I. G. B. T. BASED 3-PHASE 415VAC, 25KVA INVERTER FOR RAILWAYS AC COACHES

RDSO SPECIFICATION NO. SPEC/E-20/04(Rev .3)

 

The IGBT (Insulated Gate Bipolar Transistor) represents  the union of a power MOSFET and a power bipolar (BJT) transistor, incorporating the best features of each.

But while the MOSFET can be used in applications exceeding 1 MHz, the fastest IGBTs are limited to only a fraction of that.

Therefore, the only real drawback of the IGBT is its switching speed. Yet the conduction characteristics of the IGBT really outshine those of the power MOSFET, especially at voltages greater than about 200V.

MODEL: PHOTON

This is the design and development of IGBT based Booster_inverter Technology.

It works on the principle of “Chopper and Inverter” technique.

It evolves the chopping of the input voltage by using IGBT’s at high frequency to generate a high DC link voltage. This DC link voltage  is applied to the  Inverter input. The inverter Converts this DC Link voltage into 3-phase AC Supply.

The system      

Input:    90V to 140 V DC with 15% ripples

Output:415V +/- 5%, 3 Phase Ac 50 Hz +3% 

The system is dependant on the following Design parameters.

Frequency of chopping

Heat Sink Calculations of diode for Chopper

Duty Cycle of Chopping

Power Loss calculations of Diode for Chopper

Selection of Chopping Device(IGBT) for Chopper

Selection of output capacitor

Power Loss calculations of Chopper IGBT

Selection of Switching Device ( IGBT) for Inverter

Heat Sink calculations of Chopper IGBT

Power Loss Calculations of inverter IGBT.

Selection of diode for Chopper

Heat Sink Calculations of Inverter IGBT


This Inverter 25KVA consists of

Input DC Control and Protection Section

Power Supplies DC/DC Converter

Booster section

Protection

Inverter Section

Supervisory and Display section

The 110VDC nominal input voltage from the coach battery and Alternator-Rectifier cum regulator  is converted to 415VAC 3 Phase., 50Hz PWM Sine wave Output.

Power Devices IGBT’s are used in both in Booster and inverter Sections. This will run the Air-conditioning plant of the Railway Coaches.

The Inverter has to meet high Current requirements of the Compressor Cut in and this is a very critical aspect of the design.

Raw Materials  and their cost

 

Moulded case Circuit Breaker, DC Choke, DC to DC Converter, (IGBT’s 300A, 1200V), (Diodes 300A, 1200V), (IGBT’s 150A, 1200V), Control card inverter, Cubicles, Digital display, Busbar, etc

Approximately Rs 5 Lakhs

 

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