how to order - I.C.T. Power Company Inc.

•
5780 Thornwood Drive
Goleta, California 93117
www.enerpro-inc.com
Number PD744
September 29, 2000
THE MVTB FAMILY OF FIBER-OPTICALLY COUPLED
MEDIUM VOLTAGE THYRISTOR TRIGGER BOARDS
Introduction
The MVTB family of Medium Voltage
Trigger Boards offers engineers a turnkey
solution for thyristor-based systems
requiring enhanced hard dc gate drive with
complete control electronics isolation.
Fiber-optically coupled gate commands allow
unlimited voltage isolation between the
delay determinator logic unit and the trigger
board. The MVTB drives thyristors fed with
up to 2400 Vac (4160 Vac by January 2001)
with respect to the trigger board control
circuit power supply. This isolation is
accomplished with high-voltage pulse
transformers and with creepage in
conforming to EN 50178 and UL 840.
Key Specifications
• 4 A/µs Initial Gate Current Rate-of-Rise
• 2 A Initial Peak Current
• 0.5 Adc Sustaining Current for 120 deg.
• Pulse Transformer Isolation >5000 Vac
• Gating & Bias-Supply Status Read-Back
Applications
High isolation voltage and fast, high current
gate drive make the MVTB trigger board
especially suitable for high power rectifiers,
inverters and ac controllers using:
• Advanced Design Thyristors
(to 12 kV Blocking Voltage)
• Series-Connected Thyristors
• Multiple Converters Series Connected
• Parallel-Connected Thyristors
Specific Applications Include:
• Sub-Cycle ac Transfer Switches
• 1200 V to 4160 V Motor Starters
• MV or HV* Rectifiers With Series-
Connected Thyristors
• Rectifiers for High Energy Physics
• Plasma Arc Rectifiers
• Pulsed Power Systems
*A floating trigger board power supply permits
MVTB operation at an arbitrarily high voltage.
The MVTB-6, Six-Channel Trigger Board shown above is ideal for 2.4 kV motor soft start systems.
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Background
The MVTB family was developed to
accommodate three specific requirements:
First, many industrial environments require
the electrical isolation, noise immunity and
enhanced safety provided by fiber optic
signal transmission.
Second, stringent power quality regulations
frequently necessitate control at medium
voltages, such as sub-cycle transfer
switches and motor soft starters.
Third, large systems such as pulse
amplifiers and power supplies for highenergy
physics often use series or paralleled
devices. These devices often require dc
gating with high open-circuit voltage, high
peak currents and short rise time pulses.
This helps ensure a small spread in the
turn-on times and adequate immunity
against gate inversion.
Circuit Operation
Each channel of a MVTB board is made up
of four sections: 1) fiber optic receiver and
gating logic, 2) driver stage and pulse
forming network, 3) isolation transformer,
and 4) output rectifier and terminating
resistor.
Fiber-optic receiver (FOR) converts the
gate command light signal into the logic
signal *A. The *A signal is characterized by
a square wave pulse train of 256 pulses at a
nominal frequency of approximately 23kHz
and 5.6 ms duration when the mains
frequency is 60 Hz.
This gate command pulse train is standard
output on all of Enerpro’s firing boards.
Firing cards can be specified with optional
fiber-output pulse modules. The modules
are also available as drop-in field-upgrades
for existing Enerpro boards.
Medium Voltage Trigger Board System
(One Channel Shown)
"Blue"
Fiber-
Optic
Links
"Gray"
System Controller
Gate
Command
Receiver
R-2522
"BLUE"
Status
Transmitter
T-1522
"GRAY"
*A
Gating
Logic
(Gate Delay Determinator Board)
Status
Logic
+
H
L
39Ω
+30 V
"GATE ON"
"FAULT"
Current
Limiting
Resistor
Gate
Driver
22µ
22µ
+ +
2Ω
Pulse
Forming
Network
22Ω
6000V
Isolation Barrier
2T
Toroidal
Isolation
Transformer
5T
Pulse
Rectifier
200Ω
G
K
A
K
Bias Supply
(Grounded or Floating)
24 Vac / 30 Vdc
10VA per Channel
5A
COM
Vth H
Vth L
IN
Bias
Supply
+ 30 V
+13V
+5 V
"POWER ON"
MVTB Board
E1193 MVTB Block Diagram.McDraw
Block diagram showing the Medium Voltage Trigger Board system’s. basic functionality.
Number PD744 - 2 - PD744 - MVTB Family.doc

Gate Drive Stage
Logic converts the *A signal into high- and
low-side power MOSFETs. The logic
disables the driver in the absence of gate
command. The half-bridge applies 128
positive and 128 negative pulses to the
transformer’s 2-turn primary over a period
of 1/3 of the mains voltage cycle.
The toroidal pulse transformer is wound
with corona-resistant, high voltage wire
rated for 7.5kV nominal (20 kV B.I.L.).
Additionally, PCB slotting and ample
creepage distance assure >5000 Vac
isolation. MVTB boards are available with
potted outputs and higher voltage wire for
isolation to 20 kV (80 kV B.I.L.).
Output Pulse Characteristics
The bipolar square wave signal derived
from the 5-turn secondary is full-wave
rectified into a direct current pulse. The
amplitude is initially 30 V decaying to ≈12 V
as the half-bridge capacitors discharge. The
primary-side pulse-forming network creates
high-amplitude initial gate current (2.0 A)
and a lower amplitude (0.5 A) sustaining
current.
The fast recovery rectifiers and 200Ωterminating
resistor provide added noise
immunity and gate reversal protection.
Status Readback
The fiber-optic transmitter (FOT) for each
channel outputs a diagnostic light signal. In
normal operation, the output of the
primary-side gate driver is converted to a
logic signal that drives the photodiode of
FOT. The result is a light signal that
mimics the gate command. The bias
supply’s window comparator will turn on
the FOT continuously if the nominal +30 V
supply is outside preset thresholds.
On-Board LED Diagnostics Include:
• “POWER ON” indicates board power
• “GATE ON” indicates gate activity
• “FAULT” indicates bias out-of-range
Circuit Board
The circuit boards are assembled at the
Enerpro plant in Goleta, California and are
made by a UL listed fabricator from 0.093-
in. (2.36-mm) thick FR4 fire-resistant
epoxy-fiberglass laminate. All creepage
distances conform to UL 508 and VDE
0110. Boards are conformal-coated (MIL-1-
46058 [Type UR]).
The boards are designed for operation from
0°C to +65°C. The boards require forced air
cooling (75 CFM across length of board) at
ambient temperatures above 35°C.
Rugged AMP Mate-N-Lok connectors are
used for customer electrical interface and
are keyed to simplify maintenance and
ease trouble-shooting.
Open Circuit Voltage (2 x 30° Bursts Mode).
Ordering Information
Please contact Enerpro for assistance or
use the following "How to Order"
worksheet to determine the correct part
number. Consult Enerpro’s applications
and design-engineering staff for assistance
when specifying thyristor gate drivers for
custom applications.
Number PD744 - 3 - PD744 - MVTB Family.doc

HOW TO ORDER
Model
Number Medium Voltage Fiber-Optically Coupled Trigger Board
Code Output Configuration
1
2
3
4
6
Single Output
Dual Output
Triple Output
Quad Output
Hex Output
Code Thyristor Gating Configuration
- Independent Command Inputs
S Single Command Input
Code Physical Configuration
- Standard One-Piece Construction
X Separated Output Circuit Construction
Code Mains Voltage ( In kilovolts)
Code Board Supply Voltage
24 24 Vac
30 30 Vdc
MVTB - - - - -
For more information:
Please contact Enerpro, Inc. by telephone at (805) 683-2114, 7:00 A.M. to 5:00 P.M.
(PST), M-F, or e-mail Enerpro via Frank Peter Wahl at f.wahl@enerpro-inc.com.
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Version 9/29/00
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