Emerge as the times require of high-pressured green transducer

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  • source:GERHOLD CNC Machining
The technology of section report timing that frequency control is the world's at present accepted ideal. However high-pressured frequency control implement use rarely however. Transducer of block up high pressure popularizes the biggest difficult problem of application, the pollution of high-pressured transducer harmonic that is a tradition is big, harmonic is used up not only without result, increase line damage, influence protection moves reliably, make electric machinery produces add moment of force and loss, undertake disturbing to weak cable system, and still can make voltage of electrified wire netting produces serious distortion, produce accident of power system safety even. Accordingly, emerge as the times require of high-pressured green transducer. Harmonic pollution is little, power factor is this kind high high-pressured transducer, it is every photograph establish ties each other by unit of power of many low-pressure frequency conversion, will realize high-pressured output through overlay. 2 winding that give power unit power supply are put in a phasic difference each other, in order to realize an input voltage is multiple change. It is with transducer of 6 kilovolt green exemple, every photograph is the power unit of 690 bend over to establish ties by 5 rated voltage, three-phase shares 15 power unit, keep apart 15 of transformer 2 winding power supply by the input respectively, 15 2 winding cent become 5 groups, every are put in 12 ° phasic difference between the group, form be equivalent to 30 pulse commutate. Because the input is 30 pulse, so theoretic 29 the following harmonic are OK and quits, more satisfactory sine wave voltage and sine wave electric current can be obtained inside all sorts of speed limits, rate of voltage total distortion has 1 only.

2 ％ , rate of voltaic total distortion is only 0.

8 ％ , have " perfect without harmonic " beautiful praise, need not use input filter, with respect to the strict requirement of can contented IEEE519-1992. Reliability is high, maintain convenient power unit to input the PWM of single-phase output transducer for 13 photographs. Comprise circuit of three-phase bridge-type commutate by diode, rectification hind becomes single-phase communicating to output by inversion of 4 low-pressure IGBT. Because use groovy low-pressure IGBT, drive circuit is simple, the technology is mature and reliable. Transducer of this kind of high pressure, because use modular structure, what use power unit identical, can crossing-over, the connection of every power unit and system communicates 2 input terminal, communication to output terminal and a fiber-optic outlet for 3 only, unit maintenance changes very convenient. Not only such, because use structure of power unit series connection, still can adopt technology of power unit bypass and power unit to be designed redundantly. The transducer of green of HVF high pressure that develops like our country, designed heat to back up heat is inserted unplug protection is mixed advocate loop adds up to protection continuously. In addition, because this kind of transducer has sufficient filter wave electric capacity, the system can stand - voltage of 30 ％ power source drops and 5 periodic power source are lost. Loss is small, efficiency does not have output transformer high as a result of this kind of transducer, also need not filter of device of power factor compensation, harmonic, at the same time because harmonic weight is very little, cause power source transformer to decrease greatly to the loss of electric machinery by harmonic, plus IGBT drive power very small, peak value power is controlled for 5 tile, average power is less than 1 tile, switch frequency is inferior, and need not use all press circuit and draw circuit, make efficiency of frequency conversion part is as high as 98 ％ above, the efficiency that includes to input the system of whole frequency conversion that keeps apart transformer inside is as high as 96 ％ above. Without special limitation to electric machinery and output cable length this is planted transducer output voltage jumps change the dc generatrix voltage that step is unit, voltage change ratio is very small, because use,move at the same time photograph type PWM, the equivalent switch frequency of electric machinery voltage rises greatly, and output n number increases. It is with 6 kilovolt transducer exemple, output phase voltage is 11 n, line voltage is 21 n, output equivalent switch frequency to be 6 kilohertz. N counts the addition with equivalent switch frequency, improved output weaveform greatly, reduced output harmonic, the electric machinery that causes by harmonic calorific, noise, torsion is pulsatile, in all modular voltage decreases greatly. So this kind of transducer does not have special requirement to electric machinery, can use at electric machinery of any common high pressure directly, and need not reduce nominal capacity to use, also do not have special limitation to outputting cable length. CNC Milling