Control method for starting stage of compressor controller

Abstract

The invention discloses a control method for a starting stage of a compressor controller, and belongs to the technical field of automobile air conditioner compressor motor control. The control method for the starting stage of the compressor controller comprises a positioning stage, an open-loop stage and a closed-loop stage, in the open-loop stage, the rising slope of the rotating speed of a compressor is increased, the rising maximum value of q-axis current is reduced, and the time for reaching the closed-loop rotating speed of a motor is shortened. According to the method, in the open-loop time period, the given q-axis current can be continuously increased through proper time setting, the motor can be started when a certain current is finally reached, meanwhile, the rotating speed gradually tends to the closed-loop rotating speed, the rotating speed can be increased to the closed-loop rotating speed in a very short time by shortening the open-loop time, and due to the fact that the time is shortened, the rotating speed can be increased to the closed-loop rotating speed. In the open-loop stage, the process of the open-loop stage is shortened, hum hum generated in the open-loop stage is short accordingly, and therefore the NVH problem generated by the combined action of current, rotating speed and the like in the open-loop stage and a motor is restrained.

Description

Technical Field

[0001] The present invention relates to a control method for the starting stage of a compressor controller, belonging to the technical field of automotive air-conditioning compressor motor control. Background Art

[0002] In the starting stage of an existing automotive air-conditioning compressor, the IF starting method is adopted, which mainly includes three stages: positioning, open-loop, and closed-loop. The IF starting method uses a short-time positioning current to find the position, a stable current loop to control the open loop, and a stable control of the rotational speed after switching to the closed loop to achieve the effective operation of the motor. Due to the influence of current changes and time, some NVH problems will also be introduced during this process. Since the motor is dragged by a continuously changing current, and the combined action of the current and the bare machine part, NVH problems such as a humming sound will occur during startup. Summary of the Invention

[0003] The purpose of the present invention is to provide a control method for the starting stage of a compressor controller to solve the NVH problem of a humming sound existing in the IF starting method of an existing automotive air-conditioning compressor.

[0004] The present invention adopts the following technical solution: A control method for the starting stage of a compressor controller, which includes a positioning stage, an open-loop stage, and a closed-loop stage. In the open-loop stage, the slope of the compressor speed increase is increased, the maximum value of the q-axis current increase is decreased, and the time to reach the motor closed-loop speed is shortened.

[0005] In the positioning stage, a given current is used to position the compressor at a speed of rpm1. During the positioning stage: 0 < t < t1, rpm = rpm1, iq = iq0 + b1; where t is the time variable, t1 is the positioning time, rpm is the motor required speed, rpm1 is the motor speed during the positioning stage; iq is the given q-axis current, iq0 is the given q-axis current at the previous moment, and b1 is a constant. During the open-loop stage, t1 < t < t2, rpm = k1 * t + b2, iq = iq0 + b3, rpm1 < rpm < rpm2; where t is the time variable, t1 is the positioning time, t2 - t1 is the open-loop time, rpm is the motor required speed, rpm1 is the motor speed during the positioning stage, rpm2 is the motor speed during the closed-loop stage, k1 is the slope constant, b2 is a constant; iq is the given q-axis current, iq0 is the given q-axis current at the previous moment, and b3 is a constant.

[0006] rpm1 during the positioning stage is 30, the maximum value of iq is 4A, b1 = 0.004, and t1 = 0.5s.

[0007] In the open-loop stage, rpm2=800rpm, k1=770, b2=-355, b3=0.006, t2=1.5s.

[0008] Beneficial effects of the present invention: The present invention shortens the time of the open-loop stage. During the open-loop stage, the parameters of the given required speed and the given q-axis current will change. The output values ​​of the given required speed and the given q-axis current will be affected by the open-loop time. In the proportional relationship diagram between the two and time, the relationship between the rising speed and the current over time is close to the rising straight line, and the relationship between the falling current and time is close to the falling curve; the longer the time, the smaller the slope of the speed rising to the target value, and the larger the maximum value of the q-axis current; the shorter the time, the larger the slope of the speed rising to the target value, and the smaller the maximum value of the q-axis current. If the open-loop time is reduced, the slope of the speed rise during the open-loop process will be increased and the maximum value of the q-axis rise will be reduced, so that the overall time of the current and speed acting on the motor when rising is shortened, so that the humming sound will also be shortened, and the stage is passed in a very fast way, so as to achieve the technical effect that the sound is optimized when the compressor is running. The present invention can deal with the NVH problem of the humming sound during the startup process of the compressor, reduce the negative experience of actual use, and has a wide range of application. Whether it is under normal temperature, high temperature, low temperature and other environments, the compressor can start normally within a suitable sound range. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a comparison diagram of the speed and time during the start-up phase of the compressor of the prior art and the start-up phase of the compressor of the present invention; Figure 2 is a comparison diagram of current and time during the start-up phase of a compressor of the prior art and the start-up phase of a compressor of the present invention; Figure 3 It is a schematic diagram of the present invention; Figure 4 is a flow chart of the steps to actually run the test. DETAILED DESCRIPTION

[0010] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0011] The specific IF starting method of the automobile air-conditioning compressor is as follows: the controller is powered on at low voltage, and the control operation strategy of the compressor is obtained after initialization; it is powered on at high voltage to obtain the normal working voltage; the compressor is started by the host computer control, and after going through the three stages of positioning, open loop, and closed loop, it enters closed-loop stable operation, and the compressor operates normally.

[0012] A control method for the start-up phase of a compressor controller according to an embodiment of the present invention includes a positioning phase, an open-loop phase, and a closed-loop phase. In the open-loop phase, the slope of the compressor speed increase is increased, the maximum value of the q-axis current increase is decreased, and the time to reach the motor closed-loop speed is shortened.

[0013] In the positioning phase, a given current is used to position the compressor at a speed of rpm1. During the positioning phase: 0 < t < t1, rpm = rpm1, iq = iq0 + b1; where t is the time variable, t1 is the positioning time, rpm is the motor required speed, rpm1 is the motor speed during the positioning phase; iq is the given q-axis current, iq0 is the given q-axis current at the previous moment, and b1 is a constant.

[0014] In the open-loop phase, when t1 < t < t2, rpm = k1 * t + b2, iq = iq0 + b3, rpm1 < rpm < rpm2; where t is the time variable, t1 is the positioning time, t2 - t1 is the open-loop time, rpm is the motor required speed, rpm1 is the motor speed during the positioning phase, rpm2 is the motor speed during the closed-loop phase, k1 is the slope constant, b2 is a constant; iq is the given q-axis current, iq0 is the given q-axis current at the previous moment, and b3 is a constant.

[0015] In a specific embodiment, for example, in the positioning phase, rpm1 = 30, the maximum iq is 4A, b1 = 0.004, t1 = 0.5s; in the open-loop phase, rpm2 = 800rpm, k1 = 770, b2 = -355, b3 = 0.006, t2 = 1.5s.

[0016] During the compressor startup process, the current of about A1 (A1 is the maximum current in the positioning stage) will be used within the time of t1 to position the compressor at a very low speed rpm1. The positioning stage is not long and uses a low speed to find the position; after the positioning time is over, it will enter the open loop stage. The speed in the open loop stage is unstable. The speed control is achieved by adjusting the current loop. This process will give a continuously rising q-axis current to drive the motor to run. Within the open loop time t2-t1, the current is expected to rise to about A2 ( A2 is the maximum current in the open-loop stage). The rate of current rise will gradually increase and eventually reach the set maximum peak value, so that the motor open-loop can stably increase the speed to an ideal state. After reaching the time corresponding to the set closed-loop speed (for example, when the speed is 800rpm), the compressor begins to converge into the closed-loop, and the estimated angle (the rotor position angle obtained by control estimation) is also approaching the actual angle (the actual rotor position angle), so that the motor rotor can successfully find the correct position. In the actual operation process, there will be a certain error in the angle. At this time, it is necessary to adjust the parameters in the convergence process to ensure stable operation. If the error between the estimated angle and the actual angle is very small (for example, within 5°) or the closed-loop time (a specific application example is 0.2s) is reached, the compressor will enter the closed-loop stage, and the actual compressor speed will be stably controlled.

[0017] The convergence process refers to the process of motor control before entering the closed loop while reducing the current and angle error. Figure 2 Current reduction process. Parameters in different embodiments may be different. For example, the current reduction coefficient is 0.9998, the number of times is 2000, and the maximum reduction time is 0.2s, in order to make the motor run stably.

[0018] Through the above technical solution, the startup phase time of the compressor can be shortened, which is specifically manifested in the shortening of the open-loop time. During actual operation, the open-loop phase time will be accompanied by parameter changes of the given required speed and the given q-axis current. The output values ​​of the given required speed and the given q-axis current will be affected by the open-loop time. In the proportional relationship diagram between the two and time, the relationship between the rising speed and current and time is close to an ascending straight line, and the relationship between the falling current and time is close to a descending curve; the proportional relationship between the two and time is close to a slowly rising straight line and curve, respectively. Figure 1 In the figure, the black line shows the relationship curve between the speed and time of the compressor startup phase of the present invention (t2'-t1 represents the open loop time in the present invention), and the blue line shows the relationship curve between the speed and time of the compressor startup phase of the prior art (t2-t1 represents the open loop time of the prior art); Figure 2 In the figure, the dotted line shows the relationship curve between the current and time in the start-up phase of the compressor in the prior art, and the solid line shows the relationship curve between the current and time in the start-up phase of the compressor of the present invention. Figure 1 and Figure 2 It can be seen that the longer the time is, the smaller the slope of the speed rising to the target value will be, and the larger the maximum value of the q-axis current will rise to; the shorter the time is, the larger the slope of the speed rising to the target value will be, and the smaller the maximum value of the q-axis current will rise to. If the open-loop time is reduced, the slope of the speed rise during the open-loop process will increase and the maximum value of the q-axis rise will decrease, thereby shortening the overall time that the current and speed act on the motor when they rise, reducing the NVH problem caused by the IF starting method, and significantly optimizing the NVH sound when the compressor starts.

[0019] like Figure 4 As shown in the figure, the actual test and operation process is as follows: (1) Burn the software program into the controller; (2) Initialize the control logic at low voltage; (3) Set the normal working voltage of the compressor at high voltage; (4) Control the operation of the compressor through the upper computer software; (5) Listen to the sound during the compressor startup phase.

[0020] Technical principle of the present invention: In the prior art, the compressor generates NVH problems such as humming noise when starting. In order to deal with this phenomenon, the actual situation of the humming noise is analyzed. By pulling the phase current waveform curve, it is found that this sound is mainly concentrated in the open-loop stage of the motor. Around this process, we have tried to reduce and increase the peak current of the startup, adjust the given q-axis current rise rate, improve the time of the open-loop stage, etc., and finally found that shortening the open-loop time appropriately can improve the problem. Figure 3As shown, for the IF starting mode, there is a certain linear relationship between the set speed and the current, and the current that continues to rise in this process will also be affected by the time parameter variable. In the open-loop time period, the appropriate time setting can make the given q-axis current continue to rise, and finally reach a certain current to enable the motor to start. At the same time, the speed gradually tends to the closed-loop speed. Shortening the open-loop time can make the speed rise to the closed-loop speed in a very short time. Due to the shortened time, the open-loop stage process will be shortened, and the humming sound occurring in this stage will also be shorter, thereby suppressing the NVH problem caused by the pull-up of the current, speed, etc. in the open-loop stage and the motor. In the prior art, when the compressor IF starts running, whether it is the abnormal sound caused by the air flow between the current and the motor, or the resonance of the mechanical structure, etc., more or less causes NVH problems. From the perspective of motor control, we can suppress the point where the sound is generated larger, specifically in the open-loop stage. By reducing the open-loop stage time, the overall time for the current and speed to act on the motor when rising is shortened, so that the humming sound will also be shortened, and the stage will be passed in a very fast way to achieve the optimization effect of the sound when the compressor is running. Theoretically, further shortening the time will improve the sound to a greater extent. However, since the current, speed, etc. are affected by time factors, too short a time will cause the current and speed rise values ​​to become smaller, affecting the starting ability of the motor. Therefore, in the actual process, we need to appropriately shorten (the parameters of different embodiments may be different. For example, in the open-loop time of 0.5-1.5s, the open-loop time of 1s can be appropriately shortened to 0.7s) the time in the open-loop stage of the motor to optimize the sound at startup and achieve the greatest benefit in improving NVH problems.

Claims

1. A control method for a compressor controller startup phase, comprising a positioning phase, an open-loop phase and a closed-loop phase, characterized in that: In the open-loop stage, increase the slope of the compressor speed increase, reduce the maximum value of the q-axis current increase, and shorten the time to reach the motor closed-loop speed.

2. The control method of the compressor controller startup phase according to claim 1, characterized in that: In the positioning stage, use the given current to position the compressor at a speed of rpm1. During the positioning stage: 0 < t < t1, rpm = rpm1, iq = iq0 + b1; where t is the time variable, t1 is the positioning time, rpm is the motor required speed, rpm1 is the motor speed during the positioning stage; iq is the given q-axis current, iq0 is the current at the previous moment on the given q-axis, and b1 is a constant. In the open-loop stage, when t1 < t < t2, rpm = k1 * t + b2, iq = iq0 + b3, rpm1 < rpm < rpm2; where t is the time variable, t1 is the positioning time, t2 - t1 is the open-loop time, rpm is the motor required speed, rpm1 is the motor speed during the positioning stage, rpm2 is the motor speed during the closed-loop stage, k1 is the slope constant, b2 is a constant; iq is the given q-axis current, iq0 is the current at the previous moment on the given q-axis, and b3 is a constant.

3. The control method of the compressor controller startup phase according to claim 2, characterized in that: The rpm1 in the positioning stage is 30, the maximum value of iq is 4A, b1 = 0.004, and t1 = 0.5s.

4. The control method of the compressor controller startup phase according to claim 2, characterized in that: The rpm2 in the open-loop stage is 800 rpm, k1 = 770, b2 = -355, b3 = 0.006, and t2 = 1.5s.

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