Modeling and simulation of power systems at low levels of abstraction is supported by specialized tools such as SPICE and MATLAB. But when power systems are part of larger systems including digital hardware and software, low-level models become over-detailed; at the system level, models must be simple and execute fast. We present an extension to SystemC that relies on efficient modeling, simulation, and synchronization strategies for Ideally Switched Circuits. Our solution enables designers to specify circuits and to jointly simulate them with other SystemC hardware and software models. We test our extension with three power converter case studies and show a simulation speed-up between 1.2 and 2.7 times while preserving accuracy when compared to the reference tool. This work demonstrates the suitability of SystemC for the simulation of heterogeneous models to meet system-level goals such as validation, verification, and integration.