PWM Generation

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.

This PLECS demo model shows a grid-connected battery charger with cascaded AC/DC and DC/DC converters. The AC/DC converter is regulated by a digital PI controller to achieve power factor correction (PFC) and maintain the DC bus voltage at 300 VDC. The DC/DC converter is designed to provide a maximum 120 VDC output at a power rating of 1.4 kW.

This PLECS demo model shows a medium-voltage static synchronous compensator (STATCOM) system. Converters with cascaded connections are common in high-power applications such as medium-voltage drives, high-voltage direct current (HVDC) and flexible alternating current transmission systems (FACTS). These types of converters have the advantages of low switching losses and high redundancy, but require sophisticated control, e.g., cell-capacitor voltage balancing. The STATCOM’s purpose is to compensate for the reactive power required by various loads on a power system.

This PLECS demo model shows an isolated DC/DC resonant converter operated under frequency control. The output voltage of the converter is controlled by changing the switching frequency of the semiconductors. Zero-Voltage Switching (ZVS) is used to reduce switching losses, allowing the operation of the converter at higher switching frequencies.

This PLECS demo model shows a Vienna Rectifier with an output voltage of 700 V and an output power of 12.25 kW. The simulation combines the electrical power circuit and the cascaded controls.

The TL431 is a reference voltage source that is commonly used in the control circuit of isolated power supplies. In this example, the design of a TL431-based type 2 voltage controller for a flyback converter is presented.

Space vector control is a popular technique used in the control of motor drives or three-phase rectifiers since it offers reduced switching losses and better utilization of the DC bus compared to conventional PWM control. This PLECS demo model demonstrates space vector control of a three-phase boost-type rectifier.