JP2017169332A - Motor driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor driving device that can appropriately perform correction of a rotation position of a rotor which is detected by a Hall sensor.SOLUTION: When rotation speed of a started-up motor 52 becomes predetermined rotation speed or more, a main power source current-carrying part 62 stops current-carrying to coils 14U, 14V and 14W by stopping output of drive waveforms to an FET driver 70, and a correcting part 54 calculates correction amounts of the rotation position of the rotor detected by a Hall element 12B on the basis of the rotation position of the rotor based on inducted voltages by the coils 14U, 14V and 14W to which current-carrying is stopped. After predetermined time has elapsed, an actual rotation number calculating part 56 corrects the rotation position of the rotor detected by the Hall element 12B on the basis of the correction amounts, and a current-carrying control drive-waveform determining part 64 determines drive-waveforms of voltages to be applied to the coils 14U, 14V and 14W on the basis of the corrected rotation position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor drive device.

  A drive device for a brushless DC motor (hereinafter abbreviated as “motor”) used in a blower motor of a vehicle air conditioner uses a PWM (pulse width modulation) to convert a phase voltage corresponding to the position of the rotor into an FET (field effect transistor). ) Is generated in the inverter circuit used for the switching element, and the generated voltage is applied to the motor coil.

  For detecting the position of the rotor, the magnetic field of a sensor magnet provided coaxially with the shaft of the motor for detecting the position of the rotor or the rotor is detected by a Hall sensor using a Hall element that is a semiconductor. However, if there is a deviation in the mounting position of the Hall sensor, the position of the rotor cannot be detected accurately, and the rotation of the motor becomes irregular.

  In Patent Document 1, the position of the rotor is calculated based on the induced voltage generated in each coil that has been de-energized after energization of each coil of the motor for a certain period of time, and the Hall sensor is calculated at the calculated rotor position. An invention of a brushless motor control device that corrects the position of the rotor detected by the motor is disclosed.

JP 2010-268673 A

  However, the brushless motor control device described in Patent Document 1 detects an induced voltage generated in each coil when the motor is in a non-energized state and idles at a predetermined rotation speed. Therefore, when an external force acts on the output shaft of the motor, the rotational speed of the motor deviates from a predetermined rotational speed, which may make it difficult to detect the induced voltage.

  For example, when the motor is a blower motor of a vehicle air conditioner, the external force acting on the output shaft of the motor can be generated by the ram pressure of the traveling wind interfering with the fan of the vehicle air conditioner.

  As a result of some external force acting on the output shaft of the motor, for example, the rotational speed of the idling motor may be higher than a predetermined rotational speed. In the invention described in Patent Document 1, when the rotational speed of the motor does not reach a predetermined rotational speed, it is not possible to proceed to the step of detecting the induced voltage, and as a result, the rotational position of the rotor detected by the Hall sensor is corrected. There was a risk of difficulty.

  The present invention has been made in view of the above, and an object of the present invention is to provide a motor drive device capable of accurately correcting the rotational position of the rotor detected by the Hall sensor.

  In order to solve the above-mentioned problem, the motor drive device according to claim 1 is predetermined according to each phase of the three-phase motor based on a magnetic field of a magnet attached to a rotation shaft of the three-phase motor. A first rotational position detector for detecting the rotational positions of the magnetic poles of the rotor; and a second rotational position detector for detecting the rotational positions of the magnetic poles of the rotor based on an induced voltage generated in a non-conducting phase coil of the three-phase motor. The three-phase motor rotates based on a rotational position detected by the rotational position detector, a drive circuit that generates a voltage to be applied to each phase coil of the three-phase motor, and the first rotational position detector. The drive circuit is controlled so that the coils of each phase of the three-phase motor are de-energized for a predetermined period after the rotational speed of the three-phase motor exceeds a predetermined value. After the predetermined period of time The first rotational position detector based on a correction value for making the rotational position detected by the first rotational position detector in the non-energized state equal to the rotational position detected by the second rotational position detector. And a control unit for controlling the drive circuit based on the rotational position obtained by correcting the rotational position detected in (1).

  According to this motor drive device, the induced voltage related to the correction of the rotational position detected by the rotational position detection unit when the rotational speed of the three-phase motor becomes equal to or higher than the predetermined rotational speed is detected. The Hall sensor can detect the induced voltage related to the correction of the rotational position even when the external force such as traveling wind acts on the output shaft of the three-phase motor and the rotational speed of the three-phase motor exceeds the predetermined rotational speed. Thus, the rotational position of the rotor detected by the first rotational position detector can be accurately corrected.

  According to a second aspect of the present invention, in the motor driving device according to the first aspect, the rotor rotates 360 degrees in electrical angle after the coils of each phase are de-energized during the predetermined period. Until the rotor rotates 360 degrees at a mechanical angle, and the control unit performs the operation based on the induced voltage detected after the rotor is rotated 360 degrees at an electrical angle after de-energizing the coils of the respective phases. A correction value is calculated.

  According to this motor drive device, by detecting the induced voltage after the rotor has rotated 360 degrees in electrical angle after being de-energized, the effect of the reflux current remaining immediately after de-energizing the coil is eliminated. Thus, it is possible to extract an induced voltage that is optimal for detecting the rotational position.

  According to a third aspect of the present invention, in the motor drive device according to the first or second aspect, the three-phase motor is based on the rotational position of the rotor corrected by the correction value after the predetermined period has elapsed. The drive circuit is controlled so that the rotational speed of the motor becomes the target rotational speed.

  According to this motor drive device, after calculating the correction value of the rotational position of the rotor, the voltage applied to the three-phase motor is controlled based on the rotational position of the rotor calculated by the correction value, and the rotation of the three-phase motor is controlled. The speed is reached to the target rotational speed. By controlling the rotation of the three-phase motor based on the corrected rotational position of the rotor, the rotation speed of the three-phase motor can be changed smoothly.

  According to a fourth aspect of the present invention, in the motor drive device according to any one of the first to third aspects, the control unit executes the calculation of the correction value a predetermined number of times and a correction calculated a predetermined number of times in each phase. The rotational position of the rotor detected by the first rotational position detection unit is corrected with an average value.

  According to this motor drive device, the correction of the rotational position of the rotor detected by the Hall sensor is performed accurately by using the average value of the correction values of the rotational position of the rotor calculated a plurality of times for correcting the rotational position of the rotor. be able to.

It is a figure which shows the outline of the motor drive device which concerns on embodiment of this invention. (A) is the schematic which showed an example of the sensor magnet of the motor drive device which concerns on embodiment of this invention, (B) is the schematic which showed an example of arrangement | positioning of the Hall element with respect to a sensor magnet. . It is a block diagram which shows the outline of an example of a structure of the correction | amendment part which concerns on embodiment of this invention. It is an example of the time chart of the output signal of a Hall sensor, and the inverter output voltage of an inverter circuit in the motor drive device of an embodiment of the invention. It is the schematic which showed an example when the Hall sensor on the same axis | shaft has produced the position shift in the delay direction with respect to the rotation direction. It is an example of the time chart in case the Hall sensor which concerns on embodiment of this invention has produced the position shift in the delay direction. It is a flowchart of an example of the detection and correction | amendment method of position shift of the Hall sensor which concerns on embodiment of this invention. It is an example of the time chart for demonstrating the noise by the return current which generate | occur | produces at the time of electricity supply of the brushless motor which concerns on the 1st Embodiment of this invention, and PWM off noise. It is explanatory drawing which showed an example of the relationship between the rotational speed of the motor which concerns on embodiment of this invention, and command value DUTY. It is an example of the time chart for demonstrating operation | movement of the correction | amendment part which concerns on embodiment of this invention. It is an example of the time chart which showed the relationship with the output signal U for detecting the position shift of the Hall sensor which concerns on embodiment of this invention, the comparator signal W, and the EX-OR signal, (A) is a position A case where no deviation occurs is shown, (B) shows a case where there is a delay, and (C) shows a case where advance occurs.

  FIG. 1 is a diagram schematically illustrating a motor drive device 20 according to the present embodiment. The inverter circuit 40 shown in FIG. 1 switches the electric power supplied to the coil of the stator 14 of the motor 52 by FET. For example, the FETs 44A and 44D switch the power supplied to the U-phase coil 14U, the FETs 44B and 44E switch to the V-phase coil 14V, and the FETs 44C and 44F switch the power supplied to the W-phase coil 14W.

  The drains of the FETs 44 </ b> A, 44 </ b> B, 44 </ b> C are connected to the positive electrode of the vehicle-mounted battery 80 via the choke coil 82. The sources of the FETs 44D, 44E, and 44F are connected to the negative electrode of the battery 80.

  In addition to the inverter circuit 40 described above, the correction unit 54, the correction control unit 54A, the actual rotation number calculation unit 56, the command rotation number calculation unit 58, and the standby circuit are provided on the substrate of the motor drive device 20 of the present embodiment. 60, a main power supply energization unit 62, an energization control drive waveform determination unit 64, a PI control unit 66, a voltage correction unit 68, an FET driver 70, and the like are mounted.

  Further, a choke coil 82 and smoothing capacitors 84A and 84B are mounted on the substrate of the motor drive device 20 of the present embodiment, and an air conditioner ECU (Electronic Control Unit) 78 and a battery 80 are connected. The choke coil 82 and the smoothing capacitors 84A and 84B together with the battery 80 constitute a substantially DC power source. The air conditioner ECU 78 is an electronic control unit for the vehicle air conditioner. When the user turns on the air conditioner by the air conditioner ECU 78, the motor 52 is operated by the control of the motor driving device 20. Further, when the user adjusts the air volume of the vehicle air conditioner, a signal for instructing the rotation speed of the motor 52 (rotor thereof) is input via the air conditioner ECU 78.

  In the present embodiment, the Hall element 12B detects the magnetic field of the sensor magnet 12A provided coaxially with the shaft. The correction unit 54 detects the positional deviation of the Hall element 12B relative to the sensor magnet 12A based on the output signals U, V, W input from the Hall element 12B and the induced voltage generated in the coils 14U, 14V, 14W, The rotor position detected by the Hall element 12B is corrected. In addition, the correction unit 54 converts the analog output of the Hall element 12B whose position of the rotor has been corrected into a digital signal.

  The correction control unit 54A is for controlling the timing and number of times the correction unit 54 performs correction (acquisition of data for correction), and includes a timer (not shown).

  The actual rotational speed calculation unit 56 calculates the actual rotational speed of the rotor based on the digital signal output from the correction unit 54. The command rotational speed calculation unit 58 calculates a target rotational speed based on an instruction from the air conditioner ECU 78 or the like. In the present embodiment, the target rotation speed is approximately 1000 to 5000 rpm.

  The PI controller 66 changes the coil of the stator 14 when changing the actual rotational speed to the target rotational speed from the target rotational speed calculated by the command rotational speed calculator 58 and the actual rotational speed calculated by the actual rotational speed calculator 56. The voltage applied to is calculated by so-called PI control. The PI control unit 66 includes a deviation proportional unit 66P that calculates a voltage at the target rotational speed based on a proportional relationship between a deviation between the target rotational speed and the actual rotational speed and a deviation between the voltage at the target rotational speed and the voltage at the actual rotational speed. Including. Further, the PI control unit 66 includes a deviation integration unit 66I that eliminates the residual deviation by deviation integration when the residual deviation is generated only by the proportional relationship. The voltage correction unit 68 corrects the calculation result by the PI control unit 66 according to the voltage of the battery 80, and outputs the corrected calculation result by the PI control unit 66 to the energization control drive waveform determination unit 64.

  The standby circuit 60 is a circuit that controls power supply from the battery 80 to each unit. Further, the main power supply energization unit 62 turns on the power supply to the motor drive device 20 according to the control of the standby circuit 60. Further, the main power supply energizing unit 62 issues a command to the forced 500 rpm command unit 88 via the OR circuit 86 when the motor 52 is started, that is, when the motor 52 is rotated from a rotation speed of 0 rpm. The forced 500 rpm command unit 88 controls the command rotational speed calculation unit 58 so that the target rotational speed becomes 500 rpm at a predetermined time when the motor 52 is started, and the command rotational speed calculation unit 58 performs PI control on a signal related to 500 rpm. The data is output to the unit 66. For example, the predetermined time is 500 to 1000 ms.

  After the predetermined time has elapsed, the control to the command rotational speed calculation unit 58 by the forced 500 rpm command unit is terminated, and the energization to the coils 14U, 14V, and 14W is interrupted to detect the induced voltage. The correcting unit 54 corrects the signal output from the Hall element 12B based on the detected induced voltage. After correcting the signal output from the hall element 12B, the command rotational speed calculation unit 58 outputs a signal related to the target rotational speed calculated based on an instruction from the air conditioner ECU 78 to the PI control unit 66.

  When power is supplied through the standby circuit 60 and the main power supply energization unit 62, the energization control drive waveform determination unit 64 drives the drive waveform of the voltage applied to the coil of the stator 14 based on the signal from the voltage correction unit 68. To decide.

  The FET driver 70 generates a PWM signal for controlling switching of the inverter circuit 40 based on the drive waveform determined by the energization control drive waveform determination unit 64 and outputs the PWM signal to the inverter circuit 40.

  A chip thermistor RT that detects the temperature of the substrate as a resistance value is mounted on the substrate of the motor drive device 20 according to the present embodiment. The chip thermistor RT used in the present embodiment is, for example, an NTC (Negative Temperature Coefficient) thermistor whose resistance decreases with increasing temperature. Note that a PTC (Positive Temperature Coefficient) thermistor whose resistance value increases as the temperature rises by using an inverting circuit together may be used.

  The chip thermistor RT constitutes a kind of voltage dividing circuit, and a voltage that changes based on the resistance value of the chip thermistor RT is output from the output terminal of the voltage dividing circuit constituted by the chip thermistor RT. The voltage output from the output terminal of the voltage dividing circuit constituted by the chip thermistor RT is compared with the overheat determination value output from the overheat determination value output unit 104 in the overheat state determination unit 106, and the output voltage is equal to or less than the overheat determination value. In this case, the command rotational speed calculation unit 58 is controlled so that the target rotational speed is forcibly set to 0 rpm. As described above, since the chip thermistor RT according to the present embodiment is a type in which the resistance decreases as the temperature rises, the voltage output from the output terminal of the voltage dividing circuit constituted by the chip thermistor RT is the temperature It shall decrease as the rise of The overheat state determination unit 106 determines that the circuit is overheated when the voltage output from one end of the chip thermistor RT is equal to or less than the overheat determination value. The overheat determination value varies depending on the element mounted on the substrate, the position of the chip thermistor RT, and the like. As an example, the overheat determination value is a voltage output from a voltage dividing circuit constituted by the chip thermistor RT at 145 ° C.

  Further, a current detector 94 for detecting the current of the inverter circuit 40 is provided between the source of each of the FETs 44D, 44E, and 44F and the battery 80. The current detector 94 detects a potential difference between both ends of the shunt resistor 94A having a resistance value as small as about 0.2 mΩ to several Ω and the shunt resistor 94A that changes according to the current of the inverter circuit 40, and outputs a signal of the detected potential difference. And an amplifier 94B for amplification. The signal output from the amplifier 94B is input to the overload determination unit 98 and the overcurrent determination unit 102, respectively. The overcurrent determination unit 102 compares the signal output from the amplifier 94B with the overcurrent determination value output from the overcurrent determination value output unit 100. When the signal output from the amplifier 94B is equal to or greater than the overcurrent determination value, The overcurrent detection signal is output to the protection priority determination unit 112. The overload determination unit 98 compares the signal output from the amplifier 94B with the overload determination value output from the overload determination value output unit 96, and when the signal output from the amplifier 94B is equal to or greater than the overload determination value. Sends a command to the forced 500 rpm command section 88 via the OR circuit 86 to control the motor 52 to forcibly reduce the rotational speed of the motor 52 to a predetermined rotational speed of 500 rpm.

  When the motor 52 is determined to be in an overload state and the rotation speed of the motor 52 is set to 500 rpm, the current value detected by the current detection unit 94 (the amplified value of the potential difference at both ends of the shunt resistor 94A that changes according to the current value) becomes the overload determination value. The rotational speed of the motor 52 is controlled to 500 rpm until it falls below. After the current value detected by the current detector 94 falls below the overload determination value, the voltage applied to the coil of the stator 14 is set so that the motor 52 rotates at the target rotational speed calculated by the command rotational speed calculator 58. Control.

  In the present embodiment, the overcurrent determination value is a value that exceeds the overload determination value, and current that must be de-energized to the motor 52 by stopping the generation of voltage by the inverter circuit 40 for circuit protection. Value. Since the specific values of the overcurrent determination value and the overload determination value depend on the specifications of the motor 52, they are specifically determined for each motor specification through simulation and experiment at the time of design.

  Connected between the choke coil 82 and the inverter circuit 40 is an overvoltage determination unit 110 that detects the power supply voltage and compares the value of the power supply voltage with the overvoltage determination value output from the overvoltage determination value output unit 108. . The overvoltage determination unit 110 outputs an overvoltage detection signal to the protection priority determination unit 112 when the power supply voltage is equal to or higher than the overvoltage determination value.

  The protection priority determination unit 112 rotates the motor 52 or stops the rotation of the motor 52 based on the overvoltage detection signal output from the overvoltage determination unit 110 and the overcurrent detection signal output from the overcurrent determination unit 102. The FET driver 70 is controlled so that the

  For example, when the overcurrent detection signal is not output and the overvoltage detection signal is output, the protection priority determination unit 112 rotates the motor 52 at a predetermined rotation speed in order to relax the power supply voltage that is too high. The forced ON state is continued for one control cycle (10 ms as an example) that is a unit cycle of control of the protection priority determination unit 112 that is a kind of processor.

  When the overcurrent detection signal is output, the FET driver 70 is controlled so as to stop the energization of the motor 52 in order to stop the rotation of the motor 52 even if the overvoltage detection signal is output. The elements constituting the inverter circuit 40 and the like are protected. In order to immediately stop energization, interrupt processing or the like is used as an example. After the overcurrent detection signal is output, the overcurrent OFF state in which the rotation of the motor 52 is stopped is continued for a predetermined time longer than the aforementioned one control cycle. The predetermined time is a predetermined positive integer multiple of one control cycle, and is 100 ms as an example in the present embodiment.

  2A is a schematic diagram illustrating an example of the sensor magnet 12A of the motor drive device 20 according to the present embodiment, and FIG. 2B illustrates an example of the arrangement of the Hall elements 12B with respect to the sensor magnet 12A. It is the shown schematic.

  As shown in FIG. 2A, the sensor magnet 12A is a permanent magnet, and N poles and S poles are alternately positioned around the axis at predetermined angles (for example, 60 degrees). A polar magnet that creates a specific magnetic field around it.

  The hall element 12B is for detecting the position (rotation position) of the rotor by detecting the magnetic field formed by the sensor magnet 12A. It includes a hall sensor 53U, a hall sensor 53V, and a hall sensor 53W corresponding to each phase. As shown in FIG. 2B, the hall sensors 53U, 53V, 53W are provided around the axis of the sensor magnet 12A every 20 degrees so as to face the sensor magnet 12A. Magnetic field lines constituting the magnetic field of 12A are detected, and position detection signals ("output signal U", "output signal V", and "output signal W") are output.

  FIG. 3 is a block diagram schematically illustrating an example of the configuration of the correction unit 54 according to the present embodiment. Based on the output signals U, V, W input from the hall sensors 53U, 53V, 53W and the induced voltage generated in the coils 14U, 14V, 14W, the correction unit 54 detects the sensor magnets of the hall sensors 53U, 53V, 53W. This is for detecting a positional deviation with respect to 12A and correcting the position of the rotor detected by the hall sensors 53U, 53V, 53W. As shown in FIG. 4, the correction unit 54 corrects the output signal V based on the induced voltage generated in the U-phase correction unit 54U that corrects the output signal U based on the induced voltage generated in the coil 14W and the coil 14U. A V-phase correction unit 54W that corrects the output signal W based on the induced voltage generated in the V-phase correction unit 54V and the coil 14V is included.

  As shown in FIG. 3, the U-phase correction unit 54U, the V-phase correction unit 54V, and the W-phase correction unit 54W include comparators 120U, 120V, 120W, EX-OR circuits 122U, 122V, 122W, and detection units 124U, 124V, 124W. Are included.

  A neutral point of the coils 14U, 14V, and 14W is connected to one input end of the comparator 120U of the U-phase correction unit 54U, and the other input end is connected to a terminal of the coil 14W. Further, the output signal of the comparator 120U and the output signal of the hall sensor 53U are input to the EX-OR circuit 122U.

  The neutral point is connected to one input terminal of the comparator 120V of the V-phase correction unit 54V, and the other input terminal is connected to the terminal of the coil 14U. The EX-OR circuit 122V is supplied with the output signal of the comparator 120V and the output signal of the hall sensor 53V.

  The neutral point is connected to one input terminal of the comparator 120W of the W-phase correction unit 54W, and the other input terminal is connected to the terminal of the coil 14V. Further, the output signal of the comparator 120W and the output signal of the hall sensor 53W are input to the EX-OR circuit 122W.

  The detection units 124U, 124V, and 124W according to the present embodiment convert the positional deviation amounts of the hall sensors 53U, 53V, and 53W relative to the sensor magnet 12A based on the output signals of the EX-OR circuits 122U, V, and W into electrical angles. The output signals U, V, and W of the hall sensors 53U, 53V, and 53W corrected for the detected positional deviation amount are output to the actual rotational speed calculation unit 56. The detection units 124U, 124V, and 124W are configured by a CPU, ROM, RAM, memory, and the like (not shown), and correct and output the output signals U, V, and W based on correction data stored in the memory and the like. .

(Operation of motor drive device)
The detection and correction of the positional deviation of the hall sensors 53U, 53V, 53W with respect to the sensor magnet 12A in the motor drive device 20 of the present embodiment will be described.

  FIG. 4 shows one electrical angle cycle of an example of a time chart of the output signals of the hall sensors 53U, 53V, and 53W and the inverter output voltage of the inverter circuit 40 in the motor drive device 20 of the present embodiment. FIG. 4 is a time chart in a state where the positional deviation or the like of the Hall sensors 53U, 53V, 53W has not occurred (the state of FIG. 2), that is, an ideal state. In FIG. 4, “on FET-U” is FET 44A, “below FET-U” is FET 44D, “on FET-V” is FET 44B, “below FET-V” is FET 44E, and “on FET-W” is The FET 44C and “under FET-W” indicate the FET 44F, respectively. When the output signals U, V, and W are at the H level, the N pole is indicated, and when the output signals U, V, and W are at the L level, the S pole is indicated.

  FIG. 5 is a schematic diagram showing an example in which the Hall sensors 53U, 53V, 53W on the same axis are displaced in the delay direction with respect to the rotation direction. FIG. 6 shows an example of a time chart when the positional deviation as shown in FIG. 5 occurs. As shown in FIG. 6, the output levels of the output signals U, V, and W are switched with a delay of an electrical angle X1 degrees corresponding to the positional deviation. In the present embodiment, an electrical angle corresponding to the positional deviation is detected based on the induced voltage, and correction is performed based on the detected electrical angle.

  FIG. 7 shows a flowchart of an example of a method for detecting and correcting misalignment of the hall sensors 53U, 53V, 53W of the present embodiment with respect to the sensor magnet 12A. In the present embodiment, when the user activates the air conditioner, the flowchart shown in FIG. 7 is started.

  When a command to turn on the air conditioner is input from the air conditioner ECU 78 in step 100, in step 102, the standby circuit 60 controls the main power supply energizing unit 62 and starts up with normal logic to turn on the motor drive device 20. To start. In step 104, the command rotational speed calculation unit 58 is controlled so that the target rotational speed is 500 rpm in a predetermined time.

  In step 106, it is determined whether or not the rotational speed of the motor 52 (rotor) has reached 450 rpm or higher. If it has not yet reached 450 rpm, the determination is negative and a standby state is established. In step 108, the main power supply energization unit 62 stops the output of the drive waveform from the energization control drive waveform determination unit 64 to the FET driver 70, thereby starting to cut off the energization to the coils 14 U, 14 V, and 14 W.

  In this embodiment, when the motor speed becomes 450 rpm or more immediately after the motor 52 is started, the energization to the coils 14U, 14V, and 14W is cut off, that is, the motor output is turned off for all phases, and the positional deviation is corrected. Correction data is acquired.

  In general, at the moment when the energized phase is switched in a state where the brushless motor is energized, as shown in FIG. 8, a reflux current flows, so that the induced voltage of the non-energized phase is deformed. Further, in order to control the energization state of the motor, PWM control is generally performed. However, as shown in FIG. 8, when monitoring the induced voltage of the non-energized phase, the PWM signal of the other phase is turned off. As a result, the reflux current flows, and the induced voltage of the non-conducting phase is deformed. In FIG. 8, the output signal of the U-phase, V-phase, and W-phase coils and the neutral point voltage are “H level” when the energized state is H level during energization. When L is at the L level, the comparison waveform is shown as “L level” when only the non-energized sections are compared.

  Thus, in the state where the brushless motor is energized, the induced voltage may be deformed.

  Corresponding to this, there is known an induced voltage type sensorless drive that performs mask processing of a comparison result between the reflux time after switching the energized phase and the OFF time of the PWM signal for detection of the zero cross point of the induced voltage. However, in this method, when the setting of the reflux time is inappropriate, and because the zero cross point in the PWM signal off-mask is detected with a delay of the mask time, an ideal timing and an error occur, resulting in noise and noise. Vibration or the like may increase.

  Therefore, in the present embodiment, all phases of the coils 14U, 14V, and 14W are turned off (energization cut off), the motor 52 (rotor) is idled, and correction data is acquired in a state where the induced voltage is stable. . When acquiring the correction data, it is sufficient that the rotation speed of the motor 52 is 450 rpm or higher. In this embodiment, the upper limit of the rotation speed of the motor 52 at the time of acquiring the correction data is not set. The motor 52 is stalled by cutting off the energization of the coils 14U, 14V, and 14W when the correction data is acquired. Therefore, when acquiring correction data (cutting off energization) so that the motor does not stop during the acquisition of correction data, it is preferable that the rotation speed of the motor 52 be sufficiently increased. Further, the rotation speed of the motor 52 may increase due to the rotation of the air conditioner fan caused by the ram pressure generated by the traveling wind. In this embodiment, the upper limit of the rotational speed of the motor 52 at the time of acquisition of correction data is not set so that correction data can be acquired even in such a case.

  In the present embodiment, the energization interruption time is set to about one rotation of the motor 52 (rotor) (one mechanical angle) so that the rotation of the motor 52 does not vary.

  In the present embodiment, specifically, when the rotational speed is 450 rpm or higher after the motor 52 is started, the energization to the coils 14U, 14V, and 14W is cut off, and correction data is acquired. FIG. 9 shows the relationship between the motor rotation speed of the motor 52 of the present embodiment and the command value DUTY. In addition, the normal rotation speed of the motor 52 of this Embodiment is 1000-5000 rpm as a specific example. As shown in FIG. 9, the range of the motor rotation speed of 0 to 1000 rpm only passes when the motor 52 is started or stopped, and thus is a range in which the user does not easily feel strange feelings such as noise, noise, and vibration. .

  Within this range, during the acquisition of the correction data, specifically, in the present embodiment, energization is performed until the motor 52 (rotor) makes one rotation (one mechanical angle period, that is, 360 degrees mechanical angle). Even when the motor is shut off, the motor 52 is not stalled due to the stalling of the motor 52, and the user is less likely to recognize the uncomfortable feeling of idling, and the zero cross point of the induced voltage can be reliably determined by the comparator 120. As a high rotation speed, a rotation speed of 450 rpm or more is used. In addition, since the said appropriate rotational speed changes with the normal rotation speed etc. of a motor, it is good to use the value obtained by experiment etc. previously.

  Further, in the motor 52 of the present embodiment, a regular output signal may be difficult to catch immediately after the energization is interrupted due to the influence of the reflux current. In this embodiment, it has been experimentally obtained in advance that regular correction data can be obtained without causing such a problem if at least one electrical angle period (360 electrical degrees) has elapsed after the energization is cut off. Therefore, the correction data is acquired after one electrical angle cycle.

  Therefore, in step 110 after energization interruption is started in step 108, it is determined whether or not one electrical angle cycle has elapsed since the energization was interrupted. In the present embodiment, the correction control unit 54A determines whether or not a time corresponding to one electrical angle cycle has elapsed. If the time has not elapsed, the result is negative and a standby state is entered. If the time has elapsed, the result is affirmed and the process proceeds to step 112 to start obtaining correction data.

  The operation of the correction unit 54 of the present embodiment will be described with reference to FIG. The comparator 120 compares the induced voltage of the coil 14 </ b> W with the neutral points of the coils 14 </ b> U, 14 </ b> V, and 14 </ b> W, and outputs an HL signal indicating the comparison result at the H level and the L level as the comparator signal W. The comparator W signal is output at an ideal timing that is not affected by the positional deviation of the hall sensors 53U, 53V, and 53W. The EX-OR circuit 122 outputs an EX-OR signal obtained by exclusive ORing the comparator W signal and the output signal U of the hall sensor 53U. From the driving principle of the brushless motor, it is an ideal state that the output phase is switched at a timing shifted by 30 degrees from the zero cross point of the induced voltage of the motor 52 (see FIG. 5). In other words, in the case shown in FIG. 10, when the electrical angle during the period in which the EX-OR signal is at the H level is 30 degrees, the Hall sensor 53U is not arranged at a shifted position in terms of mounting. The detection unit 124 stores an electrical angle of 30 degrees in an ideal state as a reference electrical angle, and the positional deviation of the Hall sensor 53U is determined by the difference between the electrical angle of the period in which the EX-OR signal is at the H level and 30 degrees. The detected deviation electric angle is stored as correction data.

  Therefore, in step 112, it is determined whether or not the EX-OR signal is at the H level. If the EX-OR signal is at the L level, the determination is negative and the standby state is established. The corner or time is counted, and in the next step 116, it is determined whether or not the EX-OR signal is at the L level. While it is still at the H level, the result is negative and the process returns to step 114 to continue counting the electrical angle or time. When the level is switched to the L level, the result is affirmed and the process proceeds to step 118.

  In step 118, it is determined how many times the counted electrical angle, that is, the electrical angle during the period when the EX-OR signal is at the H level. As shown in FIG. 11B, when the output signal U is delayed and is smaller than 30 degrees, the process proceeds to step 120, and the correction data is set to 30 degrees-electrical angle = electrical angle X2 degrees, and the advanced angle. On the other hand, as shown in FIG. 11A, when the hall sensor 53U is not displaced and is 30 degrees, the process proceeds to step 122 and no correction is performed (correction data = 0 degrees). Further, as shown in FIG. 11C, when the output signal U is advanced and is larger than 30 degrees, the process proceeds to step 124, and the correction data is set to the electrical angle −30 degrees = the electrical angle X3 degrees and the retarded angle. To do.

  In step 126 after steps 120, 122, and 124, the detection unit 124 stores the correction data. In the next step 128, the main power supply energization unit 62 releases the interruption of energization, and then the present process ends. When the energization cut-off is released in step 128, a current is energized from the inverter circuit 40 to each phase of the coils 14U, 14V, and 14W.

  Since the position shift of the hall sensor 53U is detected by the processing, the correction unit 54 corrects the output signals U, V, and W of the hall sensors 53U, 53V, and 53W based on the correction data stored in the detection unit 124. Is output to the actual rotational speed calculation unit 56. For example, in the case shown in FIG. 11B, the signal output timing is advanced (accelerated) by the electrical angle X2 degrees and output. Further, in the case shown in FIG. 11C, the output timing of the signal is sent (delayed) by the electrical angle X3 degrees and output. Thereby, the position shift of the hall sensor 53U can be corrected. The calculation of the correction data may be executed two or more times in each phase. The average value of the correction data calculated a plurality of times is defined as the correction data, and the output signal U of the hall sensors 53U, 53V, 53W. , V, and W may be used for correction.

  In the present embodiment, the detection unit 124 of the correction unit 54 measures the output of the EX-OR circuit 122, but is not limited thereto, and directly measures the switching of the waveforms of the output signal U and the comparator signal W. You may do it. In addition, although the electrical angle during the period when the output of the EX-OR circuit 122 is at the H level is measured, the electrical angle is not limited thereto, and the electrical angle during the period when the output is at the L level may be measured. In the above description, the correction unit 54 detects the positional shift of the Hall sensor 53U based on the output signal U and the induced voltage W. However, the present invention is not limited to this, and based on the induced voltage V, the induced voltage U, and the output signal U. May be detected. Similarly, the positional deviation of the Hall sensor 53V can be detected based on the output signal V and any one of the induced voltages U, V, and W, and any of the output signal W and the induced voltages U, V, and W can be detected. Therefore, the positional deviation of the hall sensor 53W can be detected.

  Further, although the coils 14U, 14V, and 14W of the present embodiment are illustrated with respect to a star-type stator coil (FIGS. 1 and 3), the present invention is not limited thereto, and may be a delta-type stator coil. When a delta stator coil is used, a pseudo neutral point is created so that the induced voltage output from the pseudo neutral point is input to the negative input terminal of the comparator 120. That's fine. Further, although a 6-pole motor is illustrated (FIGS. 1, 2, and 5), the present invention is not limited to this, and the positional deviation of the Hall sensors 53U, 53V, and 53W is similarly detected regardless of the number of motors. Can do.

  In the present embodiment, correction data is acquired after one electrical angle cycle has elapsed. However, the detection unit 124 ignores the input signal until one electrical angle cycle has elapsed by the correction control unit 54A. Control may be performed so that a signal is not input to the comparator 120 or the EX-OR circuit 122.

  In the present embodiment, the energization interruption to the coils 14U, 14V, and 14W is released (the energization is resumed) after the detection unit 124 stores the correction data. However, the present invention is not limited to this. After acquiring the electrical angle in the period of the H level, the energization may be resumed promptly so that the time during which the energization is interrupted is made shorter.

  Further, while the motor 52 is idling while the power is cut off, the rotation of the motor 52 decreases, and the deviation from the command value increases. Therefore, the feedback control in the rotational speed control of the motor is temporarily stopped. Yes. If the motor DUTY is not stopped, the calculation for increasing the drive DUTY proceeds. When the energization is resumed after the motor 52 is idled once, the drive DUTY value greatly changes immediately before the energization is interrupted and immediately after the energization is resumed. Therefore, the noise is prevented from increasing due to sudden torque fluctuation.

  Further, in the present embodiment, it is monitored that the motor 52 does not make one rotation during a predetermined time (one cycle of the mechanical angle exceeds the predetermined time). For example, it is considered that an excessive load is applied to the motor 52 and the motor driving device 20, and correction data is not acquired. This is because, when an excessive load is applied, normal correction data cannot be acquired, and therefore, when correction is performed using the correction data, appropriate correction cannot be performed.

  As described above, in the present embodiment, after the motor 52 is started, when the rotational speed becomes 450 rpm or more, the main power supply energization unit 62 interrupts the energization of the coils 14U, 14V, and 14W. The correction control unit 54A controls the correction unit 54 to acquire correction data for correcting the positional deviation of the hall sensor 53U after one electrical angle cycle has elapsed since the start of the energization interruption. The comparator 120 of the correction unit 54 outputs a comparator signal W that compares the neutral points of the coils 14U, 14V, and 14W with the induced voltage of the coil 14W, and the EX-OR circuit 122 outputs the comparator signal W and the Hall sensor 53U. An EX-OR signal that is an exclusive OR with the output signal U of the signal is output. The detection unit 124 acquires the electrical angle during the period in which the EX-OR signal is at the H level, and stores the difference between the acquired electrical angle and the reference electrical angle of 30 degrees as correction data. When the correction unit 54 acquires the correction data, the main power supply energization unit 62 resumes energization of the coils 14U, 14V, and 14W. That is, in the detection unit 124 of the correction unit 54 of the present embodiment, the relationship between the output signals of the Hall sensors 53U, 53V, 53W and the induced voltages of the coils 14U, 14V, 14W satisfies the time chart shown in FIG. Is detected and stored as correction data.

  As described above, according to the present embodiment, the correction data is acquired after one electrical angle cycle, which is a period in which noise is likely to occur in the output signal after the power supply to the coils 14U, 14V, and 14W is cut off. Since a stable output signal can be obtained, appropriate correction data can be acquired. Accordingly, it is possible to appropriately correct the relative positional deviation between the sensor magnet 12A and the hall sensors 53U, 53V, 53W.

  Further, since correction data appropriate for one rotation of the motor 52 (one mechanical angle cycle) can be acquired, the correction data can be acquired quickly. Therefore, since the energization interruption period to the coils 14U, 14V, and 14W can be shortened, it is possible to prevent the generation of noise and vibration due to the increase in the energization interruption period, so that the user does not feel uncomfortable. Can be.

  Further, according to the present embodiment, after the motor 52 is started, the correction data is acquired when the rotation speed of the motor 52 is 450 rpm or more, and the upper limit of the rotation speed of the motor 52 when the correction data is acquired is set. Not. Correction data can be acquired even when the rotation speed of the motor 52 is increased by rotating the fan of the air conditioner with the ram pressure generated by the traveling wind, so the Hall sensors 53U, 53V, and 53W detect it. It is possible to accurately correct the rotational position of the rotor.

DESCRIPTION OF SYMBOLS 12A ... Sensor magnet, 12B ... Hall element, 14 ... Stator, 14U, 14V, 14W ... Coil, 20 ... Motor drive device, 40 ... Inverter circuit, 44A, 44B, 44C, 44D, 44E, 44F ... FET, 52 ... Motor 53U, 53V, 53W ... Hall sensor, 54 ... correction unit, 54A ... correction control unit, 54U ... U-phase correction unit, 54V ... V-phase correction unit, 54W ... W-phase correction unit, 56 ... actual rotational speed calculation unit, 58 ... Command rotational speed calculation unit, 60 ... Standby circuit, 62 ... Main power supply energization unit, 64 ... Electrification control drive waveform determination unit, 66 ... PI control unit, 66I ... Deviation integration unit, 66P ... Deviation proportional unit, 68 ... Voltage Correction unit, 70 ... FET driver, 78 ... Air conditioner ECU, 80 ... Battery, 82 ... Choke coil, 84A ... Smoothing capacitor, 86 ... OR circuit, 88 Forced 500 rpm command unit, 94 ... Current detection unit, 94A ... Shunt resistance, 94B ... Amplifier, 96 ... Overload determination value output unit, 98 ... Overload determination value output unit, 100 ... Overcurrent determination value output unit, 102 ... Overcurrent determination , 104 ... Overheat determination value output unit, 106 ... Overheat state determination unit, 108 ... Overvoltage determination value output unit, 110 ... Overvoltage determination unit, 112 ... Protection priority determination unit, 120U, 120V, 120W ... Comparator, 122U, 122V , 122W ... EX-OR circuit, 124U, 124V, 124W ... detector, RT ... chip thermistor, X1, X2, X3 ... electrical angle

Claims (4)

A first rotational position detector for detecting a rotational position of a magnetic pole of a rotor determined in advance corresponding to each phase of the three-phase motor based on a magnetic field of a magnet attached to a rotational shaft of the three-phase motor;
A second rotational position detector for detecting each rotational position of the magnetic poles of the rotor, based on an induced voltage generated in a non-energized phase coil of the three-phase motor;
A drive circuit for generating a voltage to be applied to each phase coil of the three-phase motor;
Based on the rotational position detected by the first rotational position detector, the drive circuit is controlled so that the three-phase motor rotates, and the rotational speed of the three-phase motor reaches a predetermined value or higher. During the period, the drive circuit is controlled so that the coils of each phase of the three-phase motor are not energized, and after the predetermined period has elapsed, the rotation detected by the first rotational position detector in the unenergized state The drive based on the rotational position obtained by correcting the rotational position detected by the first rotational position detector based on a correction value for making the position equal to the rotational position detected by the second rotational position detector. A control unit for controlling the circuit;
A motor driving device. The predetermined period is a period from when the coils of each phase are de-energized until the rotor rotates 360 degrees in electrical angle, and further, the rotor rotates 360 degrees in mechanical angle,
2. The motor driving apparatus according to claim 1, wherein the control unit calculates the correction value based on an induced voltage detected after the rotor rotates 360 degrees in electrical angle after the coils of each phase are de-energized. 3.   The control unit controls the drive circuit so that a rotation speed of the three-phase motor becomes a target rotation speed based on a rotation position of the rotor corrected by the correction value after the predetermined period has elapsed. 3. The motor driving device according to 1 or 2.   The controller executes the calculation of the correction value a predetermined number of times in each phase and corrects the rotational position of the rotor detected by the first rotational position detection unit with an average value of the correction values calculated a predetermined number of times. Item 4. The motor driving device according to any one of Items 1 to 3.