the control voltage in accordance with the voltage control pattern, and the energization control unit applies a dc drive voltage for a certain period of time to a specific energization phase by controlling the switching element in accordance with the control voltage and the dc excitation condition.

9. The sensorless control apparatus according to any one of claims 1 to 7,

when the phase is successfully identified based on the phase detection signal, the voltage control unit outputs the control voltage based on the control command signal and the phase detection signal, and the energization control unit controls the switching element based on the control voltage and the phase detection signal, thereby switching the energized phase at an energization switching speed determined by the phase detection signal while applying a drive voltage corresponding to the control command signal to the energized phase.

10. An electric oil pump device, comprising:

a motor having a shaft;

a pump located on one axial side of the shaft and driven by the motor via the shaft to discharge oil; and

the sensorless control apparatus of any one of claims 1 to 9 which controls the motor without a position sensor.

11. A sensorless control method for controlling a motor without a position sensor, wherein,

when the motor is started and the phase of the motor cannot be identified, the following forced commutation control is performed: changing an energization switching speed, which is a switching speed of the energized phase, with time on the basis of a predetermined speed control pattern while changing a driving voltage applied to the energized phase of the motor with time on the basis of a predetermined voltage control pattern,

the combination of the drive voltage and the energization switching speed at any time during the forced commutation control always satisfies a linear function having the drive voltage and the energization switching speed as variables and having a negative slope.

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