Technical Proposal of 250kW solid state HF Welder.docx

1、Technical Proposal of 250kW solid state HF Welder Technical Proposal of250kW Solid State HF WelderBaoding Sifang Sanyi Electric Co., Ltd.2015.4CATALOGUE. Technical Description 11. Features of new generation H.F. solid state welder 12. Model instructions for solid state H.F. welder 13. Working princi

2、ple of solid state H.F. welder 13.1 Main circuit structure of solid state H.F. welder 13.2 Working principle of solid state H.F. welder 24. Technical parameters of 200kW solid state H.F. welder 45. Core technical instructions of control and protection 56. Main parts list for solid state H.F. welder

3、6. Composition and Brief Introduction for Solid State H.F. Welder 71. Equipment composition 72. Brief introduction for solid state H.F. welder 7. Supply List 8. Requirements for Equipment Operation 91. Environment requirements 92. Power net requirements 93. Water quality requirements for external ci

4、rculation water pool 9. Supply Scope 101. Supply scope for seller 102. Supply scope for buyer 10. Technical Description1. Features of new generation H.F. solid state welder 1.1 The solid state H.F. welder adopts Germany IXYS company IXFN38N100Q2 38A/1000V high-power MOSFET and DSEI 261-12B 60A/1200V

5、 rapid recovery diode to compose series type invertible circuit.1.2 The solid state H.F. welder adopts modularization design with more compact structure which makes maintenance and high-power realization much easier.1.3 It has particular technology of bridge-divided over-current protection that guar

6、antees equipment safety.1.4 It combines international advanced control method of same products, adopts advanced technologies like fixed angle phase-locking control, upper frequency limit/lower frequency limit lock-lost protection and etc. With these technologies, the equipments run more stably, more

7、 efficiently, more accurate and effective protections to the inductor short-circuit and open-circuit malfunction during pipe welding production.1.5 Line-in end of solid state H.F. welder does not need step-up /step-down rectifier transformer, compared with vacuum tube welder and parallel type welder

8、; it has significant energy-saving effects (Under same welding condition, energy-saving 30% compared with vacuum tube welder).2. Model instructions for solid state H.F. welder3. Working principle of solid state H.F. welder 3.1 Main circuit structure of solid state H.F. welderSolid state H.F. welder

9、main circuit structure is as follows fig.1; it is a typical AC-DC-AC variable frequency structure. Rectifier adopts 3-phase bridge style thyristor phase-control rectifier circuit, DC side adopts inductor, capacitor to compose LC filter which meet the working requirements of voltage type inverter. Th

10、e voltage type inverter adopts modularization parallel structure to extend power supply power, each inverter module is single phase MOSFET bridge style circuit connected with series resonance tank circuit by H.F. matching transformer. On one hand, the matching transformer realizes power combination

11、and impedance matching; on the other hand it realizes electric isolation of load and power supply. To put effective and swift protection on over-current malfunction of voltage type inverter, our company introduces special and stable over-current protection circuit which guarantees safe and stable ru

12、nning of inverter.Fig 1 Circuit structure of solid state H.F. welder3.2 Working principle of solid state H.F. welderVoltage type resonance inverter also called series connection type resonance inverter is the most critical part of the whole solid state H.F. power supply; fig 2 shows the structure, o

13、utput voltage and current wave of inverter module. By controlling connection and disconnection alternatively of MOS 1&3, MOS 2&4, the series connection type inverter output voltage uH is close to square-wave, due to the inverter output voltage frequency is near by resonance frequency of resonance ta

14、nk circuit, and now the inverter output voltage fundamental wave from resonance tank circuit to inverter has the minimum impedance value, the maximum impedance value to other high harmonics, therefore load current iH is close to sine waveform.Fig 2 Voltage type resonance inverter circuit structure a

15、nd output waveformSeries connection resonance inverter typical working state can be divided into three types: sensibility, resistive leakage, capacitive. Fig 3 shows separately the three working status inverter output voltage, current and experiment waveforms.（a）small sensitivity status （b）small cap

16、acitive status （c）resistive leakage statusFig 3 Series connection resonance inverter output waveformsWhen series connection resonance inverter works at small sensitivity status (fig 3a), inverters working frequency is higher than inherent resonance frequency of resonance tank circuit a little bit, i

17、.e. load current iH lag to load voltage uH a electric angle. Now current-exchange of inverter has several features: 1) Parts startup is zero voltage (ZVS), zero current (ZCS), theoretically the wastage of the parts startup is zero; 2) Parts shutdown is zero voltage, non-zero current, but due to smal

18、l current when parts shutdown, plus zero voltage current-exchange (ZVS), so parts shutdown wastage is small too; 3) circuit stray inductance has small effect on inverter current-exchange; 4) current-exchange has no requirement on backward recovery features of inverse parallel diode, the parts suffer

19、 very small surge impact when current-exchanging. When series connection resonance inverter works at capacitive status (fig 3b), inverters working frequency is lower than inherent resonance frequency of resonance tank circuit a little bit, i.e. load current iH advance to load voltage uH a electric a

20、ngle. Now current-exchange of inverter has several features: 1) Parts shutdown is zero voltage (ZVS), zero current (ZCS), theoretically the wastage of the parts shutdown is zero; 2) Parts startup is high voltage, large current, so parts startup wastage is very big; 3) circuit stray inductance has st

21、rong effect on inverter current-exchange; 4) backward recovery current of inverse parallel diode of MOS yield strong voltage current oscillation, the parts suffer very strong surge impact when current-exchanging, it threatens power part safety running severely. When series connection resonance inver

22、ter works at resistive leakage status (fig 3c), its working frequency equals inherent resonance frequency of resonance tank circuit, i.e. load current iH has the same phase position with load voltage uH. Theoretically the resistive leakage status is the best working status, but actually due to the e

23、ffects of dead zone period and resistance & capacitance absorption circuit, inverter current-exchange parts working status is not in good condition, also load fluctuation makes inverter deviate to capacitive working status easily, it threatens stable and safe running of inverter. From the analysis a

24、bove we know that the best working status of series connection resonance inverter is small sensitivity standard resonance status. Besides, compared with other companys parallel connection resonance H.F. power supply, our companys series connection resonance H.F. power supply parts not only has small

25、 switch wastage and high power supply efficiency, but also has much better protection to various malfunctions of resonance tank circuit. 4. Technical parameters of 250kW solid state H.F. welder Designed parameters Nominal power: 250kW Rated DC power: Pd=300kW Rated DC voltage: UdN=450V Rated DC curr

26、ent: IdN=670A Power supply efficiency: 85% Output power: Pout250kW Designed frequency: f=300350kHz MOSFET inverter: 60kW5 Tank circuit output mode: no welding transformer output, secondary resonance Power distribution requirements Nominal power: 250kW Rated DC power: Pd=300kW Line-in power factor: C

27、OS0.9 Power distribution capacity: S330kVA Power supply voltage: 3-phase 380V/50Hz Line-in current: I=540A Line-in cable: each phase adopts 240mm2 copper cable, 3-phase 4-line Water-water cooling system With the adoption of water-water heat exchanger Pressure of inner circulation water: 0.150.25MPa

28、Flow of inner circulation water: 25m3/h Temperature of inner circulation out water: 40 Temperature of inner circulation back water: 45 Heat exchanger area: 12m2 Flow of external circulation water: 25m3/h（provided by user） Temperature of external circulation inlet water: 35 Pressure of inlet water: 0

29、.200.3MPa (approximately 2.03kg/cm2)5. Core technical instructions of control and protection5.1 Solid state H.F. welder adopts the most advanced fixed-angel phase-locking control technique, inverter working status do not change as load tank circuit change, which keep the work at the best small sensi

30、tivity resonance status all the time, welder works stably with high efficiency.5.2 Solid state H.F. welder has advanced functions like high/low lock-lost protection, frequency upper limit/lower limit protection, invert over-current, tank circuit over-voltage and etc. Also more accurate and efficient

31、 on open-circuit, short-circuit, arcing of inductor malfunction, it guarantees welder stable running.5.3 Besides regular protections, each inverter bridge adopts multiple protections, such as DC side over-current, AC side over-current, AC side over-voltage and etc. It realizes protection redundancy,

32、 guarantees inverter safe running. 5.4 Rectifier side control circuit adopts single chip technology which solves automatic phase-recognize successfully, i.e. no requirements on 3-phase power supply input line; thyristor trigger circuit adopts all digital equal interval triggering, it reduces non-characteristics harmonics furthest and power net pollution. 5.5 Rectifier control circuit has soft startup, soft stop function which pre