Motor driver circuit and driving method

Abstract

To provide a motor driver circuit and a driving method capable of properly driving a three-phase brushless motor.SOLUTION: A phase signal generator 250 generates a reference phase signal θ that changes in 60-degree increments in response to edges of the U-phase Hall signal, V-phase Hall signal, and W-phase Hall signal. The phase signal generator also cumulatively adds an angular velocity signal ω corresponding to the motor rotation speed to the current phase signal φ. When the error between the current phase signal φ and the reference phase signal θ is not within a predetermined range in a case in which an edge of the U-phase Hall signal, V-phase Hall signal, or W-phase Hall signal occurs, the phase signal generator resets the current phase signal φ to the reference phase signal θ.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a driving technique for a three-phase brushless motor. [Background technology]

[0002] When driving a three-phase brushless motor, it is necessary to switch the drive phase depending on the rotor position. Three-phase brushless motor drive methods are classified into sensorless methods and hall sensor drive depending on the method used to detect the rotor position. Hall sensor drive uses the output of a sensor such as a hall element (called a hall signal) to detect the rotor position.

[0003] When three-phase Hall elements are installed in the appropriate position relative to the motor to be driven, the three-phase Hall signals have an ideal waveform with a 50% duty cycle and an even phase difference of 120 degrees. However, if the three-phase Hall elements are installed in an incorrect position, the positions of the positive and negative edges of the Hall signal will deviate from the ideal waveform. Driving a motor based on Hall signals with errors can cause noise and vibration. In the 180-degree conduction method (sine wave drive method), the current flowing through the coil is controlled based on a sine wave or similar waveform according to the phase angle. Therefore, the rotor position (phase angle) must be accurately known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-175328

[0005] [overview] The present disclosure has been made in view of the above-mentioned problems, and one purpose of an embodiment thereof is to provide a motor driver circuit and a driving method that can appropriately drive a three-phase brushless motor.

[0006] One aspect of the present disclosure relates to a motor driver circuit for driving a three-phase brushless motor. The motor driver circuit includes a phase signal generator that generates a current phase signal indicating the rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal. The phase signal generator performs the following operations: generating a reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; integrating the current phase signal by cumulatively adding an angular velocity signal corresponding to the motor rotation speed; and resetting the current phase signal to the reference phase signal if an error between the current phase signal and the reference phase signal is not within a predetermined range when an edge of the U-phase Hall signal, the V-phase Hall signal, or the W-phase Hall signal occurs.

[0007] Another aspect of the present disclosure also relates to a motor driver circuit for driving a three-phase brushless motor. The motor driver circuit includes a phase signal generator that generates a current phase signal indicating the rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal. The phase signal generator executes the following processes: generating a first reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; generating a slope signal having a gradient corresponding to the rotation speed of the motor; generating the first reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; resetting a second reference phase signal to the value of the first reference phase signal and resetting the slope signal if an error between the current phase signal and the first reference phase signal is not within a predetermined range when an edge of the U-phase Hall signal, the V-phase Hall signal, or the W-phase Hall signal occurs; and generating the current phase signal by adding the second reference phase signal and the slope signal.

[0008] Another aspect of the present disclosure relates to a method for driving a sensor-equipped three-phase brushless motor, the method comprising the steps of: generating a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; generating a reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; cumulatively adding an angular velocity signal corresponding to the rotation speed of the motor to the current phase signal; and resetting the current phase signal to the reference phase signal when an edge of the U-phase Hall signal, the V-phase Hall signal, or the W-phase Hall signal occurs and an error between the current phase signal and the reference phase signal is not within a predetermined range.

[0009] Another aspect of the present disclosure also relates to a method for driving a three-phase brushless motor. The method includes generating a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal. The step of generating the current phase signal includes generating a first reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal, generating a slope signal having a slope corresponding to the rotation speed of the motor, resetting a second reference phase signal to the value of the first reference phase signal to reset the slope signal if an error between the current phase signal and the first reference phase signal is not within a predetermined range when an edge of the U-phase Hall signal, the V-phase Hall signal, or the W-phase Hall signal occurs, and generating the current phase signal by adding the second reference phase signal and the slope signal.

[0010] Any combination of the above components or mutual substitution of the components or expressions of the present disclosure between methods, devices, systems, etc. are also valid aspects of the present disclosure. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a circuit diagram of a motor circuit according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the transition of the three-phase hall signals HU, HV, and HW when the motor is rotating. [Figure 3] FIG. 3 is a functional block diagram of the phase signal generator. [Figure 4] FIG. 4 is a block diagram of a phase signal generator according to a comparative technique. [Figure 5] FIG. 5 is a waveform diagram illustrating the operation of the phase signal generator according to the comparative technique. [Figure 6] FIG. 6 is a waveform diagram illustrating the operation of the phase signal generator according to the embodiment. [Figure 7] FIG. 7 is a block diagram of a phase signal generator according to the first modification. [Figure 8] FIG. 8 is a functional block diagram of a phase signal generator according to the second modification. [Figure 9] FIG. 9 is a functional block diagram of a phase signal generator according to the third modification. [Figure 10] FIG. 10 is a functional block diagram of a phase signal generator according to the fourth modification.

[0012] [Detailed explanation] (Outline of the embodiment) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows. It is not intended to limit the scope of the invention or disclosure. Furthermore, this summary is not an exhaustive overview of all possible embodiments, nor does it limit essential elements of the embodiments. For convenience, the term "one embodiment" may refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0013] A motor driver circuit according to one embodiment drives a three-phase brushless motor. The motor driver circuit includes a phase signal generator that generates a current phase signal indicating the rotor position of the three-phase brushless motor based on U-phase, V-phase, and W-phase Hall signals. The phase signal generator generates a reference phase signal that changes in 60-degree increments in response to edges of the U-phase, V-phase, and W-phase Hall signals. The phase signal generator performs an integration process that cumulatively adds an angular velocity signal corresponding to the motor's rotation speed to the current phase signal. When an edge of the U-phase, V-phase, or W-phase Hall signal occurs, the phase signal generator resets the current phase signal to the reference phase signal if the error between the current phase signal and the reference phase signal is not within a predetermined range.

[0014] With this configuration, when the error between the current phase signal and the reference phase signal is small, the frequency of occurrence of discontinuities in the current phase signal can be reduced by continuing to add the angular velocity signal without resetting.When the error between the current phase signal and the reference phase signal exceeds a threshold, the erroneous current phase signal can be restored to its correct state by resetting the current phase signal so that it matches the reference phase signal.

[0015] In one embodiment, the phase signal generator may correct the angular velocity signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient. With this configuration, in a situation where a reset state continues for a long period of time, the accumulation of error can be reduced by correcting the angular velocity.

[0016] A motor driver circuit according to one embodiment includes a phase signal generator that generates a current phase signal indicating the rotor position of a three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal. The phase signal generator executes the following processes: generating a reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; generating a slope signal having a gradient corresponding to the rotation speed of the motor; generating the current phase signal by adding the reference phase signal and the slope signal; and resetting the current phase signal to the reference phase signal and the slope signal if an error between the current phase signal and the reference phase signal is not within a predetermined range when an edge of the U-phase Hall signal, the V-phase Hall signal, or the W-phase Hall signal occurs.

[0017] With this configuration, when the error between the current phase signal and the reference phase signal is small, the frequency of occurrence of discontinuities in the current phase signal can be reduced by continuing to add the angular velocity signal without resetting.When the error between the current phase signal and the reference phase signal exceeds a threshold, the erroneous current phase signal can be restored to its correct state by resetting the current phase signal so that it matches the reference phase signal.

[0018] In one embodiment, the phase signal generator may correct the gradient of the slope signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient. With this configuration, in a situation where a reset state continues for a long period of time, the accumulation of errors can be reduced by correcting the angular velocity.

[0019] In one embodiment, the threshold may be configurable, allowing adjustment of the frequency of resets and therefore the trade-off between suppressing discontinuities in the current phase signal and maintaining accuracy of the current phase signal.

[0020] In one embodiment, the phase signal generator may adaptively change the threshold value depending on the state of the motor.

[0021] In one embodiment, the phase signal generator may set a relatively large threshold value when the motor rotates at a constant speed, and set a relatively small threshold value when the motor accelerates or decelerates. When the motor accelerates or decelerates, i.e., when the angular velocity signal changes, the threshold value may be set to a small value to increase the reset frequency and improve the accuracy of the current phase signal.

[0022] In one embodiment, the motor driver circuit may be monolithically integrated on a single semiconductor substrate. "Monolithic integration" includes cases where all of the circuit components are formed on a semiconductor substrate, or where the main circuit components are monolithically integrated, and some resistors and capacitors for adjusting circuit constants may be provided outside the semiconductor substrate. By integrating the circuit on a single chip, the circuit area can be reduced and the characteristics of the circuit elements can be maintained uniformly.

[0023] (Embodiment) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be designated by the same reference numerals, and redundant descriptions will be omitted where appropriate. Furthermore, the embodiments are merely examples and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0024] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected to each other, but also a case in which component A and component B are indirectly connected to each other via other components that do not substantially affect the electrical connection between them or that do not impair the function or effect achieved by their connection.

[0025] Similarly, "a state in which component C is provided between component A and component B" includes not only cases in which components A and C, or components B and C, are directly connected, but also cases in which they are indirectly connected via other components that do not substantially affect the electrical connection state between them or impair the functions or effects achieved by their combination.

[0026] 1 is a circuit diagram of a motor circuit 100 according to an embodiment. The motor circuit 100 includes a three-phase brushless motor (hereinafter simply referred to as a motor) 102 and a motor driver circuit 200 that drives the motor 102. The motor 102 is a motor with three Hall sensors, in which three Hall elements 104U, 104V, and 104W are attached. Each of the Hall elements 104U, 104V, and 104W is supplied with a Hall bias voltage V generated by the motor driver circuit 200 or a separate power supply circuit. HB Each Hall element 104 generates a pair of Hall voltages V that indicate the rotor position of the motor 102. H+ ,V H- Output.

[0027] The motor driver circuit 200 drives the motor 102 based on a command from the host controller 106. The motor driver circuit 200 has a U-phase output OUTU, a V-phase output OUTV, and a W-phase output OUTW that are connected to the U-phase, V-phase, and W-phase coils of the motor 102. The motor driver circuit 200 also outputs a Hall voltage V H+ ,V H- The output OUT# (#=U, V, W) of each phase can be high (H), low (L) or high impedance (HiZ). High H can be not only a fixed high but also a PWM modulated state.

[0028] The motor driver circuit 200 includes a controller circuit 210, a pre-driver 220, an inverter circuit 230, and Hall comparators 240U, 240V, and 240W, all of which are monolithically integrated on a single semiconductor substrate. "Monolithically integrated" includes cases where all of the circuit components are formed on the semiconductor substrate, and cases where the main circuit components are monolithically integrated, and some resistors, capacitors, etc. may be provided outside the semiconductor substrate to adjust the circuit constants.

[0029] The power supply (VDD) terminal of the motor driver circuit 200 is supplied with a power supply voltage V from an external power supply (not shown). DD is supplied.

[0030] The Hall comparator 240U detects the Hall voltage V H+ and V H- and generate a Hall signal HU that indicates the magnitude relationship. The Hall signal HU is H+ , V H- The same applies to the Hall comparators 240V and 240W.

[0031] The controller circuit 210 generates a control signal S that controls the state of the inverter circuit 230 based on the Hall signals HU, HV, and HW. CNT For example, the controller circuit 210 generates the control signal S CNT The controller circuit 210 may scale the duty cycle of the PWM control of the motor 102 according to the target rotation speed of the motor 102.

[0032] The pre-driver 220 receives the control signal S generated by the controller circuit 210. CNT The inverter circuit 230 is driven based on this. The inverter circuit 230 is a three-phase inverter and includes a U-phase leg, a V-phase leg, and a W-phase leg. The U-phase leg includes an upper arm UH and a lower arm UL, the V-phase leg includes an upper arm VH and a lower arm VL, and the W-phase leg includes an upper arm WH and a lower arm WL. When the upper arm #H is on and the lower arm #L is off, the output OUT# is high. When the upper arm #H is off and the lower arm #L is on, the output OUT# is low. When both the upper arm #H and the lower arm #L are off, the output OUT# has high impedance.

[0033] In the 120-degree conduction method, the state machine 212 switches the coil (drive phase) to which the drive current is supplied in synchronization with the Hall signals HU, HV, and HW (commutation control).In the 180-degree or 150-degree conduction method, the state machine 212 also switches the drive phase in synchronization with the Hall signals HU, HV, and HW (commutation control).

[0034] 2 is a diagram showing the transitions of the three-phase Hall signals HU, HV, and HW when the motor 102 is rotating. The three-phase Hall signals HU, HV, and HW are pulse signals whose phases are shifted by 120 degrees, and the positive and negative edges of each Hall signal appear every 60 degrees. The combinations of the three-phase Hall signals HU, HV, and HW cyclically repeat (HLH), (HLL), (HHL), (LHL), (LHH), and (LLH).

[0035] Returning to Fig. 1, the controller circuit 210 includes a phase signal generator 250 and a waveform generator 260. Note that the controller circuit 210 may be implemented by hardware such as a logic circuit or an FPGA (Field Programmable Gate Array), or may be implemented by a combination of software and a processor.

[0036] The phase signal generator 250 uses the U-phase Hall signal HU, the V-phase Hall signal HV, and the W-phase Hall signal HW to generate a current phase signal φ that indicates the current rotor position. The current phase signal φ is a signal with one cycle of 360 degrees. The waveform generator 260 uses the current phase signal φ in the 180-degree conduction method or the 150-degree conduction method to generate a waveform signal that defines the drive current. The waveform signal can be a sine wave, a pseudo-sine wave, or a trapezoidal wave.

[0037] 3 is a functional block diagram of phase signal generator 250. Phase signal generator 250 includes reference phase generator 252, integrator 254, and reset unit 256. For ease of understanding, the phase is treated as having a minimum value of −180 degrees and a maximum value of +180 degrees, and values ​​exceeding the maximum value or below the minimum value are assumed to be wrapped so as to fall within the range of −180 degrees to +180 degrees.

[0038] The reference phase generator 252 generates a reference phase signal θ that changes in 60-degree increments in response to edges of the three-phase Hall signals HU, HV, and HW. In this embodiment, the current phase signal φ changes within a range of -180 degrees to +180 degrees, and the reference phase signal θ takes on discrete values ​​of -180 degrees (+180 degrees), -120 degrees, -60 degrees, 0 degrees, 60 degrees, and 120 degrees depending on the combination of the Hall signals HU, HV, and HW. For example, the relationship between the reference phase signal θ and (HU, HV, HW) is as follows: 1 indicates H and 0 indicates L. The reference phase generator 252 is represented, for example, as a selector. θ (HU,HV,HW) 0 degrees = (110) -60 degrees = (100) -120 degrees = (101) -180 degrees = (001) +120 degrees = (011) +60 degrees = (010)

[0039] The accumulator 254 cumulatively adds the angular velocity signal ω, which corresponds to the rotation speed of the motor, to the current phase signal φ for each control time. This generates a current phase signal φ that changes substantially continuously. The accumulator 254 may include an adder 270 and a selector 272. The reference phase signal θ and the current phase signal φ are input to the selector 272. When the selector 272 selects the current phase signal φ, the adder 270 adds the angular velocity signal ω to the current phase signal φ to update the current phase signal φ.

[0040] When a positive edge (rising edge) or negative edge (falling edge) of the U-phase hall signal HU, the V-phase hall signal HV, or the W-phase hall signal HW occurs, if the error (difference) err between the current phase signal φ and the reference phase signal θ is not within a predetermined range, that is, if the absolute value |err| of the error err is greater than a predetermined threshold value, the reset unit 256 resets the current phase signal φ to the value of the reference phase signal θ.

[0041] The reset section 256 includes a subtractor 280 , a comparator 282 , an edge detector 284 , and a logic gate 286 .

[0042] The subtractor 280 generates an error (difference) err between the current phase signal φ and the reference phase signal θ. When the error err is within a predetermined range (-TH to TH) (-TH < err < TH), the comparator 282 negates (1) the mask signal / MSK. When the error err is outside the predetermined range (err < -TH or TH < err), the comparator 282 asserts (0) the mask signal / MSK. / indicates that it is a negative logic signal. In other words, when the absolute value |err| of the error err is smaller than the threshold TH, the mask signal MSK is negated (1), and when the absolute value |err| of the error err is larger than the threshold TH, the mask signal MSK is asserted (0).

[0043] The edge detector 284 receives the three-phase Hall signals HU, HV, HW and generates an edge detection signal (pulse) EDGE that goes high (1) at the timing of their positive edges and negative edges. The edge detection signal EDGET goes high for one control period.

[0044] The logic gate 286 performs a logical operation on the mask signal MSK and the edge detection signal EDGE to generate a reset signal RST. The reset signal RST goes high (1) during the period when the edge detection signal EDGE is high and the mask signal / MSK is negated (1). When the reset signal RST goes high (1), the selector 272 selects the reference phase signal θ. As a result, the value of the current phase signal φ is reset to the value of the reference phase signal θ. During the period when the mask signal / MSK is asserted (0), the reset signal RST is fixed to low (0), so the reset operation is disabled.

[0045] The above is the configuration of the phase signal generator 250. The advantages of the phase signal generator 250 will become clear by comparison with the comparison technology. Therefore, the phase signal generator 250R related to the comparison technology will be described.

[0046] 4 is a block diagram of a phase signal generator 250R according to the comparison technique. In the comparison technique, the reset section 256R includes only an edge detector 284, and the edge detection signal EDGE is supplied to the integrator 254 as a reset signal RST.

[0047] 5 is a waveform diagram illustrating the operation of the phase signal generator 250R according to the comparative technique. In an ideal state where the Hall element 104 is mounted in an appropriate position, the edges of the Hall signals HU, HV, and HW are generated at 60-degree intervals. However, in reality, due to assembly errors, the mounting position of the Hall element 104 deviates from the ideal position. As a result, the intervals between the edges of the Hall signals HU, HV, and HW become wider or narrower than 60 degrees.

[0048] In the comparative technology, the integrator is reset at each edge of the Hall signals HU, HV, and HW. As a result, a discontinuity occurs in the current phase signal φ at the reset timing. If a motor is driven based on a current phase signal φ that has such a discontinuity, noise may be generated and control may become unstable.

[0049] Next, the operation of the phase signal generator 250 according to the embodiment will be described. FIG. 6 is a waveform diagram illustrating the operation of the phase signal generator 250 according to the embodiment. In the embodiment, while the deviation (error) of the current phase signal φ from the reference phase signal θ is small, the integrator 254 free-runs without being reset. FIG. 6 shows the free-running state. If the free-running period continues for a long time and the error err between the current phase signal φ and the reference phase signal θ falls outside the allowable range, a reset is applied, and the current phase signal φ is reset by the reference phase signal θ.

[0050] In this way, according to the embodiment, it is possible to suppress the discontinuity of the current phase signal φ that occurs in the comparison technique.

[0051] The embodiment has been described above. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present invention. These modifications will be described below.

[0052] (Variation 1) FIG. 7 is a block diagram of a phase signal generator 250A according to Modification 1. In addition to the configuration shown in FIG. 3, the phase signal generator 250A further includes a multiplier 258. The multiplier 258 calculates a value (correction value Δω=K×err) obtained by multiplying the error err between the current phase signal φ and the reference phase signal θ by a predetermined coefficient K. This correction value Δω is added by an adder 270 to the angular velocity signal ω and the output of a selector 272. Adding the correction value Δω is equivalent to correcting the angular velocity signal ω. In other words, the adder 270 adds the corrected angular velocity signal ω+Δω to the output of the selector 272.

[0053] In this modification, the subtractor 280, the multiplier 258, and the adder 270 form a feedback loop of proportional control, and the correction value Δω is adjusted so that the error err approaches zero.

[0054] According to this modification, in a free-running state in which resets do not occur at the edges of the Hall signals HU, HV, and HW, the error err can be kept within a small range, the free-running period can be extended, and the frequency of resets can be further reduced.

[0055] (Variation 2) 8 is a functional block diagram of a phase signal generator 250B according to Modification 2. This phase signal generator 250B has substantially the same functions as the phase signal generator 250 in FIG.

[0056] Phase signal generator 250B includes slope generator 255 instead of accumulator 254. Slope generator 255 generates slope signal RAMP having a slope according to angular velocity signal ω. Slope generator 255 may be configured similarly to accumulator 254 in FIG. 3 and may include adder 290 and selector 292.

[0057] The slope generator 255 receives a reset signal RST generated by the reset unit 256. In response to the assertion of the reset signal RST, the slope generator 255 resets the slope signal RAMP to a predetermined value (for example, 0) and resumes generating the slope signal RAMP.

[0058] The memory 253 stores the reference phase signal (first reference phase signal) θ generated by the reference phase generator 252. The value of the memory 253 (second reference phase signal θ′) is updated in response to a reset signal RST generated by the reset unit 256.

[0059] The adder 271 adds the second reference phase signal θ′ stored in the memory 253 to the slope signal RAMP to generate the current phase signal φ.

[0060] In other words, the phase signal generator 250B can be understood as executing the following processes. (1) A process for generating a first reference phase signal θ that changes in 60-degree increments in response to edges of the U-phase Hall signal HU, the V-phase Hall signal HV, and the W-phase Hall signal HW. (2) Processing to generate a slope signal RAMP having a gradient according to the rotation speed (angular velocity signal ω) of the motor (3) When an edge of the U-phase hall signal, the V-phase hall signal, or the W-phase hall signal occurs, if the error between the current phase signal φ and the first reference phase signal θ1 is not within a predetermined range, the second reference phase signal θ′ is reset to the value of the first reference phase signal θ, and the slope signal RAMP1 is reset. (4) A process of generating a current phase signal φ by adding the second reference phase signal θ′ and the slope signal RAMP.

[0061] 3, in Modification 2, the slope generator 255 free-runs without being reset while the deviation (error) of the current phase signal φ from the first reference phase signal θ' is small. If the free-running period continues for a long time and the error err between the current phase signal φ and the first reference phase signal θ falls outside the allowable range, the memory 253 and the slope generator 255 are reset so that the current phase signal φ matches the first reference phase signal θ.

[0062] According to this modification, it is possible to reduce the frequency with which discontinuities occur in the current phase signal φ.

[0063] (Variation 3) 9 is a functional block diagram of a phase signal generator 250C according to Modification 3. Modification 3 differs from Modification 2 in that, in Modification 3, the gradient of the slope signal RAMP can be corrected according to the error err between the current phase signal φ and the first reference phase signal θ.

[0064] The output Δω of multiplier 258 may be provided to adder 271 or to adder 290 .

[0065] According to the third modification, the free-run period can be extended and the frequency of resets can be further reduced compared to the second modification.

[0066] (Variation 4) 10 is a functional block diagram of a phase signal generator 250D according to Modification 4. In the embodiment or Modifications 1 to 3, the threshold value TH, which is the criterion for determining whether to perform a reset, may be set by the user. For example, the motor driver circuit 200 may be provided with a register 294 accessible from the host controller 106. The host controller 106 may access the register 294 to change the threshold value TH. This makes it possible to adjust the frequency of resets and to adjust the balance between the effect of suppressing discontinuities in the current phase signal φ and the accuracy of the current phase signal φ.

[0067] The host controller 106 may adaptively change the threshold value TH according to the state of the motor 102. Specifically, the threshold value TH may be relatively large when the motor 102 rotates at a constant speed, and may be relatively small when the motor 102 accelerates or decelerates. When the motor 102 accelerates or decelerates, that is, when the angular velocity signal ω changes, the threshold value TH may be reduced to increase the frequency of resets and improve the accuracy of the current phase signal φ.

[0068] The process of adaptively controlling the threshold value TH in accordance with the state of the motor may be performed by the controller circuit 210 in the motor driver circuit 200 through software processing or hardware processing, rather than by the host controller 106.

[0069] The embodiments described using specific terms merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments as long as they do not deviate from the spirit of the present invention as defined in the claims.

[0070] (Addendum) One aspect of the technology disclosed in this specification can be understood as follows.

[0071] (Item 1) A motor driver circuit for driving a three-phase brushless motor, a phase signal generator that generates a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The phase signal generator generating a reference phase signal that changes in 60-degree increments in response to edges of the U-phase hall signal, the V-phase hall signal, and the W-phase hall signal; an integration process for cumulatively adding an angular velocity signal corresponding to the rotation speed of the motor to the current phase signal; resetting the current phase signal to the reference phase signal when an error between the current phase signal and the reference phase signal does not fall within a predetermined range when an edge of the U-phase hall signal, the V-phase hall signal, or the W-phase hall signal occurs; To run the motor driver circuit.

[0072] (Item 2) 2. The motor driver circuit according to item 1, wherein the phase signal generator corrects the angular velocity signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient.

[0073] (Item 3) A motor driver circuit for driving a three-phase brushless motor, a phase signal generator that generates a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The phase signal generator generating a first reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; generating a slope signal having a gradient according to the rotation speed of the motor; resetting the second reference phase signal to the value of the first reference phase signal and the slope signal to zero when an error between the current phase signal and the first reference phase signal is not within a predetermined range when an edge of the U-phase hall signal, the V-phase hall signal, or the W-phase hall signal occurs; generating the current phase signal by adding the second reference phase signal and the slope signal; To run the motor driver circuit.

[0074] (Item 4) 4. The motor driver circuit according to item 3, wherein the phase signal generator corrects the gradient of the slope signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient.

[0075] (Item 5) 5. The motor driver circuit according to any one of items 1 to 4, wherein the threshold value is configurable.

[0076] (Item 6) 6. The motor driver circuit according to any one of items 1 to 5, wherein the phase signal generator adaptively changes the threshold value depending on the state of the motor.

[0077] (Item 7) 7. The motor driver circuit according to item 6, wherein the phase signal generator makes the threshold value relatively large when the motor rotates at a constant speed, and makes the threshold value relatively small when the motor accelerates or decelerates.

[0078] (Item 8) 8. The motor driver circuit according to any one of items 1 to 7, which is monolithically integrated on a single semiconductor substrate.

[0079] (Item 9) A method for driving a sensor-equipped three-phase brushless motor, comprising: generating a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The step of generating a current phase signal includes: generating a reference phase signal that changes in 60 degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; a step of cumulatively adding an angular velocity signal corresponding to the rotation speed of the motor to the current phase signal; resetting the current phase signal to the reference phase signal when an error between the current phase signal and the reference phase signal does not fall within a predetermined range when an edge of the U-phase hall signal, the V-phase hall signal, or the W-phase hall signal occurs; A driving method including:

[0080] (Item 10) The step of generating a current phase signal includes: 10. The driving method according to item 9, further comprising the step of correcting the angular velocity signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient.

[0081] (Item 11) A method for driving a three-phase brushless motor, comprising: generating a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The step of generating a current phase signal includes: generating a first reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; generating a slope signal having a slope according to the rotation speed of the motor; resetting a second reference phase signal to the value of the first reference phase signal and resetting the slope signal to zero when an error between the current phase signal and the first reference phase signal is not within a predetermined range when an edge of the U-phase Hall signal, the V-phase Hall signal, or the W-phase Hall signal occurs; generating the current phase signal by adding the second reference phase signal and the slope signal; A driving method comprising:

[0082] (Item 12) Item 12. The driving method according to item 11, further comprising the step of correcting the gradient of the slope signal by a value obtained by multiplying the error between the current phase signal and the first reference phase signal by a predetermined coefficient. [Explanation of symbols]

[0083] 100 Motor Circuit 102 Motor 104 Hall element 200 Motor driver circuit 210 Controller Circuit 220 Pre-driver 230 Inverter Circuit 240U, 240V, 240W Hall comparator 250 Phase Signal Generator 252 Reference Phase Generator 253 memory 254 Accumulator 255 Slope Generator 256 Reset section 258 multiplier 260 Waveform Generator 270,271 Adder 272 Selector 280 Subtractor 282 Comparator 284 Edge Detector 286 Logic Gates 290 Adder 292 Selector 294 registers

Claims

1. A motor driver circuit for driving a three-phase brushless motor, a phase signal generator that generates a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The phase signal generator generating a reference phase signal that changes in 60-degree increments in response to edges of the U-phase hall signal, the V-phase hall signal, and the W-phase hall signal; an integration process for cumulatively adding an angular velocity signal corresponding to the rotation speed of the motor to the current phase signal; resetting the current phase signal to the reference phase signal when an error between the current phase signal and the reference phase signal does not fall within a predetermined range when an edge of the U-phase hall signal, the V-phase hall signal, or the W-phase hall signal occurs; To run the motor driver circuit.

2. 2. The motor driver circuit according to claim 1, wherein the phase signal generator corrects the angular velocity signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient.

3. A motor driver circuit for driving a three-phase brushless motor, a phase signal generator that generates a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The phase signal generator generating a first reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; generating a slope signal having a gradient according to the rotation speed of the motor; resetting the second reference phase signal to the value of the first reference phase signal and the slope signal to zero when an error between the current phase signal and the first reference phase signal is not within a predetermined range when an edge of the U-phase hall signal, the V-phase hall signal, or the W-phase hall signal occurs; generating the current phase signal by adding the second reference phase signal and the slope signal; To run the motor driver circuit.

4. 4. The motor driver circuit according to claim 3, wherein the phase signal generator corrects the gradient of the slope signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient.

5. 5. The motor driver circuit according to claim 1, wherein the threshold value is configurable.

6. 5. The motor driver circuit according to claim 1, wherein the phase signal generator adaptively changes the threshold value depending on the state of the motor.

7. 7. The motor driver circuit according to claim 6, wherein the phase signal generator makes the threshold value relatively large when the motor rotates at a constant speed, and makes the threshold value relatively small when the motor accelerates or decelerates.

8. 5. The motor driver circuit according to claim 1, which is monolithically integrated on a single semiconductor substrate.

9. A method for driving a sensor-equipped three-phase brushless motor, comprising: generating a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The step of generating a current phase signal includes: generating a reference phase signal that changes in 60 degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; a step of cumulatively adding an angular velocity signal corresponding to the rotation speed of the motor to the current phase signal; resetting the current phase signal to the reference phase signal when an error between the current phase signal and the reference phase signal does not fall within a predetermined range when an edge of the U-phase hall signal, the V-phase hall signal, or the W-phase hall signal occurs; A driving method including:

10. The step of generating a current phase signal includes: The driving method according to claim 9 , further comprising the step of correcting the angular velocity signal by a value obtained by multiplying the error between the current phase signal and the reference phase signal by a predetermined coefficient.

11. A method for driving a three-phase brushless motor, comprising: generating a current phase signal indicating a rotor position of the three-phase brushless motor based on a U-phase Hall signal, a V-phase Hall signal, and a W-phase Hall signal; The step of generating a current phase signal includes: generating a first reference phase signal that changes in 60-degree increments in response to edges of the U-phase Hall signal, the V-phase Hall signal, and the W-phase Hall signal; generating a slope signal having a slope according to the rotation speed of the motor; resetting a second reference phase signal to the value of the first reference phase signal and resetting the slope signal to zero when an error between the current phase signal and the first reference phase signal is not within a predetermined range when an edge of the U-phase Hall signal, the V-phase Hall signal, or the W-phase Hall signal occurs; generating the current phase signal by adding the second reference phase signal and the slope signal; A driving method comprising:

12. The driving method according to claim 11 , further comprising the step of correcting the gradient of the slope signal by a value obtained by multiplying the error between the current phase signal and the first reference phase signal by a predetermined coefficient.

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