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DC-to-AC Converters LAB 1 - 4. Panel

Owned by Sylvain Ménard
Last updated: Mar 06, 2023
6 min read

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4.1 Understanding the Panel

When starting the demo, the panel in figure 7 appears first with the default settings.



Figure 7: Start-Up Panel of the Single-Phase Inverter Laboratory – Inverter Mode Scenario

The panel is to be operated while following the three steps below:

Step 1: Select Scenario

In the upper left corner, the student can select the scenario using the two tabs:

  • Inverter Mode
  • LC Filter

Step 2: Change Parameters / Switch Buttons

In the lower left corner, the student can change the control parameters and can switch the control buttons (to enable/disable their associated functions) in the following categories:

  • Scope Parameters
  • Protection
  • DC Source
  • Inverter Parameters
  • AC Source

Table 3 below summarizes the control parameters, while table 4 is dedicated for the control buttons.  

Step 3: Observe Waveforms

On the right side, the student can observe the waveforms displayed in four scopes.
Additionally, the power flow, the fundamental voltage and total harmonic distortion (THD) for inverter and load are displayed.
More details are given in tables 5 and 6.

Control Parameters

Default Value

Interval of Variation

DC Source Vdc (V)

120

[90; 160]

PWM Frequency (Hz)

3000

[900; 3000]

Reference Amplitude/modulation

0.8

[0; 0.8]

AC-source Amplitude (V)

70

[0; 100]

AC-source Frequency (Hz)

60

[0; 60]

AC-source Phase-Shift (Deg)

0

[-90; 90]

Table 3: Control Parameters of the Single-Phase Two-Level Inverter

Note

The “Save File” under Scope Parameters allows the student to give different file names for data acquisition, while the “Switch (50 Hz/60 Hz)” allows selecting a reference frequency for power, THD and RMS computation.
It is possible to save up to eleven .mat files with the name “FileSavedcurrents_X (where X can be anywhere from 0 to 10).
The student can give X values via the “Save File”, and press “Data Acq.” for acquiring data.
The data acquired can be used for offline harmonic studies.
The saved data are in the following folder:

C:\OPAL-RT\TestDrive\v2.9.0.16\Models\Package3_1_CPU\twolevel_singlephase_sm_master\OpNTtarget

Control Buttons

Associated functions

Trigger

The waveforms are not triggered. They “move”

The waveforms are triggered with respect to a reference signal.

This button is accessible and enabled in all scenarios

SYNCHRONIZE

The reference frequency is fixed to 60 Hz (or 50 Hz).

The reference frequency used for the PWM generator is dictated by the AC-source frequency.

Apply Deadtime

The dead-time is not applied in the control of the switches.

The dead-time is applied in the control of the switches.

Connect Filter

The capacitors mounted in delta configuration are disconnected from the circuit.

The capacitors mounted in delta configuration are connected to the circuit, thus enabling the LC filter.

This button is accessible in LC Filter Mode scenario only

Data Acq.

Data acquisition is disabled.

Data acquisition is activated and allows to record .mat files for offline studies, in particular harmonic analysis.

Reset

The reset push button is disabled.

The reset push button is activated and simulates replacement of fuses after a fault.

This button is accessible and enabled in all scenarios

HELP / BACK

Open the Help page associated to the scenario currently running.

Close the Help page and go back to the simulations.

This button is accessible and enabled in all scenarios

Fuse


The protection fuse is blown.


The protection fuse is intact.

Switch

Reference frequency for PWM generation, 50 Hz or 60 Hz.

Table 4: Control Buttons and LED Fuse Status Indicators of the Single-Phase Inverter

On scope localization, the indices used will be like those of matrix elements.
Hence, the scope located at the upper left corner (first row, first column) is denoted Scope11, while the scope in the upper right corner (first row, second column) is Scope12.
By the same token, the scope in the lower left corner is Scope21 while the scope in the lower right corner is Scope22.

Scenario

Scope

Content of Scopes & Displayed Waveforms

Inverter Mode

Scope11

Output Voltage of the inverter: 

Scope21

Line current at the output of the inverter: 

Scope12

AC-source voltage

Scope22

, , and AC-source voltage

LC Filter

Scope11

Load voltage  vL

Scope21

Load current iL

Scope12

Source Current at the input of the inverter: 

Scope22

vL, iL, AC-source voltage, and filter current

Table 5: Content of Scopes and Displayed Waveforms of the Single-Phase Inverter


Three power displays are available in all the scenarios.
They are located below the scopes in the observation section.
From left to right they are identified as Display1, Display2 and Display3.
They refer to the power measurements described in section 3.5.
Additionally, two RMS voltage displays and two THD (related to inverter and load currents) displays, referred to as Display4 to Display7, are located below the scopes of Inverter mode and LC Filter scenarios.
Finally, an extra display, referred to as Display8, is available for RMS filter current in the LC Filter scenario.

Scenario

Display

Content of Displays

LC Filter

Display1

DC Power released by the DC source at the input of the inverter

Display2

AC Power at the output of the inverter

Display3

AC Power absorbed by the AC load

Display4

RMS of fundamental inverter voltage

Display5

RMS of fundamental load voltage

Display6

THD of inverter current

Display7

THD of load current

Display8

RMS of fundamental filter current

Table 6: Content of Displays of the Single-Phase Inverter

Consequently, the power dissipated in the LC Filter and the converter bridge can be deduced as shown in table 7:

Scenario

Difference

Description

LC Filter

Display1 - Display2

Power dissipated in the inverter bridge (IGBT/Diodes)

Display2 - Display3

Power dissipated in the LC Filter

Table 7: Power Dissipated in LC Filter and the Single-Phase Converter Bridge

4.2 First scenario - Inverter Mode with Load: R, L, AC-Source

When starting the demo, the panel corresponding to the Inverter Mode scenario opens by default, as shown in figure 7 above.
A concise scheme of the circuit is given below the tabs in the scenario selection area.
More details on the circuit, the control parameters, and buttons, as well as the observed waveforms are available when clicking the Help button.
The student can directly start exercises related to the Inverter Mode, available in section 5.1.

4.3 Second scenario – Adding LC Filter at the Inverter Output

When clicking on the “LC Filter” tab, the panel in figure 8 below is displayed.


Figure 8: Second Panel in the Single-Phase Inverter Laboratory – LC Filter Scenario

By clicking the Connect Filter button, the student activates the LC filtering and can start the exercises of section 5.2 that are associated with this scenario.

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