JPH09149678A - Driver of brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a current-carrying efficiency by a method wherein the phase of a phase signal is adjusted in accordance with a current carried by a motor. SOLUTION: Position detection signals (a), (b) and (c) whose phases are shifted from each other by 120 deg. are obtained by position detectors HU, HV and HW. In a wave shaping circuit 3, the position detection signals (a), (b) and (c) are subjected to the wave-shaping and reversed by comparators 3a, 3b and 3c to be outputted as phase signals (d), (e) and (f). A current detector 6 detects a current carried by a motor 1 and outputs a voltage signal (g). A current-carrying phase adjusting circuit 4 discharges a certain capacity of charge with a voltage (k) every edge of the phase signal (d) and recharge with the voltage signal (g) as a threshold. Then a current-carrying phase signal (h) whose edge is a point at which the threshold value overlaps the discharge voltage. The phase of the current-carrying signal (h) leads in comparison with the phase of a conventional phase signal (d1) which is obtained from the position detector HU. In the same way, current-carrying signals (i) and (j) corresponding to the phase signals (e) and (f) are obtained. The current-carrying signals (h), (i) and (j) are synthesized by a driver 5 to turn the rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor drive device applied to office automation equipment, audio equipment, video equipment and the like.

[0002]

2. Description of the Related Art In recent years, as the power consumption of OA equipment and the like has advanced, higher efficiency of motors has been demanded. A conventional DC brushless motor driving device will be described below. FIG. 5 shows a conventional DC brushless motor drive device. In FIG. 5, reference numeral 1 is a brushless motor composed of a rotor having permanent magnets magnetized in multiple poles, a stator having an armature, and position detectors HU, HV, HW, and 2 is composed of comparators 2a, 2b, 2c. Waveform shaping circuit 5 creates a drive signal and brushless motor 1
Is a drive circuit for energizing the winding of each phase.

The operation of the drive circuit for the brushless motor configured as described above will be described with reference to FIG. First, the position detectors HU, HV, HW of the brushless motor 1
Are position detection signals a, b, which are electrically 120 ° out of phase with each other.
Output c. The position detection signals a, b and c are waveform-shaped by the comparators 2a, 2b and 2c of the waveform shaping circuit 2 and output the phase signals d1, e1 and f1. The phase signals d1, e1, f1 of the waveform shaping circuit 2 are supplied to the drive circuit 5
Is input to the armature of the brushless motor 1 to generate a drive signal for energizing the winding of each phase of the armature.
When the phases of the armature of the brushless motor 1 are sequentially energized, the rotor having permanent magnets rotates.

[0004]

However, in the above-mentioned conventional structure, as the current increases due to the load of the brushless motor, the current is delayed by the L component of the armature winding and the like, and the current to the armature winding is delayed. There is a problem in that the energization position is delayed, and thus the efficiency of the brushless motor is deteriorated.

The present invention solves the above-mentioned conventional problems, and provides a highly efficient brushless motor drive device capable of electrically adjusting the current to the optimum energizing position without changing the position of the position detector. The purpose is to do.

[0006]

According to a first aspect of the present invention, there is provided a brushless motor driving device including a brushless motor including a rotor having a permanent magnet magnetized in multiple poles and a stator having an armature, and a permanent magnet and an armature. A position detector that detects the positional relationship and outputs a position detection signal, a waveform shaping circuit that waveform-shapes the position detection signal of this position detector and outputs a phase signal, and a current that flows in the armature is detected and output. A current detector that outputs a signal, a conduction phase adjustment circuit that outputs a conduction phase signal in which the phase of the phase signal of the waveform shaping circuit is adjusted according to the output signal of the current detector, and a conduction phase signal of this conduction phase adjustment circuit And a drive circuit for driving the armature by inputting.

According to the brushless motor driving device of the first aspect, the position detection signal for detecting the position of the rotor is waveform-shaped and converted into a phase signal, and the phase signal is phased according to the current flowing through the brushless motor. It is adjusted and converted into an energization phase signal, and the energization phase signal causes the drive circuit to operate to rotate the rotor. In this case, since the energization phase adjustment circuit that adjusts the phase of the phase signal according to the current flowing in the brushless motor is provided, even if the current flowing in the brushless motor increases due to the load, by advancing the energization phase according to the current, It is possible to realize a brushless motor drive device having good current-carrying efficiency without being affected by a delay due to the L component of the brushless motor such as armature reaction. Moreover, there is no need to change the position of the position detector.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, 1 is a DC brushless motor composed of a rotor having permanent magnets magnetized in multiple poles and a stator having an armature, and 2 is a position detector HU composed of elements for detecting the positional relationship between the permanent magnets and the armature. , HV, HW, 3 waveform-shape the position detection signals of the position detectors HU, HV, HW and output a phase signal, and the comparators 3a, 3
The waveform shaping circuit 4 composed of b and 3c outputs an energization phase signal in which the phase of the phase signal of the waveform shaping circuit 3 is adjusted according to the output signal of the current detector 6.
The energizing phase adjusting circuit 5 for adjusting in proportion to the magnitude of the output signal of 5 inputs the energizing phase signal of the energizing phase adjusting circuit 4 to drive the armature, and outputs a signal for driving the brushless motor 1. The drive circuit 6 is a current detector that detects a current flowing through the armature and outputs an output signal, and is a current detector that detects an output signal proportional to the current.

The energization phase adjusting circuit 4 will be described with reference to FIG. The phase signal d of the waveform shaping circuit 3 is delayed by the buffer circuit 41. The exclusive OR circuit 42 takes the exclusive OR of the signal d and the signal of the buffer circuit 41 to obtain the phase signal d
The signal for each edge is output to the SR latch circuit 43. S
The R latch circuit 43 is set by the signal of the exclusive OR circuit 42, turns on the transistor 45, and turns on the transistor 4
A signal for turning off 4 is output. The capacitor 47 is discharged by the constant current source 46 with a constant current. The terminal voltage k of the capacitor 47 is compared with the voltage signal g of the current detector 6 by the comparison circuit 48, and when the potential becomes lower than the voltage signal g, the comparator 4
8 to SR latch circuit 43 and D flip-flop circuit 4
9 is output. The SR latch circuit 43 is reset by the signal from the comparator 48, the transistor 44 is turned on, the transistor 45 outputs a signal to be turned off, and the terminal voltage k of the capacitor 47 is recharged. Further, the D flip-flop circuit 49 obtains the energization phase signal h from the phase signal d and the signal of the comparison circuit 48.

The drive circuit 5 will be described with reference to FIG. The drive circuit 5 amplifies the energization phase signals h, i, j by the output amplifiers 51, 52, 53, respectively, and the brushless motor 1
Drive current is output to the armature winding, and the current flowing in the armature winding is output to the current detector 6. Regarding the operation of the brushless motor driving device configured as described above,
This will be described with reference to FIG. First, in the brushless motor 1, the position detectors HU, HV, HW of the rotor are arranged at the intermediate points of the respective slots of the stator, and by the rotation of the rotor,
Position detection signals a, b, c that are electrically 120 ° out of phase
Get. The waveform shaping circuit 3 waveform-shapes the position detection signals a, b and c by the comparators 3a, 3b and 3c and outputs inverted phase signals f, d and e. Current detector 6
Detects a current flowing through the brushless motor 1 and outputs a voltage signal g. The energization phase adjustment circuit 4 discharges the electric charge of the voltage k of a certain capacitance for each edge of the phase signal d for the phase signal d, and recharges the voltage signal g using the threshold value as a threshold value. Then, the energization phase signal h whose edge is a point where the discharge voltage and the threshold value overlap each other is generated. The energization phase signal h leads the phase as compared with the conventional phase signal d1 obtained from the position detector HU.

Similarly, the energization phase adjusting circuit 4 obtains the energization phase signals i and j for the phase signals e and f. The energizing phase signals h, i, j thus obtained are combined in the drive circuit 5, and the armature winding of the brushless motor 1 is energized by the drive circuit 5 in accordance with the energizing phase of the energizing phase signals h, i, j. , The rotor rotates. As described above, according to this embodiment, the position detection signals a to c for detecting the position of the rotor are waveform-shaped and converted into phase signals d to f, and the phase signals d to f are transmitted to the brushless motor 1. The energization phase signals h to j are phase-adjusted according to the flowing current.
And the drive circuit 5 is converted by the energization phase signals h to j.
Operates and rotates the rotor.

In this case, since the energization phase adjusting circuit 4 for adjusting the phases of the phase signals d to f according to the current flowing through the brushless motor 1 and varying the energization phase is provided, the current flowing through the brushless motor 1 increases due to the load. Even if, however, the energization phase is advanced in proportion to the current, for example, in proportion to the current, there is no influence of delay due to the L component of the brushless motor 1 such as armature reaction, and a drive device for the brushless motor 1 having good energization efficiency. Can be realized. Moreover, it is not necessary to change the positions of the position detectors HU, HV, HW.

[0013]

According to the brushless motor driving device of the first aspect of the invention, since the energization phase adjusting circuit for adjusting the phase of the phase signal according to the current flowing through the brushless motor is provided, the current flowing through the brushless motor due to the load is reduced. Even if the current increases, by advancing the current-carrying phase according to the current, it is possible to realize a brushless motor drive device having good current-carrying efficiency without being affected by a delay due to the L component of the brushless motor such as armature reaction. Moreover, there is no need to change the position of the position detector.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a brushless motor drive device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the brushless motor drive device.

FIG. 3 is a circuit diagram of a conduction phase adjusting circuit.

FIG. 4 is a circuit diagram of a drive circuit.

FIG. 5 is a configuration diagram of a conventional brushless motor drive device.

FIG. 6 is a waveform diagram for explaining the operation of a conventional brushless motor drive device.

[Explanation of symbols]

 1 Brushless motor 3 Waveform shaping circuit 4 Energization phase adjustment circuit 5 Drive circuit 6 Current detector a to c Position detection signal d to f Phase signal g Voltage signal h to j Energization phase signal HU to HW Position detector

Claims (1)

[Claims] 1. A brushless motor comprising a rotor having a multi-pole magnetized permanent magnet and a stator having an armature, and position detection for detecting a positional relationship between the permanent magnet and the armature and outputting a position detection signal. And a waveform shaping circuit for shaping the position detection signal of the position detector to output a phase signal, a current detector for detecting a current flowing in the armature and outputting an output signal, and the waveform shaping An energization phase adjusting circuit that outputs an energization phase signal in which the phase of the phase signal of the circuit is adjusted according to the output signal of the current detector, and the armature by inputting the energization phase signal of the energization phase adjustment circuit. And a drive circuit for driving the brushless motor drive device.