JP2008193802A - Motor drive method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform speed control over a wide range, using a high voltage higher than a DC voltage from a smoothing circuit by boosting and stepping down a DC voltage to a motor drive circuit using a step-up/step-down means. <P>SOLUTION: In this motor drive method and a device, there is provided the step-up/step-down means (10) between the smoothing circuit (2) and the motor drive circuit (3), and the DC voltage from the smoothing circuit (2) is fed to the motor drive circuit (3), after being stepped up and stepped down by the step-up/step-down means (10). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor driving method and apparatus, and in particular, it is possible to control a wide range of speeds by a high voltage that is higher than a DC voltage from a smoothing circuit by raising and lowering a DC voltage to a motor driving circuit using a step-up / step-down means. It relates to a new improvement.

  Conventionally, as this type of motor driving method that has been used, for example, a PWM (Pulse Width Modulation) method and a PAM (Pulse Amplitude Modulation) method disclosed in Patent Documents 1 to 3 are generally used. In the system, an input power source (three-phase AC input signal) is smoothed to be a DC voltage, and this DC voltage is subjected to pulse modulation or amplitude modulation to determine the motor input voltage to the three-phase motor.

  FIG. 2 schematically shows the above-described known PWM motor driving method. A three-phase AC input signal 1 is converted into a DC voltage by a smoothing circuit 2, and this DC voltage passes through a PWM generation circuit (not shown). After the pulse width modulation, the three-phase motor 4 having a three-phase drive coil (not shown) is driven by being supplied to the motor drive circuit 3 including six transistors UH to UW and UL to UW. A rotation detection signal 5 a from the rotation sensor 5 of the motor 4 is input to the inverter control circuit 6 of the motor drive circuit 3. In FIG. 2, the PWM signal generator is not shown.

JP-A-11-332282 JP 2004-104954 A JP-A-6-165573

Since the conventional motor driving method is configured as described above, the following problems exist.
That is, as shown in the conventional circuit of FIG. 2, the DC voltage supplied from the smoothing circuit 2 to the motor drive circuit 3 is pulse-modulated to determine the motor input voltage to the motor drive circuit 3.
However, this motor input voltage does not exceed the DC voltage from the smoothing circuit, and the maximum rotation speed of the three-phase motor is determined by the DC voltage, and it is impossible to obtain an increase in the rotation speed beyond this. It was.
Further, as a method for increasing the rotation speed of the three-phase motor, it is possible to increase the rotation speed by controlling the field of the motor. However, the reactive current is caused to flow to the motor, resulting in a decrease in efficiency. It was.

  In the motor driving method according to the present invention, a three-phase motor having a three-phase driving coil is controlled via a motor driving circuit having a total of six transistors, and a three-phase AC input signal is input to the front side of the motor driving circuit. In the motor driving method in which the smoothing circuit is connected to drive the three-phase motor, a step-up / step-down means is provided between the smoothing circuit and the motor driving circuit, and the DC voltage from the smoothing circuit is increased or decreased. The step-up / step-down pressure is supplied to the motor drive circuit after the pressure means, and the step-up / step-down means includes a pair of capacitors, a pair of switching elements, a reactor, and a diode. The motor driving device according to the invention controls a three-phase motor having a three-phase driving coil via a motor driving circuit having a total of six transistors, In a motor driving apparatus that drives a three-phase motor by connecting a smoothing circuit to which a three-phase AC input signal is input in front of the motor driving circuit, the motor driving circuit moves up and down between the smoothing circuit and the motor driving circuit. And a step-up / step-down means for supplying a voltage to the motor drive circuit after the step-up / step-down means raises / lowers the DC voltage from the smoothing circuit. It is the structure which consists of a switching element, a reactor, and a diode.

Since the motor driving method and apparatus according to the present invention are configured as described above, the following effects can be obtained.
That is, since the DC voltage from the smoothing circuit is stepped up / down via the step-up / step-down means, the number of rotations of the three-phase motor can be made freely, and the number of rotations higher than the number of rotations by the DC voltage can be set. it can.

  The present invention relates to a motor driving method that enables a wide range of speed control by a high voltage that is equal to or higher than a DC voltage from a smoothing circuit by boosting or lowering a DC voltage to a motor driving circuit by using a step-up / step-down means. An object is to provide an apparatus.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a motor driving method and apparatus according to the present invention will be described with reference to the drawings.
In addition, the same code | symbol is attached | subjected and demonstrated to a part the same as that of a prior art example, or an equivalent part.
FIG. 1 shows a configuration in which a step-up / step-down means 10 composed of a step-up converter is provided in the conventional configuration of FIG. 2, and a well-known PWM signal generation unit or PAM signal generation unit is not shown.

  The three-phase AC input signal 1 is converted into a DC voltage by the smoothing circuit 2, and this DC voltage is pulse-modulated or amplitude-modulated and supplied to the motor drive circuit 3 comprising six transistors UH to WH and UL to WL. A three-phase motor 4 having a phase drive coil (not shown) is driven, and a step-up / step-down means 10 comprising a step-up / step-down converter is provided between the smoothing circuit 2 and the motor drive circuit 3.

  The step-up / step-down means 10 is connected to the first capacitor C1 connected in parallel to the smoothing circuit 2, the reactor L and the first switching element S1 connected in series to the first capacitor C1, and the first switching element S1. A second switching element S2 in parallel with the first capacitor C1, a diode D connected to the switching elements S1 and S2, and a parallel connection with the first capacitor C1 and the second switching element S2 connected to the diode D. The second capacitor C2 is connected to the second capacitor C2.

  In the configuration described above, the first switching element S1 is kept on and the second switching element S2 is turned on / off, thereby generating a voltage in the reactor L and controlling the on / off ratio of the second switching element S2. Thus, the DC voltage output from the smoothing circuit 2 can be boosted from the voltage at that time.

  In contrast to the above-described step-up, the second switching element S2 is kept on and the DC voltage output from the smoothing circuit 2 is controlled by controlling the on / off ratio of the first switching element S1 at the time of step-down. It can be made lower than the voltage at that time.

  Accordingly, the direct current voltage from the smoothing circuit is boosted or stepped down by the step-up / step-down means 10 and then supplied to the motor drive circuit 3 via a PWM generation circuit or PAM generation circuit (not shown). Drive is controlled. The step-up / step-down means 10 can use a known configuration other than the converter described above.

It is a circuit diagram which shows the motor drive device by this invention. It is a circuit diagram which shows a conventional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 3 phase alternating current input signal 2 Smoothing circuit 3 Motor drive circuit 4 3 phase motor 10 Buck-boost means L Reactor C1, C2 1st, 2nd capacitor S1, S2 1st, 2nd switching element D Diode

Claims (4)

A three-phase motor (4) having a three-phase drive coil is controlled via a motor drive circuit (3) having a total of six transistors (UH to WL). In a motor driving method in which a smoothing circuit (2) to which a phase AC input signal (1) is input is connected to drive the three-phase motor (4).
A step-up / step-down means (10) is provided between the smoothing circuit (2) and the motor drive circuit (3), and the DC voltage from the smoothing circuit (2) is stepped up / down by the step-up / down means (10). A motor driving method characterized by being supplied to a motor driving circuit (3).   The motor according to claim 1, wherein the step-up / step-down means (10) comprises a pair of capacitors (C1, C2), a pair of switching elements (S1, S2), a reactor (L), and a diode (D). Driving method. A three-phase motor (4) having a three-phase drive coil is controlled via a motor drive circuit (3) having a total of six transistors (UH to WL). In the motor driving apparatus which connects the smoothing circuit (2) to which the phase alternating current input signal (1) is input and drives the three-phase motor (4),
A step-up / step-down means (10) is provided between the smoothing circuit (2) and the motor drive circuit (3), and the DC voltage from the smoothing circuit (2) is stepped up / down by the step-up / down means (10). A motor drive device characterized by being supplied to a motor drive circuit (3).   The motor according to claim 3, wherein the step-up / step-down means (10) includes a pair of capacitors (C1, C2), a pair of switching elements (S1, S2), a reactor (L), and a diode (D). Drive device.

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