Dynamic power management for multi-core system on chip (MPSoC) platforms has become an increasingly critical design problem. In this paper, we present EmPower, an FPGA based rapid prototyping framework for dynamic power management algorithms targeted at MPSoC platforms. EmPower supports two advanced power management techniques (per-core dynamic frequency scaling and clock gating, and thread migration), enables software based expression of the power management algorithm, and provides on-chip power measurement capabilities. EmPower also includes two fully-functional parallel applications for benchmarking - video encoding and software-defined radio. We demonstrate the use of EmPower in rapid exploration of the large design space of power management algorithms using two illustrative case studies.