A Multi-Matrix Based Network for Multi-Module Parallel Megahertz Inverter System

As key subsystem of the semiconductor etching system, the multimodule megahertz inverter needs to modulate power through load differences efficiently and accurately, however, losses of resonant inverter modules are reduced only within narrow load range. The existing inverters often fail to mathematically resolve the conflict between power range and efficiency range. This article proposes a method that balances efficiencies and power range for multimodule parallel systems. The essence lies in mathematically designing load trajectories for each module that covers wide power range within efficiency boundaries through a three-matrix passive network. A two-inverters paralleled system is designed with load-sensitive class D inverter modules as an example. Through passive network, the ideal load trajectory is guaranteed. Two 40 V input, 13.56 MHz prototypes are built and experimental results demonstrate that the proposed method offers various way of designing network, and both networks are able to control the effective impedance trajectory of modules within the desired range. Therefore, the inverter operates with efficiencies above 60% with power varying from 10 W to 100 W.