TWM563699U - Torque position encoding device of brushless motor - Google Patents

Abstract

This invention creates a brushless motor torque position encoding device, including a motor position encoder, a controller, a code selector and a PWM drive circuit, wherein the motor position encoder is connected to a motor to measure the angular displacement of the motor rotor Generates a UVW signal and an ABI signal; the controller is used to estimate the position angle of the motor rotor; the code selector is connected to the UVW signal and ABI signal of the motor position encoder, when the motor starts, it receives the switching signal output by the controller and selects the UVW signal Send to the controller. When the controller judges that the UVW signal is in a specific interval, it receives the switching signal output by the controller and selects the ABI signal to send to the controller. This can quickly and accurately calculate the current position angle of the motor rotor, so that the controller It can drive the rotor of the motor to operate according to the torque control.

Description

Brushless motor torque position coding device

This creation relates to a torque position encoding device for a brushless motor, and in particular to an encoding device for estimating the torque position of a rotor of a brushless motor, which can optionally output UVW signals or ABI signals to quickly and accurately calculate the position angle of the motor rotor To facilitate accurate control of subsequent motor torque.

The brushless DC motor consists of a rotating permanent magnet (rotor) and three or more fixed coils (stator) with the same pitch. By controlling the current in the stator coil, a magnetic field of any direction and size can be created. The attracting / repelling action of the rotor and stator magnetic fields on the rotating shaft, that is, generating torque. The brushless DC motor control system needs to use the angular displacement measurement results of the rotor to establish a set of closed-loop feedback loops. This measurement can be performed by a magnetic position sensor or an optical position sensor. The measurement results of the angular displacement of the rotor are fed back to the controller to control the current flowing through the stator coil to generate a orthogonal magnetic field to drive the rotor. By measuring the angular displacement of the rotor, it can be fed back to the system that controls the stator coil current, thereby achieving accurate control of the rotor torque.

At present, the encoder used to measure the position angle of the brushless motor is shown in the block diagram of the conventional motor torque encoding circuit in FIG. 1. It is performed by using the traditional UVW signal combined with the ABI signal of the quadrature encoder interface (QEI, Quadrature Encoder Interface). Encoding, the UVW signal can only divide the motor rotation into six intervals, and ABI can accurately estimate the angle of the brushless motor 1 Degrees position. Therefore, in addition to providing the UVW signal input to the controller 3, the conventional motor position encoder 2 also has a quadrature encoder (QEI) encoding function, which can provide information about the mechanical angle of the motor, including phase A (QEA) , Phase B (QEB) and Index three signals (ABI) are input to the controller 3, so the conventional motor position encoder 2 must have six pin outputs. When the controller 3 receives the UVW signal and the ABI signal output from the motor position encoder 2, it outputs a control signal to the PWM drive circuit 4, and the PWM drive circuit 4 outputs the drive current that controls the stator coil of the brushless motor 1 to drive the The rotor rotation angle or torque of the brush motor 1.

However, when reading the ABI signal, the conventional controller 3 needs to know the starting position of the brushless motor 1 from the Index signal, and the Index signal must require the rotor of the brushless motor 1 to rotate to the “zero point” set by the encoder. The position will appear only when the brushless motor 1 is not in the "zero" position when starting, the controller 3 cannot know the current rotor position angle, resulting in the subsequent control process cannot accurately control the motor torque, so the current known motor The position encoder 2 has the disadvantage that it cannot accurately calculate the position angle of the motor rotor when the motor is started. It is necessary to wait for the motor rotor to rotate more than one revolution before the ABI signal can be correctly read, so it takes a long time to calculate Time, which is unbearable for the need for fast and precise motor torque control systems, so there is much room for improvement.

In order to solve the lack of knowledge, the main purpose of this writing is to propose a brushless motor torque position encoding device, including a motor position encoder, a controller, a code selector and a PWM drive circuit, in which the motor position encoding The controller is connected to a motor to measure the angular displacement of the motor rotor to generate a UVW signal and an ABI signal; the controller is used to estimate the position angle of the motor rotor; the code selector is connected to the UVW signal and ABI signal of the motor position encoder. When the switch is started, the switch signal output by the controller is received, and the UVW signal is selected to be sent to the controller. When the controller determines that the UVW signal is in a specific interval, the switch signal output by the controller is received, and the ABI signal is selected to be sent to the controller. Accurately calculate the current position angle of the motor rotor, so that the controller can drive the motor rotor to operate according to torque control.

1‧‧‧brushless motor

2‧‧‧Motor position encoder

3‧‧‧Controller

4‧‧‧PWM drive circuit

10‧‧‧Motor

11‧‧‧Motor position encoder

12‧‧‧Controller

13‧‧‧Code selector

14‧‧‧PWM drive circuit

FIG. 1 is a block diagram of a conventional brushless motor torque encoding circuit.

FIG. 2 is a circuit block diagram of a torque position encoding device for a brushless motor.

FIG. 3 is a schematic circuit diagram of an embodiment of an authoring code selector.

Figure 4 is a schematic diagram of the control flow of the authoring controller.

Figure 5A is a schematic diagram of the creation of a UVW signal waveform.

FIG. 5B is a schematic diagram of the creation switching signal waveform.

Figure 5C is a schematic diagram of ABI signal waveform creation.

Please refer to FIG. 2, which is a block diagram of a torque position coding device for a brushless motor. This creation is mainly used to accurately calculate the position angle of the rotor of the motor 10 to drive the precise position of the rotor of the motor 10 according to the control torque. Therefore, this creation includes a motor position encoder 11, a controller 12, and a code selector 13 And a PWM drive circuit 14. The motor position encoder 11 is connected to the rotor of the motor 10 to measure the angular displacement of the rotor of the motor 10, and can generate a set of UVW signals and a set of ABI signals, as shown in FIG. 5A, which is a schematic diagram of the UVW signal waveform. The UVW signal is a Hall signal, which can divide the rotor of the motor 10 360 degrees in one rotation into six intervals, each of which is 60 degrees. As shown in Table 1 below, the interval value is defined for this creative embodiment.

X: This combination will not appear

As shown in Figure 5C, it is a schematic diagram of the waveform of the ABI signal. The ABI signal obtains the starting position of the motor 10 from the I signal. The A-phase and B-phase signals will count the angular displacement of the rotor in pulses. When the set magnification is 1, each pulse counted by the A-phase and B-phase signals rotates the rotor of the motor 10 by 1 degree. When the A phase and B-phase pulse (Pulse) number is 500, ABI 333 times the resolution of signals UVW signal (500 * ^22/333 = 6).

Although the ABI signal can accurately calculate the angular position of the rotor of the motor 10, it cannot be estimated when the motor 10 is started. Therefore, this creation first uses the UVW signal to calculate the interval of the rotor of the motor 10, and defines the UVW signal as a The commutation point, and this commutation point is the "zero" position of the ABI signal, so when the motor 10 is in the starting state, only the UVW signal is read first, and the ABI signal is read when the commutation point is turned, so It is possible to quickly and accurately calculate the angular position of the rotor of the motor 10.

Therefore, please refer to FIG. 2, FIG. 3, FIG. 4 and FIGS. 5A, B, and C of this creation together. In the circuit of the embodiment of FIG. 2 of the creation, the controller 12 can reduce three input terminals compared to the conventional circuit, as long as An encoding selector 13 can switch to the ABI signal when the UVW signal reaches the “commutation point”. FIG. 3 is a circuit diagram of an embodiment of a creative encoding selector 13, and FIG. 4 is a creative UVW signal. Schematic diagram of the control flow when switching to ABI signal.

The controller 12 of this creation only has three input terminals, a switching control terminal (CS) and three output terminals. The controller 12 can be used to calculate the position angle of the rotor of the motor 10 to accurately control the rotor torque of the motor 10. The code selector 13 has six input terminals, which are respectively connected to the UVW signal and the ABI signal of the motor position encoder 11. The PWM drive circuit 14 is connected to the three output terminals of the controller 12 and the stator coil winding of the motor 10. The PWM drive circuit 14 receives the torque control of the controller 12 and outputs a control current to the stator coil winding to drive the rotor of the motor 10 to rotate Moment control operation.

As shown in the embodiment of FIG. 4, when the motor 10 is in the starting state (flow 100), the controller 12 first sets the switching control terminal (CS) to 0, which is to read the UVW signal (flow 110), and the code selector 13 receives The "0" switching signal of the switching control terminal (CS) output by the controller 12, the code selector 13 selects the output of the UVW signal and sends it to the input terminal of the controller 12, at this time the controller 12 will judge the motor 10 according to the UVW signal Whether the position of the rotor is in the "commutation point" (process 120), if the "commutation point" is not reached, the rotor continues to rotate, and the controller continuously determines whether the UVW signal reaches the "commutation point".

When it is judged that the UVW signal has reached the "commutation point", the controller 12 sets the switching signal of the switching control terminal (CS) to "1", that is, it switches to the ABI signal (process 130), and the code selector 13 receives The "1" switching signal output by the controller 12 selects the ABI signal output and sends it to the input terminal of the controller 12. At this time, after receiving the ABI signal, the controller 12 first confirms whether the angle is correct (process 140). If it is incorrect, it indicates that the rotor of the motor 10 has not reached the "zero point", and then switches back to reading the UVW signal. This process is to avoid interference. Calculate the error torque angle. If the controller confirms that the angle is correct, the controller 12 outputs torque control to the PWM drive circuit 14, and the PWM drive circuit 14 depends on the angle Torque control is performed (flow 150), and the control current is transferred to drive the motor 10 to operate stably according to the torque control (flow 160).

Please refer to FIG. 5A, FIG. 5B and FIG. 5C together again. FIG. 5A is a waveform diagram of a UVW signal in the creative embodiment, FIG. 5B is a waveform diagram of a switching signal in the creative embodiment, and FIG. 5C is a waveform diagram of the creative embodiment. ABI signal waveform. In the UVW signal of FIG. 5A, the phase is divided into six intervals as shown in Table 1. In this embodiment, the transition from the sixth phase interval to the first phase interval is defined as the “commutation point”, which is the ABI signal. The "zero" position of the I signal in the middle, in other words, when the rotor turns to the "commutation point" of the UVW signal, the signal of the switching control terminal (CS) will change from "0" to "1", and the code selector 13 switches To the output of the ABI signal, the controller 12 reads the ABI signal to estimate the corresponding rotor position angle of the motor 10. The A and B phases of the ABI signal increase according to the bit rate set by the controller 12, and the waveforms of the A and B phases also It will increase, the controller 12 detects the "0,1" change (pulse) of phase A and phase B and accurately calculates the current position angle of the rotor.

In summary, compared with the conventional controller, the original brushless motor torque position coding device reduces the encoder input pins from 6 Pin to 4 Pin to reduce the cost, and the UVW is controlled by the control logic method according to the motor speed. Switching the signal to the ABI signal can increase the efficiency of the motor without waiting for the rotor to rotate an angle, reducing the motor alignment time. Therefore, this creation is not only innovative in terms of technical ideas, but also can improve the above-mentioned multiple effects compared to conventional articles. It should be based on the legal patent requirements that fully meet the novelty and progress, and file an application in accordance with the law. To encourage creation, to feel virtuous.

Claims (5)

A torque position encoding device for a brushless motor includes: a motor position encoder connected to a motor for measuring the angular displacement of the motor rotor to generate a UVW signal and an ABI signal; a controller with an input terminal, Switch the control end and the output end to estimate the position angle of the motor rotor; and a code selector with an input end connected to the UVW signal and the ABI signal of the motor position encoder, respectively, to receive the controller when the motor is started A switching signal output from the switching control end selects the UVW signal to be sent to the input end of the controller, and when the controller determines that the UVW signal is a specific interval, receives the switching signal output by the controller to select the ABI signal to send To the input of the controller. The torque position encoding device of the brushless motor as described in claim 1, further comprising: a PWM drive circuit, connected to the output end of the controller and the stator coil winding of the motor, to accept a torque control of the controller , Drive the motor rotor to operate under torque control. The brushless motor torque position encoding device as described in claim 1, wherein the UVW signal output by the motor position encoder rotates the motor rotor 360 degrees into six sections, each section being 60 degrees, set The UVW signal is a commutation point when switching to the specific interval. The torque position encoding device for a brushless motor as described in claim 3, wherein the commutation point is the "zero" position of the ABI signal, that is, the I signal (start counting signal) in the ABI signal is generated to make the ABI signal The A-phase signal and B-phase signal in the start counting an angle pulse. When the A-phase signal and the B-phase signal are set to a multiplier of 1, each angle pulse of the A-phase signal and the B-phase signal is 1 degree of the motor rotor rotation angle. The torque position encoding device for a brushless motor according to claim 1, wherein the controller outputs the switching signal to the code selector when the motor is started, and controls the code selector to select the UVW signal transmission To the input end of the controller to read the UVW signal to determine whether the rotor of the motor is turned to a commutation point. When it is turned to the commutation point, the switching control end outputs the switching signal to the code selector , Control the code selector to select the ABI signal to be sent to the input terminal of the controller, to read the ABI signal to calculate the position angle of the motor rotor.