阅读说明：本技术 一种无位置传感器电机的启动方法 (Starting method of motor without position sensor ) 是由 颜宇杰 许幼奇 王国栋 郭忠涵 于 2020-03-06 设计创作，主要内容包括：本发明公开的一种无位置传感器电机的启动方法,包括以下步骤：步骤S1,以开环方式启动无位置传感器电机至目标转速,并稳定保持一段时间；步骤S2,计算开环电角度和估算出电角度差,并根据估算出的电角度差调节电机给定扭矩；步骤S4,若估算出的电角度差的绝对值小于设定值,将调节得到的电机给定扭矩作为电机启动时的扭矩；步骤S5,将调节得到的电机给定扭矩进行折算并作为电机闭环控制的前馈给定,启动无位置传感器电机。本发明通过不断调节电机给定扭矩,使得开环电角度与估算电角度差不断减小,方便过渡到闭环控制,从而使得电机顺利启动。(The invention discloses a method for starting a motor without a position sensor, which comprises the following steps: step S1, starting the motor without position sensor to the target speed in open loop mode, and keeping it stably for a period of time; step S2, calculating an open-loop electrical angle and an estimated electrical angle difference, and adjusting the given torque of the motor according to the estimated electrical angle difference; step S4, if the absolute value of the estimated electrical angle difference is smaller than a set value, the adjusted given torque of the motor is used as the torque when the motor is started; and step S5, converting the adjusted motor set torque and using the converted motor set torque as a feed-forward set torque of motor closed-loop control to start the motor without the position sensor. According to the invention, the difference between the open-loop electrical angle and the estimated electrical angle is continuously reduced by continuously adjusting the given torque of the motor, so that the transition to closed-loop control is facilitated, and the motor is smoothly started.)

1. A method for starting a position-sensorless motor, comprising the steps of:

step S1, starting the motor without position sensor to the target speed in open loop mode, and keeping it stably for a period of time;

step S2, calculating an open-loop electrical angle and an estimated electrical angle difference, and adjusting the given torque of the motor according to the estimated electrical angle difference;

step S4, if the absolute value of the estimated electrical angle difference is smaller than a set value, the adjusted given torque of the motor is used as the torque when the motor is started;

and step S5, converting the adjusted motor set torque and using the converted motor set torque as a feed-forward set torque of motor closed-loop control to start the motor without the position sensor.

2. The method of claim 1, wherein the target rotation speed satisfies a condition that enables a substantial estimation of the electrical angle and speed of the motor.

3. The method of starting a position sensorless motor according to claim 1, wherein the target rotation speed is 200rpm to 600 rpm.

4. The method of starting a position sensorless motor according to claim 1, wherein the period of time is 20ms to 40 ms.

5. The method for starting a position sensorless motor according to claim 1, further comprising filtering the calculated open loop electrical angle and the estimated electrical angle difference, respectively, in step S2.

6. The method for starting a position sensorless motor according to claim 1, wherein in step S4, if the absolute value of the estimated electrical angle difference is greater than or equal to a set value and the electrical angle difference is greater than zero, the motor set torque is reduced, and the process returns to step S2; if the absolute value of the estimated electrical angle difference is greater than or equal to the set value and the electrical angle difference is less than zero, the motor set torque is increased, and the process returns to step S2.

Technical Field

The invention relates to the technical field of motor control methods, in particular to a starting method of a motor without a position sensor.

Background

The motor without the position sensor is widely applied to the fields of air conditioners, water pumps and the like due to low price and high reliability. The motor without the position sensor usually adopts the speed/angle estimation of a motor fundamental wave model or an observer algorithm to calculate the angle and the speed of the motor, but at zero speed and low speed, the back electromotive force of the motor without the position sensor is too small, the signal to noise ratio is low, and the algorithm cannot estimate the correct angle and speed. It is therefore necessary to start the position sensorless motor to a certain speed in an open loop manner. From speed open-loop control to speed closed-loop control, the electrical angle of the motor without the position sensor is set to be switched from the accumulated angle of the open loop to the estimated electrical angle, the difference is large, direct switching cannot be achieved, a transition process is needed, and otherwise starting of the motor without the position sensor can be influenced.

The applicant has therefore found, through useful research and study, a solution to the above-mentioned problems, in the context of which the technical solutions to be described below have been created.

Disclosure of Invention

The invention aims to: the method for starting the motor without the position sensor is provided, and the motor without the position sensor can be started smoothly on the basis of not changing the original control mode.

The purpose of the invention can be realized by adopting the following technical scheme:

a method for starting a position-sensorless motor includes the steps of:

step S1, starting the motor without position sensor to the target speed in open loop mode, and keeping it stably for a period of time;

step S2, calculating an open-loop electrical angle and an estimated electrical angle difference, and adjusting the given torque of the motor according to the estimated electrical angle difference;

step S4, if the absolute value of the estimated electrical angle difference is smaller than a set value, the adjusted given torque of the motor is used as the torque when the motor is started;

and step S5, converting the adjusted motor set torque and using the converted motor set torque as a feed-forward set torque of motor closed-loop control to start the motor without the position sensor.

In a preferred embodiment of the present invention, the target rotation speed should satisfy a condition capable of substantially estimating the electrical angle and speed of the motor.

In a preferred embodiment of the present invention, the target rotation speed is 200rpm to 600 rpm.

In a preferred embodiment of the present invention, the period of time is 20ms to 40 ms.

In a preferred embodiment of the present invention, in step S2, the method further includes filtering the calculated open-loop electrical angle and the estimated electrical angle difference, respectively.

In a preferred embodiment of the present invention, in step S4, if the absolute value of the estimated electrical angle difference is greater than or equal to the set value and the electrical angle difference is greater than zero, the motor set torque is reduced, and the process returns to step S2; if the absolute value of the estimated electrical angle difference is greater than or equal to the set value and the electrical angle difference is less than zero, the motor set torque is increased, and the process returns to step S2.

Due to the adoption of the technical scheme, the invention has the beneficial effects that: according to the invention, the difference between the open-loop electrical angle and the estimated electrical angle is continuously reduced by continuously adjusting the given torque of the motor, so that the transition to closed-loop control is facilitated, and the motor is smoothly started.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a method of starting a position sensor-less motor of the present invention.

FIG. 2 is a graph of open loop electrical angle versus estimated electrical angle difference for a position sensor-less motor of the present invention at open loop start-up.

FIG. 3 is a graph of the open loop electrical angle of the sensorless motor of the present invention after torque adjustment and the estimated electrical angle difference slowly approaching zero.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further explained below by combining the specific drawings.

Referring to fig. 1, a method of starting a position sensor-less motor is shown, comprising the steps of:

step S1, after the sensorless motor is initialized, the sensorless motor is started to the target rotation speed in an open-loop manner and is kept stable for a period of time, where the relationship between the open-loop electrical angle and the estimated electrical angle difference is shown in fig. 1. In the present embodiment, the target rotation speed should satisfy the condition of basically estimating the electrical angle and speed of the motor, and the target rotation speed is preferably 200rpm to 600 rpm. The period of time is 20ms to 40 ms.

Step S2, during the PWM control period, calculating the open-loop electrical angle and the estimated electrical angle difference, and adjusting the given torque of the motor according to the estimated electrical angle difference during the torque control period, where the relationship between the open-loop electrical angle and the estimated electrical angle difference is shown in fig. 3. In step S2, the method further includes filtering the calculated open-loop electrical angle and the estimated electrical angle difference, and obtaining a stable open-loop electrical angle and electrical angle difference after the filtering.

And step S4, in the PWM control period, if the absolute value of the estimated electric angle difference is smaller than a set value, the regulated given torque of the motor is used as the torque when the motor is started. If the absolute value of the estimated electrical angle difference is greater than or equal to the set value and the electrical angle difference is greater than zero, reducing the given torque of the motor, and returning to the step S2; if the absolute value of the estimated electrical angle difference is greater than or equal to the set value and the electrical angle difference is less than zero, the motor set torque is increased, and the process returns to step S2.

And step S5, converting the adjusted motor set torque in a torque control period, using the converted motor set torque as a feedforward set of motor closed-loop control, and starting the motor without the position sensor.

According to the invention, the difference between the open-loop electrical angle and the estimated electrical angle is continuously reduced by continuously adjusting the given torque of the motor, so that the transition to closed-loop control is facilitated, and the motor is smoothly started.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.