JP3387009B2 - Three-phase brushless motor driving method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase brushless motor driving method, and in particular, generates a three-phase switching signal of six channels by using a three-phase excitation method. The present invention relates to a novel improvement for simplifying a circuit configuration compared to a conventional two-phase excitation system. 2. Description of the Related Art Conventionally, this type of three-phase brushless motor and six channels supplied to a motor drive circuit for selecting a three-phase DC motor drive signal output from a motor drive circuit of an AC motor The configuration shown in FIG. 8 has been adopted as the motor drive control circuit 11 for generating the three-phase switching signal. That is, each gate circuit 11a, 1 to which the rotation direction signal 3 among the signals on the input side of the processing circuit 2A to which the control signal group 2 from the CPU 1 is input is input.
1b and 11c receive three-phase detection signals U _E , V _E and W _E relating to the three-phase drive coils U, V and W in FIG. 7, and the outputs from the gate circuits 11a, 11b and 11c are three. Six-channel three-phase switching signals U _{H to} W _H and U _{L to} W _L are output via an inverter 11d and nine gate circuits 11e and 11f, and the processing circuit 2 is provided to the gate circuit 11f.
The output 2Aa of A and the current signals U _{S1 to} W _S1 from the three-phase current sensors U _{S to} W _S are input. [0003] Next, 3-phase switching signal U _H to _W-H and U _L to _W-L 6-channel described above, the motor drive circuit (not shown) 6
And is always in a two-phase excitation state as indicated by the phase switching control logic shown in FIG. In the two-phase excitation method using the above-described control logic, two channels out of the six-channel three-phase switching signals U _{H to} W _H and U _{L to} W _L are always turned on for each electrical angle and the two-phase excitation signal is turned on. Excitation is performed. FIG. 10 shows a line induced voltage waveform at the time of two-phase excitation. [0004] Since the conventional three-phase brushless motor driving method is configured as described above,
The following issues existed. In other words, since the motor drive control circuit of FIG. 8 that generates a six-channel three-phase switching signal is configured to perform two-phase excitation drive using a large number of gate circuits, the circuit configuration is complicated and cost reduction is achieved. It was difficult to improve the reliability. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in particular, by using a three-phase excitation method, a circuit configuration for generating a six-channel three-phase switching signal is replaced with a conventional two-phase switching circuit. It is an object of the present invention to provide a three-phase brushless motor driving method that is simpler than the excitation method. A three-phase brushless motor driving method according to the present invention uses a three-phase detection signal and a rotation direction signal for a three-phase driving coil of a three-phase brushless motor obtained by a motor drive control circuit. in 3-phase brushless motor driving method for selectively driving the 3-phase drive coils on the basis of the 3-phase switching signal channels, the rotating direction
The direction signal is based on the DC motor drive signal with brush detection
Of the three-phase switching signal.
This is a method in which any three channels are always turned on . BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG.
A preferred embodiment of the phase brushless motor driving method will be described. The same or equivalent parts as those in the conventional example will be described using the same reference numerals. First, the driving method according to the present invention will be described below as an example in which the present invention is applied to a method of driving a brushless DC motor 4 using DC brush motor driving signals A and B. It can also be applied to methods. In FIG. 1, what is indicated by reference numeral 1 is a bipolar DC with brush.
This is a full-wave rectifier circuit to which motor drive signals A and B are input. The full-wave rectifier circuit 1 converts the brushed DC motor drive signals A and B into a unipolar drive signal 2 by full-wave rectification. The unipolar drive signal 2 is input to the motor drive circuit 3. The three-phase DC motor drive signal 30 including the U-phase, V-phase, and W-phase output from the motor drive circuit 3 is a brushless DC motor 4 (AC motor, (A brushless motor).
The DC motor drive signals with brushes A and B are simultaneously input to a rotation direction detection circuit 6 provided in the control unit 5, and CW and C output from the rotation direction detection circuit 6 are output from the rotation direction detection circuit 6.
The rotation direction signal 7 in the CW direction is input to a motor drive control circuit 11 to which three-phase detection signals U _E , V _E , and W _E output from a well-known Hall element 10 connected to the brushless DC motor 4 are input. Have been. A three-phase three-phase switching signal 1 of six channels consisting of three phases in two directions output from the motor drive control circuit 11
2 is supplied to the motor drive circuit 3 after being amplified via the preamplifier 13. In addition, the aforementioned preamplifier 1
3. The 28 V power supply 14 is connected to the voltage converter 1 for the rotation direction detection circuit 6, the motor drive control circuit 11, and the Hall element 10.
5V drive power supply 16 converted in 5 is supplied to each. Next, the full-wave rectifier circuit 1 is configured as shown in FIG. 2, and uses four Schottky barrier diodes D1 to D4 and a constant voltage diode D5 to achieve high speed and low voltage. The operation and protection of the back electromotive force of the motor are achieved, and the bipolar brush DC motor drive signals A and B are converted into the unipolar drive signal 2. The control unit 5 is configured as shown in FIG. 3, and the first and second rotation direction detection circuits 6
DC with brush input to photocouplers 20 and 21
The motor drive signals A and B are converted into rotation direction signals CW and CCW by the respective photocouplers 20 and 21, and then the three-phase detection signals U _E and
The first of the motor drive control circuit 11 to which V _E and W _E are input,
After being input to the second and third gate circuits 11a, 11b, 11c, a six-channel three-phase switching signal 12 is output,
The 6-channel _{(U H, V H, W} H, U L, V L, W L) 3 -phase switching signal 12 is input to the motor driving circuit 3 through the preamplifier 13. The three-phase switching signal 12 output from the preamplifier 13 is supplied to the motor drive circuit 3 shown in FIG.
, The unipolar drive signal 2 is sequentially switched by the switching transistors TR _{1 to} TE ₆ , and the U-phase, V-phase, W
The three-phase DC motor driving signals 30 are sequentially input to the brushless DC motor 4 to perform three-phase driving. Therefore, in the present invention, when the brushless DC motor 4 used so far is replaced with a brushless DC motor,
The brushless DC motor 4 can be driven using the DC motor drive signals A and B with brush. The six-channel three-phase switching signal 12 described above has a motor drive control circuit 11 as shown in the waveform of FIG.
, On / off is controlled, and by always turning on three channels at each electric angle of the motor, three-phase excitation can be always performed. In addition, 3 shown in the waveform of FIG.
The state of phase excitation indicates that three phases are excited at CW and CCW at each electrical angle. In the present embodiment, the case where three-phase driving is performed using the DC motor drive signals with brushes A and B has been described. However, it is needless to say that the known three-phase driving method can be changed to three-phase excitation. . [0012] The three-phase brushless motor driving method according to the present invention is configured as described above, so that the following effects can be obtained. That is, by changing to the three-phase excitation drive system, the hardware of the motor drive control circuit that outputs the six-phase three-phase switching signal based on the rotation direction signal and the three-phase detection signal as the commutation signal is significantly larger than before. (About 50%), which can contribute to cost reduction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing a driving circuit to which a three-phase brushless motor driving method according to the present invention is applied. FIG. 2 is a circuit diagram showing the full-wave rectifier circuit of FIG. FIG. 3 is a circuit diagram showing a control unit of FIG. 1; FIG. 4 is a circuit diagram showing a motor drive circuit of FIG. 1; FIG. 5 is a driving waveform diagram. FIG. 6 is an explanatory diagram showing three-phase excitation according to the present invention and conventional two-phase excitation. FIG. 7 is a configuration diagram showing a three-phase drive coil of the motor. FIG. 8 is a configuration diagram showing a conventional motor drive control circuit. FIG. 9 is an explanatory diagram showing a conventional phase switching control logic. FIG. 10 is a waveform diagram showing a conventional driving state. [Description of symbols] A, DC motor drive signal 4 3-phase brushless motor U with B brush, V, W 3-phase drive coils _{U E, V E, W E} 3 -phase detection signal 6 rotating direction detecting circuit 7 rotating direction signal 10 Hall element 11 Motor drive control circuit 12 Six-channel three-phase switching signal

Claims (1)

(57) [Claims] [Claim 1] Three-phase detection signals (U _E , V _E , W _E ) and rotation of three-phase drive coils (U, V, W) of a three-phase brushless motor (4) A three-phase brushless device for selectively driving the three-phase drive coils (U, V, W) based on a six-channel three-phase switching signal (12) obtained by a motor drive control circuit (11) by a direction signal (7). In the motor driving method, the rotation direction signal (7) is
A DC motor drive signal (A, B) with a brush detects the direction of rotation (6)
And the three-phase detection signals (UE, VE, WE)
Obtained from the Hall element (10) of the three-phase brushless motor (4)
And any one of the three-phase switching signals (12)
A three- phase brushless motor driving method, wherein the three channels are always turned on .