Frequency conversion energy-saving transformation of Liuzhou Fidelity Air Compressor Du Yanfei, Wang Peihua (Luquan Jinyu Dingxin Cement Co., Ltd., Luquan 050200, China)1Basic Overview In the cement industry, air supply for various dust collectors and pneumatic equipment is provided. Presses are mostly high-power equipment (generally above 132kW). The air compressor station of our company's 5000t/d clinker production line uses two air compressors, and both air compressors are designed to be in operation during normal operation. One of them is in full load operation and the other is in basic load or unload operation. However, in the production operation, there was an accident that the compressed air pressure of the two air compressors was low due to the increase in the amount of gas used, which in turn caused the coal feeding scale to stop (the interlocking of the coal feeding scale and the compressed air pressure). In order to ensure the normal operation of the production line, our company has configured an air compressor, but through the monitoring of the current control current curve, it is found that the third air compressor added is only two or three times a day and only 1 ~ 2h at a time. The output state, that is, most of the time is in a completely empty running state. To this end, we use the variable frequency speed control technology to technically transform the three air compressors, so that the air compressor can automatically adjust the motor speed according to the amount of gas used, and also reduce the frequent loading and unloading of the motor; The PFC macro of the device solves the idling problem of the third air compressor that is added. 2 Reconstruction plan and implementation (1) For an air compressor, set the upper and lower pressure parameters so that they are always in the loaded state; The other two air compressors use the PFCTRAD macro of the frequency converter for operational control. The PFCTRAD megafunction of the inverter can be used for parallel control of 1~5 devices (one for the main unit and the other for the auxiliary equipment) of the fan, pump and compressor station. Among them, the host is directly controlled by the inverter, the other auxiliary machines are directly connected to the power grid, and the switch is switched by the relay system; when the pipeline pressure is reduced due to the increase of the gas consumption, the auxiliary machine starts to run immediately. In this example, the PFCTRAD macro control device of the inverter has one main and one auxiliary machine; one of the main units is controlled by the inverter to directly control the gas production to meet the normal production requirements; if the air compressor is fully loaded, the amount of gas used When it is still not enough, start another air compressor (auxiliary machine). In the normal production operation, the air compressor station only needs to run two air compressors to meet the production needs, thereby reducing the operating energy consumption and cost of an air compressor. (2) The variable frequency speed control system takes the pipeline pressure as the control object, and the closed loop control system consists of the inverter cabinet, the motor and the pressure sensor. (3) The starting mode of the air compressor system is started by the star-delta triangle. In order to ensure the reliability and modification of the control system, the original control system is not canceled and connected in series in the main circuit. In addition, there are five air compressors in the air compressor station of our company's clinker production line, and there are enough spare machines. Therefore, it is not necessary to consider the power frequency and frequency conversion of the control system during the transformation. The main circuit diagram of the frequency conversion cabinet is as follows. The frequency converter produced by the main circuit diagram of the frequency conversion cabinet has been used for up to 10 years in our company. (5) The host startup mode is on-site automatic. The inverter is started and stopped on the cabinet front panel. The pressure setting is given by the panel. When the normal operation is completed after the commissioning, the auxiliary contact of the contactor of the air compressor is started. (6) The pressure sensor adopts compressor, air conditioner special pressure sensor, 24V power supply, 4~20mA output; see the wiring line, see the inverter control panel wiring. Pressure sensor wiring line The constant pressure control debugging and debugging process of the air compressor is carried out in two steps. Firstly, the main engine is the air compressor with variable frequency speed regulation. After the main engine is commissioned, the auxiliary air compressor is commissioned. When the BP pressure is low, the main engine starts. Machine process. The related debugging process and parameter settings are described below. (1) After the power is turned on, the low frequency is turned on and the motor steering is checked first. After the completion, the inverter is prohibited from reverse output (protecting the motor and compressor); at the same time, check whether the pressure sensor is normal. If the wiring is correct, the pressure is displayed on the control panel. In order to prevent the inverter from running out of control after the sensor is damaged, the upper and lower limits are set by the running frequency control. Du Yanfei, etc.: Liuzhou Fidelity air compressor frequency conversion energy-saving transformation electrical control given voltage value -10VDC1kn given voltage value 1VDCikn torque given G (4 b default state, undefined 0 (4)-20 motor speed (4) 20s 0~ motor rated speed *n. output current 0 motor rated current, R| stop/start forward/reverse speed/torque control selection u constant speed 4: parameter 12.052) twisting and decrementing ramp time selection 3 ) Run permission 4) Digital ground start interlock (= stop) 5) 3 Inverter control panel wiring panel directly set. (3) The basic functions of the PFC macro and the PID macro are similar, but there are some differences in the details. Therefore, some problems are encountered during the technical debugging, as follows. 1 The inverter cannot be started. After the line is connected, starting from the terminal block and starting the inverter on the panel can not be started. After consulting ABB inverter after-sales service, it is known that the interlock between the host and the auxiliary machine should be canceled when using the PFC macro. After the parameters are removed and the interlock is removed, the inverter can start normally. 2 The pressure setting cannot be changed. The set value of the pressure is always a fixed value (40%). For this reason, the parameter 41.02 is modified to EXTERNAL, that is, the default internal default of the original program is modified to an external reference, and then the pressure setting value can be changed. 3 The inverter cannot be adjusted automatically. After starting with the inverter panel, the inverter can not automatically adjust the given frequency according to the pressure change, always running at the lowest frequency (30Hz). After the inverter is driven by the panel, the controller is bypassed and can only operate according to the originally set pressure value. After the terminal is driven (DI6), the inverter is automatically adjusted. After the host debugging is completed, start debugging the second air compressor. First, the parameter of the frequency conversion parameter 14.01 is set to M1 as a drive to start the second air compressor; in the control panel of the air compressor, the operation mode is changed to the remote control mode (because the air compressor used is in the remote control mode) Under the local mode, automatic loading can be realized, but in the local mode, manual loading is required to automatically load and unload); when the system pipeline pressure is lower than the set value, the second air compressor is started. 4 Note and transformation effect should pay attention to the production operation: First, when the gas consumption is small and the inverter is running at low frequency, it should be noted whether the motor winding temperature rises. It has been observed that the air compressor system is equipped with a cooling fan exhaust air. When the air compressor operating frequency is around 30 Hz, the motor winding temperature is normal, and the motor temperature does not rise due to the lowering of the speed. Secondly, it is understood that the air compressor used can achieve normal operation at low speed, but the best speed in production operation is not too low. Third, it should be proficient in the operation of the control system of the air compressor, such as the local control mode operation and the realization of the remote control function. In the actual operation, the inverter frequency range is 25~40Hz; after the transformation, the annual power saving 110.768MWh can save 66,000 yuan, and the price of a frequency conversion cabinet is more than 90,000 yuan. There is no air compressor that saves idling.) Obviously, this transformation has a good effect on energy saving and consumption reduction. (Editor: Liu Cuirong) (:2013-04-10) 2014 "Concrete and Cement Products" magazine subscription notice monthly magazine (postal code: 28-80) National Building Materials Technical Journal, started in 1974. The magazine specializes in new achievements, new technologies, new products and latest developments in production (construction), applications, research, design, teaching and corporate management in the concrete and cement products industry at home and abroad. The main columns are "Expert Forum", "Industry Work", "Concrete Research", "Cement Concrete Products", "Fiber Cement and Products", "Building Materials and Products", "Construction Technology", "Quality Management", etc. The magazine is a standard 16-page book with 12 issues throughout the year. Pricing: 8 yuan per period, 96 yuan for the whole year. Post offices around the country can subscribe, or subscribe to our reader service department. 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