| Traditional traction elevators cannot fully meet the needs of modern urban development due to their limitations in height,low efficiency,and high energy consumption.The direct-drive multi-car elevator has the advantages of no wire rope,no counterweight,no lifting height,and multiple cars.It can cope well with the problems existing in traditional elevators,and has received wide attention from all walks of life.Compared with traditional elevators,direct-drive multi-car elevators carry high-power electronic equipment,floor controllers,wireless receivers,and unique drive source linear motors,which will generate more complex electromagnetic interference during normal operation,resulting in electromagnetic compatibility problem is more obvious.In order to predict the electromagnetic compatibility of the direct-drive multi-car elevator,this paper focuses on the electromagnetic interference of the linear motor and control unit DC cable and motor input cable in the drive system.The specific work contents are as follows:1.Firstly,the structure of the direct drive multi-car elevator is introduced.Secondly,through the analysis of the working principle of the drive system,the linear motor and the control circuit switching device are determined as the main interference sources of the direct drive multi-car elevator,and finally the basis of electromagnetics.Analyze the electromagnetic radiation interference mechanism of the cable to lay the foundation for establishing the electromagnetic simulation prediction model.2.Based on the SVPWM vector control method,a vector control joint simulation model of bilateral permanent magnet linear motor is used.The feasibility of the model is verified by simulation experiments.At the same time,fuzzy random switching frequency is added under the premise of reducing the narrowband harmonics of the input voltage spectrum of the motor.As a result,the motor input voltage spectrum is evenly distributed over the frequency band.3.Study the electromagnetic field radiation of the bilateral permanent magnet linear motor under different working conditions,and predict the conducted electromagnetic interference of the AC power port and the motor output power port in the elevator control system according to GB/T 24808-2009.The experimental results show that the electromagnetic field radiation of the linear motor meets the relevant electromagnetic emission limit,and the electromagnetic conduction interference emission of the control system port meets the national standard.4.Based on the 3D electromagnetic simulation model of direct drive elevator,the electromagnetic radiation distribution trend of DC cable and motor input cable under different conditions is simulated and analyzed.The experimental results show that the longer the cable,the greater the end resistance,the motor the faster the speed and the heavier the load,the stronger the electromagnetic radiation effect is.At the same time,compared with the fixed switching frequency,the electromagnetic radiation intensity obtained by simulation of the electromagnetic radiation at the fuzzy random switching frequency is more uniform at the same frequency,which verifies the control.The method reduces the feasibility of the spectrum amplitude.5.In the electromagnetic simulation model,the current distribution of the DC cable in the direct drive multi-car elevator surface and the electromagnetic interference interaction between the two cars in the single shaft are simulated.The simulation results show that the intensity of the radiated electric field is proportional to the surface current,and the closer the distance is from the interference source,the stronger the current effect is.The electromagnetic radiation theory and simulation results are consistent,which is the cable layout,floor distance setting and scheduling of the direct drive multi-car elevator.The question is provided as a reference. |
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