JP2006034086A - Apparatus and method of driving motor and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost apparatus of driving a motor which accurately performs the phase control of the motor with high efficiency. <P>SOLUTION: The apparatus of driving the motor includes a motor driver, a rotor position detector, a current phase detector, a voltage signal generator, and a drive signal generator. The motor driver has a plurality of half-bridge circuits, having a set of a drive transistor of high potential side and a drive transistor of low-potential side connected in series. The rotor position detector detects the rotor position of the motor and outputs rotor position signal. The current phase detector detects the phase of the phase current flowing a stator coil drive terminal. The voltage signal generator controls voltage profile signal so that the phase difference of the phase current and the rotor position signal is maintained at a predetermined electric angle, and generates the voltage profile signal. The drive signal generator generates a PWM signal for driving the drive transistors of the respective phases, in response to the voltage profile signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention generally relates to a motor driving device, a motor driving method, and an electronic device including the motor driving device.

  The brushless motor drive device detects the position of the rotor of the motor to be controlled, and energizes the stator coil based on the position signal. However, the phase of the position signal may be shifted due to factors such as the rotational speed of the motor and load torque. As a result, the energization phase shifts, the driving efficiency of the motor decreases, and the power consumption increases. Further, when the motor is driven with a rectangular wave voltage based on rotor position information obtained several times during one rotation of the motor, vibration and noise are generated when the motor rotates.

  Japanese Unexamined Patent Application Publication No. 2001-037279 discloses the motor driving devices of Conventional Examples 1 and 2. With reference to FIGS. 14 and 15, the motor driving devices of the conventional examples 1 and 2 will be described. 14 and 15 show block diagrams of the motor driving devices of the conventional examples 1 and 2, respectively.

  The motor driving apparatus of Conventional Example 1 shown in FIG. 14 will be described. In FIG. 14, a DC power source 1 supplies power to a motor drive device. The current detection unit 4 detects a power supply current flowing through the motor driving unit 2. The rotor position detector 13 outputs a position signal having a fixed phase relationship with the induced voltage generated in the multi-phase stator coil according to the rotational position of the rotor of the permanent magnet motor 3. The period measurement unit 1401 measures the change period of the position signal. The pulse generator 1402 generates a plurality of clock pulses within the change period.

  The peak hold unit 1408 holds the peak value of the detection signal of the current detection unit 4. For any one of the position signals, the rotational speed detection unit 1405 counts, for example, the number of rising edges output per second as the rotational speed of the permanent magnet motor 3. Next, the rotation speed detection unit 1405 outputs the voltage signal Vf at a level corresponding to the rotation speed to the addition unit 1409 to perform F / V conversion. The adder 1409 adds the voltage signal levels output from the rotation speed detector 1405 and the peak hold unit 1408 in an analog manner. The A / D converter 1406 A / D converts the analog voltage signal supplied from the adder 1409 and outputs digital data.

  The phase estimation unit 1403 includes a counter that counts the number of generated clock pulses, and estimates the phase of the rotor based on the count value of the counter based on the timing at which the position signal changes. The phase correction unit 1407 corrects the rotor phase by setting the correction value derived based on the output signal of the A / D conversion unit 1406 in the counter at the timing when the position signal changes. Specifically, the phase correction unit 1407 corrects the phase so that the commutation timing in the stator coil is advanced in accordance with, for example, an increase in the load torque of the motor 3. The voltage signal generator 1404 generates a predetermined voltage signal according to the phase of the rotor. The triangular wave generator 8 generates a triangular wave for generating a carrier wave of the PWM signal. The drive signal generator 9 generates a drive signal by comparing the signal level of the voltage signal with the signal level of the carrier wave. The motor drive unit 2 energizes the multi-phase stator coil based on the drive signal.

  The motor driving device of the conventional example 1 energizes each stator coil of the motor 3 based on the torque current information from the current detection unit 4 and the rotation speed information and phase information from the rotor position detection unit 13.

  A motor driving device of Conventional Example 2 shown in FIG. 15 will be described. The motor drive device of Conventional Example 2 has a configuration similar to that of the motor drive device of Conventional Example 1. In FIG. 15, the same or equivalent components as those of the conventional example 1 are denoted by the same reference numerals and description thereof is omitted. Only the parts different from the conventional example 1 will be described below.

  As shown in FIG. 15, the motor driving device of the conventional example 2 deletes the adding unit 1409, the current detection unit 4 and the peak hold unit 1408 from the configuration of the conventional example 1 and adds a speed control unit 1501 and a phase control unit 1502. It is a thing. The speed control unit 1501 compares a speed command given from the outside with the rotation number detected by the rotation number detection unit 1405, and outputs a voltage command corresponding to the difference. The phase control unit 1502 differentially amplifies the difference between the voltage command and the voltage signal Vf from the rotation speed detection unit 1405 to generate a phase command. Then, the phase correction unit 1407 sets the digital data obtained by A / D converting the phase command as the phase correction value PC.

  The motor driving device of Conventional Example 2 energizes each stator coil of the motor based on the speed command and the rotational speed information and phase information from the rotor position detector 13.

  The motor driving devices of the conventional examples 1 and 2 estimate the phase of the rotor based on the count value of the counter. As a result, the motor driving devices of the conventional examples 1 and 2 obtain the phase of the rotor with a finer resolution than the change period of the position signal, and drive the motor 3 with a sinusoidal voltage based on the detailed phase information of the rotor. To do. As a result, the motor driving devices of the conventional examples 1 and 2 drive the motor with high efficiency by reducing vibration and noise generated in the motor.

  In the motor driving devices of Conventional Examples 1 and 2, the phase difference between the induced voltage of each phase and the phase information from the rotor position detector 13 is uniquely determined from the characteristics of each motor. The phase of the voltage supplied to each stator coil is a predetermined value corresponding to the rotational speed of the motor.

JP 2001-037279 A

  The conventional motor driving apparatus described above performs phase control based on a predetermined value that is individually determined by the characteristics of each motor. For this reason, it is necessary to determine a predetermined value depending on the electric constants of the resistance and inductance of the motor. In a motor drive device that controls a motor by a microcomputer, it is easy to change these predetermined values. For example, a motor control device for a device having an expensive and large motor such as a washing machine or an air conditioner performs accurate phase control using a microcomputer. However, in a motor drive device that controls a relatively small motor, low cost and versatility that does not depend on the structure and / or characteristics of the motor are required.

  In the motor driving devices of Conventional Examples 1 and 2, low cost and versatility cannot be realized. The amount of phase correction that changes as the motor speed or load torque increases or decreases depends on the characteristics of each motor. The motor driving devices of Conventional Examples 1 and 2 are configured for the purpose of driving a specific motor. Therefore, the motor driving devices of the conventional examples 1 and 2 cannot perform optimum phase correction when driving a motor having an electric constant (resistance, inductance, etc.) different from that of the motor.

  An object of the present invention is to provide a low-cost motor driving device and a motor driving method that perform motor phase control with high efficiency and accuracy.

An object of the present invention is to provide a low-cost motor driving device and a motor driving method that perform phase control of a motor with high efficiency and accuracy without depending on the characteristics of the motor.
An object of the present invention is to provide a highly efficient and low-cost electronic device.

In order to solve the above problems, the present invention has the following configuration.
A motor driving apparatus according to one aspect of the present invention includes a plurality of half bridges in which a high potential side driving transistor and a low potential side driving transistor are connected in series, and the connection point is a stator coil driving terminal of each phase of the motor. A motor drive unit having a circuit; a rotor position detection unit for detecting a rotor position of the motor and outputting a rotor position signal; and a current phase detection for detecting a phase of a phase current flowing through the stator coil drive terminal And a voltage signal generator that controls and generates a voltage profile signal so that a first phase difference that is a difference between the phase of the phase current and the phase of the rotor position signal is maintained at a predetermined electrical angle. And a drive signal generation unit that generates a PWM signal for driving the drive transistor of each phase according to the voltage profile signal.
The present invention realizes a motor driving device that performs phase control of a motor with high efficiency and accuracy by the above-described configuration that is small and low-cost.

According to another aspect of the present invention, there is provided a motor drive device, wherein the voltage signal generation unit is configured to output the current phase signal in a state where the phase difference feedback for controlling the phase is not performed in the motor drive device. The phase is initialized to a phase further advanced with respect to the phase of the rotor position signal for a first predetermined period than the predetermined amount, and the voltage profile signal is generated and energization is started.
It is possible to reliably lock the difference between the phase of the phase current and the phase of the rotor position signal to the target value without causing a loss of control before the motor reaches the steady state from the starting state.

According to still another aspect of the present invention, there is provided a motor drive device including a plurality of sets of drive transistors for driving phase currents flowing through stator coils of respective phases of the motor and regenerative diodes connected in parallel to the drive transistors. A drive unit, a potential of one end of the regenerative diode or a potential difference between both ends generated by a regenerative current flowing through the regenerative diode in a forward direction is compared with a predetermined threshold, and a phase of a phase current is derived based on the comparison result; An output current phase detection unit; and a voltage signal generation unit that outputs a voltage to be applied to the motor drive unit based on the phase of the phase current.
The present invention realizes a motor driving device that performs phase control of a motor with high efficiency and accuracy by the above-described configuration that is small and low-cost.

A motor driving apparatus according to still another aspect of the present invention includes a plurality of high-potential-side driving transistors and low-potential-side driving transistors connected in series, and the connection points serving as stator coil driving terminals for each phase of the motor. A motor drive unit in which a regenerative diode is connected in parallel to each of the drive transistors, a potential at one or both ends of the regenerative diode on the high potential side, and one of the regenerative diode on the low potential side A potential shift circuit for shifting the potential at one end or both ends by a different predetermined voltage, a comparator for comparing the output signal of the potential shift circuit with a predetermined threshold, and an output signal of the comparator as input. A phase current phase detection circuit for deriving and outputting the phase of the current phase, and applying a signal to the motor drive unit based on the phase of the phase current. It has a voltage signal generator that outputs a voltage, a.
The present invention realizes a motor drive device that detects a zero-cross point by the above-described configuration that is small and low-cost, and performs motor phase control with high efficiency and accuracy without depending on the characteristics of the motor.

A motor driving apparatus according to still another aspect of the present invention includes a plurality of high-potential-side driving transistors and low-potential-side driving transistors connected in series, and the connection points serving as stator coil driving terminals for each phase of the motor. A motor drive unit having a regenerative diode connected in parallel to each of the drive transistors, and a potential obtained by applying a first offset voltage to the voltage of at least one phase of the stator coil drive terminal A current phase detector that compares a predetermined threshold value and derives and outputs a phase current phase based on the comparison result, and a voltage signal that outputs a voltage applied to the motor drive unit based on the phase current phase And a generation unit.
The present invention realizes a motor drive device that detects a zero-cross point by the above-described configuration that is small and low-cost, and performs motor phase control with high efficiency and accuracy without depending on the characteristics of the motor.

A motor driving apparatus according to still another aspect of the present invention includes a plurality of high-potential-side driving transistors and low-potential-side driving transistors connected in series, and the connection points serving as stator coil driving terminals for each phase of the motor. A motor drive unit having a regenerative diode connected in parallel to each of the drive transistors, and a potential obtained by applying a first offset voltage to the voltage of at least one phase of the stator coil drive terminal A first comparison result comparing the first threshold value, and a second comparison result comparing a potential obtained by applying a second offset voltage to the voltage of the stator coil drive terminal and the second threshold value. A current phase detector that derives and outputs the phase of the phase current based on the phase current, and a voltage signal generator that outputs the voltage applied to the motor drive based on the phase of the phase current. It has a part, a.
The present invention realizes a motor drive device that detects a zero-cross point by the above-described configuration that is small and low-cost, and performs motor phase control with high efficiency and accuracy without depending on the characteristics of the motor.

  According to still another aspect of the present invention, there is provided a motor drive device including a plurality of sets of drive transistors for driving phase currents flowing through stator coils of respective phases of the motor and regenerative diodes connected in parallel to the drive transistors. The potential of both ends of the regenerative diode generated by the regenerative current flowing in the forward direction through the regenerative diode is compared after applying an offset voltage to at least one potential, and the phase of the phase current based on the comparison result And a voltage signal generator that outputs a voltage to be applied to the motor drive unit based on the phase of the phase current.

  An electronic device according to one aspect of the present invention includes the motor driving device described above. The present invention realizes a small and low-cost electronic device that performs motor phase control with high efficiency and accuracy.

The present invention realizes a motor control method that exhibits the same effects as described above.
The novel features of the invention are nonetheless specifically set forth in the appended claims, but the invention, both in terms of structure and content, together with other objects and features, will be understood in conjunction with the drawings. Will be better understood and appreciated from the detailed description.

According to the present invention, by always maintaining a predetermined phase difference between the phase of the phase current and the rotor position signal, it is possible to obtain an advantageous effect that a highly efficient and low-cost motor driving device and motor driving method can be realized. .
According to the present invention, it is possible to obtain an advantageous effect that a motor driving device and a motor driving method that are highly efficient and low cost can be realized without depending on the characteristics of the motor.
According to the present invention, it is possible to obtain an advantageous effect that a high-efficiency and low-cost electronic device can be realized.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments that specifically show the best mode for carrying out the present invention will be described below with reference to the drawings.

<< Embodiment >>

Hereinafter, a motor drive device and a motor drive method according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a motor driving apparatus according to an embodiment of the present invention.
The motor drive device according to the embodiment is a drive device for a spindle motor of an optical disk.

  The DC power supply 1 supplies power to the motor drive device. The current detection unit 4 detects a power supply current flowing through the motor driving unit 2. The current signal shaping unit 5 generates a current signal corresponding to the peak value of the power supply current detected by the current detection unit 4. The error amplifier 6 receives the current signal output from the current signal shaping unit 5 and the torque command signal (current value command signal) input from the outside via the torque command signal input terminal 7. An error signal which is a value obtained by subtracting the current signal from the output signal is output.

  The rotor position detection unit 13 outputs a rotor position signal having a fixed phase relationship with the induced voltage generated in the plurality of phases of the stator coils of the motor 3. In the embodiment, the rotor position detection unit 13 is three Hall elements arranged at positions separated from each stator coil by a predetermined electrical angle. The rotor position signal from the rotor position detector 13 is input to the phase difference detector 12 and the voltage signal generator 10.

The voltage signal generator 10 generates a sine wave signal whose voltage value periodically changes according to the electrical angle phase of the rotor of the motor 3 detected by the rotor position detector 13. The voltage signal generator 10 determines the amplitude of the sine wave based on the error signal output from the error amplifier 6. The voltage signal generation unit 10 outputs three-phase sine wave signals having a phase difference of 120 degrees from each other.
The current phase detector 11 detects the phase of the phase current flowing through the stator coil and outputs a current phase signal. The phase difference detection unit 12 detects the phase difference between the rotor position signal and the current phase signal, and inputs the detected phase difference to the voltage signal generation unit 10. The voltage signal generation unit 10 corrects the phase of the generated sine wave signal with respect to the phase of the rotor position signal based on the phase difference signal from the phase difference detection unit 12.

The triangular wave generator 8 generates a triangular wave for generating a PWM signal. The drive signal generator 9 slices the triangular wave from the triangular wave generator 8 with the output value from the voltage signal generator 10 to generate a PWM signal. The drive signal generator 9 outputs a three-phase energization signal that is a PWM signal. The drive signal generation unit 9 may include a level shift stage. The level shift stage determines the level of the signal input to the level shift stage when the voltage difference exists between the power supply voltage of the drive signal generation unit 9 and the power supply voltage of the next motor drive unit 2. The signal is converted to a level corresponding to the level of the power supply voltage and transmitted.
The motor drive unit 2 includes high potential side drive transistors 56a to 56c, low potential side drive transistors 57a to 57c, and current regeneration diodes 58a to 58f.
The motor drive unit 2 inputs a three-phase energization signal that is a PWM signal from the drive signal generation unit 9, amplifies this, and drives the motor 3.

  The motor driving apparatus according to the embodiment of the present invention drives the motor so that the phase current flowing through the stator coil and the rotor position signal have a predetermined phase relationship. The rotor position signal and the induced voltage of the stator coil have a certain phase difference determined by the motor structure. The motor drive device according to the embodiment of the present invention provides a phase difference between the phase current flowing through the stator coil and the rotor position signal so that the phase current flowing through the stator coil and the induced voltage of the stator coil have an optimum phase difference. Keep the motor constant and drive the motor. As a result, the motor drive apparatus according to the embodiment of the present invention can keep the stator coil current and the induced voltage in an optimum phase relationship regardless of the electric constant of the motor, and drive the motor with high efficiency. Can do.

  In FIG. 1, the current detection unit 4 is provided between the low potential side common connection terminals of the drive transistors 57 a to 57 c and the low potential side power supply. Instead, it may be provided between the high potential side common connection terminals of the drive transistors 56a to 56c and the high potential side power supply, or may be provided in series with the three-phase power supply line to the motor 3, It may be provided so as to be interposed between any of the high potential side drive transistors 56a, 56b, and 56c and the high potential side common connection terminal. Further, it may be provided between any of the low potential side drive transistors 57a, 57b and 57c and the low potential side common connection terminal, or in parallel with any of the high potential side drive transistors 56a, 56b and 56c. It may be provided in a connected current mirror circuit (not shown) or may be provided in a current mirror circuit (not shown) connected in parallel to any of the low potential side drive transistors 57a, 57b, 57c.

FIG. 2 shows an example of phase correction by the motor driving apparatus of the present embodiment. 2 (a), 2 (b), and 2 (c) show a driving voltage, a phase current (driving current), and a rotor position signal for a one-phase stator coil, respectively. In FIG. 2A, reference numeral 14 denotes a one-phase waveform among the three-phase drive voltages output from the voltage signal generation unit 10. Reference numerals 15a and 15b denote zero cross points at which the drive voltage, which is a sine wave, crosses the AC component 0 level (AC reference potential).
In FIG. 2 (b), three phase current signals 100, 101, 102 are shown. The phase of the phase current signals 100, 101, 102 is delayed with respect to the phase of the drive voltage 14. The phase current signal 100 is a current waveform when the phase of the phase current is in an optimum condition for improving efficiency. The phase current signal 101 is a current waveform in a state where the phase is slightly advanced from the optimum phase. The phase current signal 102 is a current waveform when the phase is slightly delayed from the optimum phase. The phase of the rotor position signal shown in FIG. 2 (c) differs depending on the mounting position of the Hall element constituting the rotor position detecting unit 13.

  In many motors, when the motor is driven so that the phase current signal zero-crosses at a position advanced by 30 degrees or delayed by 30 degrees from the cross position (zero cross position) with respect to the AC component 0 level of the rotor position signal, the drive efficiency of the motor Is maximized. 2A to 2C showing examples of each signal waveform, the zero cross position of the phase current (FIG. 2B) may be delayed by 30 degrees from the zero cross position of the rotor position signal (FIG. 2C). For example, the driving efficiency of the motor is maximized.

  If the phase current signal input by the phase difference detector 12 is the signal 100 in FIG. 2B, the zero cross point coincides with the points 18a and 18b. Points 18a and 18b are points obtained by delaying the zero cross points 17a and 17b of the rotor position signal of FIG. 2C by 30 degrees. The phase difference detection unit 12 sends phase difference information to the voltage signal generation unit 10. At this time, the drive voltage waveform 14 output from the voltage signal generator 10 is appropriate. The voltage signal generator 10 does not correct the phase of the output drive voltage.

  The phase difference detection unit 12 according to the embodiment stores an appropriate phase difference between the rotor position signal output from the Hall element and the phase current, and stores the phase difference between the measured rotor position signal and the phase current. A value obtained by subtracting an appropriate phase difference is calculated and sent to the voltage signal generator 10. An appropriate phase difference is determined by the mounting position of the Hall element. Instead of the configuration of the embodiment, the voltage signal generation unit 10 stores an appropriate phase difference between the rotor position signal output from the Hall element and the phase current, and from the measured phase difference between the rotor position signal and the phase current. Alternatively, a value obtained by subtracting an appropriate phase difference to be stored may be calculated.

  If the phase current signal input by the phase difference detector 12 is the signal 101 in FIG. 2B, the zero cross point is advanced by the phase indicated by 20 from the points 18a and 18b. Points 18a and 18b are points obtained by delaying the zero cross points 17a and 17b of the rotor position signal of FIG. 2C by 30 degrees. At this time, the phase of the drive voltage waveform 14 output from the voltage signal generation unit 10 is advanced from the optimum value. The phase difference detection unit 12 counts the period 20 and sends information on the phase difference that is the counted value to the voltage signal generation unit 10. The voltage signal generation unit 10 corrects the angle information of the drive voltage profile or corrects the start timing of the drive voltage profile (details will be described later).

  If the phase current signal input by the phase difference detector 12 is the signal 102 in FIG. 2B, the zero cross point is delayed by the phase indicated by 21 from the points 18a and 18b. Points 18a and 18b are points obtained by delaying the zero cross points 17a and 17b of the rotor position signal of FIG. 2C by 30 degrees. At this time, the phase of the drive voltage waveform 14 output from the voltage signal generator 10 is delayed from the optimum value. The phase difference detection unit 12 counts the period 21 and sends information on the phase difference that is the counted value to the voltage signal generation unit 10. The voltage signal generator 10 corrects the phase of the output drive voltage or corrects the start timing of the drive voltage.

  When the phase correction control of the voltage signal generation unit 10 is out of phase lock and the phase of the phase current is excessively delayed or excessively advanced, the control system becomes unstable. In order to prevent this, in the voltage signal generation unit 10, the zero cross points 15a and 15b in the drive voltage waveform 14 are delayed from the points 18a and 18b (the zero cross points of the phase current when the motor 3 is appropriately controlled). An upper limit value of the phase delay amount of the phase current with respect to the rotor position signal is determined so as not to be present. Points 18 a and 18 b are points where an appropriate phase difference is delayed from the zero cross points 17 a and 17 b of the rotor position signal 16. Further, the voltage signal generator 10 determines the lower limit value of the phase delay amount of the phase current with respect to the rotor position signal so that the zero cross points 15a and 15b do not advance the phase beyond the points 18a and 18b for a first predetermined period.

  By limiting the phase difference between the rotor position signal and the phase current within a predetermined range, it is possible to prevent an excessive phase advance or phase lag in a region where the rotational speed is high. By changing the first predetermined value, which is the upper limit value for advancing the phase, so as to decrease as the rotational speed increases, it is possible to prevent the control from being unlocked due to the phase advance in the high rotation range.

  In the phase current of FIG. 2B, it is important to detect the timing of the zero crossing, and it can be easily detected by the method described later. Each of the three-phase driving voltages output from the voltage signal forming circuit 10 and whose phases are shifted by 120 degrees may be phase-corrected independently. Also, one phase drive voltage is generated by phase correction, and another two phase drive voltage is generated by shifting the one phase drive voltage by 120 degrees and 240 degrees, respectively, and the three phase drive voltage is output. You can also

  The voltage signal generation unit 10 according to the embodiment generates and outputs a sinusoidal drive voltage 14 shown in FIG. Instead, the voltage signal generation unit 10 divides the electrical angle 360 degrees into three equal parts as shown in FIG. 3, and outputs a waveform 22 in which the driving voltage of each phase becomes zero level in each 120 degree section. Is also possible. The two upper peaks of the driving voltage 22 of each phase in FIG. 3 are out of phase with each other by 60 degrees. The two upper peaks of the driving voltage 22 of each phase in FIG. 3 are out of phase with each other by 60 degrees. The voltage signal generator 10 corrects the phase of the zero cross points 15a and 15b by the same method as described above.

  FIG. 4 is a block diagram illustrating a configuration of the voltage signal generation unit 10 according to the embodiment. The voltage signal generation unit 10 generates the drive voltage 14 in FIG. 2A and the drive voltage having the phase shifted by 120 degrees and 240 degrees, respectively. In FIG. 4, an error signal input terminal 401 output from the error amplifying unit 6, a rotor position signal input terminal 402, a phase difference signal input terminal 403 output from the phase difference detection unit 12, a control unit 405, and a plurality of resistors are provided. The resistor connection body 406 connected in series, the switches 407 to 409, the highest potential line 410, the lowest potential line 411, the output terminal 412 of the first phase driving voltage, the output terminal 413 of the second phase driving voltage, and the third A phase drive voltage output terminal 414 is shown.

  The control unit 405 inputs the error signal from the error amplification unit 6 and outputs the highest potential and the lowest potential of the sine wave drive voltage and sine wave drive voltage to the highest potential line 410 and the lowest potential line 411. Further, the control unit 405 inputs the rotor position signal and the phase difference signal, and outputs the phase signals of the first phase, the second phase, and the third phase indicating the phase of the driving voltage of each phase to the control terminals of the switches 407 to 409. It outputs to 417-419. The resistance connector 406 divides the voltage of the highest potential line 410 and the voltage of the lowest potential line 411 to generate voltages in various phases of a pseudo sine wave having two voltages as upper and lower peaks, It outputs to each contact of switches 407-409. A function of the voltage formed by the voltage group input to each contact of the switches 407 to 409 is called a voltage profile. In the embodiment, the voltage profile is a pseudo sine wave voltage. The voltage profile may be, for example, the waveform shown in FIG. The switches 407 to 409 switch the contacts according to the phase signals of the first phase, the second phase, and the third phase inputted to the respective control terminals 417 to 419, sequentially output the voltages inputted to the respective contacts, First-phase, second-phase, and third-phase sinusoidal drive voltages are generated. The output terminals 412 to 414 output first-phase, second-phase, and third-phase sinusoidal drive voltages to the drive signal generation unit 9. As shown in FIG. 4, each of the switches 407 to 409 has 12 contacts, and outputs a drive voltage in units of an electrical angle of 30 degrees.

When the motor is started, the control unit 405 prevents the zero cross points 15a and 15b in the drive voltage waveform 14 from being delayed from the points 18a and 18b, and the phase does not advance more than a first predetermined period from the points 18a and 18b. The phase delay amount of the phase current with respect to the position signal is initially set to a value in the range from the upper limit value to the lower limit value. Points 18 a and 18 b are points where an appropriate phase difference is delayed from the zero cross points 17 a and 17 b of the rotor position signal 16 (zero cross points of phase current when the motor 3 is appropriately controlled).
The control unit 405 determines the phase of the output phase signal (output to the control terminals 417 to 419) if the phase of the zero cross point of the phase current signal input by the phase difference detection unit 12 is advanced from the points 18a and 18b. Delay. In addition, the control unit 405 outputs a phase signal (output to the control terminals 417 to 419) when the phase of the zero cross point of the phase current signal input by the phase difference detection unit 12 is delayed from the points 18a and 18b. Advance the phase. Points 18a and 18b are points where the zero cross points 17a and 17b of the rotor position signal are delayed by 30 degrees.

  FIG. 5 is a block diagram showing a more specific configuration of the motor drive device according to the embodiment of the present invention. In FIG. 5, a three-phase power stage 2 that is a motor drive unit, a three-phase DC motor 3, a resistor 4 that is a current detection unit, an amplifier 5 that is a current signal shaping unit, an error amplification unit 6, a torque command signal input terminal 7, A triangular wave generation unit 8, a drive signal generation unit 9, a voltage signal generation unit 10, a current edge detection unit 11 which is a current phase detection unit, a phase difference detection unit 12, and a rotor position detection unit 13 are illustrated. Each block corresponds to FIG.

  The rotor position detection unit 13 includes a rotor position sensor 521 that is a Hall element, and a rotor position edge detection unit 522 that detects an edge of an output signal of the rotor position sensor 521 and outputs a rotor position signal.

  The phase difference detection unit 12 includes a current edge target signal generation unit 531 and a phase difference detector 532. The current edge target signal generation unit 531 receives the rotor position signal and generates a current edge target signal 645 obtained by shifting a phase by a certain amount from the rotor position signal. The current edge target signal 645 is a control target position of the current edge signal 646 (646a or 646b). A certain amount of phase is an appropriate phase difference between the rotor position signal and the phase current. In the embodiment, the current edge target signal 645 is a signal delayed in phase by 30 degrees from the rotor position signal. The phase difference detector 532 detects the phase difference between the current edge target signal 645 and the edge signal of the actually measured phase current output from the current phase detector 11 and outputs a phase difference signal.

  The voltage signal generation unit 10 includes a control unit 405, a series resistance stage 406 that is a resistance connection body, and switch matrices 407, 408, and 409. The control unit 405 includes a voltage peak value generation unit 501, a cycle counter 502, an electrical angle clock generation unit 503, determination units 504 and 505, a latch circuit 506, a zero delay amount 507, a voltage trigger reference delay amount 508, a voltage command trigger number 1 reference signal generation unit 509, voltage command trigger second reference signal generation unit 510, switches 511 and 512, adder 513, delay unit 514, angle feed counter 515, and decoder 516.

  The voltage command trigger first reference signal generation unit 509 receives the rotor position signal and generates a voltage command trigger first reference signal 642 having a phase advanced by a fixed amount from the current edge target signal 645. The amount by which the phase is advanced is a constant electrical angle. The voltage command trigger first reference signal generation unit 509 includes a counter, a calculation unit, and a delay circuit. The counter of the voltage command trigger first reference signal generation unit 509 inputs a clock and counts the period of the rotor position edge signal (or the period of a period obtained by dividing the period). The calculation unit of the voltage command trigger first reference signal generation unit 509 divides the count value of the period of the rotor position edge signal by a predetermined value to calculate the phase advance amount (actually, the phase delay amount from the preceding rotor position signal). Calculate the count value. Based on the calculated count value, the delay circuit of the voltage command trigger first reference signal generation unit 509 advances the phase by a certain electrical angle from the rotor position signal (the phase is delayed by a certain electrical angle from the preceding rotor position signal). ) A voltage command trigger first reference signal 642 is generated.

  The voltage command trigger second reference signal generation unit 510 receives the rotor position signal and generates a voltage command trigger second reference signal 643 having a phase advanced by a fixed amount from the current edge target signal 645. The amount that the voltage command trigger second reference signal generation unit 510 advances the phase is a constant electrical angle, and is larger than the amount that the voltage command trigger first reference signal generation unit 509 advances the phase. The configuration of the voltage command trigger second reference signal generation unit 510 is the same as that of the voltage command trigger first reference signal generation unit 509 except that the phase advance amount is different.

  The switch 512 inputs the voltage command trigger first reference signal 642 output from the voltage command trigger first reference signal generator 509 and the voltage command trigger second reference signal 643 output from the voltage command trigger second reference signal generator 510. , Select either one and output.

  The switch 511 receives the zero delay amount 507 and the voltage trigger reference delay amount 508, and selects and outputs one of them. The voltage trigger reference delay amount 508 is a difference time (651 in FIG. 6) between the voltage command trigger first reference signal 642 and the voltage command trigger second reference signal 643. The adder 513 inputs the phase difference between the current edge target signal 645 and the current edge signal 646 (646a or 646b) (the phase difference signal output by the phase difference detection unit 12) and the delay time output by the switch 511. , The time obtained by adding both is output.

  The delay unit 514 receives the voltage command trigger first or second reference signal (reference signal) output from the switch 512, and generates a voltage command trigger signal 644 (644a or 644b) delayed by a predetermined time from the reference signal. The delay amount of the delay unit 514 is a delay time output from the adder 513.

  The voltage command trigger signal 644 (644a or 644b) is generated by delaying the voltage command trigger first reference signal 642 or the voltage command trigger second reference signal 643. Therefore, the phase of the voltage command trigger signal 644 (644a or 644b) does not advance from the voltage command trigger first reference signal 642 or the voltage command trigger second reference signal 643. Therefore, the voltage command trigger first reference signal 642 or the voltage command trigger second reference signal 643 can be used as a limit when the voltage command trigger signal 644 (644a or 644b) has advanced the most phase.

In the above description, it is assumed that the voltage command trigger first reference signal 642 and the voltage command trigger second reference signal 643 are advanced from the current edge target signal 645 by a certain electrical angle. Alternatively, a signal whose phase is advanced from the current edge target signal 645 by a predetermined time using the period information can be used as the voltage command trigger signal 644 (644a or 644b).
The voltage command trigger first reference signal generation unit 509 receives the rotor position signal and generates a voltage command trigger first reference signal 642 having a phase advanced by a fixed amount from the current edge target signal 645. The amount by which the phase is advanced is a fixed time. The voltage command trigger first reference signal generation unit 509 includes a counter and a delay circuit. The counter of the voltage command trigger first reference signal generation unit 509 inputs a clock and counts the period of the rotor position edge signal (or the period of the divided period). The delay circuit of the voltage command trigger first reference signal generation unit 509 generates a voltage command trigger first reference signal 642 whose phase has advanced by a certain time from the rotor position signal (phase has been delayed by a certain time from the preceding rotor position signal). Generate. The same applies to the voltage command trigger second reference signal.

  It is assumed that the motor 3 is controlled using the voltage command trigger first reference signal 642. The switch 511 selects and activates the zero delay amount 507. The switch 512 selects and validates the voltage command trigger first reference signal 642. In this state, when it is necessary to advance the phase of the voltage command trigger signal 644 relative to the voltage command trigger first reference signal 642, that is, the voltage command trigger signal 644 (644a or 644b) is delayed from the voltage command trigger first reference signal 642. When the current edge signal 646 (646a or 646b) is behind the current edge target signal 645 when the time is zero, the following action is taken.

  The determination unit 504 determines whether the current edge signal 646 (646a or 646b) has a delay from the current edge target signal 645. The determination unit 505 delays the current edge signal 646 (646a or 646b) from the current edge target signal 645 (in phase with the voltage command trigger first reference signal 642) (output from the phase difference detection unit 12). It is determined whether or not the voltage trigger reference delay amount 508 (the phase difference 651 between the voltage command trigger second reference signal 643 and the voltage command trigger first reference signal 642) is smaller.

  The latch circuit 506 inputs the determination results of the determination units 504 and 505. Next, when the delay time from the voltage command trigger first reference signal 642 of the voltage command trigger signal 644 (644a or 644b) is zero, the latch circuit 506 generates the current edge signal 646 (646a or 646b) as the current edge target signal. If it is later than 645, the switches 511 and 512 are switched. The latch circuit 506 switches the switch 512 to validate the voltage command trigger second reference signal 643 as a reference signal for the next voltage command trigger signal 644 (644a or 644b). At the same time, since the latch circuit 506 switches the switch 511, the adder 513 outputs the phase difference output from the phase difference detection unit 12 and the delay amount 508 between the voltage trigger references (the voltage command trigger first reference signal 642 and the voltage command The difference time 651) from the trigger second reference signal 643 is added and output.

  The determination result of the determination unit 505 is that the delay time from the current edge target signal 645 of the current edge signal 646 (646a or 646b) (the phase difference signal output by the phase difference detection unit 12 is the voltage command trigger second reference signal 643) When the phase difference from the voltage command trigger first reference signal 642 (651 in FIG. 6) is smaller, the output signal of the adder 513 is a positive value.

  The delay unit 514 receives the voltage command trigger second reference signal 643 output from the switch 512 and the output signal of the adder 513, and a voltage command trigger signal 644 (delayed by a predetermined time from the voltage command trigger second reference signal 643). 644a or 644b) is generated and output.

  Next, it is assumed that the motor 3 is controlled using the voltage command trigger second reference signal 643. The switch 511 selects and validates the voltage trigger reference delay amount 508 (difference time 651 between the voltage command trigger first reference signal 642 and the voltage command trigger second reference signal 643). The switch 512 selects and validates the voltage command trigger second reference signal 643.

The determination unit 504 determines whether or not the phase of the current edge signal 646 (646a or 646b) is ahead of the current edge target signal 645. The determination unit 505 determines that the delay time of the voltage command trigger signal 644 relative to the voltage command trigger second reference signal 643 (output signal of the adder 513) is the voltage trigger reference delay amount 508 (the voltage command trigger second reference signal 643 and the voltage It is determined whether or not the phase difference 651) or more from the command trigger first reference signal 642 is reached.
A latch circuit 506 switches operations of the determination units 504 and 505.

  The latch circuit 506 inputs the determination results of the determination units 504 and 505, and the delay time of the voltage command trigger signal 644 (the output signal of the adder 513) relative to the voltage command trigger second reference signal 643 is the delay amount between voltage trigger references. When the current edge signal 646 (646a or 646b) is ahead of the current edge target signal 645 in a state equal to 508 (phase difference 651 between the voltage command trigger second reference signal 643 and the voltage command trigger first reference signal 642). The switches 511 and 512 are switched. The latch circuit 506 switches the switch 512 to validate the voltage command trigger first reference signal 642 as a reference signal for the next voltage command trigger signal 644 (644a or 644b). At the same time, since the latch circuit 506 switches the switch 511, the adder 513 adds the phase difference output from the phase difference detector 12 and the zero delay amount 507 and outputs the result.

  The determination result of the determination unit 505 is that the delay time of the voltage command trigger signal 644 relative to the voltage command trigger second reference signal 643 (the output signal of the adder 513) is the voltage trigger reference delay amount 508 (voltage command trigger second reference signal). 643 and the phase difference 651) between the voltage command trigger first reference signal 642 and the output signal of the adder 513 is a positive value.

  The delay unit 514 receives the voltage command trigger second reference signal 643 output from the switch 512 and the output signal of the adder 513, and a voltage command trigger signal 644 (delayed by a predetermined time from the voltage command trigger second reference signal 643). 644a or 644b) is generated and output.

The period counter 502 receives the rotor position edge signal 641 and a predetermined clock, and counts the period. The electrical angle clock generation unit 503 calculates a count value per predetermined electrical angle based on the count value of the period of the rotor position edge signal 641, and increments the estimated rotor angle using the count value of the rotor position edge signal. Let
The angle feed counter 515 receives the current estimated rotor angle output from the electrical angle clock generator 503 and the voltage command trigger signal 644 (644a or 644b) output from the delay unit 514, and outputs the current estimated rotor angle. Thus, an electrical angle whose phase is advanced by an angle indicated by the voltage command trigger signal 644 (644a or 644b) is output.
The decoder 516 generates and outputs control signals for the switches 407, 408, and 409 based on the electrical angle output from the angle feed counter 515.

The voltage peak value generator 501 receives the error signal output from the error amplifier 6 and outputs the highest potential and the lowest potential of the sine wave drive voltage to the highest potential line 410 and the lowest potential line 411.
The series resistor stage 406 generates a voltage at each contact of the switches 407, 408, and 409. SW matrices 407, 408, and 409 generate three-phase voltage profile signals.

The drive signal generation unit 9 includes a three-phase comparator 533 and a logic circuit 534 for preventing a through current. The three-phase comparator 533 slices the triangular wave output from the triangular wave generator 8 by using the three-phase voltage profile signal output from the voltage signal generator 10 to generate a PWM signal. The logic circuit 534 is a circuit for preventing a through current from flowing through the high-potential side drive transistor and the low-potential side drive transistor connected in series.
The three-phase power stage 2 inputs a three-phase PWM signal and drives the motor 3.

  FIG. 6 is a diagram showing waveforms of respective parts in FIG. In FIG. 6, a difference 651 indicates a phase difference between the voltage command trigger second reference signal 643 and the voltage command trigger first reference signal 642. A waveform 644 a represents a voltage command trigger signal when the motor 3 is controlled using the voltage command trigger first reference signal 642. The difference 652 indicates that the voltage command trigger signal 644a has a variable amount of delay from the voltage command trigger first reference signal 642 (a variable amount in the direction in which the delay amount decreases).

Waveforms 646 a and 646 b show current edge signals when the motor 3 is controlled using the voltage command trigger first reference signal 642. The difference 653 is a delay amount of the current edge target signal 645 with respect to the voltage command trigger signal 644a of the motor system. The difference 655 is a delay amount of the current edge signal 646b with respect to the voltage command trigger signal 644a of the motor system.
Difference 654 indicates that current edge signal 646a is delayed from current edge target signal 645. Since the difference 654 is a delay amount, the adder 513 shortens the output delay time by the delay amount 654 in order to reduce the delay amount 654 by control.
Difference 656 indicates that current edge signal 646b is more advanced in phase than current edge target signal 645. Since the difference 656 is an advance amount, the adder 513 lengthens the output delay time by the delay amount 656 in order to reduce the delay amount 656 by control.

  A waveform 644b shows a voltage command trigger signal when the motor 3 is controlled using the voltage command trigger second reference signal 643.

The control for delaying the phase and the control for advancing the phase will be described in more detail with reference to FIG. FIG. 7A shows a voltage command waveform 76 when control for delaying the phase is performed, and FIG. 7B shows a voltage command waveform 80 when control for advancing the phase is performed.
As shown in FIGS. 7A and 7B, by switching the switches 407 to 409 via the control terminals 417 to 419, a pseudo sine wave shape in which one cycle is equally divided by a unit angle 79 is used. Voltage command waveforms 76 and 80 are formed. The rotor position edge signal 71 and the previous phase control amount 72 are shown. When the current edge signal is advanced by a phase difference 73 with respect to a current edge target signal (not shown), the zero cross point of the new voltage command waveform 76 is set to a point 75 delayed by the phase difference 73 from the previous zero cross point 74. Then, the voltage command waveform 76 is formed. When the current edge signal is delayed by a phase difference 77 with respect to a target signal (not shown), the zero cross point of the new voltage command waveform 80 is set to a point 78 advanced by the phase difference 77 from the previous zero cross point 74. Then, a voltage command waveform 80 is formed.

  The above phase control is performed in units sufficiently smaller than the unit angle 79 (switching timing of the switches 407 to 409 is controlled in units of time sufficiently shorter than the time corresponding to the unit angle 79). FIG. 8 shows a voltage command waveform 83 when the control is performed with the unit angle 79. In FIG. 8, since the voltage command waveform 83 has a large minimum unit angle 79 for controlling the start timing, the zero cross point of the new voltage command waveform 84 (indicated by a broken line) is set between the points 81 and 82. Can not. The start timing of the voltage command waveform 84 is a point 82, and the jitter increases. In the present embodiment, as shown in FIGS. 7A and 7B, the phase control is performed in units sufficiently smaller than the unit angle 79, so that the jitter is small.

Next, the configuration of the current phase detector 11 will be described. FIG. 9 is a block diagram showing the configuration of the current phase detector 11 (current edge detector) according to the embodiment of the present invention. In order to drive the motor with maximum efficiency, it is important to accurately detect the zero cross point in the phase current of FIG. The current phase detector 11 of the embodiment accurately detects the zero cross point with a low cost and small circuit by the following configuration.
In FIG. 9, the current phase detector 11 includes a first potential shift unit 23, a second potential shift unit 24, a third potential shift unit 25, a fourth potential shift unit 26, a comparator 27, and a comparator 28. And a processing unit 29.
The first potential shift unit 23 receives the high potential side common connection terminal potential of the motor drive unit 2 and shifts it by the first voltage. The second potential shift unit 24 receives the stator coil drive terminal potential and shifts it by the second voltage. The third potential shift unit 25 receives the stator coil drive terminal potential and shifts it by the third voltage. The fourth potential shift unit 26 receives the low potential side common connection terminal potential of the motor drive unit 2 and shifts it by the fourth voltage. The comparator 27 inputs the output voltage of the first potential shift unit 23 and the output voltage of the second potential shift unit 24 and outputs a comparison result. The comparator 28 inputs the output voltage of the third potential shift unit 25 and the output voltage of the fourth potential shift unit 26 and outputs a comparison result.

In the embodiment, the first potential shift unit 23 lowers the high-potential side common connection terminal potential by the voltage V1 (> 0). The second potential shift unit 24 lowers the stator coil drive terminal potential by V1 + V2 (> 0). The fourth potential shift unit 26 increases the low potential side common connection terminal potential by the voltage V3 (> 0). The third potential shift unit 25 increases the stator coil drive terminal potential by V3 + V4 (> 0).
For example, in a comparator that uses a high-potential side common connection terminal potential and a low-potential side common connection terminal potential as power sources, the potential of the signal input to the non-inverting input terminal and the inverting input terminal is predetermined from the high potential side common connection terminal potential Unless the voltage is V5 (> 0) or lower and higher than the low potential side common connection terminal potential by a predetermined voltage V6 (> 0) or higher, the comparison result cannot be output normally. Therefore, V1 to V4 are determined so as to satisfy the expressions of V5 <V1 <V1 + V2 and V6 <V3 <V3 + V4. The values of V2 and V4 will be described later.

  Due to PWM driving, the stator coil drive terminal potential changes greatly from a high potential to a low potential, and swings higher than the high potential side common connection terminal potential or lower than the low potential side common connection terminal potential during current regeneration. In the motor, the end of the time region where the stator coil drive terminal potential is higher than the high potential side common connection terminal potential and the end of the time region where the stator coil drive terminal potential is lower than the low potential side common connection terminal potential are at the zero cross position of the phase current. The inventors paid attention to the coincidence. By detecting the ends of these regions, the zero cross point of the phase current can be detected. However, in a small motor, the product of the on-resistance and the regenerative current value is small. Therefore, simply comparing the motor drive terminal potential and the high potential side common connection terminal potential with a comparator, or simply comparing the motor drive terminal potential and the low potential side common connection terminal potential with a comparator. Therefore, it is difficult to detect the zero-cross position of the phase current with high accuracy. This is because the comparison result output by the comparator chatters due to factors such as noise superimposed on the stator coil drive terminal potential and variations in the offset potential of the subsequent comparator.

  The current phase detector 11 according to the embodiment uses the forward voltage drop of the regenerative diode that generates a potential difference of several hundred mV when a regenerative current is generated, so that the stator coil drive terminal potential becomes higher than the high potential side common connection terminal potential. The time domain end and the time domain end where the stator coil drive terminal potential is lower than the low potential side common connection terminal potential are accurately detected. The operation of the current phase detector 11 will be described with reference to FIG.

  In FIG. 10A, a waveform 30 indicates a signal of the stator coil drive terminal voltage, a broken line 31 indicates a high potential side common connection terminal potential, and a broken line 32 indicates a low potential side common connection terminal potential. Based on the peak 33 in which the drive terminal voltage 30 is higher than the high-potential side common connection terminal potential and the peak 35 in which the drive terminal voltage 30 is lower than the low-potential side common connection terminal potential, The switching timing is detected.

  The period 103 is a period in which the low-potential side drive transistor of this phase sucks current from the stator coil of this phase and flows it into the low-potential side common connection terminal. The period 104 is a period in which the high-potential side driving transistor or the high-potential side regenerative diode in this phase sucks current from the stator coil in this phase and flows it into the high-potential side common connection terminal. The period 105 is a period in which the high-potential side drive transistor of this phase sucks current from the high-potential side common connection terminal and flows into the stator coil of this phase. The period 106 is a period in which the low-potential side drive transistor or the low-potential side regenerative diode of this phase sucks current from the low-potential side common connection terminal and flows current into the stator coil of this phase.

A peak 33 indicates a peak of potential increase at the stator coil drive terminal due to a regenerative current flowing through a regenerative diode connected in parallel to the high potential side drive transistor. The voltage 34 indicates a forward voltage drop from the peak 33 to the high potential side common connection terminal potential 31. A peak 35 indicates a peak of a potential drop at the stator coil drive terminal due to a regenerative current flowing through a regenerative diode connected in parallel to the low potential side drive transistor. The voltage 36 indicates a forward voltage drop from the peak 35 to the low potential side common connection terminal potential 32. This figure shows a case where synchronous rectification driving is applied.
The voltage 37 is a drop voltage due to the high potential side drive transistor during energy storage, and the voltage 38 is a rise voltage due to the high potential side drive transistor during regeneration. The voltage 39 is a rising voltage due to the low potential side driving transistor during energy storage, and the voltage 40 is a dropping voltage due to the low potential side driving transistor during regeneration. The potentials 37 to 40 are all smaller than the voltages 34 and 36, and become an extremely small on-voltage especially at a small current.

  As described above, it is difficult to stably detect the small voltages 37, 38, 39, and 40 due to the influence of noise and variations in the offset of the comparator. On the other hand, the potential difference 34 between the upper peak 33 and the high potential side common connection terminal potential 31 and the potential difference 36 between the lower peak 35 and the low potential side common connection terminal potential 32 are logarithmic characteristics with respect to the current flowing through the stator coil. Indicates. Therefore, even if the current flowing through the stator coil is very small, the potential differences 34 and 36 reach several hundred mV. The current phase detector 11 of the embodiment detects these upper and lower peaks, and detects the zero cross point of the phase current based on these peaks.

  In FIG. 10B, a broken line 41 is a potential obtained from the high potential side common connection terminal potential 31 shown in FIG. 10A through the first potential shift unit 23 in FIG. A waveform 42 is a signal obtained from the stator coil drive terminal voltage 30 shown in FIG. 10A through the second potential shift unit 24 shown in FIG. FIG. 10B shows a waveform only in the vicinity of the high potential side common connection terminal potential 31.

  In FIG. 10C, a waveform 43 is a signal obtained by passing the stator coil drive terminal voltage 30 shown in FIG. 10A through the third potential shift unit 25 in FIG. A broken line 44 is a potential obtained from the low potential side common connection terminal potential 32 shown in FIG. 10A via the fourth potential shift unit 26 of FIG. FIG. 10C shows a waveform only in the vicinity of the low potential side common connection terminal potential 32. The voltages 59 and 60 are voltages obtained through the potential shift units 24 and 25 from the voltages 34 and 36 in FIG.

In the embodiment, the high potential side common connection terminal potential 41 whose voltage has dropped by the voltage V1 at the first potential shift unit 23 is driven by the stator coil whose voltage has been dropped by the voltage (V1 + V2) by the second potential shift unit 24. It is located approximately in the middle of the voltage 59 of the terminal potential 42. That is, the voltage V2 is set to a value that is approximately ½ of the voltage 59.
The low-potential side common connection terminal potential 44 whose voltage has been increased by the voltage V3 in the fourth potential shift unit 26 is the voltage of the stator coil drive terminal potential 43 whose voltage has been increased by the voltage (V3 + V4) in the third potential shift unit 25. 62 is located approximately in the middle. That is, the voltage V4 is set to a value that is approximately half of the voltage 60.
The comparators 27 and 28 accurately detect the upper peak 33 and the lower peak 35 of the stator coil drive terminal potential without being affected by noise or the like. The potential differences 61 (= V2) and 62 (= V4) shown in FIGS. 10B and 10C are set within the range of 5% to 80% of the forward drop voltages 59 and 60 of the peaks 33 and 35. Is done.

FIG. 10D shows a signal representing a comparison result obtained when the comparator 27 compares the voltages 41 and 42 shown in FIG. 10B. FIG. 10E shows a signal representing a comparison result obtained when the comparator 28 compares the voltages 43 and 44 shown in FIG. As shown in FIG. 10D and FIG. 10E, a comparison result without chattering can be obtained.
The processing unit 29 receives the signals of FIGS. 10D and 10E output from the comparators 27 and 28, and outputs a current phase signal including information on the zero cross point of the phase current.

  FIG. 11A to FIG. 11D will be described. 11 (a) and 11 (b) show FIGS. 10 (d) and 10 (e) when the PWM duty ratio of the stator coil driving transistor is always driven below 100%. It shows the time longer than the period. The processing unit 29 has an RS flip-flop. The processing unit 29 receives the signals of FIG. 11A and FIG. 11B as a set input signal and a reset input signal, respectively, and outputs a current phase signal shown in FIG. The processing unit 29 outputs a current phase signal that crosses zero when the direction in which the phase current flows is switched.

FIGS. 12 (a) and 12 (b) show FIGS. 10 (d) and 10 (e) in the case where the PWM duty ratio of the stator coil driving transistor includes 100% driving, and shows one cycle of the motor electrical angle. It shows the longer time. The processing unit 29 receives the signals shown in FIGS. 12A and 12B and outputs a current phase signal shown in FIG.
The processing unit 29 may receive the signals in FIGS. 11A and 11B and generate a current phase signal by applying a low-pass filter. Alternatively, by using the signals of FIGS. 11A and 11B as clock signals and latching the signals of FIGS. 10B and 10C through a single shot or the like, the current phase signal is obtained. It may be generated. In this case, the circuit can be configured by only one of the comparators 27 and 28.

  When the rotation speed of the motor is low, a section 1103 between the last pulse of the pulse generation section of FIG. 11A and the first pulse of the pulse generation section of FIG. 11B, and FIG. In some cases, the period of the section 1104 between the last pulse of the pulse generation section and the first pulse of the pulse generation section of FIG. 11A cannot be ignored compared to the 360-degree section. The processing unit 29 generates a current phase signal that zero-crosses at the intermediate point 1105 of the section 1103 and the intermediate point 1106 of the section 1104. The processing unit 29 measures the lengths of the section 1103 and the section 1104 and determines the timing of the intermediate point 1105 and the intermediate point 1106. The processing unit 29 generates a current phase signal that crosses zero at the intermediate point 1105 and the intermediate point 1106. FIG. 11D shows a current phase signal that zero-crosses at the intermediate point 1105 and the intermediate point 1106.

  12A to 12D, similarly, the processing unit 29 generates a current phase signal that zero-crosses at the intermediate point 1105 in the section 1103 and the intermediate point 1106 in the section 1104. FIG. 12D shows a current phase signal that zero-crosses at the intermediate point 1105 and the intermediate point 1106.

FIG. 13 is a diagram more specifically showing the configuration of the potential shift unit of the voltage signal generation unit 10 of FIG. The first potential shift unit 23 and the fourth potential shift unit 26 in FIG. 9 are omitted (V1 = V3 = 0). The second potential shift unit 24 drops the stator coil drive terminal voltage 30 by V2 (= V1 + V2) by the combination of the resistor 45 and the current source 46, and outputs the signal shown in FIG. The third potential shift unit 25 increases the stator coil drive terminal voltage 30 by V4 (= V3 + V4) by the combination of the resistor 47 and the current source 48, and outputs a signal shown in FIG.
In FIG. 13 of the embodiment, elements 45 and 47 were resistors. However, the present invention is not limited to this, and the elements 45 and 47 may be arbitrary circuit elements that generate a potential difference when a current is applied.

  The specific configuration of each of the potential shift units 23 to 26 in FIG. 9 is not limited to the configuration in FIG. Any configuration can be adopted as long as the potential relationship shown in FIGS. 10B and 10C is realized. For example, the two potential shift units 23 and 26 may be deleted. The subsequent comparators 27 and 28 may include a predetermined offset voltage in advance. In this case, all or some of the potential shift units 23 to 26 may be deleted. As long as the PWM duty ratio is always less than 100%, the circuit may be configured by one of the comparators 27 and 28.

In the description of the present invention, it has been described that the current waveform has a sine wave shape, but the present invention is effective even if it is not a sine wave. However, by combining the sine wave drive and the present invention, a highly efficient motor drive with less noise and vibration can be realized.
The motor driving device of the embodiment is a driving device for a spindle motor of an optical disk. The motor drive device of the embodiment can be applied to an arbitrary disk device other than the optical disk, or a motor drive device of another device.

Although the invention has been described in its preferred form with a certain degree of detail, the present disclosure of this preferred form should vary in the details of construction, and combinations of elements and changes in order may vary in the claimed invention. It can be realized without departing from the scope and spirit.
Part or all of the drawings are drawn in a schematic representation for illustration purposes, and do not necessarily depict the actual relative sizes and positions of the elements shown there faithfully. Please consider.

  The motor driving device and motor driving method of the present invention can be used as a motor driving device and motor driving method such as an optical disk device. The disk device and the disk control method of the present invention are useful, for example, as an optical disk device and an optical disk control method.

FIG. 1 is a block diagram showing a configuration of a motor drive device according to an embodiment of the present invention. FIG. 2 is a diagram showing the waveform of the drive voltage, the waveform of the phase current signal, and the waveform of the rotor position signal in the embodiment of the present invention. FIG. 3 is a diagram showing another drive voltage waveform in the embodiment of the present invention. FIG. 4 is a block diagram showing a specific configuration of the voltage signal generator in the embodiment of the present invention. FIG. 5 is a block diagram showing a more specific configuration of the motor drive device according to the embodiment of the present invention. FIG. 6 is a diagram illustrating waveforms of respective parts of the motor drive device according to the embodiment of the present invention. FIG. 7 is a diagram illustrating a change in phase when the phase of the drive voltage is delayed and when the phase is advanced in the embodiment of the present invention. FIG. 8 is a diagram showing a change in phase when the phase of the drive voltage is delayed in the conventional example. FIG. 9 is a block diagram showing an outline of the configuration of the current phase detector in the embodiment of the present invention. FIG. 10 is a timing chart showing signal waveforms at respective points of the current phase detector in the embodiment of the present invention. FIG. 11 is a timing chart showing signal waveforms at respective points of the current phase detector in the embodiment of the present invention. FIG. 12 is a timing chart showing another signal waveform at each point of the current phase detector in the embodiment of the present invention. FIG. 13 is a diagram specifically showing the configuration of the current phase detector in the embodiment of the present invention. FIG. 14 is a block diagram showing an outline of the configuration of the motor drive device of the first conventional example. FIG. 15 is a block diagram showing an outline of the configuration of the motor drive device of the second conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC power supply 2 Motor drive part 3 Motor 4 Current detection part 5 Current signal shaping part 6 Error amplification part 7 Torque command input terminal 8 Triangle wave generation part 9 Drive signal generation part 10 Voltage signal generation part 11 Current phase detection part 12 Phase difference detection Unit 13 Rotor position detection unit 23-26 Potential shift unit 27, 28 Comparator 29 Processing unit 56a-56c, 57a-57c Transistor 58a-58f Regenerative diode 405 Control unit 406 Resistive connector 407, 408, 409 Switch 410 Maximum potential line 411 Lowest potential line 412, 413, 414 Output terminal

Claims (29)

A motor driving unit having a plurality of half-bridge circuits in which a driving transistor on the high potential side and a driving transistor on the low potential side are connected in series, and the connection point is a stator coil driving terminal for each phase of the motor;
A rotor position detector for detecting a rotor position of the motor and outputting a rotor position signal;
A current phase detector for detecting the phase of the phase current flowing through the stator coil drive terminal;
A voltage signal generator that controls and generates a voltage profile signal so that a first phase difference, which is a difference between the phase of the phase current and the phase of the rotor position signal, is maintained at a predetermined electrical angle;
And a drive signal generation unit configured to generate a PWM signal for driving the drive transistor of each phase according to the voltage profile signal. The voltage signal generator is
Based on the rotor position signal, a current edge target signal generation unit that generates a current edge target value that is a target value of zero cross timing of the motor phase current;
A phase difference detection unit for detecting a second phase difference that is a difference between a current edge that is a zero-cross timing of the actually measured motor phase current and the current edge target value;
Generating a voltage profile signal having a phase advanced by a predetermined amount with respect to the phase of the rotor position signal, and the predetermined amount is a value obtained by correcting a constant amount according to the second phase difference; and The motor drive device according to claim 1, wherein In a state in which the feedback of the phase difference for controlling the phase is not performed, the voltage signal generation unit further increases the phase of the current phase signal with respect to the phase of the rotor position signal by a first predetermined period from the predetermined amount. The motor drive device according to claim 1, wherein the motor drive device is initialized to the advanced phase, generates the voltage profile signal, and starts energization. Even if the voltage signal generation unit outputs a drive voltage having a phase advanced by the first predetermined period, the first phase difference is not maintained at the predetermined electric angle and is not less than the predetermined electric angle. If the phase of the phase current is delayed,
With reference to a second predetermined period in which the energization start phase of the voltage profile signal is further advanced than the first predetermined period,
A value for correcting a phase difference, which is a phase advanced by the voltage profile signal with respect to the rotor position signal, is equal to a difference between the first predetermined period and the second predetermined period from the immediately preceding phase correction value. Replace with a correction value that is a phase further delayed by the phase, and generate the voltage profile signal using the replaced correction value.
The motor drive device according to claim 3, wherein the phase adjustment range at the start of energization is shifted by performing mode switching. The motor drive according to claim 1, wherein the voltage signal generation unit feeds back and controls a difference between the first phase difference and the predetermined electrical angle to a phase of a voltage profile signal or a start timing. apparatus. The motor driving apparatus according to claim 1, wherein the current phase detection unit detects a current phase of at least one phase of the motor. A motor drive unit having a plurality of sets of a drive transistor for driving a phase current flowing through a stator coil of each phase of the motor, and a regenerative diode connected in parallel to the drive transistor;
A current phase that compares the potential at one end or the potential difference between both ends of the regenerative diode caused by a regenerative current flowing in the forward direction with the regenerative diode with a predetermined threshold, derives the phase of the phase current based on the comparison result, and outputs the phase A detection unit;
And a voltage signal generation unit that outputs a voltage to be applied to the motor driving unit based on the phase of the phase current. A drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and have a plurality of half bridge circuits whose connection points are stator coil drive terminals for each phase of the motor, and a regenerative diode is connected to the drive transistor. Motor drive units connected in parallel to each other;
A potential shift circuit that shifts the potential at one end or both ends of the regenerative diode on the high potential side and the potential at one end or both ends of the regenerative diode on the low potential side by different predetermined voltages, and the output of the potential shift circuit A current phase detector comprising: a comparator for comparing the signal with a predetermined threshold; and a phase current phase detection circuit that receives the output signal of the comparator and derives and outputs the phase of the phase current;
And a voltage signal generation unit that outputs a voltage to be applied to the motor driving unit based on the phase of the phase current. A drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and have a plurality of half bridge circuits whose connection points are stator coil drive terminals for each phase of the motor, and a regenerative diode is connected to the drive transistor. Motor drive units connected in parallel to each other;
A current phase detector that compares a potential obtained by applying a first offset voltage to the voltage of at least one phase of the stator coil drive terminal and a predetermined threshold, and derives and outputs the phase of the phase current based on the comparison result When,
A motor drive device comprising: a voltage signal generation unit that outputs a voltage applied to the motor drive unit based on a phase of the phase current. A drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and have a plurality of half bridge circuits whose connection points are stator coil drive terminals for each phase of the motor, and a regenerative diode is connected to the drive transistor. Motor drive units connected in parallel to each other;
A first comparison result comparing a potential obtained by applying a first offset voltage to a voltage of at least one phase of the stator coil drive terminal and a first threshold value, and a voltage of the stator coil drive terminal to the second A current phase detector that derives and outputs the phase of the phase current based on a second comparison result obtained by comparing the potential obtained by applying the offset voltage and the second threshold;
A motor drive device comprising: a voltage signal generation unit that outputs a voltage applied to the motor drive unit based on a phase of the phase current. A motor drive unit having a plurality of sets of a drive transistor for driving a phase current flowing through a stator coil of each phase of the motor, and a regenerative diode connected in parallel to the drive transistor;
A potential at both ends of the regenerative diode generated by a regenerative current flowing in the forward direction through the regenerative diode is compared after applying an offset voltage to at least one potential, and the phase of the phase current is derived based on the comparison result, An output current phase detector;
A motor drive device comprising: a voltage signal generation unit that outputs a voltage applied to the motor drive unit based on a phase of the phase current. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector
A potential shift circuit that inputs an anode potential of a regenerative diode connected in parallel to a high potential side drive transistor and outputs a potential that is a potential drop from the anode potential by a predetermined voltage lower than a forward drop voltage of the regenerative diode;
A comparator for comparing the output potential of the potential shift circuit and the potential of the high potential side common connection terminal of the high potential side drive transistor;
The motor drive device according to claim 7, further comprising: a phase current phase detection circuit that inputs a comparison result of the comparator and derives and outputs a phase of the phase current. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector
A potential shift circuit that inputs an anode potential of a regenerative diode connected in parallel to a high potential side drive transistor and outputs a potential that is a potential drop from the anode potential by a predetermined voltage lower than a forward drop voltage of the regenerative diode;
A comparator for comparing the output potential of the potential shift circuit and the potential of the high potential side common connection terminal of the high potential side drive transistor;
The motor drive device according to claim 8, further comprising: a phase current phase detection circuit that inputs a comparison result of the comparator and derives and outputs a phase of the phase current. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector
A potential shift circuit that inputs a cathode potential of a regenerative diode connected in parallel to a low-potential side drive transistor and outputs a potential that is increased from the cathode potential by a predetermined voltage lower than a forward drop voltage of the regenerative diode;
A comparator for comparing the output potential of the potential shift circuit and the potential of the low potential side common connection terminal of the low potential side drive transistor;
The motor drive device according to claim 7, further comprising: a phase current phase detection circuit that inputs a comparison result of the comparator and derives and outputs a phase of the phase current. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector
A potential shift circuit that inputs a cathode potential of a regenerative diode connected in parallel to a low-potential side drive transistor and outputs a potential that is increased from the cathode potential by a predetermined voltage lower than a forward drop voltage of the regenerative diode;
A comparator for comparing the output potential of the potential shift circuit and the potential of the low potential side common connection terminal of the low potential side drive transistor;
The motor drive device according to claim 8, further comprising: a phase current phase detection circuit that inputs a comparison result of the comparator and derives and outputs a phase of the phase current. The motor drive unit has a plurality of sets of drive transistors that drive phase currents flowing through the stator coils of each phase of the motor, and regenerative diodes connected in parallel to the drive transistors,
The current phase detector compares a potential at one end of the regenerative diode or a potential difference between both ends, which is generated when a regenerative current flows in the forward direction in the regenerative diode, with a predetermined threshold, and based on the comparison result, the phase of the phase current The motor driving device according to claim 1, wherein the motor driving device is derived and output. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector includes a potential shift circuit that shifts the potential at one end or both ends of the regenerative diode on the high potential side and the potential at one end or both ends of the regenerative diode on the low potential side by different predetermined voltages, respectively. A comparator for comparing the output signal of the potential shift circuit with a predetermined threshold, and a phase current phase detection circuit for inputting the output signal of the comparator and deriving and outputting the phase of the phase current. The motor driving device according to claim 1. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector compares a potential obtained by applying a first offset voltage to the voltage of at least one phase of the stator coil drive terminal and a predetermined threshold value, and derives the phase of the phase current based on the comparison result. The motor driving device according to claim 1, wherein the motor driving device is output. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detection unit compares a potential obtained by applying a first offset voltage to a voltage of at least one phase of the stator coil drive terminal and a first threshold value, and the stator coil drive Deriving and outputting the phase of the phase current based on a second comparison result obtained by comparing a potential obtained by applying a second offset voltage to the terminal voltage and a second threshold value. The motor drive device according to claim 1. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector is
A potential shift circuit that inputs an anode potential of a regenerative diode connected in parallel to a high potential side drive transistor and outputs a potential that is a potential drop from the anode potential by a predetermined voltage lower than a forward drop voltage of the regenerative diode;
A comparator for comparing the output potential of the potential shift circuit and the potential of the high potential side common connection terminal of the high potential side drive transistor;
The motor drive device according to claim 1, further comprising: a phase current phase detection circuit that inputs a comparison result of the comparator and derives and outputs a phase of the phase current. The motor drive unit includes a plurality of half-bridge circuits in which a drive transistor on the high potential side and a drive transistor on the low potential side are connected in series, and the connection point is a stator coil drive terminal for each phase of the motor. A diode is connected in parallel to each of the drive transistors;
The current phase detector is
A potential shift circuit that inputs a cathode potential of a regenerative diode connected in parallel to a low-potential side drive transistor and outputs a potential that is increased from the cathode potential by a predetermined voltage lower than a forward drop voltage of the regenerative diode;
A comparator for comparing the output potential of the potential shift circuit and the potential of the low potential side common connection terminal of the low potential side drive transistor;
The motor drive device according to claim 1, further comprising: a phase current phase detection circuit that inputs a comparison result of the comparator and derives and outputs a phase of the phase current.   An electronic device comprising the motor driving device according to claim 1.   An electronic device comprising the motor drive device according to claim 7.   An electronic device comprising the motor drive device according to claim 8.   An electronic device comprising the motor drive device according to claim 9.   An electronic device comprising the motor driving device according to claim 10.   An electronic device comprising the motor driving device according to claim 11. Detecting the rotor position of the motor and outputting a rotor position signal;
Detecting the phase of the phase current flowing through the stator coil of the motor;
Generating a voltage signal of a predetermined voltage profile signal and controlling the difference between the phase of the phase current and the phase of the rotor position signal to be maintained at a predetermined electrical angle;
Generating a PWM signal for driving the stator coil of each phase according to the voltage signal;
A motor driving method characterized by comprising: Comparing a potential at one end of the regenerative diode or a potential difference between both ends, which is caused by a regenerative current flowing in a forward direction through a regenerative diode connected in parallel to a drive transistor that drives a phase current flowing through a stator coil of the motor, with a predetermined threshold; Deriving and outputting the phase of the phase current based on the comparison result; and
Based on the phase of the phase current, outputting a voltage to be applied to the motor drive unit;
A motor driving method characterized by comprising:

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