Two-Level Converter

Implement three-phase two-level power converter

Libraries:
Simscape / Electrical / Specialized Power Systems / Power Electronics

Description

The Two-Level Converter block implements a three-phase, two-level power converter. You can choose from four model types:

Switching devices — The converter is modeled with IGBT/diode pairs controlled by firing pulses produced by a PWM generator. This model provides the most accurate simulation results.
Switching function — The converter is modeled by a switching-function model. The switches are replaced with two voltage sources and two diodes on the AC side and with two current sources on the DC side.
The converter is controlled by firing pulses produced by a PWM generator (0/1 signals) or by firing pulses averaged over a specified period (PWM averaging: signals between 0 and 1). Both modes of operation produce harmonics normally generated by a PWM-controlled converter and also correctly simulate rectifying operation as well as blanking time. This model type is well-suited for real-time simulation.
Average model (Uref-controlled) — The converter is modeled using a switching-function model directly controlled by the reference voltage signals (Uref). A PWM generator is not required.
Average model (Uref-controlled, no rectifier mode) — The block uses the voltage source directly controlled by the reference voltage to model the converter. The model does not require a PWM generator and does not simulate the rectifier mode.
When doing real-time simulation, use the Switching function setting with the firing pulses averaged, or the Average model (Uref-controlled) or Average model (Uref-controlled, no rectifier mode) settings.

Examples

Power Converters Modeling Techniques

The operation of several types of power electronics converters that can be simulated using one of four selectable modeling techniques

Open Model

Ports

Input

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g — Gating signal to control converter
vector of six elements

Vectorized gating signal to control the converter. The gating signal contains six firing pulses. The first two pulses control the Q1 and Q2 switching devices (phase A of the converter), pulses three and four control the Q3 and Q4 switching devices (phase B of the converter), and the last two pulses control the Q5 and Q6 switching devices (phase C of the converter).

Dependencies

To enable this port, set Model type to Switching devices or Switching function.

Uref — Signal to control converter
vector of three elements

Vectorized signal to control the converter. The signal contains three reference voltages (one for each phase).

Dependencies

To enable this port, set Model type to Average model (Uref-controlled) or Average model (No rectifier mode).

BL — Input to block firing pulses
scalar

Input port to block all firing pulses to the converter. To block all firing pulses to the converter, apply a signal value of 1 to this port.

Conserving

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+ — Positive terminal
specialized electrical

Specialized electrical conserving port associated with the positive terminal.

- — Negative terminal
specialized electrical

Specialized electrical conserving port associated with the negative terminal.

Parameters

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To edit block parameters interactively, use the Property Inspector. From the Simulink^® Toolstrip, on the Simulation tab, in the Prepare gallery, select Property Inspector.

Model type — Model type
`Switching devices` (default) | `Switching function` | `Average model (Uref-controlled)` | `Average model (Uref-controlled, no rectifier mode)`

Select one of these values:

Switching devices — The converter is modeled with IGBT/diode pairs controlled by firing pulses produced by a PWM generator.
Switching function — The converter is modeled by a switching-function model. The switches are replaced with two voltage sources and two diodes on the AC side and with two current sources on the DC side.
Average model (Uref-controlled) — The converter is modeled using a switching-function model directly controlled by the reference voltage signals (Uref).
Average model (Uref-controlled, no rectifier mode) — The block uses the voltage source directly controlled by the reference voltage to model the converter. The model does not require a PWM generator and does not simulate the rectifier mode.

Device on-state resistance (Ohms) — Internal resistance of switching devices
`1e-3` (default) | positive scalar

Internal resistance of the switching devices, in ohms.

Dependencies

To enable this parameter, set Model type to Switching devices.

Snubber resistance (Ohms) — Snubber resistance
`1e6` (default) | positive scalar

Snubber resistance, in ohms. Set the snubber resistance to inf to eliminate the snubbers.

Dependencies

To enable this parameter, set Model type to Switching devices.

Snubber capacitance (F) — Snubber capacitance
`inf` (default) | nonnegative scalar

Snubber capacitance, in farads. Set the snubber capacitance to 0 to eliminate the snubbers.

Dependencies

To enable this parameter, set Model type to Switching devices.