Application of PI9200E permanent magnet non-inductive synchronous frequency converter in the transformation of injection molding machine
Overview
Injection molding machines and extruders are the main production equipments in the plastics industry. They are also the main power-consuming equipment. They are known as “electric tigers”, and their electricity consumption accounts for about 80% of the electricity produced by enterprises. The injection molding machine consumes a large amount of electricity, which on the one hand causes a huge waste of electrical energy in the whole society. On the other hand, the production cost of the enterprise remains high, and the product lacks a competitive advantage, which seriously affects the economic benefits of the enterprise.
The process of injection molding machine is generally divided into several stages, such as clamping, injection, melting, holding, cooling, and mold opening. Each stage requires different working pressure and flow. For the oil pump motor, the injection molding process is in a changing load state. In the hydraulic system of the dosing pump, the pump motor always provides a constant flow at a constant speed, and excess hydraulic oil is returned through the overflow valve. This process is called high pressure throttling. According to statistics, the energy loss caused by high-pressure throttling is as high as 25-60%. At the same time, due to the long-term full-speed circulation of the hydraulic fluid, the severe friction with the hydraulic parts and the mechanical parts causes the oil temperature to be too high, the noise is too large, and the mechanical life is shortened.
Second, the PI9000 renovation program process brief
In the permanent magnet synchronous transformation of the injection molding machine, the control scheme adopts the method that the flow and pressure double signals are compared and larger, and the control scheme can ensure that the user adjusts the parameters of the inverter when replacing the product mold. Moreover, the control signal is completely electrically isolated from the injection molding machine signal, which does not cause interference to the injection molding machine controller and affects product quality.
1, frequency converter selection
The oil pump motor used in this modified injection molding machine is a 14KW permanent magnet non-inductive synchronous servo motor. Therefore, the inverter uses PI9230E015G3 permanent magnet synchronous non-inductive vector control special inverter. In order to meet the control requirements of the rapid start-stop of the injection molding process, a suitable braking resistor must be selected. According to the braking resistor selection control requirements of the inverter, configure the 40Ω/1500W braking resistor.
2, inverter control terminal wiring
According to the process control requirements of the injection molding machine, the inverter control terminals use the analog control terminals AI1, AI2, GND. Digital control terminals DI1, DI2, COM. The relay outputs 1 terminals TA1 and TC1.
