This study investigates the automotive magnetorheological (MR) shock absorber behaviour in conditions of changing temperature. Its temperature-dependent behaviour was quantified between ambient and maximal operating temperatures of the device. Aspects addressed include the temperature dependence of the control coil resistance in the absorber, the influence of operating current level on control coil temperature and the temperature dependence of the absorber force response and energy dissipation in the system. The results of experiments enabled us to evaluate the mechanical performance of the absorber at varied temperatures.

The newly developed ideal rectifier bridge equipped with four N-type MOSFETs and two rail-to-rail operational amplifiers is a part of a typical energy harvesting conditioning circuit responsible for the rectification stage in the system of converting the energy harvested from vibrations into electrical energy to power the MR damper. The only energy loss in the bridge is caused by the voltage loss in transistors’ channels. The first sections of the work summarises the structural design of the bridge, the simulation procedure under the RL load and by sine voltage inputs with predetermined frequency and amplitude range, and benchmarks the results against those obtained for the conventional bridge based on Schottky diodes. In the second section, the PCB prototype of the bridge is analysed, and measurement data are compiled. The third section reports on the laboratory testing of the developed bridge converting the harvested energy in an MR damper-based vibration reduction system.

The work deals with a newly developed prototype of an electrical control unit (ECU) for a magnetorheological (MR) damper powered by energy harvested from vibrations. The ECU, consisting of a rectifying bridge, a driver unit, a microcontroller, and an internal power supply system, is an advanced version of the specially designed processing system for energy harvested from vibrations and the use of this energy to control the MR damper. Unlike a typical MR damper control system in which electrical circuits are powered from an external energy source, the ECU is powered by a part of the energy extracted from a vibrating system using an electromagnetic harvester. However, the excess amount of energy recovered over that necessary to power the MR damper and electrical circuits can be collected in harvested energy storage. The study presents the design concept of the ECU, computer simulations of the in-built driver unit (DU), the method of connecting the ECU with the harvester, the MR damper and displacement sensors, and also describes experimental tests of the engineered unit applied in a vibration reduction system (VRS) with an energy recovery function.

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