Digital Pure Sine Wave Uninterruptible Power Supply (UPS) Reference DesignPower Supply (UPS) Reference Design

Demo Instructions

What’s Included?

Offline UPS

CD-ROM withdocumentationand code

Offline UPS Reference Design

3x 12V SLA Batteries

Battery Input Cable

2x Battery Jumper CablesOutput Power Cord

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2x Battery Jumper Cables

Setup and Connections

Visually Inspect the System to ensure no damage has been caused during shipping.

Ensure the ON/OFF switch is in the OFF position as shown below.p

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Setup and Connections

Ensure that the Mains Input switch is in the OFF position as shown below

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Setup and Connections

Ensure that the battery input cable is disconnected from the system

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Setup and Connections

Use supplied batteries only! Connect the batteries in series using

the supplied battery jumper cablespp y j p

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Setup and Connections

Connect the supplied battery input cable to the positive and negative terminals of the series-connected batteries as shown.

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Setup and Connections

Caution: Ensure correct polarity for the battery cable!!

Connect Redcable to positive

Connect Blackcable to negative

terminal terminal

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Setup and Connections

Now connect the battery cable to the battery input terminal on the Offline UPS. A loud click will be heard when the connection is made.

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Setup and Connections

Connect the supplied t t bl toutput power cable to

the UPS Output terminal The otherterminal. The other end of this cable should be connected to the load. (See Application note for load specifications)

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Setup and Connections To perform load steps, connect a 5A,

250Vac switch in series with the output250Vac switch in series with the output cable (not supplied).

Differential probes must be used to observe Differential probes must be used to observe the output voltage. The differential probe can be connected to the open end of the output cable.

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Setup and Connections

With the Mains switch in the OFF position, connect a standard power cord (not supplied) to the Mains input.

Plug the other end gto a 220V, 50Hz AC outlet

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Apply Mains

First apply AC Mains input by flipping the Mains input switch to the ON position

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Turn ON UPS

Turn the Offline UPS Reference Design ON by flipping the On/Off switch to the ON position

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System Power Up

After turning the system ON, the LCD screen will briefly display the Microchip Logo and the software version. The fans will also start running.

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System Power Up

Note: AC Mains must be present when starting up the Offline UPS. If Mains is not available during startup, the UPS will enter the System Error mode.

This feature is implemented as a pprotection scheme to minimize stress on the system components during y p gstartup.

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System Operation

After the system startup sequence is completed, the LCD will display the mode of operation and other status information.

With Mains connected, the UPS will ,operate in the Battery Charger mode and AC Mains will supply power to the pp y pload.

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Switch-Over Test

To simulate a Mains failure flip the Mainsfailure flip the Mains input switch to the OFF position.

In this position, the UPS will switch to the Inverter Mode TheInverter Mode. The LCD screen will display the mode, b tt t t t tbattery status, output voltage and output current.

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Switch-Over Test

Capture the waveform on the oscilloscope during a switch-over event and observe the transfer time.

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Switch-Over Test

Flip the Mains input switch to the ONswitch to the ON position to connect AC Mains to the UPS again.

In this position, the UPS ill it h b kUPS will switch back to the Battery Charger mode and gAC Mains will provide power to the load

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load.

Switch-Over Test

Capture the oscilloscope waveform during the switch-over event and observe the transfer time.

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Load Step

Next, we will test the dynamic load response f th UPSof the UPS

With the load in the OFF state, flip the Mains i t it h t th OFF iti t it h tinput switch to the OFF position to switch to the Inverter mode.

Now turn the Load ON and observe the Now turn the Load ON and observe the response of the UPS output on the oscilloscope.oscilloscope.

Turn the Load OFF and observe the response of the UPS output on the oscilloscope.

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p p

Known Issues / Updates Depending on the load conditions, AC mains to Inverter switchover time may

exceed 10msTh Hi h C t f t i i di l d th LCD ft l The High Crest factor warning may remain displayed on the LCD after normal load conditions are reinstated

Inductive load has been tested to 1000VA .8pf In order to increase reliability of the UPS the maximum operating power was

d t d t 800W ti l d 1000W f l th 1 i tderated to 800W operational and 1000W for less than 1 minute. PCB Issues

The 15V mask should be labeled as 12V The inverter output inductor is mislabeled, should be L2 not TR1

R i t R83 d R86 h d t 1k DNP ti l Resistor R83 and R86 were changed to 1k, DNP respectively. Cooling fan for the Push-Pull section was replaced with fan P/N: PF92251B1-000U-A99

(MFG: Sunon Fans), to decrease DC loading of the Auxiliary power supply. UPS MAINS-INPUT Earth Ground connections is now connected to the UPS

Chassis and to the UPS OUTPUTChassis and to the UPS OUTPUT. Depending on the silicon revision of the LCD Display Microcontroller

(PIC18F2420) the CKE bit ( SSPSTAT register bit #6) should be set as follows: PIC18F2420 Silicon Rev 1, Rev 2, Rev 3 set CKE= 1 PIC18F2420 Silicon Rev 4 set CKE=0

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Note: LCD setup code is located in …\LCD Code pic18f2420\main.asm, line # 399