TW201125277A - Speed control method of sensorless brushless DC motor using current feedback - Google Patents

Abstract

A new current feedback speed control method for sensorless brushless DC motor was proposed. In sensorless control application, the phase-change point detection can not using Hall sensor. Therefore, a new speed control scheme comprises a back-EMF zero-crossing point detection unit, a speed estimation unit, a rotor position estimation unit, and current feedback control with three-phase square-wave or sine-wave driving signals. In this method, the speed loop is used to generate the magnitude of current command and estimation of rotor position. In the current feedback control, three-phase current signals are obtained by current sensors to complete the current control loop. Therefore, the back-EMF and phase-current could be perpendicular, and the system performance can be improved. The signal generator was used to generate three-phase driving signals to keep the motor rotating. When the specific phase-current is approximate to zero, this phase was set as floating state. The back-EMF zero-crossing point can be detected in this floating duration, and the phase-change detection is proceeding to provide phase-change information to the system.

Description

201125277 If there is a chemical formula in the case of this case, please disclose the chemical formula that best shows the characteristics of the invention: 6. Invention Description: The present invention relates to a non-sensing brushless DC motor current feedback speed control architecture. The non-sensing brushless DC motor is controlled by the rotor magnetic pole position, combined with the three-phase square wave or sine wave driving signal, and the three-phase current feedback signal generates a current control command, so that the back electromotive force and the phase current are perpendicular to each other. Architecture. [Prior Art] The brushless DC motor uses a converter switch instead of a brush for a photo for phase-shifting driving, and a motor rotor position sensor (such as a Hall sensor) is easy to sense/jnt degree's stinky effect causes its operation. The situation is limited, so the non-sensing control method must be used. The current non-sensing brushless DC motor drive method 'only uses the motor three-phase voltage command as the motor drive signal, but when using the voltage drive command applied to the non-sensing speed control, its back electromotive force and phase current It is not vertical. In this case, the motor cannot provide the optimal torque output when the load changes. Therefore, when the load changes, the motor will have problems such as large current, poor efficiency, and power consumption. SUMMARY OF THE INVENTION The non-sensing brushless DC motor current feedback speed control of the present invention

201125277 The architecture is as shown in Figure 1. The post-I DT ^ y' ” system includes a speed feedback controller, a controller, a three-phase square wave or a sinusoidal current to generate a two-current return controller, and a pulse width modulation. Yuanyi first household & change state, a brushless body, - counter electromotive force zero crossing point point measurement unit, a speed estimation unit, - rotor pole position estimation unit. The main purpose of brush straight is to provide - A novel non-sensing brushless DC motor driving and manufacturing method, the method comprising a three-phase square wave and string signal application range, when the phase current of a specific phase of the motor is close to zero, the specific phase is floated, and the counter electromotive force zero crossing is performed. Over-point detection, to estimate the rotor magnetic pole position ' and feedback the three-phase current loop signal to generate a three-phase square wave or sine wave current control command, complete the non-sensing brushless DC motor f flow feedback speed control purpose The current month uses the two-phase square wave or sine wave current to produce - the current phase difference of 12G degrees of current command to drive the brushless DC motor to run and the phase current or sine wave current is generated by the specific phase current close to zero Floating Then, the counter-electromotive zero-crossing point detecting unit can perform the commutation signal detection by the specific phase floating section to provide the three-phase driving signal commutation m' while calculating the current motor speed by using the commutation signal And the speed command is compared with each other to control the brushless DC motor to operate at a constant speed. In the present invention, the rotor magnetic pole position is estimated, and a three-phase current feedback command is added to generate a three-phase current control command to make the counter electromotive force and the phase current. Vertically to improve system power consumption and efficiency 201125277 [Embodiment] * Non-sensing brushless DC motor current feedback Schematic control architecture Clearly refer to Figure 1 'It is the system block architecture of the complete closed loop speed controller The structure includes a speed feedback controller ι〇, a PI controller 20, a three-phase square wave or sine wave current generation, a current feedback controller 40, a pulse width modulation unit 50, - Inverter 60, - Brushless DC motor body 7 () ... Back EMF zero crossing point price measuring unit 80, a rotor magnetic pole position estimating unit 81, a rotational speed estimating unit 90, when the brushless DC motor 7 When rotating, by grabbing the motor three-phase voltage to the counter electromotive force zero-crossing point detecting unit 8〇, when the motor is to be opposite to the electromotive force zero-crossing point detection, when the square wave is driven, the three-phase non-sensing The square wave drive signal is set to ## to Zc (see Figure 3) when the specific phase current is close to zero. When the sine wave is driven, the three-phase non-sensing sine wave drive signal is close to zero at a specific phase current. ~Zw is set to float (see Figure 4), using this specific phase floating connection method to detect the opposite electromotive force zero crossing point 'If the opposite electromotive force zero crossing point is detected', the commutation signal is output The speed estimation unit 9 calculates the actual speed of the motor at this time. Referring to Fig. 1 'when the actual motor speed is obtained', it is input to the speed feedback controller 10, and the speed feedback control 10 The current actual speed and speed command of the motor are compared with each other, and the speed error signal is outputted to the PI controller 20, and the proportional and integral parameter values in the PI control benefit 20 are used to improve the response condition of the system transient and steady state 'PI control 20 output a battery 201125277 size to generate three-phase command square wave or sinusoidal currents 3 billion. Referring to FIG. 1 again, when the commutation signal is generated, it is input to the rotor magnetic pole position estimating unit 81, and the commutation signal is used to estimate the current position and angle of the brushless DC motor rotor. Therefore, the rotor The magnetic pole position estimating unit 81 sends a generation 30 corresponding to the three-phase rotor magnetic pole position signal to the three-phase square wave or sine wave current, and the three-phase current feedback signal is input to the current feedback controller 4〇, which is based on The input three-phase square wave or sine wave current signal and the current feedback signal produce a current control command that differs by 120 degrees from the U and V 'W two phases. In the present invention, the rotor magnetic pole position information is generated by the rotor magnetic pole position estimation method, and the three-phase square wave or the sine wave current is generated. According to the motor rotor magnetic pole position information, a three-phase current signal is generated, and the three-phase current signal is generated. The current signal is input to the current feedback controller 4〇, and the system also inputs the three-phase current feedback signal 41 to the current feedback controller 40 by using the current sensor, and the current feedback controller 4〇 will be a three-phase square wave. Or the sine wave current s hole number and the two-phase current feedback signal are compared with each other' input to the pulse width modulation unit 50. The drive control architecture can make the phase current and the back electromotive force perpendicular to each other to improve system power consumption. And performance. Please refer to FIG. 1 again. In the pulse width modulation unit, the = phase current control signal is compared with the sawtooth wave to obtain a three-phase pulse width modulation signal, which is modulated according to the three-phase pulse width. The signal generates a turn-on timing of the six switchers in the converter 6〇, which sequentially controls the operation of the six switches of the three-phase upper and lower arms according to the turn-on timing of the switch, to determine the width of the three-phase duty cycle of the motor and Back EMF 201125277 Specific phase float interval control at zero crossing point. The invention utilizes the three-phase square wave or the generation of the sinusoidal current to produce a three-phase phase I 120 degree driving signal to drive the brushless DC motor 70 to operate, and is produced by a three-phase square wave or a sinusoidal current. The floating phase of the specific phase motor is close to zero. The counter-electromotive zero-crossing point detecting unit is configured to perform the commutation signal detection to provide the three-phase driving signal commutation information by using the special sweating interface. The invention utilizes the commutation signal to estimate the magnetic pole position of the motor rotor, and sends the estimation result to the generation 30 of the three-phase square wave or the sine wave electric μ, and measures the three-phase feedback current signal by the current sensor: current back The controller 40 uses the method of rotor magnetic pole position estimation and current feedback to generate a two-phase square wave or sine wave current control command, so that the counter electromotive force and the phase current are perpendicular to each other, and the output end can be provided when the output load changes. The required input (four) moments to improve system power consumption and performance. (7) Refer to figure f 2, which is an equivalent circuit diagram of a non-sensing brushless DC motor and a change of claws. By controlling the conduction sequence of the inverter Up~· six switches, the DC current provided by the power supply terminal voltage is determined. Through the three-phase brushless DC motor armature path, and control the direction of the motor rotation - a speed; ^ non-sensing element in the embodiment of the 'brushless DC motor commutation point is determined by the U ~ w three-phase specific phase Floating, 特定%~Vw the specific phase of the two-phase voltage 'detects one of its corresponding ones. When the zero crossing point of the specific opposite electromotive force judges that the two specific phases are commutated and sends out the specific phase driving, The three-phase non-sensing brushless DC motor performs commutation point detection in this way, and 201125277 continuously repeats the motor for continuous operation. Non-sensing square wave drive commutation point pre-measure 4 See 帛3 diagram's a three-phase non-sensing square wave current command real example, where 'three-phase current command conduction angles differ by 1 20 degrees in phase The conduction interval Us~Ws, each phase square wave signal continuously sends a fixed length current command to the brushless DC motor in the conduction interval to make the stator generate magnetic pole to drive the motor rotor to rotate. When the conduction period of each phase ends, the phase square wave current command enters the floating section heart ~ Zc', and the specific phase is in the floating section, and the other two phase square wave current commands are normally conducted, thereby performing the specific phase floating interval. The back EMF zero crossing point detection detects whether the commutation point of the particular phase has arrived. : Legend, in the Za interval, (4) Non-sensing square wave current command floating, : The purpose and W phase non-sensing square wave current command are closed in the V phase and the arm switch, the motor drive signal.., τ phase conduction 'So at this time, the U phase can be moved to pull the 佶 佶 J / J opposite electromotive force, if its counter electromotive force is Α , then _ 丨 丨, σ fruit is the zero crossing point, υ phase commutation signal makes The system sends out the % 丁 % % wave current command, which is in the range of Zb and Zc in the next cycle of 5 相 phase 5; 5 Φ knows and 洌 is also repeated μ. +, the back EMF zero crossing point Detecting the number to keep the motor running normally. This particular phase change is actually generated 201125277 Non-sensing sine wave drive commutation point detection

Please refer to Fig. 4 'which is a three-phase non-sensing sine wave current command embodiment' where 'three-phase current command conduction angles are different by 120 degrees' in the two-phase conduction interval Ut~Wt, and each phase chord signal is A fixed-length current command is continuously sent to the brushless DC motor in the conduction interval, so that the stator generates magnetic poles to drive the motor rotor to rotate. When the phase conduction interval of each phase ends, the phase sine wave current command enters the floating interval Zu~Zw. At this time, the specific phase is in the floating interval, and the other two phase sine wave current commands are still normally turned on, so that the specific phase floats The counter-electromotive zero-crossing point detection is performed to determine whether the commutation point of the particular phase has arrived. As shown in the figure, in Zu H Μ, the u-phase non-sensing sine wave current command floats, and the V-phase and W-phase non-sensing sine wave current commands are respectively Vt and Wt conduction products 1 because the u-phase upper and lower arm switches are closed. The driving signal is turned on between the v-phase and the W-phase. Therefore, the U-phase voltage can be floated to measure the opposite electromotive force of the U-phase, and the electro-potential is not thunder, and the electromotive force is the zero-crossing point, and the U-phase commutation signal is generated. Sending the sine wave current command for the next cycle of the phase, on the 7v 13⁄4 7«, Γό B day, ... and the counter-electromotive zero crossing point detection in the ¥ and Zw intervals also repeats the above process to positive ^ ^ $ 厘This particular phase is changed to 5th, and the motor is running normally. 10 201125277 [Simple description of the diagram] Figure 1: The control architecture diagram of the non-sensing brushless DC motor current feedback speed of the present invention. Figure 2: Three-phase non-sensor brushless DC motor and converter equivalent circuit diagram. Figure 3: This is a three-phase square wave current command diagram for a brushless DC motor without a sensor. Figure 4: This case has no sensor brushless DC motor three-phase sine wave current command diagram. [Illustration and main component symbol description] 1 〇 Speed feedback controller 2 〇 PI controller 30 three-phase square wave or sine wave current generation 40 current feedback controller 4 1 three-phase current feedback 50 pulse width modulation Unit 60 Inverter 70 Brushless DC Motor Body 80 Back EMF Zero Crossing Point Detection Unit 8 1 Rotor Magnetic pole Position Estimation Unit 90 Speed Estimation Unit

Vdc power supply DC terminal voltage Co capacitor [S] 201125277 Lower arm switch Lower arm switch: Lower arm switch Vw W phase voltage Back EMF Z w W phase impedance

Up U-phase upper arm switch Un U phase

Vp V phase upper arm switch Vn V phase

Wp W phase upper arm switch Wn W ^ V u U phase voltage V v V phase electric castle

Eu U opposite electromotive force Εν V phase

EwW opposite electromotive force

Zu U phase impedance Zv V phase impedance Us U phase square wave current command conduction interval Vs V phase square wave current command conduction interval WS W phase square wave current command conduction region fa' Za U phase square wave current command floating interval Zb V phase square wave current command float Interval Zc W phase square wave current command floating interval ZCP string signal zero crossing point Ut U phase sine wave current command conduction interval

V t V phase sine wave current command conduction interval Wt W phase sine wave current command conduction interval Zu U phase sine wave current command floating interval Zv V phase sine wave current command floating interval Zw W phase sine wave current command floating area fE 12

Claims (1)

201125277 • VII. Patent application scope: 1. A non-sensing brushless DC motor control architecture, as shown in the figure below, uses the speed loop to generate the current command size in the current loop, and estimates the position of the rotor pole. The current loop command is generated, and the current sensor is used to send back the three-phase current signal to complete the current feedback control, so that the back electromotive force and the phase current are perpendicular to each other to improve system power consumption and performance. 2. A non-sensing square wave driving method, as shown in FIG. 3, the u, V, #W three-phase currents in the conduction interval Us~Ws, providing a fixed length of current command drive motor 'at a specific phase current close to zero When Za~Zc, the current command is floated to perform back EMF zero crossing detection in this floating section, and the rotor pole position is estimated. 3. A non-sensing sine wave driving method, as shown in FIG. 4, the u, V, W three-phase currents provide a fixed length current command driving motor in the conduction interval Ut~Wt ', when the specific phase current approaches zero Zu~Zw 'floats the current command, performs anti-electricity® zero-crossing point detection in this floating section, and estimates the rotor pole position. 13