ST MicroelectronicsSolar DiodesSolar MPPT Booster
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Boosting solar energy conversion
At junction box or panel level cool bypass switch At photovoltaic array level solar energy booster
Load
Inverter
MeterAC grid
Photovoltaicarray
Junction box
Improving solar energy conversion
More efficient solar energy conversion
New approach to renewable energy based 100% on ST’s proprietaryIPs and technologies for:
At junction-box level Minimized power dissipation and leakage currents Improved reliability and maximized lifetime
At photovoltaic-panel array level Minimized shadowing impact on power generation Minimized panel mismatch Improved inverter efficiency Panel diagnosis using remote monitoring and control functions
System in package Embedded power MOSFET Very low forward-voltage drop Very low reverse leakage current
Key features
Main benefits
Cooler than Schottky diodes Low power dissipation Longer lifetime Higher reliability
(1) CBS available in different packages
TO-220
D2PAKTO-220 AC
MLPD 5x6(1)
(2)
(2) CBS in MLPD package: very low profile (less than 1mm) to laminate device directly on the panel
Cool bypass switch (CBS)
CBS versus standard Schottky diodes
PV panel
+-
Junction box
Hot spot
StandardSchottky diode
Cathode
Anode
Cool bypassswitch
Cathode
Anode
Cool bypass switch (CBS)
CBS vs standard Schottky diodes: power dissipation in forward biasing
StandardSchottky diode
Note: acquisitions made at steady state
Cool bypassswitch
Biasing Current [A]
0
1
2
3
4
5
1 2 3 4 5 6 7 8 9 10
Po
we
r D
iss
ipa
tio
n [
W]
Cool bypass switch (CBS)
CBS vs standard Schottky diodes: leakage current in reverse polarity
Note: acquisitions made at steady state
Cool bypassswitch
StandardSchottky diode
0.001
0.01
0.1
1
10
100
1000
5 10 15 20 25 30 35 40
Reverse Voltage [V]
Le
aka
ge
Cu
rre
nt
[mA
] 125 °C
115 °C
105 °C
95 °C
85 °C
Cool bypass switch (CBS)
CBS versus standard Schottky diodes: heat dissipation compared at ambient temperature, without dissipation tools
StandardSchottky diode
Note: acquisitions made at steady state
5 A 6 A
7 A 8 A
Cool bypassswitch
StandardSchottky diode
Cool bypassswitch
Cool bypass switch (CBS)
Removes need for centralized power conversion, moving part of the electronics from the inverter to the panel
Solar energy boosterStandard PV panel
Antiislanding
DC-ACconverter
DC-DCconverter
MPPT inverter anti-islanding control control control
Inverter basic architecture
+-
electronic parts centralized at inverter level
+
-
Boost+MPPT
Boost+MPPT
Boost+MPPT
distributed architecture DC-DC and MPPT at single cell-string level
Solar energy booster
Monolithic power converter embedded in the panel Breakthrough device allows distributed architecture:
one or more power converters integrated on the panel MPPT implemented at single cell-string level
Key features
Main benefits
MPPT computed for each cell string Maximized power extracted from a single cell string Boosted overall efficiency of the photovoltaic system
Maximum power point tracker (MPPT) algorithm Maximizes solar DC power from the PV panels under any temperature and radiation
conditions (shadowing, panel performance mismatch, thermal gradient, etc.) Tracks power-output changes from the PV modules and maintains continuous grid
connectivity
Solar energy booster demonstration board
Panel diagnostics using remote monitoring and control function
Solar energy booster
Improving photovoltaic technology
Main benefits
Cool bypass switch Solar energy booster
Reduced power dissipation
Cooler device
Smaller and lighter junction box
Higher reliability
Longer lifetime
Maximized efficiency of the photovoltaic system
Extra energy production
Higher reliability: fewer devices, lower failure rate
Panel diagnostics: remote monitoring and control