SamplexPower MSK-10A, Руководство пользователя

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14 | SAMLEX AMERICA INC.
SECTION 4 | Operation
4.3.1 Optimum PWM Frequency
The PWM frequency can range from tens of Hz to around 1000 Hz. At higher frequencies, the
time period between the cycles is lesser and is not sufficient to complete the electro-chemical
reactions. At lower frequencies, the rise times of the charging pulses are lower which results in
higher gas bubble formation resulting in lowering of active surface area and increase of internal
impedance. In MSK-10A, frequency of 25 Hz is used for optimum charging performance.
4.3.2 Benefits of pulsing nature of charging current during PWM
During PWM voltage regulated stages of Absorption, Float and Equalization, Duty Cycle is lower
and the charging current is in the form of pulses. Pulsing charging current allows some Oxygen
and Hydrogen generated during charging chemical reactions to be chemically combined again
and then absorbed. This eliminates concentration polarization and ohm polarization and reduces
the internal pressure of the battery. Consequently, charging process is smoother and more capac-
ity is returned to the battery. Further, pulsing current provides more time to react, which reduces
the gassing volume and improves the absorption rate of charging current.
4.4 CHARGING PROFILES
The controller has been set for the following 2 Charging Profiles:
(a) 3-Stage Normal Profile : See Fig 4.1A & Section 4.4.1 for details
(b) 3-Stage Equalization Profile : See Fig 4.1B & Section 4.6 for details
DAY
TIME
Vf
Va
Fig 4.1A 3-Stage Normal Profile
Bulk Absorption Float
Fig 4.1B 3-Stage Equalization Profile
Bulk Equalization Float
TIME
DAY
Vf
Ve
BA
TTER
Y VOL
TA
GE
10
11
12
13
14
15
16
20
22
24
26
28
30
32
12V 24V
STAGE 1
BULK
STAGE 2
ABSORPTION
STAGE 3
FLOAT
NIGHT NIGHT NIGHT NIGHT
STAGE 1
BULK
STAGE 2
EQUALIZATION
STAGE 3
FLOAT
2 Hrs
2 Hrs
LEGEND FOR FIG 4.1A & FIG 4.1B:
Va - Absorption Stage Voltage
Ve - Equalization Stage Voltage
Vf - Float Stage Voltage
NOTE:
Voltages represented by the Charging Curves are based on battery voltages
Figs 4.1A & 4.1B Charging Profiles
4.4.1 3-Stage Normal Charging Profile
Please refer to Fig 4.1A
This charging cycle is carried out for normal day to day charging. Charging is sequential: Stage
1: Bulk Stage (M
aximum available Current from the Solar Panel(s) = Instantaneous Short Circuit
Current “Isc” of the Solar Panel ) Stage 2: Absorption Stage ( Constant Voltage ) Stage
3: Float Stage ( Constant Voltage ).