POWER PLANT- RECTIFIER MODULE GENERAL DESCRIPTION

Rectifier Module General Description

The switch mode rectifiers (SMRs) are designed to be used in conjunction with a control and supervisory module (MiniCSU2).Operating parameters cannot be set or voltage and current displayed without using the CSU. Since the rectifiers are designed to operate in parallel in  redundant mode, it is never necessary to set individual rectifier parameters.

All electrical connections to the unit are made on the back plane via a single connector. Mating of the connector occurs automatically when a unit is inserted into its position in the specially designed magazine. Each magazine has 4 positions and fits a standard 19” rack. Installing and replacing rectifiers is easy and can be done by one person.

A bar graph display of output current on each rectifier is available as an option.

The rated input voltage for the module is 220Vrms. The tolerance is 90 – 300Vrms.

 General Operating Principles

This section describes in some detail the operating principles used in the design of the “Boost” and DC/DC power conversion stages as well as of the overall control and monitoring circuits.  The rectifier is made up of 5 printed circuit assemblies.

1)    Power Motherboard (PMB2): It has the following parts

·      EMI filter and inrush limiting circuit;

·      the AC/DC converter, a boost stage with loss less snubber;

·      a double ended forward converter to convert the regulated 420VDC from the boost 

           stage to 48V  (24V);

2)    Digital Secondary Control Card (DSCC)

It has the secondary side voltage and current feedback loops, and the microprocessor for controlling the rectifier and communication with the System Controller.

3)    Control Loop Card (CLC) With the feedback loops and the gate drives for the boost stage and the forward converter stage

4)    Primary Auxiliary Flyback Converter (PAFC) which plug directly into the motherboard This card provide power to the primary and secondary control circuits.

5)    Front Panel card (FP25A) fits into the plastic moulding at the front of the rectifier module and contains 3 status LEDs as well as optional bargraph LED display. It is connected to the DSCC inside the rectifier body by a 10 way ribbon cable. The rear panel connector (the only external connector) has the AC, DC and communication connections. Two additional pins are for sensing an address resistor at each rectifier location so that the microprocessor in the rectifier can tell at which location it is installed. An address resistor with a different value for each rectifier position is connected at the back of the magazine.