An inductive power transfer subsystem for an integrated motor drive is presented in this paper. First, the concept of an integrated motor drive system is overviewed, and its main components are described. Next, the paper is focused on its inductive power transfer subsystem, which includes a magnetically coupled resonant circuit and two-stage energy conversion with an appropriate control method. Simplified complex domain analysis of the magnetically coupled resonant circuit is provided and the applied procedure for its component selection is explained. Furthermore, the prototype of the integrated motor drive system with its control is described. Finally, the prototype based on the gallium nitride field effect transistors (GaN FET) inductive power transfer subsystem is experimentally tested, confirming the feasibility of the concept.

In order to achieve required mechanical properties of hardened elements, such as gear wheels, dual‐frequency induction heating may be used. Dual‐frequency allows heating only the outline of the gear, due to mixed penetration depth of the subject frequencies. This method of hardening requires the process to be very short as heat may spread by means of conduction. This study presents a 3 kW prototype inverter and its control scheme is used to generate dual‐frequency output current. The overall efficiency of the inverter is 96%. An analysis of the output resonant circuit is made to find the resonant frequencies. Finally, circuit and finite element method (FEM) simulations are coupled to analyse the effect of dual‐frequency current on the magnetic field, current density, and energy density on the surface of a gear wheel.

This paper presents new resonant inverter topologies for dual-frequency induction heating (IH). These 2T1C and 3T topologies combine the advantageous features of two- and one-inverter solutions. An analytical description of the load impedance of a dual-frequency series-parallel circuit has been made. Using manufacturer datasheets and LTspice models of selected transistors, a MATLAB model was parameterized. Based on it, power losses are determined as a function of the following parameters: nominal power, frequency and DC bus voltage. The obtained results allowed for determining the data necessary in the design process. The research has been experimentally verified. Tests were carried out for pulsing and simultaneous operation. Power control characteristics as a function of frequency are determined. The possibility of operating the inverter with high efficiency (>97%) in the proposed 2T1C and 3T systems at nominal power is demonstrated.

The paper presents topology of single simultaneous dual frequency serial inverter for inductive heating. The principles of power regulation control methods for each frequencies are presented. Commutation analysis of dual frequency operation is presented and illustrated by simulation tests. Occurrences of hard switching D -> sT are shown. Topology of single simultaneous dual frequency serial inverter for inductive heating

This paper presents preliminary tests on a capacitively coupled wireless energy-transfer system (C-WET). Significant emphasis has been placed on discerning the fundamental characteristics of the system. This allowed the simulation model to be refined and the parameters of the physical prototype to be fine-tuned. Then, start-up tests of the prototype of the power supply system were presented, up to about 25% of the rated power. Selected simulation and laboratory test results are presented and directions for further work are set. The system is envisaged for underground mining applications, and the work is being carried out as part of the HEET II (High-Efficiency Energy Transfer) project, funded by the Research Fund for Coal and Steel (RFCS).

Interleaved zero-voltage switching boost converters have been known for over 20 years. However, the influence of parasitic capacitance of transistors has not been described. In this paper the converter is analyzed and the equation for voltage ratio is derived for any number of converter phases. First a general description of the topology, including main voltage and current waveforms, is provided. Subsequently the converter is analyzed and conditions for soft switching are derived. Next the analysis results are compared to measurements of an experimental converter setup. Discrepancies are identified and the influence of parasitic capacitance is analyzed. By considering the parasitic capacitance the difference between experimental and analytical results of voltage ratio is reduced from 0.2 to less than 0.05.