3-Phase Current Source Inverter

Purpose

3-phase 2-level current source inverter with a Sub-cycle average implementation

Library

Electrical / Power Modules

Description

../../_images/powermodule_csi.svg

This Power Module implements a 3-phase 2-level current source inverter. It offers two configurations:

Sub-cycle average

Each gate input is controlled by a floating-point number with values between \(0\) and \(1\), representing the relative on-time of the corresponding semiconductor over one simulation step, as described in Sub-cycle Averaging. The DC side of the inverter has voltage source behavior and must be connected to positively biased inductors or current sources. The AC side is typically connected to filter capacitors. Only delta-connected filter capacitors are allowed since no neutral point is considered in the model.

In Sub-cycle average configuration, C code generated from this component is suitable for real-time simulations on the RT Box, where it is executed on the CPU or FlexArray solver. In this case, connect the gate inputs to PWM Capture blocks from the RT Box component library.

Switched

The power semiconductors are modelled as ideal switches controlled by instantaneous logical gate signals. A switch is turned on when the corresponding gate signal is non-zero. For compatibility with the Sub-cycle average configuration it is recommended to use the value \(1\) for non-zero gate signals.

The Switched configuration is not recommended for real-time simulations on the RT Box. It is intended for offline simulations that resolve each individual switching event and can serve as a reference for results obtained with the Sub-cycle average configuration.

The current source inverter model correctly accounts for live times, i.e. intervals during commutation in which at least one upper switch and one lower switch are turned on to maintain a current path for the externally connected DC-side current source.

It also supports rectifier operation, where power flows from the AC side to the DC side. In rectifier mode, the DC side can be modeled with or without a free-wheeling diode, as specified by the Free-wheeling diode on DC side parameter.

Note

The sub-cycle average implementation cannot model an open circuit of the DC side. Therefore, in inverter mode, the sum of the control signals for the upper three switches and the lower three switches must be larger than \(1\) at any point in time. The block will flag an error if this condition is not met. For rectifier mode, please see the description of the Free-wheeling diode on DC side parameter below. Also, the applied DC currents must never become negative.

Parameters

Configuration: Selects the component configuration. See the descriptions of Sub-cycle average and Switched above.
Free-wheeling diode on DC side: This parameter is only applicable for rectifier mode. The option no means no extra free-wheeling diode on the DC side is modeled and that the sum of the control signals for the upper three switches and the lower three switches must be larger than \(1\) at any point in time. Otherwise the block will flag an error. The option yes means an extra DC-side free-wheeling diode is included. In this case, no error is flagged when the sum of the control signals for the upper three switches and the lower three switches is smaller than \(1\), because the DC current can flow through this extra free-wheeling diode.

↳ Added in PLECS 4.4.