Inverter

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The aim of the [https://en.wikipedia.org/wiki/Power_inverter inverter] project is to generate a 50 Hz AC power supply from a DC input.
 
The aim of the [https://en.wikipedia.org/wiki/Power_inverter inverter] project is to generate a 50 Hz AC power supply from a DC input.
  
[[File:Inverter boards.JPG |400px|center]]
+
[[File:Inverter 110 V generator setup.JPG|500px|center]]
  
 
== Specification ==
 
== Specification ==
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An I/O board with 4 switches and 8 LEDs allows to control the operating mode and to display information about the system's state.
 
An I/O board with 4 switches and 8 LEDs allows to control the operating mode and to display information about the system's state.
  
=== Circuit ===
+
[[File:Inverter boards.JPG|400px|center]]
  
The circuit works as follows:
+
=== PWM modes ===
* the difference between the mains period and the generator period is calculated
+
 
* if the generator is too slow, the DC motor voltage is raised; if the generator is too fast, the DC motor voltage is diminished
+
Different PWM modes are to be investigated:
 +
* a two-level mode with inverted controls on each H-bridge branch
 +
* three-level modes with separate controls on each branch
 +
 
 +
=== Output ===
 +
 
 +
The system has to generate a 110 VAC power supply.
 +
 
 +
This is achieved with the help of a transformer.
 +
This transformer:
 +
* provides ah high enough voltage amplitude to allow the generation of a 110 VAC output from a 12 power supply
 +
* transforms a differential signal into a floating one, allowing a simple measurement.
 +
 
 +
As the output voltage is high, '''great care has to be taken''' with the transformer output side.
  
 
== Components ==
 
== Components ==
  
 
The system consists of
 
The system consists of
* an assembly of a DC motor and an AC generator
+
* an [[Inverter#H-bridge power board|H-bridge power board]] together with a [[Inverter#Power LC lowpass board|power LC lowpass board]]
* an [[Synchro#FPGA_board|FPGA prototyping board]]
+
* a [[Inverter#Transformer board|transformer board]]
* an [[Synchro#Synchro_I.2FO_board|I/O board]] with 2 sinewave inputs and a PWM output
+
* an [[Inverter#FPGA_board|FPGA prototyping board]]
 +
* an [[Inverter#Buttons and LEDs I/O board|buttons and LEDs I/O board]] for the control
 +
* a [[Inverter#Logic-level LC lowpass board|logic-level LC lowpass board]]
  
=== Motor-generator assembly ===
+
=== H-bridge power board ===
The DC motor is controlled via a 12 V PWM signal.
+
The H-bridge board is powered with 12 V.
It is mechanically coupled to the DC generator.
+
The 4 MOS transistors are driven by 2 [http://www.irf.com/product-info/datasheets/data/ir2110.pdf IR2110] driver circuits.
With a mean voltage of 6 V, the assembly turns at a frequency close to 50 Hz.
+
The dead time between the switching of the upper and lower part of an H-bridge branch is of about 500 ns.
 +
The PWM controls are brought to the board via a ribbon cable.
 +
 
 +
This board is also used for an [http://wiki.hevs.ch/fsi/index.php5/EMVs/AudioAmp audio amplifier] student project.
 +
 
 +
The 12 V power supply from this board is brought to the ribbon cable connector and is used to power the [[Inverter#FPGA_board|FPGA board]] as well.
 +
 
 +
=== Power LC lowpass board ===
 +
The LC lowpass board is used in conjunction with the H-bridge power board.
 +
It smooths the PWM signal into a sine wave.
 +
 
 +
The default LC cutoff frequency is something like 20 kHz, as this board is also used for an audio amplifier.
 +
 
 +
=== Transformer board ===
 +
The transformer board allows to reference the differential output to any common voltage.
 +
 
 +
The board at our disposal transforms 7.5 V to 115 V.
 +
As it provides a high voltage, it should be handled with great care.
  
 
=== FPGA board ===
 
=== FPGA board ===
The main board is the school's [http://wiki.hevs.ch/uit/index.php5/Hardware/FPGAEBS FPGA-EBS lab development board]. It hosts a [http://www.xilinx.com/products/silicon-devices/fpga/spartan-3.html Xilinx Spartan xc3s500e FPGA] and features many different interfaces.
+
The main board is the school's [http://wiki.hevs.ch/uit/index.php5/Hardware/FPGAEBS FPGA-EBS lab development board].
 +
It hosts a [http://www.xilinx.com/products/silicon-devices/fpga/spartan-3.html Xilinx Spartan xc3s500e FPGA] and features many different interfaces.
 +
The clock oscillates at 66 MHz.
  
=== Synchro I/O board ===
+
=== Buttons and LEDs I/O board ===
  
The [http://wiki.hevs.ch/uit/index.php5/Hardware/Parallelport/heb_synchro HEB-synchro] I/O board receives 2 sinewaves: one from a 50 Hz function generator and one from the AC generator.
+
The [http://wiki.hevs.ch/uit/index.php5/Hardware/Parallelport/heb_lcd buttons and LEDs board] is used in conjunction with the FPGA board.
These signals are triggered at 0 V in order to deliver logic-levels signals to the FPGA.
+
  
The FPGA delivers a PWM output which controls a power switch.
+
It has 4 buttons and 8 LEDs.
The switch then drives the DC motor.
+
It can hold an optional LCD display.
 +
 
 +
=== Logic-level LC lowpass board ===
 +
The logic-level LC lowpass board is used to verify the content of the PWM signals in the two H-bridge branches.
 +
It smooths the two FPGA output PWM signals into the components of a differential sine wave.
 +
 
 +
On this board too, the default LC cutoff frequency is something like 20 kHz.
  
 
== Getting started ==
 
== Getting started ==
Line 54: Line 93:
 
* Draw the architecture of the circuit in the form of a block diagram
 
* Draw the architecture of the circuit in the form of a block diagram
 
* Consult the guides for the first steps into the design software
 
* Consult the guides for the first steps into the design software
** [[Synchro/students_fr|Guide en français]]
+
** [[Inverter/laboratoires|Travaux de laboratoire]]
** [[Synchro/students_de|Anleitung auf Deutsch]]
+
** [[Inverter/labore|Laborprojekt]]
  
 
== Additional Information ==
 
== Additional Information ==
Additional informations for [[Synchro/teachers|teachers]].
+
 
 +
* [[Inverter/board combination|Board combinations]]
 +
* Additional informations for [[Inverter/teachers|teachers]].
  
 
[[Category:Bachelor]] [[Category:ElN]] [[Category:Inverter]]
 
[[Category:Bachelor]] [[Category:ElN]] [[Category:Inverter]]

Revision as of 13:47, 4 December 2017

Contents

The Filière Energie et Techniques environnementales (FET) has the digital systems course and labs in the 3rd (autumn) semester. The semester counts 15 weeks and ends with a little project. The aim of the inverter project is to generate a 50 Hz AC power supply from a DC input.

Inverter 110 V generator setup.JPG

Specification

Function

The 12 V power supply is chopped by the power switches of an H-bridge in order to generate a sine wave. The resulting voltage is filtered by a passive LC filter to provide a smooth sine wave. The digital system generates the PWM controls of the 4 power switches.

Inverter system.svg

An I/O board with 4 switches and 8 LEDs allows to control the operating mode and to display information about the system's state.

Inverter boards.JPG

PWM modes

Different PWM modes are to be investigated:

  • a two-level mode with inverted controls on each H-bridge branch
  • three-level modes with separate controls on each branch

Output

The system has to generate a 110 VAC power supply.

This is achieved with the help of a transformer. This transformer:

  • provides ah high enough voltage amplitude to allow the generation of a 110 VAC output from a 12 power supply
  • transforms a differential signal into a floating one, allowing a simple measurement.

As the output voltage is high, great care has to be taken with the transformer output side.

Components

The system consists of

H-bridge power board

The H-bridge board is powered with 12 V. The 4 MOS transistors are driven by 2 IR2110 driver circuits. The dead time between the switching of the upper and lower part of an H-bridge branch is of about 500 ns. The PWM controls are brought to the board via a ribbon cable.

This board is also used for an audio amplifier student project.

The 12 V power supply from this board is brought to the ribbon cable connector and is used to power the FPGA board as well.

Power LC lowpass board

The LC lowpass board is used in conjunction with the H-bridge power board. It smooths the PWM signal into a sine wave.

The default LC cutoff frequency is something like 20 kHz, as this board is also used for an audio amplifier.

Transformer board

The transformer board allows to reference the differential output to any common voltage.

The board at our disposal transforms 7.5 V to 115 V. As it provides a high voltage, it should be handled with great care.

FPGA board

The main board is the school's FPGA-EBS lab development board. It hosts a Xilinx Spartan xc3s500e FPGA and features many different interfaces. The clock oscillates at 66 MHz.

Buttons and LEDs I/O board

The buttons and LEDs board is used in conjunction with the FPGA board.

It has 4 buttons and 8 LEDs. It can hold an optional LCD display.

Logic-level LC lowpass board

The logic-level LC lowpass board is used to verify the content of the PWM signals in the two H-bridge branches. It smooths the two FPGA output PWM signals into the components of a differential sine wave.

On this board too, the default LC cutoff frequency is something like 20 kHz.

Getting started

In order to start the projects you should do the following:

  • Read carefully the specifications above
  • Draw the architecture of the circuit in the form of a block diagram
  • Consult the guides for the first steps into the design software

Additional Information

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