The electric drive adopts a PLC (programmable logic controller) controlled full digital thyristor reversible DC speed control system. The PLC of the electric control system is selected from the CPM2A integral PLC of Japan OMRON company. It is responsible for the completion of the given signal processing, the button signal of the machine tool, the various limit signals and the system fault signal. deal with. The fully digital thyristor reversible DC speed control device uses British Continental's 590+ series 500A four-quadrant logic non-circulating (reversible) full digital DC motor speed control device. Its internal main circuit is composed of two sets of anti-parallel three-phase fully controlled thyristors Composed of rectifier units, the two form a four-quadrant logic loopless (reversible) DC speed-regulated electrical drive system by triggering pulse logic interlock. All its control algorithms are completed by a high-speed 16-bit microprocessor to obtain superior dynamic control performance; self-tuning algorithm can automatically calculate the current loop P, I constant and current interruption point, so that the system obtains the best dynamic performance ; The adaptive function of its current loop makes it possible to obtain a smooth speed response when the system changes greatly. The speed regulation system adopts photoelectric encoder to form the speed negative feedback speed closed-loop control to improve the speed stability of the electrical speed regulation system, expand the speed regulation range of the system, and reduce the static rate of rotation speed. Speed ​​range The drag mode of DC generator set (JF-F-D) controlled by rail planer AC magnetic amplifier adopts voltage negative feedback and current positive feedback control, and its speed regulation range is D≤20. All digital thyristor reversible DC speed regulation drag mode (KZ-D) adopts photoelectric encoder as negative speed feedback, and its speed regulation range is D≤50. Steady-state accuracy The steady-state accuracy of the JF-F-D system can only reach 1%, while the steady-state accuracy of the KZ-D system can reach 0.1% (photoelectric encoder feedback). Operation reliability The JF-F-D system has many adjustment resistors, and the relay logic control method used has many inherent connection points, resulting in a high probability of failure of the circuit virtual connection. The DC generator, AC magnifier and exciter of the JF-F-D system have commutators and brushes, and there are many failures caused by poor contact of the brushes. After the programmable logic controller (PLC) is adopted in the KZ-D system controlled by the high-speed microprocessor, since the entire control system is an industrial computer suitable for harsh industrial environments to complete all control algorithms, the entire electronic control system The D system is greatly simplified. The relay logic control of the original control circuit replaces the soft contacts of the PLC with the soft contacts of the PLC. Full digital thyristor rectifier. The simplification of the control circuit and the reduction of high-current contacts will surely further improve the operation reliability of the electric drive system of the rail planer. Maintainability The JF-F-D system has many adjustable resistors, many control motors, and many parts to be adjusted. It is difficult to debug and difficult to maintain. The high-speed microprocessor-controlled KZ-D system adopts all-digital devices, which fully utilizes the flexible advantages of computer software and has perfect digital control and protection functions; there are few digital control adjustment points, self-tuning of debugging parameters, and accurate after failure Fault information display shortens the maintenance time. Efficiency and equipment volume The efficiency of the DC generator set dragged by the AC asynchronous motor of the JF-F-D system can only reach about 93%; in addition to the electrical control cabinet, the electrical drive system also has a DC generator set covering an area of ​​3 square meters, and the AC magnetic expansion Machine, exciter, starting resistance box and other peripheral equipment, and the unit is noisy. The high-speed microprocessor-controlled KZ-D electric drive system has an efficiency of more than 98%; all its control devices are installed in the original electrical control cabinet, no other peripheral devices, and no noise during operation. After the transformation of the 12-meter rail planer, the operator reported that the noise of the previously disturbing unit was gone, and the working environment was greatly improved. Energy saving analysis and investment benefits On August 27, 2005, we installed a three-phase four-wire active energy meter and a three-phase four-wire reactive energy meter on the modified No. 1 rail planer and the unmodified No. 2 rail planer. The table collects power saving data. The shift arrangement of the two rail planers and the processed products are almost the same. On September 28, 2005, the meter reading was recorded after one month. Monthly power consumption of the modified rail planer: active power is 43 × 60 (current transformer ratio) = 2580KW • h, reactive power is 120 × 60 (current transformer ratio) = 7200KVar • h; unmodified No. 2 rail Monthly power consumption of planer: active power is 98 × 60 (current transformer ratio) = 5880KW • h, reactive power is 398 × 60 (current transformer ratio) = 23880KVar • h. From the above data, it can be seen that the rail planer using the fully digital thyristor reversible DC speed control system saves an average monthly power consumption compared to the rail planer using the DC generator set electric drive: the active power is 3300KW • h and the reactive power is 16680KVar • h. The significance of active power saving is that it can directly save electricity costs every year: 3300 (KW • h / month) × 12 (month) × 0.5 (yuan / KW • h) = 19800 (yuan) In this project, the 93,000 yuan investment in this transformation can be fully recovered in 5 years. The significance of reactive power saving is to reduce the line loss of the power supply bus in the workshop, reduce the secondary current of the distribution transformer in the workshop, and the saved reactive current can be transferred to the newly installed equipment in the power grid, thus eliminating the workshop configuration after the new equipment is added. The problem of electrical transformer capacity increase. From the above power saving data, it can be seen that the reactive power saved after the transformation of the rail planer is much larger than the active power, and the indirect benefits of reactive power saving for the workshop grid are also very obvious.
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