Battery Management Manual FPRA D01

Battery Management Manual Revision D01

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FPRA Flexi Power Rectifier

Battery Management Manual

Revision D01

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History:

Date Version Author Change Notes

23.01.09 D01 Daniel Kreuzer Creation of document

Authors:

Daniel Kreuzer [email protected]

Abbreviations:

tbd to be done GUI Web-based User Interface DDU DC Distribution Unit PDA Power Distribution Assembly MAC Media Access Control IP Internet Protocol LCD Liquid Crystal Display CU Control PID Product Information Data VPN Virtual Private Network

Related Documents:

User Manual FPRA D02 by Daniel Kreuzer: “how to use” for the Web-based User Interface and for the LCD Front-Panel Display of the FPRA system


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Content 1 Overview .................................................................................................................................. 4 2 Battery Charge/Discharge/Recharge Concept .................................................................. 5 3 The Example System .............................................................................................................. 7

3.1 Start-up ............................................................................................................................... 7 3.2 Idle/Charge Off.................................................................................................................. 7 3.3 Discharge/Boost Discharge ............................................................................................. 8 3.4 Charge/Boost Charge........................................................................................................ 8 3.5 Battery Test ........................................................................................................................ 9


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1 Overview

This document is a “how to use” and “how it works” for the battery management of the FPRA system.


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2 Battery Charge/Discharge/Recharge Concept

System Charge Init

System Charge Start

System Discharge Start

System Charge Start Timeout

System Charge Off Battery Test

System Discharge

System Charge (const. I)

System Charge (const V)

System Boost Discharge

System Boost Charge (const I)

System Boost Charge (const V)

First Battery detected

Discharge > 1%NO Discharge

Ubat > Nominal Set Volt

Discharge > 1%

Time out initial Charge

Battery Test Request

Discharge > 1%

NO Discharge

Ubat > Nominal Set Volt

Discharge > 1%Discharge > 1%

Time out Charge

Discharge > 10%

Discharge > 1% Discharge > 1%

Ubat > (Nominal Set Volt + Boost Volt Offset)

NO discharge

Time out Boost Charge

Manual Boost Charge

Manual Boost Charge Request



Manual Boost Charge



Initial Charge

Idle

Recharge

Discharge


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The Battery state machine mainly consists of five different parts:

1. Initial Charge/Charge Start: after start-up the system is in initial charge state. This state guarantees fully charged batteries before changing to the default operational state. During this time it is not possible to start a battery test. The duration for the initial charge time is user settable and can be changed under “System Related Settings” – “Start Charge Time. It is not possible to stop the initial charge cycle in order to start a battery test, but it is possible to schedule a battery test, which starts directly after the initial charge.

2. Charge Off State/Idle State: this is the default operational state. This is the only state, which allows starting a battery test.

3. Battery Test: battery test is a simulated AC-Fail/Discharge State. After a battery test the system will change to discharge state in order to recharge the batteries.

4. Discharge State: Discharging more than 1% and less than 10% of total battery capacity will result in the Discharge State. If AC is back before discharging more than 10% of total capacity the batteries will be recharged without boost voltage. The duration for the recharge is user settable and can be changed under “System Related Settings” – “Charge Time.

5. Boost Discharge State: Discharging more than 10% of total battery capacity will result in the Boost Discharge State. After AC is back the batteries will be recharged with boost voltage. The duration for the boost recharge is user settable and can be changed under “System Related Settings” – “Boost Charge Time” Manual Boost Charge State: A manual started Boost Charge can be performed during a normal charge or during Charge Off State.

• State changes from “Charging States” or “Charge Off State” requires a discharge of more than 1% of overall battery capacity. Depending on the overall battery capacity this may take several minutes.


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3 The Example System For a better understanding of the overall battery handling the complete process will be discussed with the help of an example system:

• 200Ah Battery Block – 50% charged at start up • -54.5V set Voltage • 20A charge limit • 20A load • no battery test scheduled • 2h initial charge time • 2h recharge time • 3h Boost charge time

3.1 Start-up During start-up the System operates in the initial charge (also called start charge) cycle:

1. Lowers the System Voltage down to –44V 2. Increase Voltage until the Battery Voltage is reached 3. Increase Voltage until the charge limit is reached This state is called “constant

current” 4. During charging batteries the voltage is raising until the set Voltage of –54.5V is

reached (without violating the charge limit) changing to state “constant voltage” 5. Stay for 2 hours (initial charge time) in constant Voltage 6. Switch to Idle (also called Charge Off) state

The initial charge guarantees fully charged batteries before switching to the “normal” operation state. This allows a much more accurate handling of batteries during the normal system operation. During start up/initial charge it is not possible to start a battery test. It is also not possible to cancel or stop the initial charge.

3.2 Idle/Charge Off The normal operation state is called Idle or Charge Off State. This is the only state, which allows battery tests.


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3.3 Discharge/Boost Discharge If the AC fails and the batteries are discharge for more than 1% of their capacity (2Ah for the example system) the system switches its state to Discharge:

1. AC-Fail 2. Discharge Batteries for more than 1% of their capacity

3. Switch to Discharge State 4. 30min discharge (5Ah discharge)

system Voltage follows the battery Voltage 4. 3hours discharge (60Ah discharge)

system Voltage follows the battery Voltage 5. Stay in discharge state 5. Switch to boost discharge state

If the discharge is greater than 10% of the overall capacity of the batteries the system will switch to boost discharge state.

3.4 Charge/Boost Charge On AC back, the system will switch to the charge or boost charge state. This depends on the state reached within discharge cycle. 1. AC back switch to charge state 1. AC back switch to boost charge state 2. Increase Voltage until charge limit is reached constant current

2. Increase Voltage until charge limit is reached constant current

3. During charging batteries the voltage is raising until the set Voltage of –54.5V is reached (without violating the charge limit) changing to state “constant voltage”

3. During charging batteries the voltage is raising until the Boost set Voltage of –54.5V plus Boost Offset (user settable) is reached (without violating the charge limit) changing to state “constant voltage”

4. Stay for 2 hours (charge time) in constant Voltage

4. Stay for 3 hours (boost charge time) in constant Voltage

5. Switch to Idle (also called Charge Off) state

5. Switch to Idle (also called Charge Off) state

If not required, the complete boost discharge and charge handling can be disabled. If disabled, only the normal discharge and charge handling is used.


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3.5 Battery Test A Battery Test simulates an AC fail and measures the related data:

• Test Start Time • Test Duration • Average Current • Average Temperature • Discharged Ah • Test End-Voltage

With the measured data and the user provided test thresholds (Duration, Ah to discharge, Fail Voltage, Warning Voltage) a result is calculated.

1. Start Battery Test 2. Rectifier Voltage is decreased down to –-40V simulates an AC fail 3. From now on the handling (discharge and charge) is completely the same as if a real

AC fail occurs. Since there is no difference in battery handling between a Battery Test and a real AC fail, each AC fail triggers a Battery Test, a so-called AC-Fail Test. There is only one difference between a real Battery Test and an AC-Fail Test: if the AC supply is back during an AC-Fail Test, the test is countered as stopped with no valid result.