Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Berglund, NC: AUTHOR [+3]
Described is an improved test mechanism that provides operating system control of a "battery capacity test" which uses the system as the load and which further is executed conditionally on the results of a pre- screening "pulse test".
an improved test mechanism that provides
operating system control of a "battery capacity test" which uses the
system as the load and which further is executed conditionally on the
results of a pre- screening "pulse test".
shows the system load and its power supply and the
battery backup hardware which is one subject of this article. The
system load is normally powered via the 28-volt power supply which
receives AC from the utility. For the purposes of this discussion,
the system load block in the figure is considered to contain the DC
to DC box regulators (28 V to 5 V, etc.) and the devices or
electronics being powered by the regulators. Battery power can be
applied to the system regulators and load through fuse F1, switch S1,
and diode D1. F1 provides protection in the event a short circuit is
applied across the batteries. Switch S1 is closed, under control of
the power control processor, to apply battery power to the system
load through isolation diode D1.
can also be applied to resistor RL through switch
S2. This hardware is used to perform the pre-screening of battery
function before the 28 V power supply is switched off to allow the
battery to use the system as a load for the capacity test. RL is a
compact high wattage resistor which is able to dissipate a pulse of
battery power for a few seconds.
pulse test, switches S1 and S2 are closed. Diode D1
is reversed biased because the system 28 V power supply applies a
higher voltage to the load than the batteries. Diode D1 also
isolates the pulse load resistor from the system 28 V supply.
Voltage Vb and current are measured during the pulse test to
determine if the test is a success or failure. If a utility failure
occurs during the pulse test, causing the 28 V power supply to cease
operation, diode D1 will become forward biased and the battery will
supply power to the load. At the same time, the power control
processor will open S2 and abort the test.
If the test
is successful, the pulse test may be followed with
a capacity test. The power control processor turns off the 28 V
power supply to force the battery to power the system load for a
specified test duration.
1. A battery test is initiated when the power control processor
receives a battery test command from the operating system. If the
test is accepted, the test length is saved, the test survival time is
initialized to zero, the pulse test timer is initialized to a
response interval, and the Battery Test signal to the BBU is
activated to initiate the test.
2. The BBU receives the Battery Test signal and closes switches S1
and S2, causing the battery to supply power to RL. After a test
interval seconds, the BBU measures the battery voltage and current to
determine if the test is successful. The tes...