KR100292529B1 - A control method of brushless dc motor - Google Patents

Abstract

The present invention relates to a BCD motor control method, and conventionally, to control a BCD motor, three Hall sensors, which are minimum position sensing sensors for knowing position information, are required, thereby increasing costs. Therefore, the present invention initializes and waits for the first, second, and third timers when an interrupt signal corresponding to a change in the state of the hall sensor is generated, and loads a state flag for sequence control of the hall sensor and output control timing. A first step of determining whether the motor is in the initial stage of startup; As a result of the determination of the first step, if the motor is in the initial startup state, the initial state value of the hall sensor for initial startup is read, the first timer is operated, and the logic corresponding to the initial state value is output and the first timer is operated. A second step of obtaining a distance (90 degrees) distance value (T1), obtaining distance values (T2, T3) between modes corresponding to 60 degrees and 120 degrees through the distance value (T1), and storing and returning to RAM; As a result of the determination in the first step, if the motor is not started, the initial state value of the hall sensor is read to sense the position of the roto, and the second and third timers are operated at 60 degrees and 120 degrees, respectively. Determining whether it corresponds to T2 and T3 corresponding to FIG. A fourth step of compensating for the timing of the current output signal and outputting and returning the second and third timer values when the second and third timer values match T2 and T3, respectively; If the second and third timer values do not coincide with T2 and T3 as the determination result of the third step, the Hall sensor is reduced to two by performing the fifth step of outputting and returning the same without compensating the timing of the current output signal. By simplifying the circuit components, the PCB size can be optimized, the cost can be reduced, and other synchronous motor-driven Hall sensors can be applied to all fields.

Description

A CONTROL METHOD OF BRUSHLESS DC MOTOR}

The present invention relates to a BCD motor control method, and more particularly to a BCD motor control method to reduce the cost by reducing the number of Hall sensors through the program processing.

In general, as shown in FIG. 1 of the accompanying drawings, the BCD motor control apparatus sets the position of the counter electromotive force of the voltage supplied to the motor to each of the phases of the rotor of the motor 300 (Ha Hall). , Hb, Hc, and determine the rotational speed of the motor 300 by using the detected position information of the rotor to control the control signals (U +, V +, W +, U-, V-, W-) accordingly. A microcomputer 100 for outputting; Inverter unit 600 which is switched by control signals U +, V +, W +, U-, V-, W- of the microcomputer 100 to apply alternating current of a desired average voltage and frequency to the motor 300. It consists of.

FIG. 2 is a detailed circuit diagram for driving the BC motor 300, and receives a predetermined control signal of the microcomputer 100 through the interface unit 500, and consists of six transistors for conduction control accordingly. A stator and a stator connected to each of the six transistors in series, a common connection point of the two transistors connected in series of the inverter, and receiving a three-phase power converted by switching of the inverter. It consists of a BCD motor 300 made of a rotor operating by the magnetic field of the, the operation of such a conventional device will be described with reference to Figs.

First, the BCD motor 300 is a motor 300 that uses the characteristics of permanent magnets instead of brushes among brush motors, unlike induction motors. Hall sensors (Ha) Rotation by, Hb, Hc is always detected and the detected signal is applied to the microcomputer 100 as shown in FIGS. 3A, 3B, and 3C.

Then, the microcomputer 100 receives the detection signal to determine the rotational speed of the motor 300, and compares the determined rotational speed with a target speed set in advance of the program. Controlled by timing signals U +, V +, W +, U-, V-, and W- as shown in FIGS.

That is, the microcomputer 100 outputs a predetermined control signal through the interface unit 500 to enable the switching operation of the inverter unit 600. The microcomputer 100 has a counter electromotive force of a voltage supplied to the motor 300. To detect the current position of the rotor of the motor 300, and to determine the rotational speed of the motor 300 using the detected position information of the rotor 300 and then to determine the target rotational speed Compared with, and controls the motor 300 to rotate at the target speed according to the comparison result.

In other words, six pulse waveforms such as (d) to (i) of FIG. 3 are transmitted to the inverter unit 600 to switch each of the six transistors corresponding to each phase to each phase configured in the motor 300. By controlling the power supplied to the driving of the motor 300 is made.

However, the prior art as described above requires three Hall sensors, which are the minimum position detection sensors to know the position information, in order to control the BLC motor.

Accordingly, an object of the present invention is to provide a BCD motor control method that can reduce the cost by reducing the number of Hall sensors through the program processing.

1 is a block diagram showing a configuration for a conventional BCD motor control apparatus.

FIG. 2 is a detailed circuit diagram of a BC motor in FIG. 1; FIG.

3 is a timing diagram of each phase in FIG. 1;

Figure 4 is a block diagram showing the configuration of the BCD motor control apparatus to which the present invention is applied.

Fig. 5 is a timing diagram of the Hall sensor output control logic during driving in Fig. 4;

Fig. 6 is a timing diagram of the Hall sensor output control logic at the time of initial startup in Fig. 4;

Figure 7 is an operation flow chart for the present invention the BCD motor control method.

***** Description of the symbols for the main parts of the drawings *****

100: microcomputer 200: drive unit

300: motor 400: power supply

500: interface unit 600: inverter unit

An object of the present invention for achieving the above object is to initialize the first, second, third timer to wait when the interrupt signal corresponding to the state change of the Hall sensors (Ha, Hb, Hc), the hall sensor A first step of determining whether the motor is in the initial stage after loading the RAM (Ha, Hb, Hc) and the status flag for the sequence control of the output control timing into the RAM; As a result of the determination of the first step, if the motor is in the initial startup state, the initial state values of the hall sensors Ha, Hb, and Hc for initial startup are read, the first timer is operated, and the logic corresponding to the initial state values is output. After that, the distance value T1 between the modes (90 degrees) is obtained using the first timer, and the distance values T2 and T3 between modes corresponding to 60 degrees and 120 degrees are obtained through the distance value T1. A second step of storing and returning; As a result of the determination of the first step, if the motor 300 is not in the starting phase, the initial state values of the hall sensors Ha, Hb, and Hc are read to sense the position of the roto, and the second and third timers are operated. Determining whether the third timer value corresponds to T2 and T3 corresponding to 60 degrees and 120 degrees, respectively; A fourth step of compensating for the timing of the current output signal and outputting and returning the second and third timer values when the second and third timer values match T2 and T3, respectively; If the second and third timer values do not coincide with T2 and T3 as a result of the determination in the third step, the fifth step of outputting and returning the present output signal without compensating the timing of the current output signal may be performed.

Hereinafter, with reference to the accompanying drawings, the operation and effects of the embodiment of the BCD motor control method according to the present invention will be described in detail.

Figure 4 is a block diagram showing the configuration of the BCD motor control apparatus to which the present invention is applied, as shown in the general configuration is the same as the conventional Figure 1 except that one hall sensor is reduced.

FIG. 5 is a flowchart illustrating a BCD motor control method according to the present invention. As shown in FIG. 5, when an interrupt signal corresponding to a state change of the hall sensors Ha, Hb, and Hc is generated, first, second, and third timers are generated. The first step of determining whether the motor 300 is in the initial stage after loading the RAM and loading the Hall sensors (Ha, Hb, Hc) and a status flag (Flag) for the sequence control of the output control timing to the RAM; ; As a result of the determination of the first step, when the motor 300 is initially started, the initial state value of the hall sensors Ha, Hb, and Hc for initial start-up is read, the first timer is operated, and the logic corresponding to the initial state value. After outputting the result, the distance value T1 between modes (90 degrees) is obtained using the first timer, and the distance values T2 and T3 between modes corresponding to 60 degrees and 120 degrees are obtained through the distance value T1. Storing and returning to a second step; As a result of the determination of the first step, if the motor 300 is not in the starting phase, the initial state values of the hall sensors Ha, Hb, and Hc are read to sense the position of the rotor, and then the second and third timers are operated. Determining whether the second and third timer values coincide with T2 and T3 corresponding to 60 and 120 degrees, respectively; A fourth step of compensating for the timing of the current output signal and outputting and returning the second and third timer values when the second and third timer values match T2 and T3, respectively; As a result of the determination of the third step, if the second and third timer values do not coincide with T2 and T3, the fifth step of outputting and returning the present output signal without compensating the timing of the present output signal is performed. Explain.

First, in order to rotationally drive the BCD motor 300, which is the synchronous motor 300, the rotor position of the NS pole magnet is sensed and current direction control is performed on the stator suitable for the NS pole. shall.

In this case, the current direction control is controlled by switching the gate terminal of the six transistors of the inverter unit 600.

That is, in order to drive the BCD motor 300 in the related art, it is possible to generate a phase difference of 120 degrees between the three phases of the motor 300 so that the logic of 60-degree intervals can be configured using three Hall sensors (Ha, Hb, Hc). Since the phase difference of 120 degrees is simply reflected through the number of mode repetitions, the present invention is composed of four modes using two Hall sensors (Ha, Hb). The phase difference is compensated and reflected by the timing of 30 degrees, which will be described in detail with reference to FIG. 5.

If the position of the rotor is at the position of the first mode (Ha = 0, Hb = 1), the output control logic is W +, U- turned on so that current flows in the direction as shown in FIG. The rotor rotates in a certain direction by the flow of the current. When the rotation is performed, the next sequence is the state value of the hall sensors Ha and Hb in the order of the second, third, and fourth modes. It is read through the interrupt ports INT1 and INT2 of the microcomputer 100.

At this time, since the current is supplied through the output control logic of Fig. 5 in the same principle as the first mode to correspond to the state transition values of the respective Hall sensors Ha and Hb, the rotor is continuously rotated in a constant rotational direction. Done.

Here, when the above-described rotation control principle is applied to two Hall sensors (Ha, Hb), since there are only four modes as shown in FIG. 5, the angles between the modes have a resolution of 90 degrees. Since it does not match the logic change (on 120 degrees or more) and the mode change timing read from the Hall sensors (Ha, Hb), the timer must be operated for a certain period before and after the mode change to synchronize with the timing of the output control logic. The program should be compensated by a certain angle or interval that does not match the timing, which will be described with reference to FIG. 7.

First, a signal corresponding to a change in position (Ha, Hb) state (rising edge or falling edge) of the rotor detected by the hall sensors Ha, Hb is inputted to the interrupt ports INT1 and INT2 of the microcomputer 100. When the input is inputted through), the first timer for measuring the interval according to the mode change, which is the basic pattern of the hall sensors Ha, Hb, and Hc, and the asynchronous compensation according to the length of the interval and the control interval of the basic mode are different. The second timer for compensating the (−) value and the third timer for the (+) value compensation are initialized to wait the first, second, and third timers.

In addition, a state flag (Flag) for the sequence control of the timing diagram of the output control logic of the Hall sensors (Ha, Hb, Hc) as shown in FIGS. 5 and 6 is loaded into the RAM to prepare for interval measurement of each section. 6 shows an example of the sequence required when the initial motor 300 is started. Since the motor 300 is in a stopped state before the initial start of the motor 300, a change in the logic level as shown in FIG. Since it is not possible to measure the interval between modes, the compensation angle cannot be calculated programmatically.

Therefore, it is necessary to forcibly drive to the output control logic synchronized with the timing of the Hall sensor (Ha, Hb) interrupt signal at the time of initial start as shown in FIG.

Accordingly, at the time of initial startup, the first timer is operated and the forced drive output control logic as shown in Fig. 6 is generated once.

At this time, T2 and T3 are calculated and stored in the RAM from the value T1 obtained by calculating the interval between the predetermined section (90 degrees = Th) from the forced driving by the first timer.

Subsequently, as shown in FIG. 5, the control is continued by changing the output control logic normally. In this case, in order to control the timing corresponding to the T2 value, a second timer and a third timer for controlling the timing corresponding to the T3 value are separately provided. Operation to determine the match to each size and if the match is to change the control output logic state Solve 30 asynchronous problems.

That is, change asynchronous period of sensor signal response mode and other asynchronous elements of output control period. It can be solved by compensating for 30 degrees.

As described in detail above, the present invention can reduce the cost by optimizing the size of the PC through the reduction of circuit components by reducing the number of Hall sensors to two, and also in all fields of applying other synchronous motor drive-compatible Hall sensors. There is an effect that can be applied.

Claims (5)

When an interrupt signal corresponding to a change in the state of the hall sensors Ha and Hb is generated, the first, second, and third timers are initialized and waited, and a state for sequence control of the hall sensors Ha and Hb and output control timing is generated. A first step of determining whether the motor 300 is in the initial stage after loading the flag into the RAM; As a result of the determination of the first step, when the motor 300 is initially started, the initial state values of the hall sensors Ha and Hb for initial start are read, the first timer is operated, and the logic corresponding to the initial state values is output. After that, the distance value T1 between the modes (90 degrees) is obtained using the first timer, and the distance values T2 and T3 corresponding to 60 degrees and 120 degrees are stored through the distance value T1 and stored in the RAM. And returning a second step; As a result of the determination of the first step, if the motor 300 is not in the starting phase, the initial state values of the hall sensors Ha and Hb are read to sense the position of the roto, and the second and third timers are operated. Determining whether the timer value corresponds to T2 and T3 corresponding to 60 and 120 degrees, respectively; A fourth step of compensating for the timing of the current output signal and outputting and returning the second and third timer values when the second and third timer values match T2 and T3, respectively; If the second and third timer values do not coincide with T2 and T3 as the determination result of the third step, the BLC motor control is performed as the fifth step of outputting and returning the same without compensating the timing of the current output signal. Way. The method of claim 1, wherein when the second timer value coincides with T2, the predetermined set value (- BCD motor control method that outputs compensation by). The method of claim 1, wherein when the third timer value coincides with T3, the predetermined set value (+ BLC motor control method, characterized in that for the compensation. The method of claim 2, wherein the set value (- ) Is -30 degrees BC motor control method. The method of claim 3, wherein the set value (+ ) Is a BCD motor control method, characterized in that +30 degrees.