Single‐immittance‐network‐based inductive‐power‐transfer systems for driving multistring lighting‐emmiting diodes with current balance

Abstract

Multistring arrays of LED in parallel connection are widely applied in lighting fields. Active control and passive methods are utilized to guarantee equal current sharing between different strings with a common voltage source. Compared with active control, the passive methods that adopt purely passive components without real power dissipation are good candidates. Currently, an inductive power transfer (IPT) converter providing a constant voltage (CV) line, followed by some immittance networks that convert the CV line to constant current (CC) outputs, is commonly used to drive multiple LED strings. However, in such a two-conversion-stage scheme, the component count is as many as 3 × N $$ 3\times N $$ , where N $$ N $$ is the number of LED strings, which deviates from compact, low-cost, and simple design ideas. To address it, this paper aims to develop a single-immittance-network-based IPT system to drive multistring LEDs with the current balance. The proposed IPT system can directly provide a CV to CC conversion to drive multistring LEDs with the benefits of simplifying the circuit design, size, and cost. The proposed IPT system also features programmable luminous power, zero-phase-angle (ZPA) input, IPT technology, and load-independent-current (LIC) output. Detailed analysis, implementation, and experiment are presented in this paper.