As it has been clarified by information provided in the previous chapters, there is a necessity to convert electrical energy from one input kind into other output kind of energy.
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As it has been clarified by information provided in the previous chapters, there is a necessity to convert electrical energy from one input kind into other output kind of energy.
Power electronics is a technology to create power electronic converters associated with conversion of electrical energy using electronic means. Cumulative electronic means covers the following groups:
- 1.
Power schema made on the basis of power electronic devices (switches): Diodes, thyristors (silicon controlled rectifier - SCR), insulated gate bipolar transistors (IGBT), metal–oxide–semiconductor field-effect transistors (MOSFET), etc.
- 2.
Control and regulation system made on the basis of analogue and digital electronic elements: Analogue and digital integral circuits, microprocessors, microcontrollers, digital signal processors, etc. Additionally, software is included here, if a processor is applied in the control system.
- 3.
Sensors used to monitor the basic variables: Current, voltage, power, temperature, etc.
Figure 1 shows the basic schema to explain the definition. The conversion is made under the action of control signals, which are obtained from the control system. The most frequently, sensors are applied to monitor parameters referred to the output energy. Also, it is possible to monitor the parameters referred to the input energy, as well as variables in the converter itself. The sensor output signals are employed as feedbacks to the control system.
Figure 1. General schema of electrical energy conversion
In Figure 2 the schema is extended with showing several of the possible sources of electrical energy as input ones, as well as several of the possible loads demanding electrical energy as output energy of the conversion.
Figure 2. Sources and consumers of electrical power
Dependent on the input and output type of the electrical power, power electronic converters can be divided in several basic groups as follows:
- 1.
Converters of AC into DC power – they are called rectifiers
- 2.
Converters of AC into AC power
- 3.
Converters of DC into DC power
- 4.
Converters of DC into AC power – they are called inverters
In this chart, as well as in the whole book, international accepted symbols for the type of energy AC (alternating current) and DC (direct current) are used.
The Power Electronics is applicable within the whole field of electrical power systems. The power range of its applications is from a few VA/Watts to several MVA/MW.
The Power Electronics demands knowledge many and also different fields, thereby it is interdisciplinary (Peter, 1994). Figure 3 displays these fields, which are: