Views: 0 Author: Site Editor Publish Time: 2018-04-18 Origin: Site
Eight acceleration and deceleration mode selection: also called acceleration and deceleration curve selection. Generally, the frequency converter has three kinds of curves: linear, nonlinear and S-curve. The nonlinear curve is suitable for variable torque load, such as fan and so on, and the change of acceleration and deceleration is slow. According to the load torque characteristic, the timing can select the corresponding curve, but there are exceptions. When debugging the converter of a boiler induced fan, the author selects the acceleration and deceleration curve to the nonlinear curve first, and moves the converter together to trip the converter. Adjusting and changing many parameters has no effect, then changing to S curve is normal. The reason is: before starting, the induced fan rotates by itself because of flue gas flow, and inverts and becomes negative load, so the S curve is selected, which makes the frequency rise speed is slower when starting, thus avoiding the frequency converter tripping. Of course, this is aimed at the frequency converter without starting DC brake function. .
Nine torque vector control vector control is based on the theory that asynchronous motor and DC motor have the same torque generation mechanism. The vector control method is to decompose the stator current into the specified magnetic field current and torque current respectively and output the stator current to the motor after the combination of the two. Therefore, the same control performance as DC motor can be obtained in principle. With the torque vector control function, the motor can output the maximum torque under various operating conditions, especially in the low speed running area. Nowadays, almost all the frequency converters use non-feedback vector control. Because the frequency converter can compensate for the slip according to the load current and phase, the motor has very hard mechanical characteristics, which can meet the requirements for most occasions. The speed feedback circuit does not need to be set outside the frequency converter. This function can be set according to the actual situation in the effective and invalid can choose one item. The related function is the slip compensation control, which is used to compensate the speed deviation caused by the load fluctuation, and can add the slip frequency corresponding to the load current. This function is mainly used for positioning control. .
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