JP2014117126A - Motor Drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive device which has an interface corresponding to the PAM (Pulse Amplitude Modulation) drive system and drives a motor with the PWM (Pulse Width Modulation) drive system.SOLUTION: A motor drive device includes an input terminal 101 for inputting a Vs signal as drive voltage of a motor 300 in which voltage is adjusted in accordance with the speed of rotation of the motor 300, and a triangular wave generator 221 and a comparator 222 which generate a PWM signal of a duty ratio in accordance with the Vs signal input from the input terminal 101. Therefore the motor 300 can be controlled with the PWM drive even if a signal supplied from a host device is a signal corresponding to the PAM drive system.

Description

  The present invention relates to a motor drive device.

1A and 1B show a schematic configuration of a motor system including a motor.
The motor system shown in FIG. 1A includes a motor device 500 and a host device 10 that controls the motor device 500. The motor device 500 includes a motor 520 and a motor driving device 510 that rotationally drives the motor 520. The host device 10 shown in FIG. 1A controls the motor device 500 by a PAM (Pulse Amplitude Modulation) driving method. The PAM drive method is a method for controlling the rotational speed of the motor 520 by changing the voltage supplied to the coil of the motor 520 by the host device 10. A motor control signal (hereinafter referred to as a Vs signal) shown in FIG. 1A is a signal for supplying a voltage to the coil, and the host device 10 controls the voltage of the Vs signal to control the rotation speed of the motor 520. Control.
The motor system shown in FIG. 1B is a system in which the host apparatus 20 controls the motor apparatus 600 by a PWM (Pulse Width Modulation) drive system. In the PWM drive method, the motor drive device 610 generates a PWM signal based on a speed instruction signal (hereinafter referred to as a Vsp signal) notified from the host device 20, and flows it through a coil according to the duty of the generated PWM signal. In this method, the rotational speed of the motor 620 is controlled by controlling the drive current on and off. In the case of the PWM drive method, the voltage of the Vs signal supplied from the host device 20 to the motor device 600 is a fixed voltage.

JP 2012-70540 A

  However, in the PAM drive method, the lower limit of the rotational speed is limited by the limit of the operable voltage of an IC (for example, the driver IC shown in FIGS. 3 and 4) that controls the rotation of the motor 520 provided in the motor driving device 510. End up. On the other hand, the PWM drive method does not have such a lower limit of the rotation speed, but when a motor system employing the PAM drive method is already installed, the motor device 500 is replaced with a motor device 600 corresponding to the PWM drive method. Even if an attempt is made to replace the motor device 600, the host device 10 is compatible with the PAM drive method, so the motor device 600 of the PWM drive method cannot be introduced. FIG. 2 shows a motor system shown in FIG. 1A in which the motor device 500 is replaced with a motor device 600. Since the motor device 600 is a PWM drive method, it is necessary to input a Vsp signal. However, since the host device 10 is compatible with the PAM drive method, the Vsp signal is not output to the motor device 600.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a motor drive device that includes an interface corresponding to a PAM drive system and drives a motor by a PWM drive system.

In order to achieve such an object, a motor driving device of the present invention includes an input terminal for inputting a driving voltage of the motor adjusted according to the number of rotations of the motor, and a duty corresponding to the driving voltage input from the input terminal. A PWM signal generation circuit for generating a ratio PWM signal.
Accordingly, by supplying the PWM signal generated by the PWM signal generation circuit to a device that controls the driving of the motor, the motor can be controlled by the PWM driving method. Therefore, it is possible to provide a motor drive device that includes an interface corresponding to the PAM drive method and drives the motor by the PWM drive method.

Preferably, the motor driving device includes an output circuit that switches the driving voltage input from the input terminal according to a duty ratio of the PWM signal and outputs the switching voltage to the motor.
Therefore, the motor can be driven by the PWM drive method.

Preferably, a voltage dividing circuit that divides and outputs the driving voltage input from the input terminal is provided, and the PWM signal generation circuit outputs a duty corresponding to the divided driving voltage output from the voltage dividing circuit. A ratio PWM signal is generated.
Therefore, even when the driving voltage is high, a signal for controlling the motor by the PWM driving method can be generated by the driving voltage.

  According to the present invention, it is possible to provide a motor drive device that includes an interface corresponding to the PAM drive method and drives the motor by the PWM drive method.

(A) is a figure which shows the outline of the motor system of the conventional PAM drive system, (B) is a figure which shows the outline of the motor system of the conventional PWM drive system. It is a figure which shows the structure which connected the high-order apparatus of the PAM drive system, and the motor apparatus of a PWM drive system. It is a figure which shows an example of schematic structure of the motor system of an Example. It is a figure which shows an example of the detailed structure of the motor apparatus of an Example. (A) is a figure for demonstrating operation | movement of a comparator, (B) is a figure which shows an example of the PWM signal output from a comparator according to the result of a voltage comparison. It is a figure which shows the Vs signal used for a PAM drive system, (A) shows a Vs signal in case the rotation speed of a motor is high rotation, (B) shows Vs in case the rotation speed of a motor is low rotation. The signal is shown. It is a figure for demonstrating the PWM signal of a PWM drive system. It is a figure which shows an example of the PWM signal which the comparator of a present Example outputs to an electricity supply control part, (A) shows a PWM signal in case the rotation speed of a motor is high rotation, (B) shows a motor's rotation speed. The PWM signal when the rotation speed is low is shown. (A) is a figure which shows the relationship between the Vs signal in the case of PAM drive, and a motor rotation speed, (B) is a figure which shows the relationship between the Vs signal in the case of a present Example, and a motor rotation speed. . It is a figure which shows an example of a structure of the motor drive part of the modification 1. FIG. It is a figure which shows an example of a structure of the motor drive part of the modification 2.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 3 shows an example of a schematic configuration of the motor system 1. A motor system 1 shown in FIG. 3 includes a motor device 100 including a motor 300 and a host device 10 that controls the motor device 100. The motor device 100 includes a motor driving unit 200 and a motor 300. The motor driving unit 200 includes a voltage dividing circuit 210, a driver IC 220, and an output unit 230.

  The host device 10 is a device that controls the motor device 100 by the PAM drive method. The host device 10 serves as an interface with the motor device 100 from the motor device 100 for an output terminal 2 for the Vs signal, an output terminal 3 for the power supply voltage Vcc, and a motor rotation number signal (hereinafter referred to as FG (Frequency Generation) signal). An input terminal 4 for inputting and a ground terminal 5 are provided. The Vs signal is a signal supplied as a drive voltage to a coil included in the motor 300, and the rotation speed of the motor 300 is controlled by the voltage (amplitude) of the Vs signal. Since the host device 10 is a device compatible with the PAM drive method, the rotation speed of the motor 300 is controlled by controlling the voltage of the Vs signal. The power supply voltage Vcc is a voltage for operating the driver IC 220 included in the motor driving unit 200. The power supply voltage Vcc is a constant voltage value. The FG signal is a signal representing the number of rotations of the motor 300 detected by the driver IC 220 of the motor device 100 and is notified from the driver IC 220 to the host device 10. The host device 10 receives the FG signal and determines the actual rotational speed (actual rotational speed) [rpm] of the motor 300 based on the input FG signal. The host device 10 calculates the difference between the actual rotational speed of the motor 300 determined by the FG signal and the target rotational speed of the motor 300, and controls the voltage of the Vs signal based on the calculated difference. The host device 10 receives a commercial AC power supply, converts the input AC voltage into a DC voltage, and supplies the DC voltage to the motor device 100. The host device 10 converts the DC-converted voltage into a voltage for obtaining the target rotational speed of the motor 300 and outputs it to the motor device 100 as a Vs signal. Similarly, the host device 10 converts the DC-converted voltage into the power supply voltage Vcc and outputs it to the motor device 100. The ground terminal 5 is connected to the ground terminal 104 of the motor device 100.

The motor device 100 is a device corresponding to the PWM drive method. Control of the motor apparatus 100 corresponding to the PWM drive method requires a Vsp signal that indicates the rotation speed of the motor 300. However, since the host device 10 is a device that supports the PAM drive method, it does not output the Vsp signal.
Therefore, the motor device 100 according to the present embodiment includes a voltage dividing circuit 210 that divides the voltage of the Vs signal in the motor driving unit 200 and inputs the Vs signal divided by the voltage dividing circuit 210 to the driver IC 220. It has a configuration. Since the Vs signal is a voltage supplied to the coil included in the stator of the motor 300, it becomes a high voltage. For this reason, the Vs signal cannot be directly input to the driver IC 220. Therefore, a voltage dividing circuit 210 is provided, the voltage of the Vs signal is divided by the voltage dividing circuit 210, and the divided Vs signal is input to the driver IC 220 as a Vsp signal.
The motor device 100 includes, as an interface, an input terminal 101 for inputting a Vs signal, an input terminal 102 for a power supply voltage Vcc, an output terminal 103 for an FG signal, and a ground terminal 104, but has an input terminal for a Vsp signal. Not done.

  FIG. 4 shows an example of a detailed configuration of the motor device 100. A detailed configuration of the motor apparatus 100 will be described with reference to FIG.

  First, the voltage dividing circuit 210 will be described. The voltage dividing circuit 210 includes resistors R1, R2, R3, R4 and a capacitor C. The resistor R1 is connected to a wiring 110 having one end connected to the input terminal 101 for the Vs signal. Further, the resistor R1 connects the other end to a coupling point P in which one ends of the resistors R1 to R4 are commonly connected. The resistor R2 is connected to a wiring 120 having one end connected to the input terminal 102 for the power supply voltage Vcc. The resistor R2 connects the other end to the coupling point P. The resistor R3 connects one end to the coupling point P and grounds the other end. The resistor R4 has one end connected to the coupling point P and the other end connected to the comparator 222 provided in the driver IC 220. Capacitor C has one end connected to the wiring connecting resistor R4 and comparator 222, the other end connected to the other end of resistor R3, and grounded together with the other end of resistor R3. To do. The configuration of the voltage dividing circuit 210 is not limited to that shown in FIG.

Here, a calculation formula of a divided value by which the voltage dividing circuit 210 divides the voltage of the Vs signal is shown. The voltage dividing circuit 210 divides the voltage of the Vs signal, and the voltage output to the driver IC 220 is expressed as a divided voltage Vt. The value of the divided voltage Vt can be obtained by the following equation.
Vt [V] = Vs− {R1 × (Vs × R3−Vcc × R3 + Vs × R2) / (R1 × R2 + R1 × R3 + R2 × R3)}
For example, the resistance value of R1 is 47 [kΩ], the resistance value of R2 is 10 [kΩ], the resistance value of R3 is 5.6 [kΩ], and the resistance value of R4 is 0 [kΩ]. Further, when the value of Vcc is 5 [V] and the value of Vs is calculated as 15 [V], the value of Vt is 2.73 [V].

  Next, the driver IC 220 will be described. The driver IC 220 includes a triangular wave generator 221, a comparator 222, a hall amplifier 223, and an energization control unit 224. Note that the triangular wave generator 221 and the comparator 222 correspond to a PWM signal generation circuit.

The triangular wave generator 221 generates a triangular wave signal and outputs it to the comparator 222.
The comparator 222 receives the divided voltage Vt divided by the voltage dividing circuit 210 and the triangular wave signal output from the triangular wave generator 221. The comparator 222 compares the input divided voltage Vt and the voltage of the triangular wave signal, and outputs a PWM signal whose duty is adjusted according to the comparison result to the energization control unit 224. The processing operation of the comparator 222 will be described with reference to FIG. FIG. 5A shows the voltage of the triangular wave signal and the divided voltage Vt so that they can be compared. FIG. 5B shows the comparison result of the voltage of the triangular wave signal and the divided voltage Vt. The PWM signal produced | generated according to is shown. The comparator 222 compares the voltage of the triangular wave signal and the divided voltage Vt, the period of the triangular wave signal> the divided voltage Vt corresponds to the off duty, and the period of the triangular wave signal <the divided voltage Vt corresponds to the on duty. A PWM signal is generated. The comparator 222 generates an on-duty PWM signal proportional to the divided voltage Vt, and outputs the generated PWM signal to the energization control unit 224.

  The hall amplifier 223 inputs signals output from hall sensors Hu, Hv, and Hw provided in the motor 300. The hall sensors Hu, Hv, and Hw detect the positions of the magnetic poles of the rotor (not shown) of the motor 300, generate rotational position detection signals Su, Sv, and Sw at the detected timings, respectively, and generate the generated rotational position detection signals Su. , Sv, Sw are output to the hall amplifier 223. The hall amplifier 223 receives the rotational position detection signals Su, Sv, and Sw output from the hall sensors Hu, Hv, and Hw, amplifies the input rotational position detection signals Su, Sv, and Sw, and supplies the energization control unit 224. Output to.

  The energization control unit 224 receives the rotation position detection signal (Su, Sv, Sw) output from the hall amplifier 223 (hereinafter referred to as an output signal (Su, Sv, Sw)). The energization control unit 224 calculates the rotation speed of the motor 300 based on the input output signals (Su, Sv, Sw), and generates an FG signal that is a pulse signal corresponding to the rotation speed of the motor 300. The energization control unit 224 outputs the generated FG signal to the higher-level device 10.

  The output unit 230 includes a switching element, and is a circuit that switches the Vs signal input from the input terminal 101 under the control of the energization control unit 224 and outputs the Vs signal to the motor 300. The output unit 230 includes a three-phase (U-phase, V-phase, W-phase) inverter as a switching element. The three-phase (U-phase, V-phase, W-phase) inverter corresponds to each of the U-phase, V-phase, and W-phase, and is represented by an N-type field effect transistor (hereinafter referred to as MOS-FET) as an upper switching element. ) U +, V +, W + and N-type MOS-FETs U-, V-, W- as lower switching elements. A wiring 110 connected to the Vs signal input terminal 101 is connected to the drain electrodes of the MOS-FETs U +, V +, and W +. The source electrodes of the N-type MOS-FETs U−, V−, and W− are grounded through a resistor R5. In place of the MOS-FET, a transistor or an IGBT (Insulated Gate Bipolar Transistor) may be used.

  The energization control unit 224 controls the switching element included in the output unit 230 to control the rotation of the motor 300. The energization control unit 224 receives the output signal (Su, Sv, Sw) and the PWM signal, and outputs the output unit 230 according to the input output signal (Su, Sv, Sw) and the duty ratio of the PWM signal. A logic signal for controlling the switching element is generated. The energization control unit 224 is connected to the six MOS-FETs U +, U−, V +, V−, W +, and W− of the output unit 230. The energization control unit 224 selectively selects a logic signal generated based on the output signal (Su, Sv, Sw) of the hall amplifier 223 and the duty ratio of the PWM signal as the switching elements U +, U−, V +, V−. , W +, W− are supplied to the gate electrodes, and the switching elements U +, U−, V +, V−, W +, W− are selectively turned on / off. Then, by inputting the coil signal output from the output unit 230 to the coils Lu, Lv, and Lw, the coils are sequentially excited and the rotor rotates.

  As the motor 300, a three-phase brushless DC motor can be used. The U-phase coil Lu, V-phase coil Lv, and W-phase coil Lw of the motor 300 are Y-connected and wound around a stator (not shown) with a phase difference of 120 degrees.

  6A and 6B show an example of a coil signal in a PAM drive type motor device (described with reference to the conventional motor device 500 shown in FIG. 1A). The PAM drive method is a method in which the rotation speed of the motor 520 is controlled by directly varying the amplitude of the coil signal according to the voltage (amplitude) of the Vs signal. Therefore, when the rotational speed of the motor 520 is increased, the host device 10 increases the voltage of the Vs signal as shown in FIG. 6A, and when the motor rotational speed is decreased, the host device 10 6 (B), the voltage of the Vs signal is lowered.

  FIG. 7 shows an example of a coil signal for controlling a PWM drive system motor device (described with reference to the conventional motor device 600 shown in FIG. 1B). The coil signal is generated in the motor device 600 based on the Vsp signal output from the host device 20 shown in FIG. As described with reference to FIG. 4, the coil signal is based on the output signals (Su, Sv, Sw) of the hall amplifier 223 and the PWM signals generated by the triangular wave generator 221 and the comparator 222. 224 and the output unit 230. However, the voltage that the comparator 222 compares with the triangular wave signal generated by the triangular wave generator 221 is not the divided voltage Vt but the Vsp signal output from the host device 20 to the motor device 600. In the PWM drive method, the rotational speed of the motor 620 is controlled by changing the duty of the PWM signal. When the rotational speed of the motor 620 is increased, the host device 20 increases the voltage of the Vsp signal output to the motor device 600. As the voltage of the Vsp signal increases, the on-duty of the PWM signal increases. For example, as shown in FIG. 7, by increasing the on-duty of the PWM signal from 50% to 75%, the energization time of the coils Lu, Lv, and Lw of the motor 620 becomes longer, and the rotational speed of the motor 620 increases. In the conventional PWM drive method, the amplitude of the coil signal is constant even when the duty is changed.

  8A and 8B show examples of the signal waveform of the coil signal output from the output unit 230 of this embodiment. Since the host device 10 is a device that controls the motor device 100 by the PAM driving method, the host device 10 outputs a Vs signal having a voltage corresponding to the target rotational speed of the motor 300 to the motor device 100 as shown in FIG. The motor device 100 according to the present embodiment inputs the divided voltage Vt obtained by dividing the Vs signal by the voltage dividing circuit 210 to the comparator 222 of the driver IC 220. The divided voltage Vt output from the voltage dividing circuit 210 is a voltage proportional to the voltage of the Vs signal. Further, the duty of the PWM signal generated by the comparator 222 comparing the voltage of the divided voltage Vt and the triangular wave signal also varies in proportion to the voltage (amplitude) of the Vs signal. Thus, as is clear from comparing FIG. 8A and FIG. 8B, when the voltage (amplitude) of the Vs signal is high, the on-duty (%) and voltage of the coil signal also increase. When the voltage (amplitude) of the Vs signal is low, the on-duty (%) and voltage of the coil signal are low.

FIG. 9A shows the relationship between the rotation speed of the motor 300 and the voltage of the Vs signal when the motor 300 is controlled by the PAM drive method. For example, when the operating voltage range in which the motor driving unit 200 can operate is 5 [V] to 25 [V] due to the limitation of the operable voltage of the driver IC 220, the rotation of the motor 300 when the voltage of the Vs signal is 5V. The number is set to 500 [rpm], and the motor 300 is adjusted to have a rotational speed of 2500 [rpm] when the voltage of the Vs signal is 25 [V].
When adjusted in this way, the minimum value of the operating voltage of the output unit 230 is 5 [V]. Therefore, at a voltage lower than 5 [V], the output unit 230 does not operate normally, and the rotation speed of the motor 300 Cannot be made smaller than 500 [rpm].

  FIG. 9B shows the relationship between the rotation speed of the motor 300 and the voltage of the Vs signal when controlling the motor 300 using both the PWM driving method and the PAM driving method of this embodiment. The motor apparatus 100 of the present embodiment controls the rotation speed of the motor 300 by using both the amplitude control of the coil signal by PAM driving and the on-duty control of the coil signal by PWM driving. The operating voltage range of the driving unit 200 is not affected. For this reason, for example, the problem that the rotational speed smaller than 500 [rpm] cannot be obtained as described in FIG. 9A does not occur. Further, as shown in FIG. 9B, the number of rotations of the motor 300 can be controlled in accordance with the Vs signal output from the host device 10.

As is apparent from the above description, in this embodiment, a Vs signal adjusted according to the rotation speed of the motor 300 is input, a PWM signal having a duty ratio corresponding to the input Vs signal is generated, and the motor 300 It outputs to the electricity supply control part 224 which controls a drive. For this reason, even if the signal supplied from the host device 10 is a signal corresponding to the PAM driving method, the motor 300 can be controlled by PWM driving.
Further, a voltage dividing circuit 210 that divides the Vs signal is provided in the motor driving unit 200, and the divided voltage Vt obtained by dividing the Vs signal by the voltage dividing circuit 210 is used as the Vsp signal used in the PWM driving method. To do. Even if the voltage of the Vs signal is high, a signal for controlling the motor 300 by the PWM drive method can be generated by the Vs signal.
Further, by controlling the motor device 100 by the PWM drive method, there is no problem that the desired motor rotation speed cannot be obtained due to the limitation of the operating voltage of the output unit 230.

  A modification of the above-described embodiment will be described. Modification 1 shown in FIG. 10 is a motor device 150 in which a switch 211 is provided in a connection path between the voltage dividing circuit 210 and the wiring 110 connected to the Vs signal input terminal 101. In addition, a Vsp signal input terminal 105 is provided as an interface of the motor device 150. For example, when the host device 20 is a device that controls the motor device 150 by the PWM drive method, the Vsp signal is output from the host device 20 to the motor device 150. For this reason, for example, when the driver IC 220 of the motor device 150 recognizes the connection with the host device 10 via the input terminal 105 that inputs the Vsp signal, the driver 211 is turned off. By turning off the switch 211, the Vs signal is not input to the voltage dividing circuit 210, and the divided voltage Vt is not output from the voltage dividing circuit 210. The comparator 222 receives the Vsp signal through the input terminal 105, compares the voltage value of the Vsp signal and the triangular wave signal, and generates a PWM signal.

  11 is a motor device 160 provided with a first voltage dividing circuit 250 and a second voltage dividing circuit 260. Like the voltage dividing circuit 210, the first voltage dividing circuit 250 includes resistors R1 to R4 having fixed resistance values and a capacitor C, and divides the Vs signal at a preset voltage dividing ratio. The divided voltage Vt divided by the first voltage dividing circuit 250 is output to the resistance control unit 225 provided in the driver IC 220. The resistance control unit 225 determines the target rotational speed of the motor 300 based on the value of the divided voltage Vt, and changes the resistance value of the variable resistor R6 included in the second voltage dividing circuit 260. By changing the resistance value of the variable resistor R6, the voltage dividing ratio of the second voltage dividing circuit 260 is changed, and the divided voltage corresponding to the target rotation speed of the motor 300 can be output to the comparator 222. In the above-described embodiment, the Vs signal that is controlled by the host device 10 so that the rotation speed of the motor 300 becomes the target rotation speed is output to the motor device 100, but after the Vs signal is divided by the voltage dividing circuit 210. Since the signal is input to the comparator 222, the relationship between the rotation speed of the motor 300 and the voltage of the Vs signal is not linear as shown in FIG. 9B. However, as in this modification, the target rotational speed of the motor 300 is determined based on the divided voltage Vt output from the first voltage dividing circuit 250, and the resistance value of the variable resistor R6 provided in the second voltage dividing circuit 260 is changed. With this configuration, the rotation speed of the motor 300 can be linearly changed according to the voltage of the Vs signal.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this embodiment, and various modifications can be made without departing from the scope of the present invention.

10, 20 Host device 100 Motor device 101 Input terminal 200 Motor drive unit 210 Voltage divider circuit 220 Driver IC
230 Output unit 300 Motor

Claims (3)

An input terminal for inputting the drive voltage of the motor adjusted according to the rotational speed of the motor;
A PWM signal generation circuit that generates a PWM signal having a duty ratio corresponding to the drive voltage input from the input terminal;
A motor drive device comprising:   The motor drive device according to claim 1, further comprising an output circuit that switches the drive voltage input from the input terminal according to a duty ratio of the PWM signal and outputs the same to the motor. A voltage dividing circuit that divides and outputs the drive voltage input from the input terminal;
3. The motor driving apparatus according to claim 1, wherein the PWM signal generation circuit generates a PWM signal output from the voltage dividing circuit and having a duty ratio corresponding to the divided driving voltage.

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