CN-116104700-B - DC variable pitch motor control system

CN116104700BCN 116104700 BCN116104700 BCN 116104700BCN-116104700-B

Abstract

The invention relates to a control system of a direct current variable pitch motor, which is characterized by comprising a closed loop control method of four speed measurement feedback units in two speed feedback signal modes, wherein the four speed measurement feedback modes cover all speed measurement modes of the variable pitch system and can be flexibly and simply switched, and the control system also comprises an open loop control method of emergency processing of the direct current variable pitch motor under the condition that the speed measurement feedback units of the motor are failed or signals are lost, wherein the direct current variable pitch motor can track speed signals and current control signals before the emergency, so that the variable pitch motor can stably run, and the safety of a wind driven generator is ensured. The design of the invention is suitable for a variable speed feedback mode of the direct current motor for pitch control, and ensures the reliability and safety of the wind generating set.

Inventors

ZHANG JUN
LI SHUNMIN

Assignees

华能威海发电有限责任公司

Dates

Publication Date: 20260508
Application Date: 20230221

Claims (4)

1. The direct current variable pitch motor control system is characterized by comprising a closed loop control unit and an open loop control unit; The closed loop control unit comprises a speed loop control unit, a current loop control unit, a chopping output unit and a chopping output unit, wherein the input value of the speed loop control unit is a speed set value and a speed feedback value of a variable pitch motor respectively, the output value of the speed loop control unit is a difference value of the speed set value and the speed feedback value of the variable pitch motor, the output value of the current loop control unit is the output value of the speed loop control unit and the current feedback value of the variable pitch motor respectively, the output value of the current loop control unit is the difference value of the speed loop control unit and the variable pitch motor, and the received output value of the current loop control unit is converted into a duty ratio of 0-100% by adopting a pulse width adjustment control method for adjusting the rotating speed of the motor; The open loop control unit comprises a motor feedback broken line detection unit, a speed tracking unit, a current loop control tracking unit, a direct current driver open loop controller, a direct current driver control unit and a control unit, wherein the motor feedback broken line detection unit is used for sampling and measuring a direct current variable pitch motor speed feedback signal to judge whether the speed is lost, the feedback broken line is used for realizing the switch of a motor from a closed loop to an open loop state, the speed tracking unit is used for recording the rotating speed of the variable pitch motor in the last closed loop control as an input signal A of the open loop control unit, the current loop control tracking unit is used for recording the output signal of the current loop control unit in the last closed loop control as another input signal B of the open loop control unit, the direct current driver open loop controller is used for inputting the signal A and the signal B, the output signal C is a piecewise function of the signal A, B, and a weighted average algorithm is adopted for setting transition time T 1 to ensure the stability of the open loop controller, and the function relation is as follows: C=f(A);t<T 1 C=K 1 * f(A)+K 2 * f(B);t=T 1 ; C= f(B);t>T 1 ; wherein K 1 、K 2 is a constant; and the current limiting unit is used for collecting the current of the direct current variable pitch motor in real time and compensating the signal C according to the current change rate.
2. The direct current variable pitch motor control system as claimed in claim 1, wherein the direct current variable pitch motor control system comprises a current feedback unit for acquiring current of the direct current variable pitch motor, and the current sampling is used for inputting acquired current values into the current loop control unit by adopting a weighted filtering algorithm.
3. The direct current variable pitch motor control system of claim 1, comprising a speed feedback unit for detecting the running speed of the direct current variable pitch motor, integrating two modes of direct current variable pitch motor speed analog speed measurement feedback and digital speed measurement feedback, wherein the analog speed measurement feedback comprises a speed measuring generator mode and a rotary variable feedback mode, and the digital speed measurement feedback comprises an incremental encoder feedback mode and an absolute encoder feedback mode.
4. A DC pitch motor control system according to any one of claims 1-3, further comprising a motor stability control algorithm characterized by: the speed loop control unit is used as an outer loop, and the current loop control unit is used as an inner loop, wherein the ratio of the execution periods of the outer loop to the inner loop is different, and the fast execution current loop control unit and the relatively slow execution speed loop control unit make the loop more stable; the execution speed of the chopping output unit is higher than or equal to the execution speed of the current loop control unit according to the actual running condition; c, the execution speed of the open loop control unit is the same as that of the current loop control unit; d, the control signal E of the chopping output unit is a piecewise function of the output D of the current loop control unit and the output C of the open loop controller after current limitation, a transition time T 2 is set for ensuring smooth switching from closed loop control to open loop control, the output is carried out by adopting a weighted method in the transition time, the transition is gradually carried out to open loop control, and the weight value can be adjusted according to the actual situation, wherein the functional relation is as follows: E=f(D);t<T 2 ; E= K 3 * f(D)+ K 4 * f(C);t=T 2 ; E= f(C);t>T 2 ; where K 3 、K 4 is a constant.

Description

DC variable pitch motor control system Technical Field The invention belongs to the field of direct current motor control, and particularly relates to a direct current motor control system for a variable pitch system. Background The direct current pitch control system is a core component for long-term use of the wind driven generator due to reliability and safety, and occupies a great market share in the national land wind power generation pitch control system. The core actuating mechanism of the direct current variable pitch system consists of a direct current variable pitch motor and a variable pitch driver, and the direct current variable pitch motor is widely applied to the variable pitch system due to the reliable and simple feathering characteristic of the direct current variable pitch motor, so that the direct current variable pitch motor driving device is one of the key core components of the variable pitch control system, and is required to match the performance of the variable pitch motor, extend the use condition range of the variable pitch motor and improve the reliability and safety; the control strategy of the variable pitch drive mainly adopts the traditional method of a speed control outer ring and a current control inner ring, as the variable pitch system has special application working conditions, the variable pitch design schemes of all factories are different, and after the variable pitch system is in service for a certain period, the technical requirements of upgrading and reconstruction and the like exist, different requirements are put forward on the speed feedback mode of the variable pitch motor, in addition, in order to ensure the safety of the system, new requirements are put forward on the open-loop running of the variable pitch motor, and the open-loop control of the variable pitch drive is more limited due to limited patents and data related to the control method and the control strategy of the variable pitch drive. According to the application working condition of the direct current variable pitch motor, the control system integrating various speed measurement feedback modes is invented, smooth switching of open loop control and closed loop control of the direct current variable pitch motor can be realized, the motor speed is ensured not to jump suddenly when the motor breaks in the speed feedback mode, the motor current is not suddenly changed, and the system safety is improved. Disclosure of Invention According to the conventional control scheme of the current direct-current variable-pitch drive, the invention provides a closed-loop control method based on a mode of digital quantity and analog quantity speed feedback for expanding the application range of a direct-current variable-pitch motor in the upgrading and transformation of a direct-current variable-pitch system, and provides an open-loop control method based on rotating speed tracking and current loop tracking for improving the control stability of the variable-pitch motor, realizing smooth butt joint of switching speeds of an open loop and a closed loop and realizing smooth transition of switching currents of the open loop and the closed loop. In order to achieve the above purpose, a control system of a direct current variable pitch motor adopts the following technical scheme: The direct current variable pitch motor control system mainly comprises a closed loop control unit and an open loop control unit, and a steady state control algorithm is adopted for ensuring that the speed of the motor does not jump suddenly and the current does not suddenly change in the open-closed loop operation process and the switching process. The closed loop control unit part mainly comprises a speed loop control unit, a current loop control unit, speed setting and rotating speed selection matched with the speed loop control unit, current feedback matched with the current loop control unit and the like. The working process of the closed loop control unit is that the speed set value and the speed feedback value are differed, the difference is outputted through the PID algorithm of the speed loop control unit, the difference is outputted through the PID algorithm of the current loop control unit, and the difference becomes a control signal of the chopping output unit, so as to control the rotating speed and the current of the motor. The speed set value is the expected running speed of the DC variable-pitch motor, and can be an analog quantity, a digital quantity or a communication set of an upper computer, or can be a position control output set. The speed set value is subjected to per unit processing in the control method, and the negative maximum rotating speed is set to minus 100% -100% per unit in the control method. The speed feedback unit is used for acquiring the actual running speed of the variable-pitch motor, the direct-current variable-pitch motor generally selects a speed measuring generator as the speed feedback unit, and the