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The Real 4-Quadrant Power Amplifier

Spitzenberger and Spies 4-quadrant amplifiers are developed based on a linear push-pull design. Some of the remarkable features of this amplifier design include it’s ironless output stage, extensive use of negative feedback over all-stages of amplifier, an extended frequency range and a very low internal resistance. The fast response rate is essential for Power Hardware In the Loop (PHIL) experiments using real-time digital simulator (RTDS).
Benefits of SPS Linear Amplifiers
  • Very low internal resistance
  • Extremely low harmonic distortion

  • Power capability from 1 kVA up to 2 MVA

  • Very fast slew rate >52V/µs at 230Vrms as required by IEC/EN 61000-4-11

  • Operates from DC up to 10kHz large signal bandwidth (-3dB) with optional up to 30kHz

  • Small Signal Bandwidth up to 100kHz

  • High long-term (1 hour) overload characteristic

  • Higher short-term (5-10 min) overload characteristic

  • Very high peak overload (up to 5ms) characteristic

  • Operating as source as well as sink

  • Current control mode

  • Fast and direct optical communication with RTDS

Please contact us for further information on SPS products and price quote.
​We are the authorized distributors of SPS products in North America and India.
We also have extensive experience with PHIL testing using RTDS and can help you with the specification.

Power Hardware in the Loop

Power Hardware In Loop (PHIL) simulation involves interfacing the RTDS simulation with power devices such as motors, inverters, generators and transformers via controlled power amplifiers to facilitate exchange of real and reactive power with the amplifier-interface while closing the electric power loop of the RTDS network simulation by feeding back voltage/current measurement signals from the interface back into the RTDS simulation. The following diagram shows a typical PHIL setup.
Closed loop PHIL simulations require more complex circuitry and precision hardware compared to open loop testing of power hardware. The interface between the simulator and the device under test is non-ideal due to time delays, noise and the limited bandwidth of the interface devices including amplifiers and feedback measurement transducers, all of which can significantly impact the stability and accuracy of closed loop simulations and must be carefully considered for any PHIL simulation.

Very often open loop simulation connected to power equipment via amplifiers is misrepresented as PHIL, but strictly speaking it is only a real-time playback setup and can simply be achieved with signal generators or stored waveforms and does not demand a hard-real-time simulation.  So, when you hear about PHIL next time, make sure to ask if it is open loop or closed loop PHIL.

The following document and the video discusses the key factors to be considered for PHIL simulation. Fast and accurate power amplifier is a key component for a stable PHIL experiment.

Very valuable ... A must read if you are new to PHIL ...
This 28 page  report discusses all aspects of setting up a PHIL test set up in detail ...

PHIL Video

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