Regulation Method for Torque\u2013Angle Characteristics of Rotary Electric\u2013Mechanical Converter Based on Hybrid Air Gap

Bin Meng,Xinguo Qiu,Yongjiang Lai

doi:10.1186/s10033-020-00452-4

Bin Meng, Xinguo Qiu + Show 1 more

Open Access

https://doi.org/10.1186/s10033-020-00452-4

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Abstract

The torque–angle characteristics of electric–mechanical converters are important determinants of the quality of electrohydraulic proportional control systems. It is far more difficult for a rotary electric–mechanical converter (REMC) to obtain flat torque–angle characteristics than traditional proportional solenoid, greatly influencing the promotion and application of rotary valves for electrohydraulic proportional control systems. A simple and feasible regulation method for the torque–angle characteristics of REMCs based on a hybrid air gap is proposed. The regulation is performed by paralleling an additional axial air gap with the original radial air gap to obtain a flat torque–angle characteristic and increase output torque. For comparison, prototypes of REMCs based on hybrid and radial air gaps were manufactured, and a special test rig was built. The torque–angle characteristics under different excitation currents and step responses were studied by magnetic circuit analysis, finite element simulation, and experimental research. The experimental results were consistent with the theoretical analysis. It was shown that REMCs based on a hybrid air gap can obtain a flat torque–angle characteristic with further optimizing of key structural parameters and also increase output torque. This regulation method provides a new approach for the design of proportional rotary electromechanical converters.

Highlights

Since its advent, electrohydraulic proportional control technology has occupied a top position in the electromechanical industry because it has the advantages of a high power to weight ratio, large output force, and excellent static and dynamic characteristics, which are regarded as key to competitiveness in modern industry [1,2,3,4,5,6,7]
To validate the practicability of this method, prototypes of the rotary electric–mechanical converter (REMC) based on hybrid and radial air gaps were manufactured, and their torque–angle characteristics and step responses were analyzed through magnetic circuit analysis, finite–element method (FEM) simulation, and experimental approaches
The above analysis shows that REMC with a hybrid air gap (REMC-H) can obtain a flat torque–angle characteristic and has a larger output torque

Summary

Introduction

Electrohydraulic proportional control technology has occupied a top position in the electromechanical industry because it has the advantages of a high power to weight ratio, large output force, and excellent static and dynamic characteristics, which are regarded as key to competitiveness in modern industry [1,2,3,4,5,6,7]. Zhang et al [31] proposed an electric excitation rotary electromagnet whose stator yoke shape and rotor pole surface were specially designed to control the magnetic flux saturation at the stator yoke top to obtain a flat torque–angle characteristic. Cui et al [32] proposed a rotary proportional electromagnet based on a radial working air gap. It is based on a differential magnetic circuit, and its structure is too complex for industrial application and mass production. To validate the practicability of this method, prototypes of the REMC based on hybrid and radial air gaps were manufactured, and their torque–angle characteristics and step responses were analyzed through magnetic circuit analysis, finite–element method (FEM) simulation, and experimental approaches.

The magnetic output torque can be written as

Lower PM

Plate g

Conclusions