JP2016154422A - Motor drive controller, and control method for motor drive controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive controller capable of driving a motor stably and with high drive efficiency.SOLUTION: A motor drive controller 1 includes a control circuit unit 3 for generating a drive control signal Sd for driving a motor 20 on the basis of a Hall signal Hu corresponding to the motor's rotation position, an FG signal Sf generated by using an FG pattern 4a, and a target speed signal CLK. The control circuit unit 3 generates a torque instruction signal St for controlling the motor 20 so as to the follow target speed, according to a result of comparing the FG signal Sf with the target speed signal CLK. The control circuit unit 3 generates a pulse signal that corresponds to the target speed signal CLK and has a period shorter than that of the target speed signal CLK, and estimates the motor's rotation position on the basis of the pulse signal's number of pulses from reference timing acquired on the basis of the Hall signal Hu and the FG signal Sf. The control circuit unit 3 generates the drive control signal Sd on the basis of an estimation result on the rotation position and the torque instruction signal St.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a motor drive control device and a control method for the motor drive control device, and more particularly to a motor drive control device that controls the drive of a motor based on an FG signal corresponding to the rotational speed of a rotor, and a control method for the motor drive control device. .

  As a method for controlling the rotational speed of a motor (for example, a brushless DC motor used as a fan motor or a fan motor) by a motor drive control device, a target speed signal is input from the outside, and the rotational speed signal of the motor follows it. There is something that controls to do. This control is called feedback control. In the feedback control, the cycle (motor speed) and phase of the target speed signal and rotation speed signal are detected, and a torque command value that is a motor output command is generated by the PI (D) controller.

  In addition, in order to flow a sinusoidal current to the stator coil of the motor, there is one that calculates or converts a voltage command to be applied to the stator coil of each phase according to the angle information of the rotor position. In such a control method, drive data is generated according to the voltage command and the torque command value. The power element is switched at a duty ratio proportional to drive data by pulse width modulation (PWM), and a voltage is applied to the stator coil of the motor.

  In order to perform sinusoidal driving, it is necessary to obtain the rotor position angle with high resolution. The following Patent Document 1 discloses an inverter device provided with a pulse generation circuit that measures a signal change period of a position signal of a Hall sensor corresponding to an electrical angle of 60 degrees and generates a multiplied clock based on the measured period length. The configuration is disclosed. Patent Document 1 discloses that the number of multiplied clock pulses is counted based on the change point of the position signal, and the rotor position is estimated with a higher resolution than the electrical angle of 60 degrees, which is the detection resolution of the position signal. Yes.

Japanese Patent No. 3500348

  However, the method described in Patent Document 1 described above has the following problems. That is, the position signal output from the hall sensor includes an error due to a shift in the position where the hall sensor is disposed or a variation in characteristics. The hall signal cycle fluctuates even if the motor rotates at a constant speed, and is not a constant cycle. Therefore, when the angle information of the rotor position is generated based on the Hall signal, there is a possibility that phase shift, distortion, vibration, etc. occur in the sine wave drive signal. A phase shift, distortion, vibration, or the like of the sine wave drive signal may cause a significant decrease in drive efficiency, a significant decrease in torque generated by the motor, and a deterioration in rotation unevenness of the motor.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a motor drive control device capable of stably driving a motor with high drive efficiency and a control method for the motor drive control device. Yes.

  In order to achieve the above object, according to one aspect of the present invention, a motor drive control device for driving a motor based on a position signal corresponding to a rotational position of a motor generated by a position detector that detects a magnetic pole of a rotor is The motor follows the target speed corresponding to the target speed signal based on the FG signal generation unit that generates the FG signal corresponding to the rotational speed of the rotor using the pattern, the position signal, the FG signal, and the target speed signal. A control circuit unit that generates a drive control signal, and a motor drive unit that outputs a drive voltage signal to the motor based on the drive control signal output from the control circuit unit. The reference value obtained based on the position signal and the FG signal is generated based on the comparison result between the motor and the target speed signal, and a torque command signal for controlling the motor to follow the target speed is generated. Based on the number of pulses of a pulse signal corresponding to the target speed signal and having a shorter cycle than the target speed signal, the rotational position of the motor is estimated based on the estimation result of the rotational position of the motor and the torque command signal. Generate a drive control signal.

  Preferably, the pulse signal is a signal generated by dividing the target speed signal into a predetermined number.

  Preferably, the control circuit unit uses the fact that the zero cross point of the induced voltage of each phase of the motor matches the zero cross point of the FG signal generated by the FG pattern, based on the position signal and the FG signal. Find the reference timing.

  Preferably, the control circuit unit receives the position signal, the target speed signal, and the FG signal, and outputs the rotor position information corresponding to the estimated rotational position of the motor and the rotor position estimation circuit. And a sine wave generation circuit for generating a drive control signal based on the rotor position information.

  Preferably, the motor drive control device includes a current detector that detects a phase current, a phase current detected by the current detector, a pulse signal, and a phase difference detector that generates advance angle information based on an FG signal. The control circuit unit controls the advance angle of the motor based on the advance angle information.

  Preferably, the phase difference detector measures the number of pulses of the pulse signal up to the zero cross point of the phase current with reference to the zero cross point of the FG signal that matches the zero cross point of the induced voltage of the phase detecting the phase current. The advance angle information is generated by performing phase control so that the obtained phase error becomes zero.

  According to another aspect of the present invention, there is provided a control method for a motor drive control device that drives a motor based on a position signal corresponding to a rotational position of the motor generated by a position detector that detects a magnetic pole of a rotor, The motor follows the target speed corresponding to the target speed signal based on the FG signal generation unit that generates the FG signal corresponding to the rotational speed of the rotor using the pattern, the position signal, the FG signal, and the target speed signal. A control method for a motor drive control device comprising: a control circuit unit that generates a drive control signal, and a motor drive unit that outputs a drive voltage signal to a motor based on the drive control signal output from the control circuit unit. And a generation command for generating a torque command signal for controlling the motor to follow the target speed in accordance with a comparison result between the FG signal input to the control circuit unit and the target speed signal. Based on the number of pulses of the pulse signal corresponding to the target speed signal and having a shorter period than the target speed signal from the reference timing obtained based on the position signal and the FG signal input to the control circuit unit, An estimation step for estimating the rotational position of the motor, and an output control step for outputting a drive control signal from the control circuit unit based on the estimation result of the rotational position of the motor and the torque command signal.

  According to these inventions, the motor is estimated based on the number of pulses of the pulse signal from the reference timing obtained based on the torque command signal corresponding to the comparison result between the FG signal and the target speed signal, and the position signal and the FG signal. A drive control signal is generated on the basis of the rotational position. Therefore, a motor drive control device and a control method for the motor drive control device are provided that are less susceptible to errors due to the displacement of the position at which the Hall sensor is arranged and the variation in characteristics, and that can drive the motor stably and with high drive efficiency. can do.

It is a block diagram which shows the circuit structure of the motor drive control apparatus in one of embodiment of this invention. It is a figure which shows the circuit structure of the motor drive control apparatus which concerns on this Embodiment. It is a timing chart which shows the relationship between a pulse signal, FG signal, and an induced voltage. It is a 1st timing chart which shows the relationship between a Hall signal, FG signal, and an induced voltage. It is a 2nd timing chart which shows the relationship between a Hall signal, FG signal, and an induced voltage. It is a flowchart which shows the process regarding the production | generation of the rotor position information in a rotor position estimation circuit. It is a flowchart which shows a speed / phase lock determination process. It is a timing chart explaining the division process of a target speed signal. It is a flowchart which shows the division | segmentation process of a target speed signal. It is a flowchart which shows the reference timing production | generation process by a rotation direction. It is a flowchart which shows the production | generation process of rotor position information. It is a block diagram which shows the circuit structure of the motor drive control apparatus which concerns on the modification of this Embodiment. It is a timing chart which shows the relationship between a pulse signal, FG signal, an induced voltage, and a phase current. It is a flowchart which shows the production | generation process of the rotor position information which concerns on this modification. It is a timing chart explaining the operation | movement regarding the production | generation process of rotor position information.

  Hereinafter, a motor drive control device according to an embodiment of the present invention will be described.

  [Embodiment]

  FIG. 1 is a block diagram showing a circuit configuration of a motor drive control device according to one embodiment of the present invention.

  As shown in FIG. 1, the motor drive control device 1 is configured to drive a brushless motor 20 (hereinafter simply referred to as a motor 20) by, for example, sinusoidal drive. In the present embodiment, the motor 20 is, for example, a three-phase brushless motor. The motor drive control device 1 rotates the motor 20 by outputting a sine wave drive signal to the motor 20 and periodically passing a sine wave drive current through the armature coils Lu, Lv, Lw of the motor 20.

  The motor drive control device 1 includes a motor drive unit 2 including an inverter circuit 2a and a predrive circuit 2b, a control circuit unit 3, and an FG signal generation unit 4. The components shown in FIG. 1 are a part of the entire motor drive control device 1, and the motor drive control device 1 has other components in addition to those shown in FIG. It may be.

  In the present embodiment, the motor drive control device 1 is an integrated circuit device (IC) that is entirely packaged. A part of the motor drive control device 1 may be packaged as one integrated circuit device, or all or part of the motor drive control device 1 is packaged together with other devices as one integrated circuit device. A circuit device may be configured.

  The inverter circuit 2a constitutes the motor driving unit 2 together with the pre-drive circuit 2b. The inverter circuit 2a outputs a drive signal to the motor 20 based on the output signal output from the pre-drive circuit 2b, and energizes the armature coils Lu, Lv, Lw included in the motor 20. In the inverter circuit 2a, for example, a pair of series circuits of two switch elements provided at both ends of the DC power supply Vcc is connected to each phase (U phase, V phase, W phase) of the armature coils Lu, Lv, Lw. Are arranged and configured. In each pair of two switch elements, a terminal of each phase of the motor 20 is connected to a connection point between the switch elements.

  The pre-drive circuit 2b generates an output signal for driving the inverter circuit 2a based on the control by the control circuit unit 3, and outputs the output signal to the inverter circuit 2a. The pre-drive circuit 2b generates an output signal based on the drive control signal Sd. As output signals, for example, six types of Vuu, Vul, Vvu, Vvl, Vwu, and Vwl corresponding to each switch element of the inverter circuit 2a are output. By outputting these output signals, the switch elements corresponding to the respective output signals are turned on and off, a drive signal is output to the motor 20, and power is supplied to each phase of the motor 20.

  In the present embodiment, the control circuit unit 3 controls the motor drive unit 2 by controlling the motor drive unit 2 by outputting a drive control signal Sd for driving the motor 20 to the motor drive unit 2.

  [Description of Configuration and Operation of Control Circuit Section 3]

  FIG. 2 is a diagram showing a circuit configuration of the motor drive control device 1 according to the present embodiment.

  Hall signals Hu, Hv, Hw, FG signal Sf, target speed signal CLK, and start signal Ss are input to the control circuit unit 3. The control circuit unit 3 outputs a drive control signal Sd to the pre-drive circuit 2b based on the hall signals Hu, Hv, Hw, the FG signal Sf, the target speed signal CLK, and the start signal Ss. The control circuit unit 3 controls the rotation of the motor 20 by outputting a drive control signal Sd to the motor drive unit 2 so that the motor 20 follows the target speed corresponding to the target speed signal CLK. The motor drive unit 2 outputs a sine wave drive signal to the motor 20 based on the drive control signal Sd to drive the motor 20.

  The target speed signal CLK is, for example, a clock signal output from the clock terminal of the host device 50 outside the motor drive control device 1. The target speed signal CLK is a signal having a cycle corresponding to the target rotational speed of the motor 20. In other words, the target speed signal CLK is information corresponding to the target value of the rotational speed of the motor 20.

  The start signal Ss is a signal output from the start terminal of the host device 50. The start signal Ss is a signal for setting whether to perform drive control of the motor 20 or to set a standby state in which drive control is not performed. The start signal Ss is, for example, a signal indicating that driving is started at Low and driving is stopped (Standby state) at High.

  In the present embodiment, three Hall signals (an example of position signals) Hu, Hv, and Hw are input to the control circuit unit 3. The hall signals Hu, Hv, and Hw are output signals of, for example, three hall (HALL) elements (an example of a position detector) 25u, 25v, and 25w arranged in the motor 20.

  The three Hall elements 25u, 25v, and 25w (hereinafter, these may be collectively referred to as the Hall element 25) are, for example, substantially equal to each other (at intervals of plus or minus 120 degrees in electrical angle with those adjacent to each other). It is arranged around the rotor. The hall elements 25u, 25v, and 25w respectively detect the magnetic poles of the rotor, generate hall signals Hu, Hv, and Hw and output them. That is, the hall signal is a signal corresponding to the rotational position (rotor position) of the motor 20.

  In addition, the FG signal Sf regarding the rotation state of the motor 20 is input to the control circuit unit 3. The FG signal Sf is a signal corresponding to the rotational speed of the rotor, generated by the FG signal generator 4. In the present embodiment, an FG pattern 4a that is a coil pattern for generating the FG signal Sf is formed on the substrate on the rotor side of the motor 20. The FG signal generation unit 4 generates the FG signal Sf according to the induced voltage of the FG pattern 4a.

  Note that, for example, a brake signal and a rotation direction setting signal are input from the host device 50 to the control circuit unit 3, but these are not shown.

  In the present embodiment, the control circuit unit 3 includes a PID control circuit 31, a sine wave generation circuit 32, and a rotor position estimation circuit 33. Each circuit is a digital circuit.

  The PID control circuit 31 functions as a speed feedback control circuit that performs PID (Proportional-Integral-Derivative) control. The PID control circuit 31 generates a torque command signal St that controls the motor 20 to follow the target speed in accordance with the comparison result between the target speed signal CLK and the FG signal Sf. That is, the PID control circuit 31 detects a speed error and a phase error of the motor 20 and generates a torque command signal St so that the motor 20 follows the target speed. When the rotational speed of the rotor is stabilized by speed feedback control, control is performed so that the phase relationship between the target speed signal CLK and the FG signal Sf does not change. The PID control circuit 31 is a specific example of a feedback control circuit, and the control circuit unit 3 is not limited to the one that performs PID control.

  The hall signal Hu, Hv, Hw, the target speed signal CLK, and the FG signal Sf are input to the rotor position estimation circuit 33. The rotor position estimation circuit 33 generates rotor position information Sp based on the input signal.

  The sine wave generation circuit 32 receives the rotor position information Sp and the torque command signal St. The sine wave generation circuit 32 generates a drive control signal Sd based on the rotor position information Sp and the torque command signal St.

  Here, the rotor position estimation circuit 33 estimates the rotor position information Sp as follows. The rotor position estimation circuit 33 obtains the reference timing based on the relationship between the hall signals Hu, Hv, Hw and the FG signal Sf. Then, the number of pulses from the reference timing of the pulse signal CLK_16 corresponding to the target speed signal CLK is counted. Then, the rotor position information Sp is generated based on the count result of the number of pulses of the pulse signal CLK_16.

  The pulse signal CLK_16 is a clock signal having a shorter cycle than the target speed signal CLK. The pulse signal CLK_16 is a signal obtained by dividing the pulse of the target speed signal CLK into a predetermined number (for example, 16 divisions). The number of divisions can be arbitrarily selected.

  In the present embodiment, in the following description, the number of poles of the motor 20 is 10, the target speed signal CLK is 45 p / r (45 pulses per motor rotation), and the FG signal Sf is also 45 p / r.

  The pulse signal CLK_16 is a 720 p / r clock signal obtained by dividing the target speed signal CLK into 16 by interpolation. The divided pulse signal CLK_16 is information corresponding to one pulse of 0.5 degrees in mechanical angle and 2.5 degrees in electrical angle.

  FIG. 3 is a timing chart showing the relationship among the pulse signal CLK_16, the FG signal Sf, and the induced voltage.

  In FIG. 3, the waveform of the induced voltage (5p / r) of the motor 20, the waveform of the induced voltage (45p / r) of the FG pattern, the FG signal Sf, and the pulse signal CLK_16 are shown in order from the top.

  When the zero cross of the induced voltage of the motor 20 and the induced voltage of the FG pattern match, the timing of the zero cross of the induced voltage of each phase can be detected from the FG signal Sf as the reference timing. Further, when the rotational speed of the rotor is stable, the phase relationship between the target speed signal CLK and the FG signal Sf is controlled so as not to change, so that the pulse signal CLK_16 is a position related to the rotational position of the rotor of the motor 20. Can be used as information. That is, the FG signal Sf and the pulse signal CLK_16 are used for rotor position detection.

  Specifically, a zero cross point (reference timing) of the induced voltage is detected from the FG signal Sf, and position detection can be performed based on the number of pulses of the pulse signal CLK_16 therefrom. For example, when the zero-cross point at the rising edge of the U-phase induced voltage is set as a reference timing (time T1 in FIG. 3), every time the pulse signal CLK_16 comes from this reference, the motor 20 has an electrical angle of 2.5 degrees. It can be estimated that it has advanced. For example, it can be estimated that the motor 20 has advanced 360 degrees in electrical angle at time T2 when the pulse signal CLK_16 has elapsed by 144 pulses from time T1. The control circuit unit 3 generates energization timing by sine wave driving based on the estimation result.

  Depending on the magnetization specifications of the motor 20, the positions of the Hall elements 25u, 25v, 25w, etc., the zero-cross point of the induced voltage in each phase may not match the actual rotational phase of the rotor. In this embodiment, the reference timing corresponding to the actual rotational phase of the rotor is utilized by utilizing the fact that the zero cross point of the induced voltage of each phase matches the zero cross point of the FG signal Sf generated by the FG pattern 4a. Can be requested.

  FIG. 4 is a first timing chart showing the relationship among the Hall signal Hu, the FG signal Sf, and the induced voltage. FIG. 5 is a second timing chart showing the relationship among the Hall signal Hu, the FG signal Sf, and the induced voltage.

  FIG. 4 shows an example in which the rotation direction setting is L (Low). FIG. 5 shows an example in which the rotation direction setting is H (High).

  4 and 5, in order from the top, the waveform of the induced voltage (5 p / r) of the motor 20, the waveform of the induced voltage (45 p / r) of the FG pattern, the FG signal Sf, and the Hall signal Hu are shown. .

  As shown in FIGS. 4 and 5, the zero cross of the induced voltage and the zero cross of the FG signal Sf are configured to coincide with each other. In the sine wave drive method, the induced voltage cannot be detected because it is always energized, but the zero cross timing of the induced voltage of each phase can be detected from the Hall signals Hu, Hv, Hw and the FG signal Sf. It is.

  For example, assuming that a counter circuit is configured to reset at the falling edge of the Hall signal Hu and count the edges of the FG signal Sf, the timing of the zero cross of the induced voltage of the motor 20 can be estimated as follows.

  That is, as shown in FIG. 4, when the rotational direction setting is L (Low), the rising zero cross of the U-phase induced voltage is estimated as t17, and the falling zero cross is estimated as t8. The rising zero cross of the V-phase induced voltage is estimated as t5, and the falling zero cross is estimated as t14. It is estimated that the rising zero cross of the W-phase induced voltage is t11 and the falling zero cross is t2.

  As shown in FIG. 5, when the rotational direction setting = H (High), the rising zero cross of the U-phase induced voltage is estimated as s11, and the falling zero cross is estimated as s2. The rising zero cross of the V-phase induced voltage is estimated as s17, and the falling zero cross is estimated as s8. The rising zero cross of the W-phase induced voltage is estimated as s5, and the falling zero cross is estimated as s14.

  Note that variations in the Hall signals Hu, Hv, Hw caused by variations in the arrangement position of the Hall elements 25 need only be within a predetermined value (for example, within ± 10 degrees in electrical angle). For this reason, the timing detection accuracy is not affected by variations in the Hall signals Hu, Hv, and Hw.

  However, when the induced voltage of the FG pattern is converted into a rectangular wave FG signal Sf using the comparator in the FG signal generation unit 4, the timing is delayed. In order to avoid this, it is necessary to convert to a rectangular wave without using hysteresis. When measures against chattering are required, for example, a digital filter may be configured so that the signal state is not changed for a while after the first edge of the rectangular-wave FG signal Sf.

  As described above, the zero cross point of the induced voltage of each phase of the motor 20 can be detected based on the FG signal Sf.

  [Description of Operation of Rotor Position Estimation Circuit 33]

  Below, the flow of the process regarding the production | generation of the rotor position information Sp which the rotor position estimation circuit 33 performs is demonstrated.

  FIG. 6 is a flowchart showing processing related to generation of rotor position information Sp in the rotor position estimation circuit 33.

  As shown in FIG. 6, in step S11, the rotor position estimation circuit 33 performs a speed / phase lock determination process. By the speed / phase lock determination process, the speed lock determination signal FLL_LD and the phase lock determination signal PLL_LD are obtained.

  In step S12, the rotor position estimation circuit 33 determines whether or not both the speed lock determination signal FLL_LD and the phase lock determination signal PLL_LD are H (High; locked state). If both signals are H (if the speed and phase are stable), go to step S13, otherwise go to step S16.

  In step S13, the rotor position estimation circuit 33 performs a division process (clock signal division process) of the target speed signal CLK. Thereby, the pulse signal CLK_16 is generated.

  In step S <b> 14, the rotor position estimation circuit 33 performs a reference timing generation process based on the rotation direction of the motor 20. Thereby, a timing signal FG_EDGE_EN indicating the reference timing is generated.

  In step S15, the rotor position estimation circuit 33 performs generation processing of the rotor position information Sp. Thereby, rotor position information Sp is generated.

  On the other hand, in step S16, position information is generated from the hall signals Hu, Hv, and Hw, and corrected with the fixed advance angle information that is set, thereby generating rotor position information Sp.

  FIG. 7 is a flowchart showing the speed / phase lock determination process. FIG. 8 is a timing chart for explaining the division processing of the target speed signal.

  In FIG. 8, a 10 MHz count signal Ct, a target speed signal CLK, a signal CLK_CNT, a signal CLK_CNT_MAX, a signal CLK_CNT_16, a signal CNT_16, and a pulse signal CLK_16 are shown in order from the top.

  As shown in FIG. 7, when the speed / phase lock determination process is started, a signal CLK_CNT is generated in step S21. The signal CLK_CNT is a signal indicating the count value of the 10 MHz count signal Ct, as shown in FIG. The count value of the signal CLK_CNT is reset at the falling edge of the target speed signal CLK.

  In step S22, the signal CLK_CNT_MAX is generated. The signal CLK_CNT_MAX is a signal indicating the count value of the signal CLK_CNT at the falling edge of the target speed signal CLK, as shown in FIG. The signal CLK_CNT_MAX is updated every cycle of the target speed signal CLK.

  In step S23, the signal CLK_CNT_32 is generated. The signal CLK_CNT_32 is a value obtained by reducing the value of the signal CLK_CNT_MAX to 1/32. That is, the data of the digital circuit is a binary number. The left end is the most significant bit (MSB) and the right end is the least significant bit (LSB). Here, when the value of the signal CLK_CNT_MAX is shifted to the right by 5 bits (when the data is shifted to the right by 5 bits), the signal CLK_CNT_32 is obtained.

  The cycle of the target speed signal CLK corresponds to the target speed. That is, the signal CLK_CNT_MAX corresponds to the target speed. The value of the signal CLK_CNT_32 corresponds to 3.125% of the target speed.

  In step S24, it is determined whether or not the speed error FLL_DEV is within plus or minus 3.125% of the target speed. That is, it is determined whether or not the following equation holds for the speed error FLL_DEV. If it is within 3.125% of the target speed, the process proceeds to step S25, and if not, the process proceeds to step S26.

  CLK_CNT_32 ≧ FLL_DEV ≧ −CLK_CNT_32

  In step S25, it is determined that the speed lock determination signal FLL_LD is H. That is, it is determined that the motor 20 is in a speed locked state, that is, is driven at a stable speed. At this time, the process proceeds to the next step S27.

  On the other hand, in step S26, it is determined that the speed lock determination signal FLL_LD is L. After the determination, the speed / phase lock determination process ends.

  In step S27, it is determined whether or not the phase error PLL_DEV is within plus or minus 3.125% of the target speed. That is, it is determined whether or not the following equation holds for the phase error PLL_DEV. If it is within 3.125% of the target speed, the process proceeds to step S28, and if not, the process proceeds to step S29.

  CLK_CNT_32 ≧ PLL_DEV ≧ −CLK_CNT_32

  In step S28, since it is determined that the motor 20 is in the phase locked state, that is, driven with a stable phase, the phase lock determination signal PLL_LD becomes H. After the determination, the speed / phase lock determination process ends.

  On the other hand, in step S29, since it is determined that the motor 20 is not in the phase locked state, that is, not driven with a stable phase, the phase lock determination signal PLL_LD becomes L. After the determination, the speed / phase lock determination process ends.

  FIG. 9 is a flowchart showing a dividing process of the target speed signal CLK.

  As shown in FIG. 9, when the dividing process is started, a signal CLK_CNT_16 is generated in step S41. The signal CLK_CNT_16 is a value obtained by reducing the value of the signal CLK_CNT_MAX to 1/16. That is, the signal CLK_CNT_16 is obtained by shifting the value of the signal CLK_CNT_MAX by 4 bits to the right.

  In step S42, a signal CNT_16 is generated. The signal CNT_16 is a signal indicating the count value of the 10 MHz count signal Ct, as shown in FIG. The count value of the signal CNT_16 is reset when the count value reaches the value of the signal CLK_CNT_16.

  In step S43, a pulse signal CLK_16 is generated. The pulse signal CLK_16 is an enable signal that becomes H when the count value of the signal CNT_16 reaches the value of the signal CLK_CNT_16.

  FIG. 10 is a flowchart showing the reference timing generation process based on the rotation direction.

  FIG. 10 shows an example in which the rotor position information Sp is updated every 360 electrical angles using the U-phase zero-cross point. If the zero cross point of each phase is used, the rotor position information Sp can be updated every 60 electrical angles.

  As shown in FIG. 10, when the reference timing generation process is started, a signal FG_EDGE_CNT is generated in step S61. The signal FG_EDGE_CNT is an edge count value of the FG signal Sf. The count value of the signal FG_EDGE_CNT is reset at the falling edge of the Hall signal Hu.

  In step S62, the rotor position estimation circuit 33 determines whether or not the rotational direction setting of the motor 20 is L. If L, the process proceeds to step S63, and if not, the process proceeds to step S64.

  In step S63, when the signal FG_EDGE_CNT reaches 17, the signal FG_EDGE_CRI which becomes H is generated. That is, the signal FG_EDGE_CRI becomes H at time t17 shown in FIG.

  On the other hand, in step S64, a signal FG_EDGE_CRI that becomes H when the signal FG_EDGE_CNT reaches 11 is generated. That is, the signal FG_EDGE_CRI becomes H at time t11 shown in FIG.

  When the signal FG_EDGE_CRI is generated in step S63 or step S64, the timing signal FG_EDGE_EN is generated in step S65. The timing signal FG_EDGE_EN is an enable signal indicating a reference timing that becomes H when a rising edge of the signal FG_EDGE_CRI is detected. In the present embodiment, the timing signal FG_EDGE_EN is a signal indicating the rising zero cross point of the U-phase induced voltage as a reference timing.

  FIG. 11 is a flowchart showing a process for generating the rotor position information Sp.

  In the rotor position information generation process, the process of step S81 is performed, and the rotor position information Sp is generated. That is, the rotor position information Sp is a count value of the pulse signal CLK_16, and the count value is reset to the reference timing indicated by the timing signal FG_EDGE_EN. That is, the rotor position information Sp indicates the number of pulses of the pulse signal CLK_16 from the reference timing.

  Since the timing signal FG_EDGE_EN is a timing signal at the rising zero crossing point of the U-phase induced voltage, the electrical angle between the pulses of the timing signal FG_EDGE_EN is 360 degrees. Since the target speed signal CLK has 9 pulses at the electrical angle of 360 degrees, the pulse signal CLK_16 for 9 * 16 = 144 pulses is generated. When one pulse of the pulse signal CLK_16 is counted with reference to the reference timing indicated by the timing signal FG_EDGE_EN, the information indicates that the position of the rotor has advanced by 2.5 electrical degrees. In other words, the rotor position information Sp indicates the estimated position of the rotor by an electrical angle divided by 2.5 degrees.

  As described above, in the present embodiment, the number of pulses from the reference timing of the pulse signal CLK_16 corresponding to the target speed signal CLK is generated as the rotor position information Sp. Based on the rotor position information Sp, a drive control signal Sd is generated. Therefore, even if the Hall signals Hu, Hv, and Hw have variations within a predetermined value (for example, errors within an electrical angle of ± 10 degrees) due to variations in the arrangement position of the Hall elements 25 and variations in output characteristics. The position detection accuracy does not decrease. In other words, the position of the rotor can be estimated with high accuracy and the motor 20 can be driven regardless of variations in the arrangement position of the Hall elements 25 and variations in output characteristics. The phase shift, distortion, and vibration of the sine wave of the drive control signal Sd are reduced, and the generation of noise and vibration accompanying the rotation of the motor 20 and the occurrence of rotation unevenness can be reduced.

  In sine wave driving, a method is known in which a period for forcibly turning off the driving power to the motor 20 is provided, and the rotational position of the rotor is detected by detecting the induced voltage of each phase during that period. . However, if the driving power is forcibly turned off in this manner, the sine wave current may be distorted, and vibration and noise may occur. Instead of such a method, in the present embodiment, the rotor position estimation circuit 33 estimates the rotational position of the rotor position information Sp, so such a problem does not occur. The zero cross point of the induced voltage is detected using the FG signal Sf. Therefore, it is not necessary to provide a circuit for detecting the induced voltage itself.

  [Description of variant]

  In the present embodiment, the advance angle of the motor may be controlled as follows. In the following description, parts different from the above-described embodiment will be described.

  FIG. 12 is a block diagram showing a circuit configuration of a motor drive control device 201 according to a modification of the present embodiment.

  As shown in FIG. 12, in this modification, the motor drive control device 201 includes a current sensor (an example of a current detector) 5 in addition to the components of the motor drive control device 1 according to the above-described embodiment. And a phase difference detector 6.

  The current sensor 5 is provided, for example, between the U-phase coil of the motor 20 and the motor driving unit 2. The current sensor 5 detects the phase current Si flowing through the U-phase coil and outputs it as a current signal. The current sensor 5 may detect the phase current Si of the other phase. The number of current sensors 5 is not necessarily one, and may be two or may be provided for each phase. Various methods can be used for the current sensor 5 to detect the current. For example, a method of detecting from the voltage across the resistor, a method of detecting from the magnetic flux density generated by the flowing current, a method of detecting from the drain-source voltage when the power element driving the motor is turned on, etc. it can.

  The phase current detector 6 receives the phase current Si, the pulse signal CLK_16, and the FG signal Sf. The phase difference detector 6 generates and outputs advance angle information Sa based on these signals. Specifically, the phase difference detector 6 obtains the zero cross point of the FG signal Sf that matches the zero cross point of the induced voltage of the U phase from which the phase current Si is detected, and uses it as a reference. Then, the number of pulses of the pulse signal CLK_16 up to the zero cross point of the phase current Si is measured. Thereby, phase control can be performed so that the obtained phase error becomes zero. The generated advance angle information Sa is input to the rotor position estimation circuit 33 of the control circuit unit 3.

  In this modification, the control circuit unit 3 corrects the rotor position information Sp based on the advance angle information Sa, and controls the advance angle of the motor 20.

  FIG. 13 is a timing chart showing the relationship among the pulse signal CLK_16, the FG signal Sf, the induced voltage, and the phase current Si.

  In FIG. 13, the induced voltage and phase current Si, the FG signal Sf, and the pulse signal CLK_16 are shown in order from the top.

  As shown in FIG. 13, for example, the zero-cross point of the induced voltage of the U phase can be detected using the FG signal Sf (in the example shown in FIG. 13, time T21). Further, the phase current Si can be detected by the current sensor 5, and the zero cross point of the phase current can be detected (time T22 in the example shown in FIG. 13).

  Here, with reference to the zero cross point of the induced voltage obtained from the FG signal Sf, when a zero cross of the phase current Si is detected in the A section up to a half cycle before that, the induced voltage is detected from the zero cross point of the phase current Si. It is counted how many pulses of the pulse signal CLK_16 are input up to the zero cross point. The count value at this time is a negative value.

  On the other hand, when the zero cross point of the phase current Si is detected in the B section from the FG signal Sf to the half period after the zero cross point of the induced voltage obtained from the FG signal Sf, the phase current Si from the zero cross point of the induced voltage is detected. It is counted how many pulses of the pulse signal CLK_16 are input up to the zero cross point. The count value at this time is a positive value.

  Then, PI control is performed so that the obtained phase error (electrical angle error) becomes zero. The output after PI control is the advance angle information Sa. When the zero crossing of the phase current Si is detected in the A section, the phase current Si is excessively advanced. Therefore, the advance angle information Sa is generated so as to delay the phase current Si. On the other hand, when the zero crossing of the phase current Si is detected in the B section, the phase current Si is delayed, so the advance angle information Sa is generated so as to advance the phase current Si. The advance angle information Sa is output to the rotor position estimation circuit 33, and the rotor position information Sp is output by the rotor position estimation circuit 33 accordingly. Thereby, advance angle control is performed.

  FIG. 14 is a flowchart showing the generation processing of the rotor position information Sp according to this modification.

  When the rotor position information Sp is generated in this modification, the rotor position information generation process is performed as shown in FIG. 14 instead of the process as shown in FIG.

  In the rotor position information generation process, the process of step S91 is performed. That is, the pulse signal CLK_16 is counted and output as the rotor position information Sp. The count value is reset when it reaches 144 or more. Here, at the reference timing indicated by the timing signal FG_EDGE_EN, the advance angle information Sa is substituted into the rotor position information Sp.

  FIG. 15 is a timing chart for explaining operations related to the generation processing of the rotor position information Sp.

  In FIG. 15, the count signal Ct, the pulse signal CLK_16, the advance information Sa, the timing signal FG_EDGE_EN, and the rotor position information Sp are shown in order from the top. FIG. 15 shows an example in which the advance angle information Sa changes.

  As shown in FIG. 15, at the reference timing indicated by the timing signal FG_EDGE_EN, the value of the advance angle information Sa at that time is substituted into the rotor position information Sp. In other words, in this modification, the rotor position information Sp is reset to the value of the advance angle information Sa and output at the reference timing.

  As described above, when the pulse signal CLK_16 is counted by one pulse with reference to the reference timing indicated by the timing signal FG_EDGE_EN, the information indicates that the position of the rotor is advanced by 2.5 electrical degrees. In this modification, the advance angle information Sa is substituted into the rotor position information Sp at the reference timing. This makes it possible to correct the advance value of Sa * 2.5 degrees.

  The advance angle is represented by how many times the angle is advanced with reference to the reference timing of the timing signal FG_EDGE_EN (the rising zero cross point of the U-phase induced voltage). When the advance angle information Sa is “8”, for example, it is an electrical angle and means an advance angle of 8 * 2.5 (degrees) = 20 (degrees). Similarly, when the advance angle information Sa is “6”, for example, an electrical angle means 6 * 2.5 (degrees) = 15 (degrees). That is, the rotor position information Sp of 2.5 degrees in electrical angle can be advanced per unit of the advance angle information Sa. If the number of pulse signals with respect to the electrical angle is increased, the circuit scale increases, but higher resolution control can be performed. Note that when the advance angle information Sa is “0” meaning no advance angle, the position information Sp based on the reference timing is generated.

In this modification, in addition to the effects of the above-described embodiment, the following effects can be obtained. That is, a required advance angle can be confirmed by detecting a phase error from the zero cross point of the induced voltage detected from the FG signal Sf and the zero cross point of the phase current Si. Accordingly, it is possible to automatically correct to the optimum advance angle. Therefore, it is not necessary to confirm and set the advance angle adjustment amount in advance, and the motor 20 can be driven efficiently.
[Others]

  The motor drive control device is not limited to the circuit configuration as shown in the above-described embodiment and its modifications. Various circuit configurations adapted to meet the objectives of the present invention can be applied.

  The control circuit unit is not limited to one that generates a pulse signal having a shorter cycle than the target speed signal based on the target speed signal. For example, a pulse signal having a shorter cycle than the target speed signal may be input to the control circuit unit from a host device or the like instead of the target speed signal. In this case, the target speed signal may be generated by dividing the pulse signal for comparison with the FG signal for speed feedback. For example, the control circuit unit 3 receives the 720 p / r pulse signal CLK_16 from the host device 50 and divides the received pulse signal CLK_16 by 16 to obtain a 45 p / r clock signal. May be used for control as the target speed signal CLK. In this way, by transmitting a signal divided into a predetermined number on the host device 50 side (a signal having a frequency that is, for example, 16 times the frequency to be originally transmitted), division by the motor drive control device becomes unnecessary. In addition, the motor 20 can be controlled more accurately without using a signal one cycle before as a pulse signal.

  The motor drive method is not limited to normal sine wave drive, and the drive voltage gradually changes, such as a rectangular wave drive method, a trapezoidal wave drive method, or a drive method in which a special modulation is applied to the sine wave. It can be used for a driving method.

  Instead of the Hall element, a Hall IC may be used as a position detector for the rotor of the motor. The number of Hall elements is not necessarily three, and at least one Hall element only needs to be provided.

  The above-described flowcharts and timing charts show examples for explaining the operation, and the present invention is not limited to these. For example, in the above-described embodiment and its modifications, examples of control performed using the Hall signal Hu are shown, but other Hall signals Hv and Hw may be used. The steps shown in the flowcharts are specific examples and are not limited to this flow. For example, other processes may be inserted between the steps, or the processes may be parallelized.

  Each component of the motor drive control device may be at least partly processed by software rather than processed by hardware.

  The motor driven by the motor drive control device of the present embodiment is not limited to a three-phase brushless motor. The number of hall elements is not limited to three.

  Part or all of the processing in the above-described embodiment may be performed by software or may be performed using a hardware circuit.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1,201 Motor drive control apparatus 2 Motor drive part 3 Control circuit part 4 FG signal generation part 4a FG pattern 5 Current sensor (an example of a current detector)
6 Phase difference detector 20 Motor 25 (25u, 25v, 25w) Hall element (an example of a position detector)
31 PID control circuit 32 Sine wave generation circuit 33 Rotor position estimation circuit 50 Host device CLK Target speed signal CLK_16 Pulse signal Hu, Hv, Hw Hall signal (an example of position signal)
Sa advance angle information Sd drive control signal Sf FG signal Si phase current St torque command signal

Claims (7)

A motor drive control device that drives the motor based on a position signal corresponding to a rotational position of the motor generated by a position detector that detects a magnetic pole of the rotor,
An FG signal generator that generates an FG signal corresponding to the rotational speed of the rotor using an FG pattern;
A control circuit unit that generates a drive control signal based on the position signal, the FG signal, and a target speed signal so that the motor follows a target speed corresponding to the target speed signal;
A motor drive unit that outputs a drive voltage signal to the motor based on the drive control signal output from the control circuit unit;
The control circuit unit is
A torque command signal for controlling the motor to follow the target speed is generated according to a comparison result between the FG signal and the target speed signal,
The rotational position of the motor is estimated based on the number of pulses of a pulse signal corresponding to the target speed signal and having a cycle shorter than the target speed signal, from a reference timing obtained based on the position signal and the FG signal. And
A motor drive control device that generates the drive control signal based on the estimation result of the rotational position of the motor and the torque command signal.   The motor drive control device according to claim 1, wherein the pulse signal is a signal generated by dividing the target speed signal into a predetermined number.   The control circuit unit uses the fact that the zero-cross point of the induced voltage of each phase of the motor matches the zero-cross point of the FG signal generated by the FG pattern, and the position signal and the FG signal The motor drive control device according to claim 1, wherein the reference timing is obtained based on the reference. The control circuit unit is
A rotor position estimation circuit that receives the position signal, the target speed signal, and the FG signal, and outputs rotor position information corresponding to the estimated rotation position of the motor;
The motor drive control device according to claim 3, further comprising: a sine wave generation circuit that receives the rotor position information output from the rotor position estimation circuit and generates the drive control signal based on the rotor position information. A current detector for detecting the phase current;
A phase difference detector for generating advance angle information based on the phase current detected by the current detector, the pulse signal, and the FG signal;
5. The motor drive control device according to claim 1, wherein the control circuit unit controls an advance angle of the motor based on the advance angle information.   The phase difference detector calculates the number of pulses of the pulse signal up to the zero cross point of the phase current with reference to the zero cross point of the FG signal that matches the zero cross point of the induced voltage of the phase detecting the phase current. The motor drive control device according to claim 5, wherein the advance angle information is generated by performing phase control so that the measured phase error is zero. A control method of a motor drive control device for driving the motor based on a position signal corresponding to a rotational position of the motor generated by a position detector that detects a magnetic pole of the rotor,
The motor drive control device includes:
An FG signal generator that generates an FG signal corresponding to the rotational speed of the rotor using an FG pattern;
A control circuit unit that generates a drive control signal based on the position signal, the FG signal, and a target speed signal so that the motor follows a target speed corresponding to the target speed signal;
A motor drive unit that outputs a drive voltage signal to the motor based on the drive control signal output from the control circuit unit;
The control method of the motor drive control device is:
Generating a torque command signal for controlling the motor to follow the target speed according to a comparison result between the FG signal input to the control circuit unit and the target speed signal;
Based on the number of pulses of a pulse signal corresponding to the target speed signal and having a shorter cycle than the target speed signal from the reference timing obtained based on the position signal and the FG signal input to the control circuit unit. Estimating step for estimating the rotational position of the motor;
A control method for a motor drive control device, comprising: an output control step for outputting the drive control signal from the control circuit unit based on the estimation result of the rotational position of the motor and the torque command signal.

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