Power Hardware in the Loop
The PHIL system allows to reduce the time from conception to marketability for new technologies. While simulations can provide high testing flexibility, but not realistic results, and in-field testing can deliver high flexibility, but at high testing costs, little flexibility and long testing times, the PHIL offers the advantages of both approaches: the high testing accuracy of having the real hardware in the lab, and the flexibility to change the testing environment by means of simulations.
The real hardware to be brought to market is connected via power amplifiers to a network simulated in real time so that, for example, both real operating conditions and fault cases can be tested in this controlled environment.
For this purpose, the simulator provides at the output in each calculation step, typically 50 microseconds, the value for voltage or current at the point of the simulated network where the test object is to be connected. This signal is sent to the power amplifiers, which then output these values as actual electrical quantities to the test object. The real test object, for example a charging station for electric vehicles, "sees" a real power network at its input terminals, from which it can draw power (and feed it back if necessary). This power is measured and sent back to the real-time simulator, which calculates it accordingly in the next calculation step of the simulation, so that the simulated network reacts to the real test object.
Thus, both the influence of a real hardware component on any power network and the influence of any network (including various fault cases) on the hardware under test can be tested.
In the PHIL Lab in Energy Lab 2.0 we have developed a large power hardware in the loop unit in order to test realistically any hardware in the low voltage grids area. A power amplifier system consisting of five Egston bidirectional 200kVA amplifiers with 6 channels each is installed, which can be interconnected for a total power up to 1MVA.
Various amplifier circuits allow the following current or voltage ranges, for example:
- Three-phase AC voltage up to 850 V with a current up to 200 A
- Three-phase AC voltage up to 430 V with a current up to 1.25 kA
- Single-phase AC voltage up to 1 kV with a current up to 375 A
- Single-phase AC voltage up to 500 V with a current up to 1.3 kA
- DC voltage up to 1.5 kV with a current up to 530 A
- DC voltage up to 200 V with a current up to 4.5 kA (6 kA for short periods)