26-06-2014, 10:01 AM
Power electronic interfaces
[attachment=65342]
Power electronic converters provide the necessary adaptation functions to integrate all different microgrid components into a common system
Types of interfaces:
dc-dc: dc-dc converter
ac-dc: rectifier
dc-ac: inverter
ac-ac: cycloconverter (used less often)
Power electronic converters components:
Semiconductor switches:
Diodes
MOSFETs
IGBTs
SCRs
Energy storage elements
Inductors
Capacitors
Other components:
Transformer
Control circuit
Capacitors:
state variable: voltage
Fundamental circuit equation:
The capacitance gives an indication of electric inertia. Compare the above equation with Newton’s
Capacitors will tend to hold its voltage fixed.
For a finite current with an infinite capacitance, the voltage must be constant. Hence, capacitors tend to behave like voltage sources (the larger the capacitance, the closer they resemble a voltage source)
A capacitor’s energy is
Inductors
state variable: current
Fundamental circuit equation:
The inductance gives an indication of electric inertia. Inductors will tend to hold its current fixed.
Any attempt to change the current in an inductor will be answered with an opposing voltage by the inductor. If the current tends to drop, the voltage generated will tend to act as an electromotive force. If the current tends to increase, the voltage across the inductor will drop, like a resistance.
For a finite voltage with an infinite inductance, the current must be constant. Hence, inductors tend to behave like current sources (the larger the inductance, the closer they resemble a current source)
An inductor’s energy is
[attachment=65342]
Power electronic converters provide the necessary adaptation functions to integrate all different microgrid components into a common system
Types of interfaces:
dc-dc: dc-dc converter
ac-dc: rectifier
dc-ac: inverter
ac-ac: cycloconverter (used less often)
Power electronic converters components:
Semiconductor switches:
Diodes
MOSFETs
IGBTs
SCRs
Energy storage elements
Inductors
Capacitors
Other components:
Transformer
Control circuit
Capacitors:
state variable: voltage
Fundamental circuit equation:
The capacitance gives an indication of electric inertia. Compare the above equation with Newton’s
Capacitors will tend to hold its voltage fixed.
For a finite current with an infinite capacitance, the voltage must be constant. Hence, capacitors tend to behave like voltage sources (the larger the capacitance, the closer they resemble a voltage source)
A capacitor’s energy is
Inductors
state variable: current
Fundamental circuit equation:
The inductance gives an indication of electric inertia. Inductors will tend to hold its current fixed.
Any attempt to change the current in an inductor will be answered with an opposing voltage by the inductor. If the current tends to drop, the voltage generated will tend to act as an electromotive force. If the current tends to increase, the voltage across the inductor will drop, like a resistance.
For a finite voltage with an infinite inductance, the current must be constant. Hence, inductors tend to behave like current sources (the larger the inductance, the closer they resemble a current source)
An inductor’s energy is