Split-Pi
Encyclopedia
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
, a split-pi topology is a pattern of component interconnections used in a kind of power converter
Power converter
A power converter is an electrical or electro-mechanical device for converting electrical energy. It may be converting AC to or from DC, or the voltage or frequency, or some combination of these.Amongst the many devices that are used for this purpose are;...
that can theoretically produce an arbitrary output voltage, either higher or lower than the input voltage. In practice the upper voltage output is limited to the voltage rating of components used. It is essentially a boost (step-up) converter
Boost converter
A boost converter is a power converter with an output DC voltage greater than its input DC voltage. It is a class of switching-mode power supply containing at least two semiconductor switches and at least one energy storage element...
followed by a buck (step-down) converter
Buck converter
A buck converter is a step-down DC to DC converter. Its design is similar to the step-up boost converter, and like the boost converter it is a switched-mode power supply that uses two switches , an inductor and a capacitor....
. The topology and use of MOSFET
MOSFET
The metal–oxide–semiconductor field-effect transistor is a transistor used for amplifying or switching electronic signals. The basic principle of this kind of transistor was first patented by Julius Edgar Lilienfeld in 1925...
s make it inherently bi-directional which lends itself to applications requiring regenerative braking
Regenerative brake
A regenerative brake is an energy recovery mechanism which slows a vehicle or object down by converting its kinetic energy into another form, which can be either used immediately or stored until needed...
.
The split-pi converter is a type of DC-to-DC converter that has an output voltage magnitude that is either greater than or less than the input voltage magnitude. It is a switched-mode power supply
SMPS
SMPS may refer to:*Scanning Mobility Particle Sizer*Single member plurality system*Society for Marketing Professional Services*Switched-mode power supply...
with a similar circuit topology to a boost converter
Boost converter
A boost converter is a power converter with an output DC voltage greater than its input DC voltage. It is a class of switching-mode power supply containing at least two semiconductor switches and at least one energy storage element...
followed by a buck converter
Buck converter
A buck converter is a step-down DC to DC converter. Its design is similar to the step-up boost converter, and like the boost converter it is a switched-mode power supply that uses two switches , an inductor and a capacitor....
. Split-pi gets its name from the pi circuit
Capacitor-input filter
The capacitor-input filter, also called pi filter due to its shape that looks like the Greek letter pi, is a type of electronic filter. Filter circuits are used to remove unwanted or undesired frequencies from a signal....
due to the use of two pi filters in series and split with the switching MOSFET bridges.
Other DC–DC converter topologies that can produce output voltage magnitude either greater than or less than the input voltage magnitude include the boost-buck converter topologies (the split-pi, the Ćuk converter
Cuk converter
The Ćuk converter is a type of DC-DC converter that has an output voltage magnitude that is either greater than or less than the input voltage magnitude....
, the SEPIC, etc.) and the buck–boost converter topologies.
Principle of operation
In typical operation where a source voltage is located at the left-hand side input terminals, the left-hand bridge operates as a boost converterBoost converter
A boost converter is a power converter with an output DC voltage greater than its input DC voltage. It is a class of switching-mode power supply containing at least two semiconductor switches and at least one energy storage element...
and the right-hand bridge operates as a buck converter
Buck converter
A buck converter is a step-down DC to DC converter. Its design is similar to the step-up boost converter, and like the boost converter it is a switched-mode power supply that uses two switches , an inductor and a capacitor....
. In regenerative mode, the reverse is true with the left-hand bridge operating as a buck converter
Buck converter
A buck converter is a step-down DC to DC converter. Its design is similar to the step-up boost converter, and like the boost converter it is a switched-mode power supply that uses two switches , an inductor and a capacitor....
and the right as the boost converter
Boost converter
A boost converter is a power converter with an output DC voltage greater than its input DC voltage. It is a class of switching-mode power supply containing at least two semiconductor switches and at least one energy storage element...
.
Only one bridge switches at any time to provide voltage conversion, with the unswitched bridge's top switch always switched on. A straight through 1:1 voltage output is achieved with the top switch of each bridge switch on and the bottom switches off. The output voltage is adjustable based on the duty cycle of the switching MOSFET bridge.
Applications
- Electric drive train
- Motor controlMotor controllerA motor controller is a device or group of devices that serves to govern in some predetermined manner the performance of an electric motor. A motor controller might include a manual or automatic means for starting and stopping the motor, selecting forward or reverse rotation, selecting and...
- Battery balancing
- Regenerative brakingRegenerative brakeA regenerative brake is an energy recovery mechanism which slows a vehicle or object down by converting its kinetic energy into another form, which can be either used immediately or stored until needed...