This project is used to control the speed of single phase induction motor by employing Boost converter. The Boost converter is used to boost the input voltage. The boosted dc voltage is applied to the single phase inverter. This single phase inverter converts dc voltage into ac voltage. Single phase induction motor speed depends on the frequency of inverter. The Raspberry pi controller is used to generate the PWM pulses.
This project is mainly used for renewable energy source like solar, wind etc. The solar converts the sunlight directly into electricity. That voltage range is low, so that low voltage is boosted by using the converter circuits. Converter is used to convert the low voltage dc into high voltage dc. Solar energy is involved in power plants, homes made appliances, ventilation systems, commercial appliances, solar lighting, cars and other remote applications where transmission and distribution is done.
The Boost converter has inductor and one power devices for boosting the input voltage. If the power device duty cycle is varying the output voltage of the converter is varied. The converter output dc voltage is applied to the single phase inverter circuit. It converts the dc voltage into single phase ac voltage to drive the single phase induction motor. The Raspberry Pi controller has key function for controlling the speed of the induction motor.
Block Diagram Explanation
- Pulse generator: - Here we have used Raspberry Pi microcontroller (Raspberry Pi - 3) to generate PWM signal.
- Driver circuit: It is used to amplify the pulses and provided isolations using opto coupler. It has two functions,
- Bridge Rectifier: It converts AC supply to DC Supply.
- BOOST converter: It converts low voltage DC to high voltage DC supply.
- Single phase Inverter: It converts DC supply to single phase AC Supply to drive the single phase induction motor.
Raspberry Pi Controller Board
The Raspberry Pi controller is used to generate the PWM pulses for converter and inverter circuit. The Raspberry Pi controller pulses are given to the driver circuit as input. Driver board is mainly used to isolate and amplify the input signals from the controller. The amplified driver output is connected to the main power circuit devices. The ac supply is converted into dc by using bridge rectifier. And the dc voltage is boosted by using Boost converter. The boosted dc voltage is applied to inverter circuit and by varying the frequency of the inverter the motor speed also varied.
Circuit Diagram for Boost Converter
Circuit Diagram for Single Phase Inverter
- High efficiency
- Easy to control the speed
- Switching losses are reduced
- Industrial applications
- Pumping system
The speed control of single phase induction motor by employing Boost converter is mainly used to convert the low voltage sources to useful voltage source. The solar voltage produced is low voltage and the Boost converter is used to boost the low voltage and applied the dc voltage to single phase inverter circuit. So that low voltage solar energy is used to control the induction motor speed.
Output Waveform for Boost Converter
Inverter Output Waveform