A BRIEF DESCRIPTION
ABSTRACT: Charger/Dischargers with IGBT Front End Converter are on the way to replace traditional Thyristor based equipments because of its superior performance in every aspect and characteristics of charger/discharger. It has substantially better power factor, efficiency, THD, battery management, ripple current with lower size, weight and lower cost of operation. It is the natural choice of technically alert user. Discharger is regenerative, sinusoidal and of unity power factor.
The Circuit: The heart of the circuit is a DSP controller with speed in excess of 100 MIPS. It carries out vector analysis of current and voltage waveforms and drives the IGBTs for Bidirectional Conversion of power. The DSP Controller also has MMI Interface and SCADA interface with MODBUS and GPRS communication. The state- of-the-art technology is highly user friendly, reliable and rugged in performance. More than 2000 such FE converters are in use in Indian Railways, both in stationary and rolling stock applications. As shown in the diagram, the circuit is of three stages, bidirectional 3 phase FE converter, single phase high frequency inverter and rectifier. Because of efficient switching techniques, each stage is having efficiency higher than 98%. Use of 12bit AD converter ensures high accuracy of control.
| The performance parameters, IGBT and Thyristor – | ||||
| Sl.No | Parameters | IGBT | Thyristor | Effect of Thyristor |
| 1 | THD | < 5% | normal 26% | Transformer heating, Electrical noise |
| 2 | Efficiency, half to Full load | 94-96% | 75-82% | Higher energy consumption |
| 3 | Power Factor | Chg 98%, Dischg 100% | Chg 80%, Dischg 44% | suffers penalty charged by utility |
| 4 | Ripple content | Low | High | Higher ripple, lower battery life |
| 5 | Intelligent Battery Management | yes | No | Must for NiCd and lithium batteries |
| 6 | SCADA | yes | No | SCADA always preferable |
| 7 | Size | compact | 33% bigger | Bigger size, Higher floor space |
| 8 | Weight | Lighter | 25% heavier | |
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Article Source: Signotron (India) Pvt. Ltd. | This Product Expertise is a part of our Latest Magazine: Subscribe to our Magazine Today!
