INVERTER LOAD SPEED CONTROLLER Power demand Speed reference ENGINE 230/400V 50Hz/60Hz PMGPMG 1 f = Hz Speed =var Island Operation of the Adjustable Speed Generation System Engine speed is adjusted to meet load demand

Basic topologies off grid converter controlled generation Conversion of mechanical to electrical energy Power electronic decupling converter Standardized power ratings Primary energy Freedom in speed selection Island Operation of the Adjustable Speed Generation System 2

TOPOLOGY of three-phase distributed generation system 3

PMG ENGINE INVERTER INTEGRATED VARIABLE SPEED GENERATION SYSTEM Island Operation of the Adjustable Speed Generation System 4

Load currents 0% 50% 100% Asymmetrical loads - symmetrical voltages quality produced power = voltage 5 Island Operation of the Adjustable Speed Generation System

TRIPPING CHARACTERISTIC FOR CIRCUIT BREAKERS ( INVERTER CURRENT REQUIREMENT ) Tripping characteristic BCD Non tripping current 3·I n 5·I n 10·I n Tripping time>0.1s Tripping current 5·I n 10·I n 20·I n Tripping time<0.1s

Island Operation of the Adjustable Speed Generation System ASGS Equipped in Asynchronous By-pass Asynchronous Bypass 7

Island Operation of the Adjustable Speed Generation System 8

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Speed rpm Short circuit current p.u Island Operation of the Adjustable Speed Generation System Diesel Engine, 40kW, speed range 1300–3000 rpm Axial Flux Permanent Magnet Generator, 40kW, 400 Hz at 3000 rpm Circuit Breaker, 63 A, type B Three-Phase, Four-Wire, 40 kVA output system with stiff neutral potential V s = 230 V, I pr = 60 A, I pmax = 100 A, Lf = 0.7 mH, Cf = 200 μF, CD = 2 x 17 mF Tests of PMG short circuit current 11

TRIPPING CHARACTERISTIC FOR CIRCUIT BREAKERS ( INVERTER CURRENT REQUIREMENT ) Tripping characteristic BCD Non tripping current 3·I n 5·I n 10·I n Tripping time>0.1s Tripping current 5·I n 10·I n 20·I n Tripping time<0.1s

Phase-to-neutral short circuit test at engine at speed 1300 rpm and triple switch bypass topology (i s – total current, V d - total DC-link voltage, i p - inductor current). Phase-to-phase short circuit test at engine speed 3000rpm and single switch bypass topology (v pw, v pu - output voltages phase voltages, i p - inductor current, i TH – bypass current, t 1 – short circuit while, t 2 – while of bypass starts conducting, t 3 - while of short circuit clearing). Island Operation of the Adjustable Speed Generation System 13

Phase-to-phase short circuit test at engine speed 3000rpm and single switch bypass topology (v pw, v pu - output voltages phase voltages, i p - inductor current, i TH – bypass current, t 1 – short circuit while, t 2 – while of bypass starts conducting, t 3 - while of short circuit clearing Phase-to-neutral short circuit test at engine at speed 1300 rpm and triple switch bypass topology (i s – total current, V d - total DC-link voltage, i p - inductor current). Island Operation of the Adjustable Speed Generation System 14

Summary I The adjustable speed generation system consists of driving Diesel engine, „high” frequency permanent magnet generator and AC/DC/AC converter. The current that results in cut off of the malfunctioning load must be high enough to activate the tripping switch After disconnecting the malfunctioning load, the supply system continues its operation. The output DC/AC converter consists of high power transistors but transistors have low overload capability. The inductor of the output filter is sensitive to the current producing saturation. So the robust system requires significant over-dimensioning. Island Operation of the Adjustable Speed Generation System 15

Summary II The proposed asynchronous bypass connects, in state of short circuit event, the permanent magnet generator to the output. The bypass is made of thyristors that have ability to cope with very high overcurrent. During the case of short circuit the converter delivers controlled current but the parallel connected generator delivers not controlled high current that results in tripping action of a standard switch. The operation of the bypass has been tested using 40 kW ASGS Island Operation of the Adjustable Speed Generation System 16

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Island Operation of the Adjustable Speed Generation System 18

19 Thank you for your attention

PLC DSP IGBT HF...C ELECTRICAL DRIVE DIVISION 20

Summary II The proposed asynchronous bypass connects, in state of short circuit event, the permanent magnet generator to the output. The bypass is made of thyristors that have ability to cope with very high overcurrent. During the case of short circuit the converter delivers controlled current but the parallel connected generator delivers not controlled high current that results in tripping action of a standard switch. The operation of the bypass has been tested using 40 kW ASGS Island Operation of the Adjustable Speed Generation System 21

Summary II The proposed asynchronous bypass connects, in state of short circuit event, the permanent magnet generator to the output. The bypass is made of thyristors that have ability to cope with very high overcurrent. During the case of short circuit the converter delivers controlled current but the parallel connected generator delivers not controlled high current that results in tripping action of a standard switch. The operation of the bypass has been tested using 40 kW ASGS Island Operation of the Adjustable Speed Generation System 22

23 Summary I The adjustable speed generation system consists of driving Diesel engine, „high” frequency permanent magnet generator and AC/DC/AC converter. The current that results in cut off of the malfunctioning load must be high enough to activate the tripping switch After disconnecting the malfunctioning load, the supply system continues its operation. The output DC/AC converter consists of high power transistors but transistors have low overload capability. The inductor of the output filter is sensitive to the current producing saturation. So the robust system requires significant over-dimensioning. Island Operation of the Adjustable Speed Generation System