Owner`s manual

the two signals is not zero, then the inverter has failed. The inverter must be disconnected and shut down. Shut
down is accomplished by opening the inverters output relay as quickly as possible, turning of the drive to the IGBTs,
inhibiting the battery booster, and issue a signal to the “Controller” that the module is not OK via the MODSOK signal
line. A “minor” alarm signal will be issued by the “Controller” so the user will now that a fault has occurred. The
voltage error amplifier on the “Controller board (“current command” signal), will increase its output so that the
remaining power modules can output more current to make up for the current that was supplied by the disconnected
power module. The red/green “Status LED”, located on the power modules front panel, will turned RED. Two
additional LEDs are located on this front panel, an AMBER colored LED which will be illuminated if the internal heat
sink is hotter than desired (and a temperature warning signal, called “NOTEMP”, will be supplied to the “processor”.
If the internal heat sink temperature becomes excessive, a RED status LED will light and the power module will shut
down and a NOT OK signal issued to the processor. The circuit breaker located on the front panel of the power
module must be turned OFF, wait a few seconds, then turn it back ON to clear faults. Upon turn on of the circuit
breaker, the module will restart if no fault exist.
4.7.1.2.7 Internal Power Supply
The power supply in the “power module”, operates from the –48VDC input and is located on the “Power Supply,
Driver” printed circuit board. A 50/60 Hz bias transformer, which is located on the “Static Switch” circuit board, is
connected to the utility AC input terminal block. One of the secondary windings on this transformer is used to make
a -48VDC source, which is “Ored” with the battery –48VDC input. Thus the power supply will operate with either
battery power or AC utility power.
The supply is a 30W discontinuous mode flyback design, operating at 100KHz, which produces plus and minus
15VDC for the battery (primary) side circuits, plus and minus 15VDC for the inverter (secondary) side circuits, and
four isolated 30VDC outputs for the four isolated photo coupled inverter IGBT gate drivers. Control is via a
UCC3804N integrated circuit, which drives an IRF640 FET that is connected to a powdered iron “toroid” transformer.
The majority of the power is used to operate a 24V DC cooling fan. If the IGBT heat sink temperature is below 55C,
the fan will be operated at reduced voltage (+15VDC) so as to increase fan life. If the heat sink temperature exceeds
+55C, a mechanical thermal switch will close and the fan will receive about 26V (+15V and –11V via a resistor from
the –15VDC supply). This fan power is taken from the primary (battery) +/-15VDC supplies. The “Unitrode”
integrated circuits manual (now Texas Instruments) provides data as to the design and operation of UCC3804N chip.
4.8 Controller
This printed circuit board contains an “Intel” 80C196KC processor (U9), an Electrically Erasable Read Only Memory
(EEROM) (U8), a “Wafer Scale Integration, Inc.” PSD301 program memory chip (U10), which contains the operating
program in its Read Only Memory (ROM). It also has a Random Access Memory (RAM) section. The circuit board
also has two CMOS rail to rail quad operational amplifiers (U5, U6) which buffer the eight analog inputs to the
processor. Other circuitry includes a “watch dog” timer (U7), LED and relay driver (U11), power ON reset circuit
(U4), reference sine wave Pulse Width Modulator (PWM) filter (U12, U13, Q5, Q6), and voltage error amplifier
(U14). Power for the processor and other circuits is obtained by down regulating the -48V battery voltage. The
processor is referenced to the negative 48VDC input. The positive 78VDC input is connected to “ground” at the
user’s sight. Thus the negative DC input must be fused. There may be two processor PCBs in a system, so a flip
flop was implemented using photo-couplers (UU17, Q10). The processor that starts up first will takes control.
4.8.1 “Controller” Power Supply
The 48VDC battery voltage is applied to a 15VDC regulator circuit which is made up of a TL431ACP shunt regulator
chip and a TIP47 series pass transistor. The actual DC voltage is +14.97, +/-2%. This is applied to a LM7805
regulator chip to make the +5VDC operating voltage for the 80C196KC micro. Two other TL431ACP shunt regula-
tors are placed in series so as to make +2.495V and +4.990V reference voltage for the processor’s eight bit A/D
converter. As indicated above, the signals to the eight analog inputs of the micro are buffered by a CMOS rail to
rail amplifier (LMC660) such that the input to the micro can not exceed the limits allowed by the processor manufacturer,
3.5 to 21 kVA N+1 Inverter
Theory of Operationpage 4 — 10