Selection of the CS300 Converter, DIP-SWITCHES and Jumper

GEH-6639

Chapter 3 - SELECTION OF THE CS300 CONVERTER

The CS300 converter has to be chosen so that the sum of the inverter DC-link currents, both for class 1 and 2, is lower or equal to the corresponding ones stated in chapter 2.6.1.

3.1 DIP-SWITCHES AND JUMPER

On R-SM3-L card

S1.1-4	Selection of the delay for thyristor disabling during mains dip.
S2.1-3	Selection of the undervoltage threshold.
S3.1-4	Selection of the capacitors precharge time
S4 - S5	Selection of the AC mains frequency: 50 or 60 Hz
CV	Selection of the ML signal function

3.2 USE OF S1 SWITCH

Relevant only for limited application cases

If the system functioning allows a limited dip voltage value of the DC-LINK, (a condition obtainable by handling the DC-LINK with a suitable software or with additional external capacitors) it is possible, during a mains dip with a maximum duration time of 10mS, to prevent the thyristor switching off, of the CS300, during the detection of the voltage drop (repeating then the precharging sequence once the voltage is restored).

The disadvantage of such function is obviously the presence of a high current inside the CS300 once the voltage is restored. For this reason it is necessary to take appropriate countermeasures by checking the decreasing slope of the DC-LINK voltage during the mains dip. Therefore, knowing the value of the connected capacitors and the maximum current supplied by the CS300, it is possible to calculate the maximum “mains dip” bearable by the converter itself.

Example:

Calculate the maximum “mains dip” bearable by a converter size 185A, whose mains choke has the following values: 0.148mH 173 rated A and 350A of saturation current. The converter supplies 8 inverters AV300- 3011 (the internal capacitors value of each inverter is equal to 470∝ F); using an oscilloscope, it has been stated that during a normal functioning, in case of a mains dip, the DC-LINK discharges 70V after a 3-mS mains dip.

The aim is to state whether such “mains dip” can be overcome without the precharging phase.

Considering a series resistance (sum of the capacitor parasite drag and of the connection contact resistances) equal to 100mOHM (0.1 OHM), act as following:

DATA:	R = 0.1 W	C = 3760 mF
	L = 0.14 mH	e = 2.718
	V = 70V

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