KR100202577B1 - Sensorless bldc motor control method and apparatus - Google Patents

Abstract

The present invention relates to a drive control of a brushless DC motor without a sensor. In the conventional apparatus, a freewheeling section is lengthened when a transistor of an inverter performing PWM is current, and this section is a zero crossing point for detecting the position of the DC motor rotor. Since the failure to detect the position of the normal DC motor rotor due to include a problem that does not drive the DC motor normally, the present invention for solving this problem is the current of the two transistors of the inverter to be conducted By controlling the other transistors other than the transistors, the current flows through the diode connected in the reverse direction to the transistor before the current, and at the same time, the current flows through the diode connected in the reverse direction to the PWM controlled transistor to form a path through which the current can flow. Spiritual in time By being led to be able to normally detect the position of the rotating DC motor, e.

Description

Method and device for driving control of sensorless brushless DC motor

1 is a configuration diagram of a driving device of a general sensorless brushless DC motor.

2 is a detailed circuit diagram of the first position detection unit 4.

3 is a diagram showing the driving logic of the inverter transistor of FIG.

4 is a voltage waveform diagram of three phases (a, b, c) supplied to a direct current motor (3) according to FIG.

FIG. 5 is a detailed configuration diagram of the conventional FIG. 1 control apparatus 5. FIG.

FIG. 6 shows phase a when driving FIG. 5 with the driving logic of FIG.

(a) is a waveform diagram of a PWM applied voltage (①) and a counter electromotive force (②).

(b) is a waveform diagram of counter electromotive force (②) and current (③).

7 is a detailed configuration diagram of an embodiment of the present invention of the control device 5 of FIG.

FIG. 8 shows a phase a when driving FIG. 7 with the driving logic of FIG.

(a) is a waveform diagram of a PWM applied voltage and a counter electromotive force.

(b) is a waveform diagram of back EMF and current.

(c) is a waveform diagram of a PWM switching signal ss.

9 is a detailed configuration diagram of another embodiment according to the present invention of the control device 5 of FIG.

10 is a detailed configuration diagram of another embodiment according to the present invention of the control device 5 of FIG.

* Explanation of symbols for main parts of the drawings

1: rectifier 2: inverter

3: DC motor 4: Position detection unit

5: control unit 6: drive unit

BD: Rectifier C: Smoothing Capacitor

Ta +, Ta-, Tb +, Tb-, Tc +, Tc-: Transistors R1-R9: Resistance

Da +, Db +, Dc +, Da-, Db-, Dc-: Diodes CMP1 ~ CMP3: Comparators

51: current signal generator 52: speed control unit

53: pulse generator 54: carrier generator

55: combination portion 56: buffer portion

CMP: Comparator INV: Inverter

OR1, OR2: first or second oragate

BUF1, BUF2: Buffer

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to driving control of a sensorless brushless DC motor, and more particularly to transistors to minimize freewheeling time caused by commutation of the inverter's transistors on and off. The present invention relates to a drive control method and apparatus for a sensorless brushless DC motor which performs a pulse width modulation (PWM) so that an accurate zero potential crossing point can be detected so that a DC motor can be normally driven.

First, FIG. 1 is a configuration diagram of a drive device of a general sensessless brushless DC motor, and as shown therein, smoothes the rectifier BD and the rectified input power AC. Six transistors which are rectified and smoothed by the rectifying part 1 which consists of the smoothing capacitor C, and the rectified and smoothed DC voltage (DC-LINK) by the drive signal ds, and are controlled by the drive signal ds. It consists of (Ta +, Ta-, Tb +, Tb-, Tc +, Tc-), and each of these transistors are connected in series (Ta +, Ta-) (Tb +, Tb-) (Tc +, Tc-) in series and six An inverter (2) in which diodes (Da +, Db +, Dc +, Da-, Db-, and Dc-) are connected in anti-parallel to transistors (Ta +, Ta-, Tb +, Tb-, Tc +, and Tc-), respectively. A three-phase power source connected to each common connection point of the two transistors Ta +, Ta- (Tb +, Tb-) (Tc +, Tc-) connected in series of (2) and switched according to the switching of the inverter 2 Licensed stator and A DC motor (3) consisting of a rotor operated by the rotor's rotor field and the neutral point of the DC motor (3) are used as reference inputs, and the reference input and the counter electromotive force generated from the rotor of the DC motor (3) are input. The speed of the motor is calculated from the comparison result of the position detection unit 4 and the position detection unit 4 to be received and compared, and compared with a pre-programmed speed command to output a pulse width modulated current signal cs. The driving unit 6 which receives the control device 5 and the modulated current signal cs of the control device 5, converts the level thereof, and applies the driving signal ds to each transistor of the inverter 2. The DC motor (3) is a stator winding while the rotor is rotated by the stator resistance (Ra, Rb, Rc) and stator inductance (La, Lb, Lc) and the permanent stone mounted on the rotor Model with back EMF (EMFa, EMFb, EMFc) Ring.

In addition, as shown in FIG. 2, the position detector 4 receives the neutral point voltage Vn of the DC motor 3 through the resistors R2, R5, and R8 as a reference input to the inverting terminal. The voltages of the phases (a, b, and c) are divided through the resistors R1, R4, R7 and R3, R6, and R9, respectively, and then input to the non-inverting terminals and compared with each other (Vao, Vbo, Vco). ) Is composed of three comparators (CMP1) (CMP2) (CMP3) outputting to the control device (5).

The operation of the driving apparatus of a general sensorless brushless DC motor configured as described above is as follows.

The input power source AC is rectified via the rectifier BD of the rectifying unit 1, smoothed in the smoothing capacitor C, and then transmitted to the inverter 2 to the six driving signals ds from the driving unit 6. Accordingly, each transistor (Ta +, Ta-, Tb +, Tb-, Tc +, Tc-) is driven. As shown in FIG. 3, the driving logic of one cycle is divided into six sections and three phases (supplied to the stator) are supplied accordingly. If the voltages of a, b, and c) are Va, Vb, and Vc, the waveform diagram at this time is shown in Fig. 4, where EMFa, EMFb, and EMFc are generated in each phase of the stator by the rotation of the rotor. This counter electromotive force is changed from positive to negative value and from negative to positive value while the supply voltage Va, Vb, Vc is not applied in each phase (a, b, c).

At this time, the position detecting unit 4 detects a section in which the counter electromotive force changes, and when it is explained from FIG. 2, the neutral point potential Vn passes through the resistors R2, R5, and R8, and each comparator CMP1, CMP2, CMP3. The reverse electromotive force (EMFa) of a phase is inputted to the inverting terminal of) and is divided by the resistors R1 and R3 and inputted to the inverting terminal of the comparator CMP1 to divide the counter electromotive force EMFa and the reference voltage Vn. ) Is compared to output the output voltage (Vao), and similarly, the b-phase back electromotive force (EMFb) and the c-phase back electromotive force (EMFc) are also compared with the neutral point potential (Vn) at the comparator (CMP2) and the comparator (CMP3). , Vco) is output.

That is, as shown in FIG. 4, the zero potential crossing point is detected when the c-phase back EMF is changed from positive to negative in the first section, and the zero potential crossing point when the b phase back electromotive force (EMFb) is changed from the negative to the positive in the second section. In the third section, the zero potential crossing point is detected when the a-phase back EMF changes from positive to negative.

Thus, from the output voltages (Vao, Vbo, Vco) representing the zero potential crossing point, the control device (5) determines the position of the rotor of the DC motor (3) to calculate the current time point and calculates the inverter (2). Outputs a PWM current signal (cs) for controlling the conduction of each transistor (Ta +, Ta-, Tb +, Tb-, Tc +, Tc-) of the transistor, and accordingly, the driver 6 converts the level of the current signal (cs). By applying a drive signal ds to the gates of the transistors Ta +, Ta-, Tb +, Tb-, Tc +, and Tc- of the inverter 2 to control the position of the rotor of the DC motor 3 Will be performed.

Next, FIG. 5 is a detailed configuration diagram of the first control device 5, and as shown therein, the speed of the DC motor 3 from the output voltages Vao, VbO, Vco of the position detection unit 4 is shown. The speed controller 52 outputs a direction command rs and a voltage command vs, and compares the output voltage ((Vao, VbO, Vco) with the position detection unit 4). Current signals cs_a +, cs_b +, cs_c +, which operate the six transistors Ta +, Tb +, Tc +, Ta-, Tb-, and Tc- of the inverter 2 by the direction command rs of the speed controller 52 a current signal generator 51 for outputting cs_a-, cs_b-, cs_c-), a carrier generator 54 for outputting a carrier, an output of the carrier generator 54, and a voltage of the speed controller 52 The pulse generator 53 includes a comparator CMP for comparing the command vs and outputting a PWM command signal, and the six current signals cs_a +, cs_b of the current signal generator 51 are generated by the PWM command signal. A buffer BUF that enables or modulates three current signals cs_a +, cs_b +, cs_c + among +, cs_c +, cs_a-, cs_b- and cs_c-, and enables a modulation of the current signal generator 51; Two current signals (cs_a-, cs_b-, cs_c-) and three current signals (cs_a +, cs_b +, cs_c +) modulated through the buffer BUF, and their levels are converted to each of the inverters 10. And a driving unit 6 for applying a driving signal ds to the transistor of.

The operation of the conventional control device according to this configuration is as follows.

The six current signals cs_a +, cs_b +, cs_c +, cs_a-, cs_b-, cs_c- of the current signal generating unit 51 are transmitted to the driving unit 6, where the low potential side of the first degree smoothing capacitor C is present. Three current signals cs_a-, cs_b-, cs_c- controlling the three transistors Ta-, Tb-, and Tc- of the inverter 2 connected to are directly applied to the driving unit 6 as shown in FIG. Three current signals cs_a +, cs_b + and cs_c + controlling three transistors Ta + Tb + and Tc + connected to the high potential side of the smoothing capacitor C pass through butter BUF.

In addition, the carrier wave output from the carrier generator 54 is compared with the voltage command vs of the predetermined level of the speed controller 52 in the comparator CMP to the buffer BUP as a plurality of short pulse pulse PWM command signals. When the potential of the PWM command signal is low, the buffer BUF is disabled so that the three current signals cs_a +, cs_b +, cs_c + are blocked. On the contrary, when the potential of the PWM command signal is high, the buffer BUF is turned off. Enabled so that the three current signals cs_a +, cs_b +, cs_c + are transmitted to the driver 6 so that PWM control is performed on the transistors Ta +, Tb + and Tc + of the inverter 2.

In addition, when the inverter 2 is to be driven in the same sequence as in FIG. 3, the mechanism of changing the current supplied to the DC motor 3, for example, is as follows. FIG. The waveforms of the applied voltage (①) and the counter electromotive force (②) PWMed on the a phase of the device are shown. (B) The counter electromotive force (②) and the current (③) waveforms on the a phase are shown.

First, in the section 1 of FIG. 6, as the current signal cs_b- of the current signal generator 51 is transferred to the driving unit 6 in the high state, the transistor Tb- connected to the b-phase becomes conductive, The PWM command signal ps is applied to the buffer PUF while the current signal cs_a + having a logic value is input to the buffer BUF, and the current signal cs_a + is applied to the high or low PWM command signal ps. The PWM is performed by conducting or interrupting the transistor Ta + connected to the a phase according to the low state. Accordingly, the current of the a phase increases and the slope of the current is determined by the duty ratio of the PWM command signal ps. Equation (1) below.

Here, Vab is the total voltage of a phase and b phase of the DC motor (3), Vdc is the voltage across the inverter, t _on is the enable period of the PWM command (ps), t _off is the display of the PWM command signal Able section.

In the above formula (1), when the applied voltage Va is greater than the reverse power EMFa, the slope of the current becomes positive and the current increases.

Next, in the second section, as the transistor Ta + connected to the c-phase is conducted while the transistor Ta + is continuously controlled by the PWM command signal ps, the slope of the current is expressed by Equation (1). This can be found by converting the term for b from to the term for c.

Afterwards, in the third section, the transistor Tb + is turned on while the transistor Tc- continues to be connected, and the current on a, that is, the transistor Ta + in the second section. a-phase inductor (La) a phase resistance (Ra) Neutral point (Vn) c-phase resistance (Rc) The current flowing through the c-phase inductor Lc to the transistor Tc- passes through the transistor Tc- and then free-wheeling through the diode Da- in parallel with the transistor Ta-. And the current decreases as it is consumed through the inductor La, the resistor Ra, the resistor Rc, and the inductor Lc, and the slope of Vdc is represented by Equation (1). 0 This is calculated | required as Formula (2) below.

As shown in Equation (2), the slope of the current representing the negative value, that is, the decrease slope, is determined by the DC motor parameter, the current Ia flowing through the DC motor, and the counter electromotive force of the DC motor, and the counter electromotive force is the rotation of the DC motor. In proportion to the number and at the same rotation speed, the initial current, i.e., the greater the load, the longer the freewheeling interval of the current.

Also, the slope of the current in the 4th and 5th sections is the same as the above formula (1), and the 6th section is also the same as the formula (2), and when switching from the 5th section to the 6th section, that is, the transistor Tc + When the transistor Ta- is turned off in the present state, the current is freewheeled through the diode Da + connected in parallel with the transistor Ta +.

The conventional control device operating as described above can obtain the pure position information by detecting the zero crossing point of the counter electromotive force in the section where the supply voltage is not applied to each phase.However, in the third section of FIG. The slope of the current at the time of drift and the slope of the current when the transistor connected to the low potential side is current in six sections are different, and particularly, the delay time of the freewheeling current is long when the switching element in the three sections is current. Lose.

In the unbalanced phase of the freewheeling section, as shown in section 3, when the transistor performing PWM is current, if the freewheeling section becomes long, this section includes a zero crossing point for detecting the position of the rotor of the DC motor. Current 0 When the back electromotive force amount in Well If it is later than the time of zero crossing, the current signal generator cannot detect the zero crossing, so the output of this current signal generator keeps the previous output and the normal DC motor rotor position detection fails.

In other words, the driving logic is out of the zero crossing point, but the freewheeling section generated at the current includes more than the zero crossing point, thereby failing to derive the position information.

Therefore, the DC motor cannot be driven normally, causing a problem that the driving of the DC motor fails.

The present invention for solving such a conventional problem by the PWM control of a transistor other than the current of the two transistors that are conducting current flows through the diode connected in series to the transistor in the reverse direction before the current The purpose of the present invention is to properly detect the position of the DC motor rotor by forming a path through which a current flows in a diode connected in a reverse direction to a PWM controlled transistor, thereby reaching a zero value in a short time.

The drive control method of the sensorless brushless DC motor of the present invention for achieving the above object comprises the steps of driving two switching means by applying a control signal according to a predetermined driving logic, and performing the above process. Detecting the counter electromotive force of each phase, and if the zero crossing point of the counter electromotive force is not detected in this process, the two switching means are continuously driven; when the zero crossing point is detected, the switching means to be currented by the two switching means connected to the detected phase. When the switching means to be current is determined in the process, and the switching means to be current is determined in the process, the drive means to control the switching means to be current after a predetermined time and the PWM control to the switching means rather than the switching means to be current.

In addition, the drive control device of the sensorless brushless DC motor of the present invention calculates the speed of the DC motor from the comparison result of the position detection unit of the conventional device, and compares the voltage command with the predetermined value with the pre-programmed speed command and informs the direction of rotation. A speed control unit for outputting a direction command and outputting a PWM switching signal indicating whether to switch the switching means connected to the high potential side of the smoothing capacitor of the rectifying unit or the switching means connected to the low potential side; The current signal generating unit outputs a current signal to each of the six switching means of the inverter according to the comparison result of the position detecting unit and the direction command of the speed control unit, and receives a plurality of voltage commands of the speed control unit. A pulse generator for outputting a pulse width modulated PWM command signal having a frequency; Constitute a combiner for outputting a signal to the enable signal, the buffer portion of the conduction control the current signal of the current signal generated by the combining unit enable signal.

Such a method and apparatus of the present invention will be described with reference to FIGS. 5 to 9 as follows.

7 is a detailed configuration diagram of an embodiment according to the present invention of the control device 5 of FIG. 1, and as shown therein, from the output voltages Vao, Vbo, Vco of the position detection unit 4 of FIG. Three of the inverter (2) connected to the high potential side of the direction command (rs) and smoothing capacitor (C), which calculates the speed of (3) and compares the voltage command (vs) and the rotation direction by comparing with the pre-programmed speed command. PWM switching signal indicating whether to control the PWM (Ta +, Tb +, Tc +) or the three transistors (Ta-, Tb-, Tc-) connected to the low potential side of the smoothing capacitor (C). 6 of the inverter 10 by the speed controller 52 for outputting ss, the output voltages Vao, Vbo, Vco of the position detector 4 and the direction commands rs of the speed controller 52. Current signal generator for outputting six current signals cs_a +, cs_b +, cs_c +, cs_a-, cs_b-, cs_c- to enable transistors Ta +, Tb +, Tc +, Ta-, Tb-, and Tc- to operate Comparing the unit 51 with the carrier generator 54 for outputting the carrier and the carrier of the carrier generator 54 and the voltage command vs of the speed controller 52 to output the PWM command signal ps. The six transistors (Ta +, Tb +,) of the inverter (2) from the pulse generator (53) comprising a comparator (CMP) and the PWM command signal (ps) and the PWM switching signal (ss) of the pulse generator (53). A combination unit 55 that outputs an enable signal en1 (en2) for selectively PWMing Tc +, Ta-, Tb-, and Tc-, and the enable signal en1 (en2). Enabled by the buffer unit 56 for transmitting the current signal (cs) to the drive unit 6 and the current signal (cs) passing through the buffer unit 56 is applied to convert the level of the inverter (2) And a driving unit 6 for applying a driving signal ds to each transistor of Fig. 2).

In addition, the combination unit 55 of the first or gate (OR1) and the speed control unit 52 to output the enable signal (en1) by combining and combining the PWM (ps) and the PWM switching signal (ss) Inverter INV for inverting the PWM switching signal ss and the second OOR gate OR2 for outputting the enable signal en2 by combining and combining the output of the inverter INV and the PWM command signal ps. The buffer unit 55 is configured by the enable signal en1 to enable the current signals cs_a +, cs_b +, cs_c + to three switching elements connected to the high potential side of the smoothing capacitor C. Current signals (cs_a-,) for the first buffer BUF1 transmitted to the driver 6 and three switching elements enabled by the enable signal en2 and connected to the low potential side of the smoothing capacitor C. cs_b-, cs_c-) are configured as a second buffer BUF2 to the driving unit 6.

Referring to the operation and effect of the drive control device of the present invention sensorless brushless DC DC motor configured as described above is as follows.

The speed controller 52 outputs a direction command rs to the current signal generator 51, outputs a voltage command vs, and outputs a PWM switching signal ss for selecting a transistor performing PWM. The voltage command vs is compared to the carrier of the carrier generator 54 in the comparator CMP, and is input to the combiner 55 as a plurality of short pulse PWM command signals. In step 55, the PWM switching signal ss and the PWM command signal ps are combined to combine the PWM command signal ps with the enable signal en1 of the first buffer BUF1 or the second buffer BUF2. is applied as (en2).

In addition, the current signal generator 51 receives the output voltages Vao, Vbo, Vco of the position detector 4 of FIG. 1 and the direction command rs of the speed controller 52 of the inverter 2. Outputs six current signals (cs_a +, cs_b +, cs_c +, cs_a-, cs_b-, cs_c-) to enable six transistors to operate, wherein an inverter connected to the high potential side of the first degree smoothing capacitor (C) The three current signals cs_a +, cs_b +, cs_c + controlling the three transistors Ta +, Tb +, and Tc + of 2) are input to the first buffer BUF1 of the buffer unit 56 and the low of the smoothing capacitor C Three current signals cs_a-, cs_b- and cs_c- controlling three transistors Ta-, Tb- and Tc- connected to the potential side are input to the second buffer BUF2.

Accordingly, the six current signals cs_a +, cs_b +, cs_c +, cs_a-, cs_b-, cs_c- are blocked or passed through the first buffer BUF1 and the second buffer BUF2, and then the level is increased in the driver 6. By being converted and applied to the transistor of the inverter 2, the transistor is turned on or off and PWM is performed.

The operation of the present invention will be described in detail with reference to FIG. 8 when the inverter 2 is driven by the same drive logic as in FIG.

(A) of FIG. 8 shows the waveforms of the applied voltage (a) and the counter electromotive force (P) of the phase a according to the present invention, and (b) shows the waveforms of the counter electromotive force and current (a) of the phase a (c). Denotes a waveform diagram of the PWM switching signal ss.

First, in one section, the current signals cs_a + and cs_b- of the current signal generator 51 are output in a high state.

At this time, the PWM switching signal ss of the speed controller 52 is output in a high state as shown in (c), and the PWM switching signal ss is passed through the first oragate OR1 of the combination unit 55. The first buffer BUF1 is enabled so that the current signal cs_a + conducts the transistor Ta + of the inverter 2 through the driving unit 6 at all times, and the voltage command vs of the speed controller 52 is maintained. As the output is output, the PWM command signal ps enables or disables the second buffer BUF2 via the second orifice OR2, and the current signal cs_b- controls the transistor Tb- for PWM control. do.

Accordingly, the current of phase a increases, and the slope of the current of phase a is determined by the duty ratio of the PWM command signal ps, which can be obtained as in Equation (1), and the applied voltage in Equation (1). If (Va) is larger than the counter electromotive force (EMFa), the slope of the current becomes a positive value, and the current of (b) of FIG. 8 increases.

Next, in the second section, the current signal cs_a + is continuously output in the high state, but the current signal cs_b- is in the low state, and the current signal cs_c_ is output in the high state.

In addition, since the PWM switching signal ss is output in the low state as opposed to the one section, and is inverted to the high state in the inverter INV, the second buffer BUF2 is enabled through the second orifice OR2. The current signal cs_c- causes the transistor Tc- of the inverter 2 to conduct through the driving unit 6, and the PWM command signal ps passes through the first orifice OR1. The buffer BUF1 is enabled or disabled so that the current signal cs_a + PWM-controls the transistor Ta +.

In addition, the slope of the a-phase current at this time can be obtained by changing the term relating to b in the above formula (1) to the term relating to c.

Thereafter, the current signal cs_c- is continuously output in a high state, but the current signal cs_a + is in a low state, and the current signal cs_b + is in a high state.

In addition, the first buffer BUF2 is always enabled because the PWM switching signal ss is output in the same high state as in the first section, so that the transistor Tb + is always turned on, and the second buffer BUF2 is PWM controlled. As a result, the switching transistor Tc- is PWM controlled.

At this time, the current on a, that is, the transistor (Ta +) in two sections a-phase inductor (La) a phase resistance (Ra) Neutral point (Vn) c-phase resistance (Rc) The current flowing through the c-phase inductor Lc to the transistor Tc- is free-wheeled through the diode Da- connected in reverse parallel with the transistor Ta- via the transistor Tc-. .

In addition, since the transistor Tc- is PWM controlled, the a-phase current is reduced in two forms.

In other words, in the turn-on period in which the transistor TC- is conducted, the a-phase current is zero-potential freewheeled by Equation (2) as in the prior art.

In addition, in the turn-on period in which the transistor Tc- is cut off, the a-phase current flows toward the smoothing capacitor C through the diode Dc + connected in anti-parallel with the transistor Tc + due to the blocking of the transistor Tc-. Flow.

Therefore, the voltage of Vdc in Equation (2) 0 Unlike, it has a value of -Vdc as in Equation (3) below, and the a phase current decreases rapidly due to the DC LINK freewheeling.

Therefore, the phase a current differs from the zero crossing point of the counter electromotive force in three sections as shown in (b) of FIG. 0 Will be reached.

As described in detail above, the present invention applies the current signal to the transistor that is current in order to drive two transistors in sequence and the PWM signal to the other non-current transistor to turn the current of the PWM signal It is possible to bring a sudden decrease in the current in the off section, so that the freewheeling current does not flow at the zero crossing point of the counter electromotive force, which is an area for detecting the position of the DC motor rotor, thereby accurately detecting the position of the rotor.

9 is a detailed configuration diagram of another embodiment of the control apparatus 5 of FIG. 1 according to the present invention, and FIG. 7 shows a configuration of one embodiment of the present invention. 54), the carrier and the voltage command vs are compared in the comparator CMP, and the duty ratio is determined by determining only the reference voltage for adjusting the duty ratio, that is, the voltage command vs. Although there is an advantage in that there is a complicated problem of the configuration due to the carrier generator 54 and the comparator (CMP), on the contrary, the PWM frequency and duty ratio are software-processed inside the speed controller 52 to directly process the PWM command signal ( By configuring the output of ps), a separate configuration is not required for the conversion of the duty ratio and the PWM frequency.

In addition, FIG. 10 illustrates a PWM switching signal ss output from the speed controller 52 according to one embodiment of FIG. 7 or another embodiment of the present invention. By outputting to ss1) and ss2, it is possible to remove the inverter INV from the configuration of the combination unit 55, which also has the effect of simplifying the configuration as in the other embodiments.

Claims (1)

A first process of driving two switching means by applying a control signal according to predetermined driving logic, a second process of detecting back EMF on each DC motor while performing the first process, and a back EMF in the second process Performing a first process if the zero crossing point is not detected; and a third step of determining the switching means to be current at the two switching means connected to the detected phase when the zero crossing point is detected, and the switching means to be current at the third process. If it is determined that the fourth step of controlling the switching means that is current after a predetermined time, and performs the PWM control to the switching means other than the switching means of the current drive of the sensorless brushless DC motor Control method. [ Claim 2 ] It consists of a rectifier comprising a rectifier for rectifying AC input power and a smoothing capacitor for smoothing the rectified input power, and six switching means that are controlled by a drive signal by receiving a rectified and smoothed DC voltage from the rectifier. An inverter having diodes connected in parallel to each of the six switching means, a DC motor connected to the common connection point of the two switching means connected in series, and operated by applying a converted three-phase power source; A position detection unit for comparing the counter electromotive force and the neutral point voltage of each phase, a control device for calculating the speed of the motor from the comparison result of the position detection unit and outputting a current signal for controlling the switching means of the inverter by comparing with a pre-programmed speed command; And switching each of the inverters by receiving the current signal and converting its level. In the driving device of a sensorless brushless DC motor comprising a drive unit for applying a drive signal to the means, the control device calculates the speed of the DC motor from a comparison result of the position detection unit and compares the speed with a pre-programmed speed command. It outputs a voltage command having a value and a direction command informing the rotation direction, and pulse-modulates (PWM) the switching means connected to the high potential side of the smoothing capacitor of the rectifier, or PWM the switching means connected to the low potential side. A speed control section for outputting a PWM switching signal indicating whether or not to perform; and a current signal for outputting a current signal to each of the six switching means of the inverter according to a comparison result of the position detection section and a direction command of the speed control section; Pulse width modulated PWM paper having a plurality of frequencies in response to the generator and the voltage command of the speed controller A pulse generator for outputting a signal, a combiner for outputting the PWM switching signal and a PWM command signal as an enable signal, and a buffer unit for conducting and controlling the current signal of the current signal generator by the enable signal of the combiner A drive control device for a sensorless brushless DC motor, characterized in that. [ Claim 3 ] 3. The combining unit according to claim 2, wherein the combining unit outputs the PWM switching signal as the first enable signal and outputs the PWM command signal as the second enable signal or the PWM switching signal as the second enable signal according to the logic state of the PWM switching signal. And a PWM command signal as a first enable signal. [ Claim 4 ] 3. The combining unit according to claim 2, wherein the combining unit combines the PWM switching signal and the PWM command signal to combine and output the first enable signal, an inverter for inverting the PWM switching signal, and a PWM switching signal inverted by the inverter. And a second orifice configured to combine the PWM command signals and output a second enable signal. [ Claim 5 ] 3. The PWM controller according to claim 2, wherein the combination unit receives the first or second gate outputting the PWM enable signal by combining the PWM command signal and the PWM command signal and outputs the inverted PWM switch signal from the speed control unit. 2. A drive control apparatus for a sensorless brushless DC motor, characterized in that it is composed of a second orifice outputted as a second enable signal in combination. [ Claim 6 ] A current according to claim 4 or 5, wherein the buffer part is enabled by the first enable signal of the combination part and the currents to the three switching means connected to the high potential side of the smoothing capacitor of the rectifier in the six switching means of the inverter. A first buffer for collectively controlling the conduction of the signals and a second for collectively controlling the conduction of the current signals for the three switching means that are enabled by the second enable signal of the combination and connected to the low potential side of the smoothing capacitor of the rectifier. A drive control device for a Sensethless brushless DC motor, comprising a buffer. [ Claim 7 ] 3. The drive control apparatus of a senseless brushless DC motor according to claim 2, wherein a pulse width modulated PWM command signal is output from the speed controller instead of the pulse generator.