Three-Level NPC Converter

Implement three-phase, three-level Neutral-Point Clamped (NPC) power converter

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

Description

The Three-Level NPC Converter block implements a three-phase, three-level neutral-point clamped 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. It does not model neutral point voltage balancing.

• Average model (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. This setting provides the fastest simulations.

  When doing real-time simulation, use the Switching function setting with the firing pulses averaged, or the Average model (Uref-controlled) or Average model (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

g — Gating signal to control converter

vector of 12 elements

Vectorized gating signal to control the converter. The gating signal contains 12 firing pulses. The first four pulses control the Q1a to Q4a switching devices (phase A of the converter), pulses five to eight control the Q1b to Q4b switching devices (phase B of the converter), and the last four pulses control the Q1c to Q4c 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 in the range [-1,1]

Vectorized signal to control the converter. The signal contains three reference modulating signals (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

A — Phase A terminal

specialized electrical

Specialized electrical conserving port associated with the phase A terminal.

B — Phase B terminal

specialized electrical

Specialized electrical conserving port associated with the phase B terminal.

C — Phase C terminal

specialized electrical

Specialized electrical conserving port associated with the phase C terminal.

N — Neutral terminal

specialized electrical

Specialized electrical conserving port associated with the neutral terminal.

+ — 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

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 (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). A PWM generator is not required. It does not model neutral point voltage balancing.

• Average model (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.

Diode on-state resistance (Ohms) — Internal resistance of diodes

1e-3 (default) | positive scalar

Internal resistance of the diodes, in ohms.

Dependencies

To enable this parameter, set Model type to Switching function or Average model (Uref-controlled).

Diode snubber resistance (Ohms) — Snubber resistance of diodes

1e6 (default) | positive scalar

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

Dependencies

To enable this parameter, set Model type to Switching function or Average model (Uref-controlled).

Diode snubber capacitance (F) — Snubber capacitance of diodes

inf (default) | nonnegative scalar

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

Dependencies

To enable this parameter, set Model type to Switching function or Average model (Uref-controlled).

Diode forward voltage (V) — Forward voltage across diode

1e-3 (default) | nonnegative scalar

Forward voltage, in volts, across the diode when it is conducting.

Dependencies

To enable this parameter, set Model type to Switching function or Average model (Uref-controlled).

DC side snubber resistance (Ohms) — Snubber resistance across current sources

inf (default) | positive scalar

Snubber resistance across the two current sources, in ohms. Set the snubber resistance to inf to eliminate the snubbers.

Dependencies

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

AC side source resistance (Ohms) — Source resistance on AC side

1e-3 (default) | positive scalar

Source resistance on the AC side, in ohms. Set the snubber resistance to inf to eliminate the snubbers.

Dependencies

To enable this parameter, set Model type to Average model (No rectifier mode).

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2015b