Motor control device and controller

Abstract

To provide a motor control device which can accurately perform predetermined processing.SOLUTION: According to one embodiment, there is provided a motor control device comprising a sensor, a detection circuit and a controller. The sensor is placed at a position corresponding to the one between a winding in a first phase and a winding in a second phase in a motor. The motor comprises the winding in the first phase, the winding in the second phase and a winding in a third phase. The detection circuit detects timing in which a magnitude relation between induction voltage amplitude in the first phase and induction voltage amplitude in the second phase is exchanged. The controller performs predetermined processing for the motor on the basis of a signal of the sensor and a detection result of the detection circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This embodiment relates to a motor control device and a motor driver circuit. [Background technology]

[0002] Motor control devices may perform predetermined processes in addition to steady-state driving. In such cases, it is desirable that these predetermined processes be performed with high precision. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2018 / 226913 [Patent Document 2] Japanese Patent Publication No. 2020-108254 [Patent Document 3] U.S. Patent Application Publication No. 2017 / 163199 [Overview of the project] [Problems that the invention aims to solve]

[0004] One embodiment aims to provide a motor control device and a motor driver circuit that can perform predetermined processing with high precision. [Means for solving the problem]

[0005] According to one embodiment, a motor control device is provided having a sensor, a detection circuit, a controller, and a drive circuit. The sensor is positioned between the windings of a first phase and a second phase in the motor. The motor includes a first phase winding, a second phase winding, and a third phase winding. The motor is capable of freewheeling. The detection circuit detects the timing at which the relative magnitudes of the induced voltage amplitudes of the first phase and the induced voltage amplitudes of the second phase are reversed. The controller performs predetermined processing on the motor based on the signal from the sensor and the detection result from the detection circuit. The drive circuit is It is connected between the controller and the motor. The drive circuit is, It includes multiple switching elements. The controller is Turn off all of the multiple switching elements. situation Maintain Based on the sensor signal and the detection result from the detection circuit, the motor's rotation direction is determined. [Brief explanation of the drawing]

[0006] [Figure 1] A diagram showing the configuration of a motor control device according to the first embodiment. [Figure 2] A diagram showing the configuration of the motor and sensor in the first embodiment. [Figure 3] A waveform diagram showing the operation of the motor control device according to the first embodiment. [Figure 4] A figure showing the measurement of the delay time in the rotational direction CW in the first embodiment. [Figure 5] A figure showing the measurement of delay time in the rotational direction CCW in the first embodiment. [Figure 6] A diagram showing the configuration of a motor control device according to a modified example of the first embodiment. [Figure 7] A waveform diagram showing the operation of the motor control device according to the second embodiment. [Figure 8] This figure shows the process for detecting the rotation direction when the motor is running idly in the second embodiment. [Figure 9] A waveform diagram showing the operation of the motor control device according to the third embodiment. [Figure 10] A waveform diagram showing the phase adjustment range on the advance side in the third embodiment. [Modes for carrying out the invention]

[0007] The motor control device according to the embodiment will be described in detail below with reference to the attached drawings. However, the present invention is not limited to these embodiments.

[0008] (First embodiment) The motor control device according to the first embodiment performs a predetermined adjustment process separately from the normal driving, and a device for accurately performing the predetermined adjustment process is provided. For example, the motor control device 1 is configured as shown in FIG. 1. FIG. 1 is a diagram showing the configuration of the motor control device 1.

[0009] The motor control device 1 controls the driving of the motor M. The motor control device 1 is also called a motor driver circuit. The motor M may be a three-phase AC motor. The motor control device 1 supplies three-phase (U-phase, V-phase, W-phase) AC power to drive the motor M.

[0010] The motor control device 1 includes a drive circuit 10, a sensor 20, a detection circuit 30, and a controller 40. The drive circuit 10 is connected between the detection circuit 30 and the controller 40 and the motor M. The detection circuit 30 is connected between the controller 40 and the drive circuit 10.

[0011] The drive circuit 10 is, for example, an inverter that converts DC power into AC power and supplies the converted AC power to the motor M to drive the motor M. The drive circuit 10 has a plurality of switching elements SW. When the motor M is a three-phase AC motor, the drive circuit 10 has a plurality of switching elements SW corresponding to three phases (U-phase, V-phase, W-phase) UU , SW VU , SW WU , SW UL , SW VL , SW VL having. The switching element SW UU , SW VU , SW WU [[ID=3 0]]constitutes the upper arm. The switching element SW UL , SW VL , SW VL constitutes the lower arm.

[0012] Motor M may be configured such that each stator ST is an electromagnet and the rotor is a permanent magnet, or it may be configured such that each stator ST is a permanent magnet and the rotor is an electromagnet. In the following, the configuration in which each stator ST is an electromagnet and the rotor is a permanent magnet will be used as an example of the motor M configuration.

[0013] As shown in Figure 2, the motor M is connected to the stator ST U ,ST V ,ST W and rotor RT. Figure 2 is a diagram showing the configuration of the motor M and sensor 20, schematically showing a cross-section including the rotation axis of the motor M. Figure 2 shows a cross-section viewed from the front side (power transmission destination side).

[0014] The stator is also called the stationary component. The rotor is also called the rotating component. Stator ST U This is the U-phase winding W U Includes. Stator ST V This is the V-phase winding W V Includes. Stator ST W This is the winding W of the W phase. W The rotor RT includes n pole pairs, each containing a north pole and a south pole. n is an integer greater than or equal to 1. Regarding the rotation direction of the rotor RT, the clockwise rotation direction in Figure 2 is denoted as rotation direction CW, and the counterclockwise rotation direction in Figure 2 is denoted as rotation direction CCW.

[0015] Node N shown in Figure 1 U This is the U-phase winding W of motor M. U It connects to node N. V This is the V-phase winding W of motor M. V It connects to node N. W This is the winding W of the W phase of motor M. W It connects to the network.

[0016] Switching element SW UU SW UL Each corresponds to the U phase, with one end being node N. U It is connected to the switching element SW. UU The other end is connected to the power supply potential VDD. Switching element SW ULThe other end is connected to ground potential via a resistive element R.

[0017] Switching element SW VU SW VL Each corresponds to the V phase, with one end at node N. V It is connected to the switching element SW. VU The other end is connected to the power supply potential VDD. Switching element SW VL The other end is connected to ground potential via a resistive element R.

[0018] Switching element SW WU SW WL Each corresponds to the W phase, with one end being node N. W It is connected to the switching element SW. WU The other end is connected to the power supply potential VDD. Switching element SW WL The other end is connected to ground potential via a resistive element R.

[0019] The sensor 20 shown in Figure 1 detects the rotational position of the motor M. That is, the sensor 20 detects the rotational position of the rotor RT. The sensor 20 may also have a Hall element H, and the rotational position of the rotor RT may be detected using the Hall element H.

[0020] For example, as shown in Figure 2, the Hall element H is positioned between two of the three phase windings Wu, Wv, and Ww in the motor M, namely Wu and Ww. The Hall signal output from the Hall element H changes level when the boundary of the rotor RT's magnetic poles passes between the two phase windings Wu and Ww.

[0021] As a result, the sensor 20 can detect 2n times during one rotation of the rotor RT when the boundary of the rotor RT's magnetic poles passes between the two phase windings Wu and Ww. If the number of pole pairs n=1, the sensor 20 detects 2 times during one rotation of the rotor RT when the boundary of the rotor RT's magnetic poles passes between the two phase windings Wu and Ww.

[0022] The detection circuit 30 shown in Figure 1 detects the timing when the relative magnitudes of the signals of one phase and the signals of another phase are reversed. The detection circuit 30 may also detect the timing when the relative magnitudes of the induced voltage amplitudes of one phase and the induced voltage amplitudes of another phase are reversed. The detection circuit 30 detects the induced voltage V of the W phase. W The amplitude and the induced voltage V of the U phase U The timing at which the relative magnitude of the amplitude changes may also be detected.

[0023] The detection circuit 30 may include a comparator 31 and multiple detection nodes. The comparator 31 compares the induced voltage detected at one phase detection node with the induced voltage detected at the other phase detection nodes. The comparator 31 compares the W phase detection node N W The induced voltage V detected W and U-phase detection node N U The induced voltage V detected U You may compare this with the following. Comparator 31 has a non-inverting input node and a W-phase detection node N W The inverting input node is connected to the U-phase detection node N. U The comparator 31 is connected to the controller 40, and its output node is connected to the controller 40. The comparator 31 supplies the comparison result to the controller 40. The level of the comparison result inverts at the timing when the relative magnitudes of the induced voltage amplitudes of the W phase and the U phase are reversed. The comparator 31 can indicate the timing when the relative magnitudes of the induced voltage amplitudes of one phase and the induced voltage amplitudes of another phase are reversed by the edge timing at which the comparison result inverts.

[0024] During maintenance periods such as startup, the controller 40 performs a predetermined adjustment process on the motor M based on the signal from the sensor 20 and the detection result from the detection circuit 30. The predetermined adjustment process may be an adjustment that improves the efficiency of the motor M's operation. With the predetermined adjustment process completed, the controller 40 controls the motor M based on the signal from the sensor 20 during steady-state operation. This allows the controller 40 to control the motor M efficiently.

[0025] The controller 40 includes a control circuit 41 and a processing circuit 42. The control circuit 41 drives and controls the motor M. The processing circuit 42 determines the offset amount and delay amount based on the signal from the sensor 20 and the detection result from the detection circuit 30.

[0026] The offset amount is expressed as an electrical angle, representing the deviation from the midpoint position of one phase winding and the other phase winding at the placement position of the sensor 20 (Hall element H). For example, in Figure 2, the U phase winding W U Based on the position of the W phase winding, W The position of the element is at angle α, and its midpoint is at angle α / 2. The position of the Hall element H is at angle β. The offset amount ΔOF, which indicates the amount of deviation of the Hall element H's position from its midpoint, is expressed in electrical angle as shown in equation 1 below. ΔOF = β - α / 2 ... Equation 1

[0027] The delay amount ΔD indicates, in electrical angle, how much the edge timing of the signal from sensor 20 is delayed from the correct timing. The delay amount ΔD mainly includes the operating delay of the Hall element H, the delay of the wiring connecting the Hall element H and the processing circuit 42, and the operating delay of the circuit in the processing circuit 42.

[0028] The processing circuit 42 notifies the control circuit 41 of the offset amount ΔOF and the delay amount ΔD. The control circuit 41 drives and controls the motor M after applying corrections according to the offset amount ΔOF and the delay amount ΔD.

[0029] For example, the control circuit 41 drives and controls the motor M in the same way as in steady state. The control circuit 41 drives and controls the motor M in the rotation direction CW. The control circuit 41 controls the U-phase output voltage UU, V-phase output voltage VU, W-phase output voltage WU, U-phase output voltage UL, V-phase output voltage VL, and W-phase output voltage WL as shown in Figure 3, using switching elements SW UU SW VU SW WU SW UL SW VL SW VLIt is supplied to the control terminal. Figure 3 is a waveform diagram showing the operation of the motor control device 1.

[0030] The U-phase output voltage UU, V-phase output voltage VU, and W-phase output voltage WU are out of phase by approximately +120° in each phase. The U-phase output voltage UU and U-phase output voltage UL are out of phase by approximately 180° from each other. The V-phase output voltage VU and V-phase output voltage VL are out of phase by approximately 180° from each other. The W-phase output voltage WU and W-phase output voltage WL are out of phase by approximately 180° from each other. As a result, the switching element SW UU SW VU SW WU SW UL SW VL SW VL The switching is controlled.

[0031] Accordingly, the U-phase motor current I U V-phase motor current I V W-phase motor current I W These currents flow with a phase difference of approximately +120° from each other and are supplied to the U-phase winding Wu, the V-phase winding Wv, and the W-phase winding Ww, respectively. As a result, the rotor RT rotates in the CW direction, and the U-phase induced voltage V U V-phase induced voltage V V W-phase induced voltage V W This occurs with a phase difference of approximately +120°. U-phase induced voltage V U V-phase induced voltage V V W-phase induced voltage V W This changes depending on the rotational position of the rotor RT.

[0032] Subsequently, the control circuit 41 stops driving the motor M. At this time, the rotor RT rotates in the CW direction at a nearly constant rotational speed due to its inertia. As a result, the U-phase induced voltage V is generated, as shown in Figure 4. U V-phase induced voltage V V W-phase induced voltage V W This continues to occur with a phase difference of approximately +120°. Figure 4 shows the delay time ΔT in the rotation direction CW. CW This is a diagram showing the measurement.

[0033] In this state, the sensor 20 detects the rotational position of the rotor RT and supplies the detection result to the processing circuit 42. For example, the Hall element H supplies a Hall signal as shown in FIG. 4 to the processing circuit 42. The Hall signal output from the Hall element H changes in level at the timing when the boundary of the magnetic poles of the rotor RT passes through the position between the two-phase windings Wu and Ww. For example, the Hall signal transitions from the H level to the L level at timing t0, from the L level to the H level at timing t01, and from the H level to the L level at timing t2. If the number of pole pairs n = 1, the period ΔT from timing t0 to t2 P1 is one cycle of the Hall signal and corresponds to the period during which the rotor RT rotates once in the clockwise (CW) direction.

[0034] The detection circuit 30 detects the timing at which the magnitude relationship between the induced voltage amplitude of one phase and the induced voltage amplitude of the other phase is reversed, and supplies the detection result to the processing circuit 42. The comparator 31 compares the induced voltage V W of the W phase with the induced voltage V U of the U phase, and reverses the comparison result at the timing when the magnitude relationship between the amplitude of the induced voltage V W of the W phase and the amplitude of the induced voltage V U of the U phase is reversed.

[0035] For example, the comparison result of the comparator 31 transitions from the H level to the L level at timing t1. This timing is the timing when the induced voltage V W changes from a state where it is greater than the induced voltage V U to a state where it is less than the induced voltage V W and the induced voltage V​​​​​​​​​​​​​​​​​The processing circuit 42 acquires timing t0 and timing t2 according to the Hall signal from the sensor 20. The processing circuit 42 acquires timing t1 according to the comparison result from the detection circuit 30. Accordingly, the processing circuit 42 obtains the period ΔT from t0 to t2 P1 and obtains the delay time ΔT from timing t1 to t2 CW .

[0037] Also, the control circuit 41 drives and controls the motor M in the counterclockwise (CCW) rotation direction. The counterclockwise rotation direction is the rotation direction opposite to the clockwise (CW) rotation direction. Although not shown, the control circuit 41 generates the U-phase output voltage UU, the V-phase output voltage VU, and the W-phase output voltage WU such that their phases are shifted by approximately -120° in sequence, and supplies them to the switching elements SW UU , SW VU , SW WU The control circuit 41 generates the U-phase output voltage UU and the U-phase output voltage UL such that their phases are shifted by approximately 180° from each other, and supplies them to the switching elements SW UU , SW UL The control circuit 41 generates the V-phase output voltage VU and the V-phase output voltage VL such that their phases are shifted by approximately 180° from each other, and supplies them to the switching elements SW VU , SW VL The control circuit 41 generates the W-phase output voltage WU and the W-phase output voltage WL such that their phases are shifted by approximately 180° from each other, and supplies them to the switching elements SW WU , SW WL As a result, the switching elements SW UU , SW VU , SW WU , SW UL , SW VL , SW VL are switched and controlled.

[0038] Accordingly, the U-phase motor current I U , the V-phase motor current I V , and the W-phase motor current I W flow with a phase difference of approximately -120° from each other, and are supplied to the U-phase winding Wu, the V-phase winding Wv, and the W-phase winding Ww, respectively. As a result, the rotor RT rotates in the counterclockwise (CCW) rotation direction, and the U-phase induced voltage V UV-phase induced voltage V V W-phase induced voltage V W This occurs with a phase difference of approximately -120°. U-phase induced voltage V U V-phase induced voltage V V W-phase induced voltage V W This changes depending on the rotational position of the rotor RT.

[0039] Subsequently, the control circuit 41 stops driving the motor M. At this time, the rotor RT rotates in the CCW direction at a nearly constant rotational speed due to its inertia. As a result, the U-phase induced voltage V is generated, as shown in Figure 5. U V-phase induced voltage V V W-phase induced voltage V W This continues to occur with a phase difference of approximately -120°. Figure 5 shows the delay time ΔT in the CCW rotation direction. CCW This is a diagram showing the measurement.

[0040] In this state, the sensor 20 detects the rotational position of the rotor RT and supplies the detection result to the processing circuit 42. For example, the Hall element H supplies a Hall signal to the processing circuit 42 as shown in Figure 5. The level of the Hall signal output from the Hall element H changes at the timing when the boundary of the magnetic poles of the rotor RT passes between the two-phase windings Wu and Ww. For example, the Hall signal transitions from an H level to an L level at timing t10, from an L level to an H level at timing t101, and from an H level to an L level at timing t11. If the number of pole pairs n=1, the period ΔT from timing t10 ​​to t11 is... P2 However, this corresponds to one cycle of the Hall signal and the time it takes for the rotor RT to complete one rotation in the counter-clockwise (CCW) direction.

[0041] The detection circuit 30 detects the timing when the relative magnitudes of the induced voltage amplitudes of one phase and the induced voltage amplitudes of other phases are reversed, and supplies the detection result to the processing circuit 42. The comparator 31 detects the induced voltage V of the W phase. W and the induced voltage V of the U phase U By comparing this with the induced voltage V of the W phase, W The amplitude and the induced voltage V of the U phase UThe comparison result is reversed at the moment when the relative magnitudes of the amplitudes change.

[0042] For example, the comparison result of comparator 31 transitions from L level to H level at timing t12. This timing corresponds to the induced voltage V W The induced voltage V U Induced voltage V from a smaller state W The induced voltage V U This is the timing for transitioning to a larger state. Furthermore, this timing corresponds to the induced voltage V. W and induced voltage V U Difference V W -V U In terms of the waveform, this corresponds to the zero-crossing timing. U -V V The waveform is shown for reference.

[0043] The processing circuit 42 acquires timings t10 and t11 in response to the Hall signal from the sensor 20. The processing circuit 42 acquires timing t12 in response to the comparison result from the detection circuit 30. Based on these, the processing circuit 42 calculates the period ΔT from t10 to t11. P2 We calculate the delay time ΔT from timing t11 to t12. CCW We seek.

[0044] Here, the offset amount ΔOF is an angle indicating the displacement of the position of the sensor 20 (Hall element H), and is a physical quantity that depends on the rotation direction of the rotor RT. Therefore, it is included in the delay time with the sign reversed between the rotation direction CW and the rotation direction CCW. For this reason, the processing circuit 42 calculates the delay time ΔT in the rotation direction CW. CW and delay time ΔT in the rotation direction CCW CCW Using these, the offset amount ΔOF[°] can be calculated by the following equation 2. ΔOF = (360 × ΔT) CW / T P1 -360 × ΔT CCW / T P2 ) / 2······Formula 2

[0045] The delay amount ΔD is a physical quantity that does not depend on the rotation direction of the rotor RT. Therefore, it is included in the delay time with the same sign in both the rotation direction CW and the rotation direction CCW. CW and delay time ΔT in the rotation direction CCW CCW Using these, the delay amount ΔD[°] can be calculated by the following equation 3. ΔD = (360 × ΔT) CW / T P1 +360 × ΔT CCW / T P2 ) / 2······Formula 3

[0046] As a result, the controller 40 can perform adjustment processing to correct the signal (Hall signal) from the sensor 20 by the offset amount ΔOF calculated by Equation 2 and the delay amount ΔD calculated by Equation 3 during maintenance periods such as startup. With this adjustment processing completed, the controller 40 drives and controls the motor M based on the signal from the sensor 20 during steady-state operation. This allows the controller 40 to control the motor M efficiently.

[0047] As described above, in the first embodiment, in the motor control device 1, the controller 40 determines the offset amount and delay amount based on the signal from the sensor 20 and the detection result from the detection circuit 30 during the maintenance period. For example, the controller 40 drives the motor M in the rotation direction CW and keeps all switching elements in the off state to determine the delay time ΔT in the rotation direction CW. CW The motor M is driven in the counter-clockwise (CCW) direction of rotation, and all switching elements are kept in the OFF state, and the delay time ΔT in the CCW direction of rotation is measured. CCW The controller 40 measures the delay time ΔT. CW and delay time ΔT CCW Using these, the offset amount and delay amount are determined, respectively. This allows us to determine the delay time ΔT measured with the motor M's rotational speed stabilized. CW ,ΔT CCWBy using this method, the offset amount and delay amount can be determined with high precision.

[0048] For example, the offset amount can be determined from the induced voltage corresponding to the current flowing through one phase Hall signal and the lower output stage of one phase. For example, the upper switching element SW of the V / W phase in the drive circuit 10. VU and SW WU Turn off the lower switching element SW VL and SW WL The switch is turned on, and the offset amount is detected so that the time from the falling edge of the U-phase Hall signal to the falling edge of the U-phase induced voltage corresponds to an electrical angle of 150°. In this case, with respect to the rotation of the rotor RT, the switching element SW VL and SW WU The activation of this component triggers a braking action. This changes the induced voltage of the U-phase, causing its falling edge timing to deviate from the timing corresponding to the offset amount. As a result, it becomes difficult to accurately detect the offset amount.

[0049] In contrast, in this embodiment, the motor control device 1, the controller 40 drives the motor M in the rotation direction CW and maintains all switching elements in the off state, thereby controlling the delay time ΔT in the rotation direction CW. CW The motor M is driven in the counter-clockwise (CCW) direction of rotation, and all switching elements are kept in the OFF state, and the delay time ΔT in the CCW direction of rotation is measured. CCW The controller 40 measures the delay time ΔT. CW and delay time ΔT CCW Using these methods, the offset amount and delay amount are determined. This eliminates the need for braking during detection, thereby suppressing changes in induced voltage during detection. Consequently, it becomes easier to accurately detect the offset amount.

[0050] Note that the placement of the Hall element H is not limited to the position shown in Figure 2.

[0051] For example, the Hall element H is a two-phase winding Wu, Wv, Ww of the three-phase windings Wu, Wv, Ww in a motor M.V It may be positioned between these two points. In this case, the detection circuit 30 detects the induced voltage V of the U phase. U The amplitude and the induced voltage V of the V phase V The timing at which the magnitude relationship with the amplitude changes may also be detected. The comparator 31 is the U-phase detection node N U The induced voltage V detected U and V-phase detection node N V The induced voltage V detected V You may also compare this. Comparator 31 has a non-inverting input node and a detection node N in the U phase. U The inverting input node is connected to the V-phase detection node N. V It is connected to the controller 40, and the output node is connected to the controller 40.

[0052] Alternatively, the Hall element H is one of the three windings Wu, Wv, Ww in the motor M, specifically two of the windings W V ,W W It may be positioned between these two points. In this case, the detection circuit 30 detects the induced voltage V of the V phase. V The amplitude and the induced voltage V of the W phase W The timing at which the magnitude relationship with the amplitude changes may also be detected. Comparator 31 is the V-phase detection node N V The induced voltage V detected V and the W-phase detection node N W The induced voltage V detected W You may also compare this. Comparator 31 has a non-inverting input node and a V-phase detection node N V The inverting input node is connected to the W-phase detection node N. W It is connected to the controller 40, and the output node is connected to the controller 40.

[0053] Furthermore, as a modification of the first embodiment, as shown in Figure 6, the detection circuit 30i in the motor control device 1i may be configured to detect the timing of the change in the magnitude relationship of the motor currents of multiple phases instead of the timing of the change in the magnitude relationship of the induced voltages of multiple phases. Figure 6 is a diagram showing the configuration of the motor control device 1i according to a modification of the first embodiment.

[0054] The detection circuit 30i may also detect the timing when the relative magnitudes of the motor currents of one phase and the motor currents of other phases are reversed. The detection circuit 30i detects the motor current I of the W phase. W The amplitude and U-phase motor current I U The timing at which the relative magnitude of the amplitude changes may also be detected.

[0055] The detection circuit 30i may include a comparator 31 and multiple current detectors CT. The comparator 31 compares the motor current I detected by the current detector CT of one phase with the motor current I detected by the current detector CT of the other phase. The comparator 31 compares the current detector CT of the W phase W Motor current I detected W and U-phase current detector CT U Motor current I detected U You may compare this with the following. Comparator 31 has a W-phase current detector CT as its non-inverting input node. W The inverting input node is connected to a U-phase current detector CT. U The output node is connected to the controller 40. The comparator 31 supplies the comparison result to the controller 40. The comparison result is the W-phase motor current I W and the motor current I of the U phase U The level reverses at the moment when the relative magnitudes of the two phases are swapped. The comparator 31 can detect the timing when the relative magnitudes of the motor current I of one phase and the motor current I of another phase are swapped by the edge timing at which the comparison result reverses.

[0056] Here, as shown in Figure 3, there is a timing difference Δt between the timing at which the relative magnitudes of the induced voltage amplitudes of one phase and the other phases are reversed, and the timing at which the relative magnitudes of the motor currents of one phase and the other phases are reversed. The processing circuit 42 may experimentally acquire and store the timing difference Δt in advance. When the processing circuit 42 has determined the timing at which the relative magnitudes of the motor currents I of one phase and the other phases are reversed, it may correct that timing with the difference Δt. As a result, the processing circuit 42 can acquire the timing at which the relative magnitudes of the induced voltage amplitudes of one phase and the other phases are reversed, and can accurately determine the offset amount and delay amount in the same manner as in the first embodiment.

[0057] (Second embodiment) Next, a motor control device 1 according to a second embodiment will be described. The following description will focus on the differences from the first embodiment.

[0058] As a predetermined adjustment process performed separately from steady-state driving, the first embodiment exemplifies determining the offset amount and delay amount, while the second embodiment exemplifies detecting the rotation direction when the motor is idling.

[0059] For example, if the motor M driven by the motor control device 1 is a fan motor, even when the motor control device 1 is not actively driving the motor, the fan may rotate due to the wind, and this rotational motion may be transmitted to the motor M, causing it to spin freely. When the motor M is spinning freely, the motor control device 1 will have difficulty controlling the motor M to rotate in the correct direction if it does not know the direction of rotation of the motor M. Therefore, it is desirable for the motor control device 1 to properly detect the direction of rotation of the motor M when it is spinning freely.

[0060] In the motor control device 1 shown in Figure 1, the controller 40 determines the rotation direction of the motor M based on the signal from the sensor 20 and the detection result from the detection circuit 30. As shown enclosed by the dotted line in Figure 7, the controller 40 detects the rotation direction of the motor M when it is idling when the U-phase output voltage UU, V-phase output voltage VU, and W-phase output voltage WU are of high impedance. Figure 7 is a waveform diagram showing the operation of the motor control device 1.

[0061] Even if the U-phase output voltage UU, V-phase output voltage VU, and W-phase output voltage WU are in a high impedance state, if the motor M is running idly, the U-phase induced voltage V U V-phase induced voltage V V W-phase induced voltage V W These are generated in each case. For example, if motor M is idling in the rotation direction CW, the U-phase induced voltage V will occur as shown in Figure 4. U V-phase induced voltage V V W-phase induced voltage V W This occurs. If motor M is idling in the CCW rotation direction, the U-phase induced voltage V will occur as shown in Figure 5. U V-phase induced voltage V V W-phase induced voltage V W This will occur.

[0062] As shown in Figures 4 and 5, the Hall signal V HU Comparison result of the level and comparator 31 (for example, W-phase induced voltage V W and U-phase induced voltage V U Depending on the combination of the magnitudes of the two factors, the controller 40 can detect the rotation direction of the motor M when it is idling. The controller 40 may also detect the rotation direction of the motor M when it is idling, as shown in Figure 8. Figure 8 is a diagram showing the process for detecting the rotation direction of the motor M when it is idling.

[0063] For example, if the target rotation direction is rotation direction CW, the controller 40 receives the Hall signal V HU The result is at the H level and the comparison result is at the H level (i.e., V W >V UIf this is the case, then motor M is idling in the CW direction (see Figure 4), so it is determined that the direction of rotation is "forward" relative to the target.

[0064] Controller 40 receives the Hall signal V HU The first is at the H level and the second is at the L level (i.e., V W <V U If this is the case, then motor M is idling in the CCW direction (see Figure 5), so it is determined that the direction of rotation is "reverse" relative to the target.

[0065] Controller 40 receives the Hall signal V HU The first is at the L level and the second is at the H level (i.e., V W >V U If this is the case, then motor M is idling in the CCW direction (see Figure 5), so it is determined that the direction of rotation is "reverse" relative to the target.

[0066] Controller 40 receives the Hall signal V HU The L level and the comparison result is L level (i.e., V W <V U If this is the case, then motor M is idling in the rotation direction CW (see Figure 5), so it is determined that the rotation direction is "forward" relative to the target.

[0067] Alternatively, if the target rotation direction is CCW, the controller 40 receives the Hall signal V HU The result is at the H level and the comparison result is at the H level (i.e., V W >V U If this is the case, then motor M is idling in the CW direction (see Figure 4), so it is determined that the direction of rotation is "reverse" relative to the target.

[0068] Controller 40 receives the Hall signal V HU The first is at the H level and the second is at the L level (i.e., V W <V U If this is the case, then motor M is free-spinning in the CCW direction (see Figure 5), so it is determined that the direction of rotation is "forward" relative to the target.

[0069] Controller 40 receives the Hall signal V HU The first is at the L level and the second is at the H level (i.e., V W >V U If this is the case, then motor M is free-spinning in the CCW direction (see Figure 5), so it is determined that the direction of rotation is "forward" relative to the target.

[0070] Controller 40 receives the Hall signal V HU The L level and the comparison result is L level (i.e., V W <V U If this is the case, then motor M is idling in the CW direction (see Figure 5), so it is determined that the direction of rotation is "reverse" relative to the target.

[0071] As described above, in the second embodiment, in the motor control device 1, the controller 40 determines the rotation direction of the motor M based on the signal from the sensor 20 and the detection result from the detection circuit 30. The controller 40, for example, uses the Hall signal V HU Comparison result of the level and comparator 31 (for example, W-phase induced voltage V W and U-phase induced voltage V U The rotation direction of motor M during idle is detected according to the combination of the magnitudes of the two factors. This allows for accurate determination of the rotation direction of motor M during idle and enables proper drive control of motor M in the appropriate rotation direction.

[0072] For example, the rotational direction of motor M during idle can be determined from the polarity of the current flowing through one phase Hall signal and the lower output stage of one phase. For example, the upper switching element SW of the V phase in the drive circuit 10. VU Turn off the lower switching element SW VL The switching element SW is turned on, and the rotation direction of the motor M is detected from the level of the U-phase Hall signal and the polarity of the U-phase induced voltage. In this case, with respect to the rotation of the rotor RT, the switching element SW VL The activation of this component triggers a braking action. This can cause a change in the induced voltage of the U-phase, which may alter its polarity. This can lead to incorrect detection of the motor M's rotation direction.

[0073] In contrast, according to the second embodiment, in the motor control device 1, the controller 40 determines the rotation direction of the motor M based on the signal from the sensor 20 and the detection result from the detection circuit 30. This makes it possible to properly determine the rotation direction of the motor M when it is idling and to drive and control the motor M in the appropriate rotation direction.

[0074] (Third embodiment) Next, a motor control device 1i according to the third embodiment will be described. The following description will focus on the differences from the first and second embodiments.

[0075] As a predetermined adjustment process performed separately from the steady-state drive, the first embodiment exemplifies determining the offset amount and delay amount, the second embodiment exemplifies detecting the rotation direction when the motor M is idling, and the third embodiment exemplifies adjusting the phase of the drive voltage of the motor M.

[0076] The phase of the induced voltage of motor M and the phase of the motor current may be out of sync. For example, in Figure 3, there is a timing difference Δt between the phase of the induced voltage of motor M and the phase of the motor current. If the phase of the induced voltage of motor M and the phase of the motor current can be matched, it is expected that the power efficiency of driving motor M will improve.

[0077] Therefore, in the motor control device 1i shown in Figure 6, the controller 40 adjusts the phase of the motor M drive voltage based on the signal from the sensor 20 and the detection result from the detection circuit 30i.

[0078] For example, assume that the offset and delay amounts have been adjusted. The control circuit 41 drives and controls the motor M in the same way as in steady state. The control circuit 41 may also drive and control the motor M in the rotation direction CW. The control circuit 41 controls the U-phase output voltage UU, V-phase output voltage VU, and W-phase output voltage WU, as shown in Figure 9, using switching elements SW UU SWVU SW WU It supplies power to the control terminals. Similarly, although not shown in the diagram, the control circuit 41 controls the U-phase output voltage UL, V-phase output voltage VL, and W-phase output voltage WL, respectively, to the switching element SW UL SW VL SW VL It supplies power to the control terminal. Figure 9 is a waveform diagram showing the operation of the motor control device 1i.

[0079] In this state, the sensor 20 detects the rotational position of the rotor RT and supplies the detection result to the processing circuit 42. For example, the Hall element H receives a Hall signal V as shown in Figure 9. HU The Hall signal V output from the Hall element H is supplied to the processing circuit 42. HU The level changes as the boundary of the rotor RT's magnetic poles passes between the two phase windings Wu and Ww. For example, the Hall signal V HU At timing t21, it transitions from L level to H level.

[0080] The detection circuit 30i detects the timing when the relative magnitudes of the motor currents of one phase and the motor currents of other phases are reversed, and supplies the detection result to the processing circuit 42. The comparator 31 detects the motor current I of the W phase. W and the motor current I of the U phase U Compared with the W-phase motor current I W The amplitude and U-phase motor current I U The comparison result is reversed at the timing when the relative magnitudes of the amplitudes are swapped. For example, the comparison result of comparator 31 transitions from L level to H level at timing t22.

[0081] The processing circuit 42 receives the Hall signal V from the sensor 20. HU Accordingly, timing t21 is obtained. Processing circuit 42 obtains timing t22 according to the comparison result from detection circuit 30i. Based on these, processing circuit 42 calculates the period Δt' from t21 to t22. Processing circuit 42 notifies control circuit 41 of the period Δt'. The period Δt' indicates that the phase of the motor current is delayed relative to the phase of the induced voltage of the motor M.

[0082] The control circuit 41 selectively advances the W-phase output voltages WU and WL by an electrical angle corresponding to the period Δt'. While maintaining the U-phase output voltages UU and UL and the V-phase output voltages VU and VL, the control circuit 41 selectively advances the W-phase output voltages WU and WL as shown by the dotted line in Figure 9. As a result, the U-phase motor current I U V-phase motor current I V While maintaining the W-phase motor current I W The ignition timing is selectively advanced. This allows the phase of the induced voltage of motor M to be matched with the phase of the motor current.

[0083] Although not shown in the diagram, if it is detected that the phase of the motor current is shifted relative to the phase of the induced voltage of the motor M in the advance direction for a period of Δt'', the control circuit 41 may selectively advance the W-phase output voltages WU and WL by an electrical angle corresponding to the period of Δt''. This also makes it possible to match the phase of the induced voltage of the motor M with the phase of the motor current.

[0084] Regarding the phase adjustment range, as shown in Figure 10, the Hall signal V HU Around the rise time t21, the output voltage levels of the two phases (in this case, the U phase and the W phase) used for control are close. Therefore, within the range where the balance of the three phases (U phase, V phase, and W phase) can be maintained, if one phase (for example, the W phase) is selectively advanced, the advance value can be up to a maximum electrical angle of 60°, regardless of the amplitude. In other words, the controller 40 can adjust the phase difference between the phase of the induced voltage of the motor M and the phase of the motor current up to a difference corresponding to the period Δtmax. Also, if one phase (for example, the W phase) is selectively retarded, the retard value can be up to -50°. As a result, the controller 40 can adjust the phase of the induced voltage of the motor M and the phase of the motor current within the electrical angle range of -50° to 60°.

[0085] As described above, in the third embodiment, in the motor control device 1i, the controller 40 adjusts the phase of the drive voltage of the motor M based on the signal from the sensor 20 and the detection result from the detection circuit 30i. This improves the power efficiency of driving the motor M.

[0086] For example, as a phase adjustment, one might consider adjusting the advance angle so that the difference in polarity of the current flowing when switching one phase Hall signal and turning on the lower output stage of one phase is 30° in electrical angle. In this case, if the duty cycle of the drive voltage of one phase (e.g., V-phase output voltage VU) is high, it becomes difficult to turn on the lower output stage, and the range in which phase adjustment is possible tends to be limited to around the middle of the H level of the drive voltage of one phase. For example, the range in which phase adjustment is possible may be limited to an electrical angle of -30° to 30°.

[0087] In contrast, according to this embodiment, the timing difference is detected by the rising edge of one phase Hall signal and the reversal of the relative magnitudes of the motor currents of the two phases, and the drive voltage of one phase is adjusted by a phase amount corresponding to the detected timing difference. This makes it possible to perform phase adjustment over a wide electrical angle range and improves the robustness of the phase adjustment. For example, the range in which phase adjustment is possible can be expanded to an electrical angle range of -50° to 60°.

[0088] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0089] 1.1i motor control unit, 20 sensors, 30.30i detection circuits, 40 controller.

Claims

1. A sensor positioned between the first phase winding and the second phase winding in a motor that includes a first phase winding, a second phase winding, and a third phase winding and is capable of free rotation, A detection circuit that detects the timing at which the relative magnitudes of the signals of the first phase and the signals of the second phase are reversed, A controller that performs predetermined processing on the motor based on the signal from the sensor and the detection result from the detection circuit, A drive circuit, which includes a plurality of switching elements, is connected between the controller and the motor. Equipped with, The controller maintains all of the multiple switching elements in the off state and determines the rotation direction of the motor based on the signal from the sensor and the detection result from the detection circuit. Motor control device.

2. The detection circuit detects the timing at which the relative magnitudes of the induced voltage amplitudes of the first phase and the induced voltage amplitudes of the second phase are reversed. The motor control device according to claim 1.

3. The detection circuit detects the timing at which the relative magnitudes of the motor currents of the first phase and the motor currents of the second phase are reversed. The motor control device according to claim 1.

4. The controller determines, based on the signal from the sensor and the detection result from the detection circuit, the offset amount from the midpoint position of the first phase winding and the second phase winding at the given position, and the delay amount from the appropriate timing of the edge timing of the sensor signal. The motor control device according to claim 1.

5. The controller controls the drive circuit to drive the motor in a first rotation direction and keeps all of the plurality of switching elements in the off state to measure a first delay time in the first rotation direction, controls the drive circuit to drive the motor in a second rotation direction and keeps all of the plurality of switching elements in the off state to measure a second delay time in the second rotation direction, and uses the first delay time and the second delay time to determine the offset amount and the delay amount, respectively. The motor control device according to claim 4.

6. The controller adjusts the phase of the motor drive voltage based on the signal from the sensor and the detection result from the detection circuit. The motor control device according to claim 1.

7. The controller is capable of adjusting the phase of the motor's drive voltage up to an electrical angle of 60°. The motor control device according to claim 6.

8. A controller that determines the rotation direction of a motor based on the signal from the sensor and the detection result of a detection circuit that detects the timing when the relative magnitudes of the signals from the first phase and the second phase are reversed, while keeping all of the multiple switching elements in the drive circuit, which includes a first phase winding, a second phase winding, a third phase winding and a rotor, connected to a motor that is capable of free rotation, and while keeping all of the multiple switching elements in the drive circuit in the drive circuit in the off state.

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