New filter control of synchronous motor against low-speed interference

Abstract

The application discloses a new filter control for low-speed anti-interference synchronous motor and relates to the technical field of filter control. The application comprises the following steps: S1: setting the number of encoder pulses Pulseper per revolution through a program and setting a T0 interrupt timing function; S2: detecting the encoder feedback pulse in the T0 interrupt timing function in real time, calculating the current motor feedback speed according to the feedback pulse, filtering the feedback speed, and obtaining the filtered feedback speed Ffed. The application judges the effectiveness of the number of feedback signal pulses through the filtered feedback speed value, thereby ensuring the effectiveness of the number of feedback signal pulses and the correctness of the motor angle calculated through the feedback pulse signal. The angle is corrected through the photoelectric pulse Z signal within one mechanical angle of the motor, thereby ensuring the correctness of the motor angle throughout the whole process and effectively preventing the instability of the control performance caused by interference.

Description

Technical Field

[0001] This invention relates to the field of filtering control technology, specifically to a novel filtering control for low-speed anti-interference of synchronous motors. Background Technology

[0002] In the field of synchronous motor driver speed closed-loop control, the photoelectric encoder at the motor end often generates numerous interference signals due to environmental disturbances. These interference signals, along with the normal photoelectric pulse signals, are sent to the CPU chip. Since the main sources of speed and motor angle for synchronous motor speed control rely on these feedback pulse signals, interference not only causes large speed fluctuations but also introduces errors in the synchronous motor's angle, thus degrading the performance of the speed closed-loop control or causing low-speed jitter.

[0003] Current solutions employ various filtering methods for feedback signals, but the final result is simply filtering the feedback signal individually. In reality, the main issue is that the final result filters the feedback speed generated by the feedback signal, but not the number of feedback signals, because filtering the number of feedback signals would affect the motor angle. Summary of the Invention

[0004] The purpose of this invention is to provide a novel low-speed anti-interference filtering control for synchronous motors to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a novel low-speed anti-interference filtering control for synchronous motors, comprising the following steps:

[0006] S1: Set the number of encoder pulses per revolution (Pulseper) through the program, and set the T0 interrupt timing function;

[0007] S2: In the T0 interrupt timing function, the encoder feedback pulse is detected in real time, the current motor feedback speed is calculated based on the feedback pulse, the feedback speed is filtered, and the filtered feedback speed Ffed is obtained.

[0008] S3: Calculate the theoretical number of additional feedback pulses required during the T0 interrupt time. The calculation formula is: M0 = (Ffed * Pulseper) * T0 / 1000;

[0009] S4: Set the error band for the real-time detection encoder feedback pulse increment value, specifically: M1 = M0 + K1, where M1 is the small error band range and M2 = M0 + K2, where M2 is the large error band range.

[0010] S5: Real-time detection of encoder feedback pulse increment value M in the T0 interrupt timer function;

[0011] S6: Determine the relationship between M, M1, and M2, i.e., determine which error band M is in. If M is less than or equal to M1, the detected M pulse value increments are not discarded, and the M pulse values ​​are directly used as the actual pulse value increment, i.e., Mok = M. If M is greater than M1 but less than M2, the detected actual pulse value increment is equal to (M1 + M2) / 2, i.e., Mok = (M1 + M2) / 2. If M is greater than M2, the detected actual pulse value increment is directly discarded, and M0 is used as the current actual detected pulse value increment, Mok = M0.

[0012] S7: When a Z signal is encountered, update the current motor angle pulse count by the motor angle pulse count corresponding to the Z signal;

[0013] S8: The final obtained Mok is added to the current motor angle pulse count, and the current motor angle pulse count is updated in real time. This motor angle pulse count is used in performance control calculations.

[0014] As a further aspect of the present invention, the T0 time is in the millisecond range.

[0015] As a further aspect of the present invention, Ffed is calculated in terms of frequency, with the unit being Hz.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The novel low-speed anti-interference filtering control for synchronous motors differs from existing technologies in that it uses the filtered feedback speed value to determine the validity of the number of feedback signal pulses. Invalid feedback pulses are invalidated, thus ensuring the validity of the feedback signal pulse count and guaranteeing the accuracy of the motor angle calculated from the feedback pulse signal. Within one revolution of the motor's mechanical angle, the angle is corrected again using a photoelectric pulse Z signal. This ensures the accuracy of the motor angle throughout the entire process and effectively prevents instability in control performance caused by interference. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the steps of the novel low-speed anti-interference filtering control for synchronous motors according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1As shown, the present invention provides a technical solution: a novel filtering control for low-speed anti-interference of synchronous motors.

[0021] Working Principle: In closed-loop speed control of a synchronous motor using ABZ signal encoder feedback at the motor end, the AB pulse signal is the speed and real-time angle signal fed back by the motor to the motor driver. The Z pulse signal is fed back only once per mechanical revolution. The Z signal can be used to correct the pulse angle of the motor feedback. This invention not only uses common filtering algorithms to filter the detected feedback speed, but also utilizes the filtered feedback speed to simultaneously solve the problem of effectively calculating the motor feedback pulse within one revolution of the motor's mechanical angle. When acquiring the AB pulse feedback signal, various existing filtering methods can be used to smoothly filter the acquired speed, obtaining a stable speed feedback value Ffed, where Ffed is calculated in Hz. Since the number of AB signal feedbacks is an important input for calculating the synchronous motor angle, currently, the number of feedback pulses is not filtered; instead, the motor angle pulses are corrected using the feedback Z signal, and then the number of AB pulses is corrected using the number of motor angle pulses. This method cannot address the issue of the number of pulse feedbacks occurring before the Z signal arrives within one revolution of the motor. Interference signals from the first revolution before the Z signal arrives accumulate in the feedback AB signal, causing errors in the motor angle pulse at that moment. This invention utilizes the filtered feedback speed Ffed and the encoder pulses per revolution Pulseper to invalidate interference signals. Typically, the ABZ signal is acquired in a 2ms interrupt function, but 1ms is also possible; we will assume this interrupt time is T0, where T0 is in milliseconds. The formula is as follows:

[0022] M0 = (Ffed * Pulseper) * T0 / 1000

[0023] Where T0 is the interrupt time (in milliseconds), Ffed is the filtered feedback speed (in Hz), Pulseper is the number of pulses the encoder can feed back in one revolution, and M0 is the theoretically required number of pulse increments within the T0 interrupt time (in milliseconds). If theoretically no pulse increment arrives within the T0 interrupt time (in milliseconds), then K*T0 interrupt times can be used, where K*T0 interrupt times is the minimum time theoretically required for a pulse increment to occur. For simplicity, K here is 1, i.e., one T0 interrupt time.

[0024] We define M1 = M0 + K1, where M1 is the number of pulses added to the original M0 within the T0 interrupt time (in milliseconds). For example, K1 can be set to 3. M2 = M0 + K2, where M2 is the number of pulses added to the original M0 within the T0 interrupt time (in milliseconds). For example, K2 can be set to 10.

[0025] If M pulses are detected in real-time during the T0 interrupt, and M is less than or equal to M1, the increment of the detected M pulse values ​​is not discarded; the M pulse count is directly used as the actual pulse value increment Mok, i.e., Mok = M. If M is greater than M1 but less than M2, the actual pulse value increment is equal to (M1 + M2) / 2, i.e., Mok = (M1 + M2) / 2. If M is greater than M2, the actual pulse value increment is discarded, and M0 is used as the current actual detected pulse value increment, i.e., Mok = M0. The above Mok is the final increment value used to calculate the motor angle pulses. Finally, the current number of motor angle pulses is calculated by accumulating the pulse value increments Mok within the T0 interrupt.

[0026] When a Z signal is encountered, because the Z signal is mechanically fixed, the corresponding motor angle pulse count is also fixed. Therefore, the motor angle pulse count corresponding to the Z signal can be used to update the current motor angle pulse count and correct the motor angle pulse count after one revolution.

[0027] This invention primarily uses the filtered speed value to determine the validity of the number of feedback signal pulses. Invalid feedback pulses are invalidated, thus ensuring the validity of the feedback signal pulse count. This guarantees the accuracy of calculating the motor angle within one revolution using the feedback pulse signal before encountering the Z signal, preventing excessive motor angle errors caused by large interference, which could lead to performance control failure.

[0028] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A novel low-speed anti-interference filtering control for synchronous motors, characterized in that, Includes the following steps: S1: Set the number of encoder pulses per revolution (Pulseper) through the program, and set the T0 interrupt timing function; S2: In the T0 interrupt timing function, the encoder feedback pulse is detected in real time, the current motor feedback speed is calculated based on the feedback pulse, the feedback speed is filtered, and the filtered feedback speed Ffed is obtained. S3: Calculate the theoretical number of additional feedback pulses required during the T0 interrupt time. The calculation formula is: M0 = (Ffed * Pulseper) * T0 / 1000; S4: Set the error band for the real-time detection encoder feedback pulse increment value, specifically: M1 = M0 + K1, where M1 is the small error band range and M2 = M0 + K2, where M2 is the large error band range. S5: Real-time detection of encoder feedback pulse increment value M in the T0 interrupt timer function; S6: Determine the relationship between M, M1, and M2, i.e., determine which error band M is in. If M is less than or equal to M1, the detected M pulse value increments are not discarded, and the M pulse values ​​are directly used as the actual pulse value increment, i.e., Mok = M. If M is greater than M1 but less than M2, the detected actual pulse value increment is equal to (M1 + M2) / 2, i.e., Mok = (M1 + M2) / 2. If M is greater than M2, the detected actual pulse value increment is directly discarded, and M0 is used as the current actual detected pulse value increment, Mok = M0. S7: When a Z signal is encountered, update the current motor angle pulse count by the motor angle pulse count corresponding to the Z signal; S8: The final obtained Mok is added to the current motor angle pulse count, and the current motor angle pulse count is updated in real time. This motor angle pulse count is used in performance control calculations.

2. The novel low-speed anti-interference filtering control for synchronous motors according to claim 1, characterized in that: The T0 time is in milliseconds.

3. The novel low-speed anti-interference filtering control for synchronous motors according to claim 1, characterized in that: The Ffed is calculated in terms of frequency, with the unit being Hz.

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