An electrical machine with integrated drive LCL filter components

In recent years, integrated passive components technology has gained significant popularity in integrated drives research. An integrated drive may be considered to be a full mechanical integration of the machine, power electronic converter and passive components into a single package. This approach is important for applications such as traction motors, aerospace, electric vehicles and cars where space, mass or volume constraints are high. Incorporation of electromagnetic components, such as line filters, into electric machines can be achieved by sharing the existing machine's magnetic circuit with the filter component. In this paper part of an LCL line filter has been chosen to be integrated with a permanent magnet synchronous machine. An LCL filter has been selected as it has lower inductance compared to other input filter types such as LC and L filters. This paper also presents a several novel techniques for integrating the largest portion of LCL input power filter which is the 3-phase ac inductors located in the drive side producing a single mechanically packaged unit without significant increase in size and loss which in turn achieves high power density. Different integrated 3-phase input inductors designs have been simulated with finite element analysis to prove the effectiveness of integration of passives within the machine structure. In each case the design has been iteratively optimised to determine the optimal mass of copper and core for the integrated filter inductors targeting parity in power density when compared to a traditionally separated package. The paper demonstrates that an approach utilising a double slot machine with input filters wound into the outermost slots was the most appropriate choice in terms of power density compared to other proposed methods.