Power Electronics Circuits Types Lecture 03 week 2

Power Electronics Circuits & Types Lecture #03 (week #2) ENGR. BILAL AHMAD KUNDY B. TECH (ELECTRICAL)

Power Electronics Circuits Power electronic circuits are essential parts in any renewable energy system. Power semiconductor devices are used as switches in these power electronic circuits. The Power device, the product of the switch voltage and current, is identically zero at all times. A switch therefore controls energy flow with no loss. In addition, reliability is also high. All power electronic circuits manage the flow of electrical energy between an electrical source and a load. A general power conversion system is shown in Figure. The power converter in the middle controls the energy flow between a source and a load.

Block Diagram The complete concept, shown in Figure, represents a power electronic system.

Power Electronics Circuits A power converter connected between a source and a load also affects system reliability. The complete concept, shown in above Figure, represents a power electronic system. Such a system consists of an electrical energy source, an electrical load, a power electronic circuit, and a control function.

Power Electronics Circuits The power electronic circuit contains switches, lossless energy storage elements, and magnetic transformers. The controls take information from the source and the load, and the designer then determine how the switches operate to achieve the desired conversion. The controls are built up with low-power analog and digital electronics.

Types of Power Electronics Circuits Power Electronics circuits can be divided into the following categories: 1. AC-DC Converters (Uncontrolled Rectifiers) 2. AC-DC Converters (Controlled Rectifiers) 3. AC-AC Converters (AC Voltage Controllers) 4. DC-DC Converters (DC Choppers) 5. DC-AC Converters (Inverters) 6. Static Switches. (AC Or DC)

Types of Power Electronics Circuits AC-DC Converters (Uncontrolled Rectifiers) It converts Single-phase or three-phase AC Voltage into a FIXED DC Voltage. Diodes are used as the rectifying element to provide power conversion. AC-DC Converters (Controlled Rectifiers) It converts Single-phase or three-phase Fixed AC Voltage to a Variable DC Voltage. SCRs are used as the rectifying element to providing both power conversion & control.

Types of Power Electronics Circuits AC-AC Converters (AC Voltage Controllers) It converts Fixed AC Voltage to a Variable AC Voltage at the same frequency. There are two basic methods used: On-Off Control & Phase Control. DC-DC Converters (DC Choppers) It converts Fixed DC Voltage to a Variable DC Voltage. The average output voltage is controlled by varying the conduction of transistor.

Types of Power Electronics Circuits DC-AC Converters (Inverters) It converts Fixed DC Voltage to a Fixed or Variable single-phase or three-phase AC Voltage and frequency. Static Switches (AC or DC) The power devices (SCR & TRIAC) can be operated as AC or DC switch, therefore the switches are called as AC static switches or DC switches.

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