Solar inverter

Solar Power System

VISHAY TODAY

KEY

FOR COMPONENTS SOLAR PANELS & INVERTERS

THE VISHAY ADVANTAGE: Long Life, High Reliability Small Size Safety Approvals High Power density

Opto-coupler &Solid State Relays

Snap in electrolytic Snap-in electrolytic capacitors

Film-capacitors for Snubber Buffer EMC Inverter-modules

Power Schottky Snubber, Buffer, EMC applications

Power Schottky by-pass diodes

2010 PV Market by Country

Solar Box

Junction

Bypass Diodes

?Diode fitted across each panel (in parallel) in a multi panel setup.

?Most panel have bypass panel incorporated them.

large into them

?When a panel is damaged, weak, or in shade (most likely), then there is risk that full current from damage.

the rest of panels will pass through the shaded panel and cause overheating damage

?Bypass diodes are not essential for 12V and 24V

systems, but over 36V they should always used.

for be

Blocking Diodes

g

?PV cells (also applies to entire panels) is either a power producer or consumer depending on whether it is exposed to sunlight or not.

?Diode is blocking capacity are installed between paralleled panel strings

and/or between array and the battery. They prevent current from

flowing back into shaded parallel series strings or arrays that are acting

as power consumers, discharging all the power produced by the other

di h i ll h d d b h h

strings and/or the power stored in the battery at night (dark current).

y p

?A 12V system will lose more power from losses due to this

blocking diode (drop on voltage up to 0.7V) than you will

through the solar panel at night.

?24V to solar system the losses through diode would be

t48V l t th l th h di d ld b

much lower thus should be considered.

y g g p()

?If more than one battery is being charged from the same panel(s)

then a diode should be fitted for each battery.

?Low loss Schottky diodes are best since the least power is less.

?Blocking diode are seldom needed in system with controllers as they have built in method of preventing reverse current.

Maximum Power Point Tracker

VISHAY TODAY

Solar Panel Characteristic

?Generate max voltage when panel is in full sunlight with no load, referred to as the open circuit voltage (Voc) of the panel. As increases, the output voltage of panel will decrease in a non linear ?load of panel‐fashion until max output current,the short‐circuit current (Jsc) is reached.

?Operate the panel at different load points to maximize the output power.

?Solar panel have negative Voc temperature coefficient and a positive Jsc temperature coefficient.

?The relationship between illumination and temperature make it difficult to estimate the proper

p p p p p

point at which to operate the solar panel in order to maximize the output power.

?Solution for this problem is MPPT

Max power output

Typical PV module system

Maximum Power Point Converter

Maximum Power Point Converter

MPPT Circuits

MPPT Circuits

Circuits MPPT

MPPT Circuits

Solar

Inverters

Solar Energy (PV Grid-Connected Inverters) String Inverters (Professional>10KW)

String Inverters(Professional>10KW)

Power Plant Inverters (Professional>300KW)

Solar Inverter Market by Power Ratings

<10kW primarily for EU market

>250kw demand expect to increase significant in the next few years driven by demand in Asia

Key of PV systems Challenges

?High Conversion Efficiency

?Low failures (Reliability)

?Able to withstand tough conditions

ambient ?Economic Cost