Controls

Motor Drive with Failure Modes

This PLECS demo model examines a current-controlled permanent magnet machine under several drive fault mitigation strategies. The system includes an inverter with field-oriented control (FOC) that supplies the machine operating at a constant speed. Fault conditions such as loss of auxiliary power supply or microprocessor trip can result in loss of power to the inverter. Usually under such faults, the power stage is disabled. However, when operating in flux-weakening mode, a fault mitigation strategy may be required as the rectified back-emf may be larger than the DC-link voltage. In this simulation, failure mitigation strategies by closing all the lower inverter switches or opening the battery pack contactor are investigated.

Microgrid In Island Operation

This PLECS demo model illustrates a microgrid with three active generators (solar, wind, etc.) of different VA ratings (1 MVA, 500 kVA, 200 kVA). A supervisory controller at the Point of Common Coupling ensures that the frequency and voltage are kept at their rated values. Load sharing among the multiple generator units is provided by the local droop control.

Type 2 and Type 3 Compensator Analysis for Power Supplies

This PLECS demo model analyzes the performance of Type 2 and Type 3 analog compensators used in power supply units (PSUs). The analyzed PSU is a buck converter with modeled-in inductor and capacitor non-idealities. The role of the capacitor and its effective series resistance (ESR) on the plant zero and poles is discussed. Furthermore, the compensators' performance is analyzed with respect to the phase margin, system bandwidth, and rate of change in gain at the crossover frequency.

Single-Phase, Grid-Connected PV Inverter with Partial Shading (Equation-Based PV Cell, P&O and dP/dV MPPT)

This PLECS demo model illustrates a grid-connected solar panel system with a boosted front end and a single-phase inverter back end. The boost converter is designed to operate the panel at its maximum power point (MPP). A maximum power point tracking (MPPT) algorithm is implemented to improve the performance of the solar panel under partial shading conditions. Further, the inverter is operated with an outer voltage loop to control the DC-link voltage and a synchronous regulator to maintain unity power factor.

HVDC Transmission System with MMCs

This PLECS demo model shows a 320 kV, 200 MW high-voltage direct current (HVDC) transmission system with two modular multi-level converters (MMC) interconnecting two 110 kV high-voltage AC grids. MMCs are the prevalent type of voltage-source converter topology for HVDC applications. At high voltages the transmission of direct current can be more efficient than alternating current. The MMC is a bi-directional voltage source converter that interfaces high-voltage AC and DC power systems. It comprises a positive and negative arm for each of the three phases. Each arm further contains a set of switching submodules connected in series, the number of which can be chosen in this model to achieve the desired harmonic performance.

Pages