electronic engl
TRANSCRIPT
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Electronic Components for
Photovoltaic Solarsystems
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LoadSolar
Generator
Principal Circuit of a PV-Solarsystem
StorageElectronicControl Syste
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Lead Acid
Accumulator
LoadSolarGenerator
Charge Controller
Circuit of a Solar Home System with
Charge Controller
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Tasks of a Charge Controller:
Overcharge protection
Over charge protection: - Strom Gassing has to be prevented- Circulation of the Acid- Battery has to be charged properly
- Preventing Backward Current at NightV [V]
t [h]
UnlimitedCharging
Boost
Stand By Charging
Vopt=f(T;SOC)
Equalize
LimitedCharging
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Overcharge Protection:
Types of Charge Controllers
SolarGenerator
+
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Parallel- or Shunt- Controller Design:
PowerSwitch
ControlCircuit
BackwardDiode
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Overcharge Protection:
Types of Charge Controllers
Parallel- or Shunt- Controller Design:
Problems:
- Current from Solar Generator cannot beinterrupted
- Short Circuit can Effect Hot Spot
I
V
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Overcharge Protection:
Types of Charge Controllers
SolarGenerator
+
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Serial- Controller Design:
PowerSwitch
ControlCircuit
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Overcharge Protection:
Types of Charge Controllers
Serial- Controller Design:
Advantages:
- Current can be Interrupted
- No risk of Hot Spot
I
V
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Overcharge Protection:
Types of Charge Controllers
Different Control Circuits:
Continues Regulation (Switch is partly conductive)
- Very high power losses
On-Off Regulation (with Hysteresis)
- No Prober Charging!!!
- only way to use relay
PWM Regulation
- Low losses and proper charging
- Need MOS-FET
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Overcharge Protection:
Types of Charge Controllers
+-
PWM:
Signal for Power Switch
PowerSwitch
ControlCircuit
t [ms]
Switch
Conductive
Non conductive
T < 100ms
t 1 t 2
t1 and t2 are variable; T is fixed
t 1 t 2
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Overcharge Protection:
Types of Charge Controllers
Conclusions:
Best solution is
- Series Controller- PWM
- Temperature Compensation
- Float, Boost and Equalize Cycle
Never use
- Relay
Be careful
- Shunt Controller
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Tasks of a Charge Controller:
Overdischarge Protection
Overdischargecharge protection:
- Prevention of deep discharging
- Prevention of Sulfation
- Prevention of Overcurrent and
Short Circuit
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Overdischarge Protection:
Types of Charge Controllers
+
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Power Electronic Design:
PowerSwitchControl
Circuit
Load
I
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Overdischarge Protection:
Types of Charge Controllers
State Of Charge (SOC) Calculation:
Target
-Load Cut Off at SOC=30%
ISIL
UBSOC=90%
SOC=30%
SOC=f(I;SOC;T;Age;.......)
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Overdischarge Protection:
Types of Charge Controllers
Load Cut Off at
Constant Voltage
Evaluation- average failure 50%
- max. failure 100%!!
ISIL
UBSOC=90%
SOC=30%
SOC=f(I;SOC;T;Age;.......)
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Overdischarge Protection:
Types of Charge Controllers
Load Cut Off at
Current Controlled
Voltage
Evaluation
- average failure 20%
- max. failure 30%
ISIL
UBSOC=90%
SOC=30%
SOC=f(I;SOC;T;Age;.......)
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Overdischarge Protection:
Types of Charge Controllers
SOC Calculation
with Fuzzy Logic
Evaluation- average failure 10%
- max. failure 20%
ISIL
UBSOC=90%
SOC=30%
SOC=f(I;SOC;T;Age;.......)
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Tasks of an charge controller:
Communication
Display:
- SOC- Load and Charge Current
- Voltage
- Failure Display
- Additional acoustical
signal support warnings!!
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Main problem in rural electrification: Sulfation
1.Tag Nacht 2.Tag Nacht 3.Tag Nacht 4.Tag Nacht 5.Tag Nacht 6.Tag Nacht 7.Tag Nacht 8.Tag Nacht
0
10
20
30
40
50
60
70
80
90
100
Abs cha ltsch we lle
Ladezustand
Lead sulfate grows to large crystals --> accumulator cannot be charged
and discharged anymore!!!
Overdischarge Protection:
Types of Charge Controllers
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Main problem in rural electrification: Sulfation
Overdischarge Protection:
Types of Charge Controllers
Sulfation depends on:
- SOC
- Acid density
- duration of discharge
A new type algorithm can calculate
the risk of sulfation
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1 .Ta g N a ch t 2 .Ta g N ac ht 3 .Ta g N ac ht 4 .Ta g N ac ht 5 .Ta g N ac ht 6 .Ta g N ac ht 7 .Ta g N ac ht 8 .Ta g N a ch t
0
10
20
30
40
50
60
70
80
90
100
Abschaltschwelle
Ladezustand
SOS Parameter
New method against sulfation:
The Cut off level is increased under higher risk of sulfation
Overdischarge Protection:
Types of Charge Controllers
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Advances charge controllers:
MPP-Tracking
V
IMaximum Power PointMPP
IMPP=f(B)UMPP=f(T)
==
UMPP UL
V
PAdaptiv-
Regler
Power Gain:
10-25%
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Solar
Generator
+
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Power
Switch
ControlCircuit
Advanced charge controllers:
MPP-Tracking
Switch is PWM controlled
Vi Vo
Vo = t1/T x ViFunction of MPPT
t 1
T
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Advanced charge controllers:
Excess Energy Management
SolarGenerator
+
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PowerSwitch
ControlCircuit
Excessload
PWM1
PWM2
(sometimes
On-Off Signal)
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Advanced charge controllers:
Hybridsystems
SolarGenerator
+
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PowerSwitch
ControlCircuit
Dumpload
PWM1
PWM2
G
Wind- or
Hydrogenerator
Solar Hybrid System with Wind or Hydrogenerator
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Advanced charge controllers:
Hybridsystems
SolarGenerator
+
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PowerSwitch
ControlCircuit
PWM
G
Fuelcell or
Dieselgenerator
Solar Hybrid System with Fuelcell or Dieselgenerator
On-Off
Signal