Switch-mode Power Electronics
This hands-on lab introduces core DC-DC converter topologies—buck, boost, buck-boost, flyback, forward, and full-bridge—on a GaN/Si power electronics platform.
Objectives
- Demonstrate the ability to set up and operate the GaN/Si power electronics platform and run pre-built DC-DC converter models in real time using safe lab practices.
- Measure and compare the switching characteristics of Si MOSFETs, GaN FETs, and diodes (turn-on, turn-off, reverse recovery, switching energy) using appropriate instrumentation.
- Analyze CCM and DCM operation of buck, boost, and buck-boost converters; verify duty-cycle–to–voltage-gain relationships, inductor current ripple, and conduction intervals from measured waveforms.
- Evaluate device and component stresses (switch voltage/current, diode stress, inductor current, output-capacitor ripple) and relate them to efficiency and thermal/design trade-offs.
- Design, implement, and tune voltage-mode control for a buck converter to achieve accurate regulation with adequate phase and gain margins and fast transient response.
- Characterize flyback and forward converters in CCM and DCM; identify magnetizing current behavior, demagnetization interval, and core-reset requirements.
- Design and validate a snubber network for the flyback (and related topologies) to clamp switch voltage and mitigate ringing; estimate clamp level, damping, and loss.
- Compare and justify topology selection (buck, boost, buck-boost, flyback, forward, full-bridge) for a given specification based on isolation needs, efficiency, control complexity, and component stresses.
- Develop proficiency with oscilloscopes, differential and current probes, and safe high-dv/dt measurement techniques for accurate capture of switch-node and inductor waveforms.
Photos
Equipment
Power electronics lab kit (CUSP Power Electronics Kit)
Sciamble Corp.
Isolated DC power supply
B&K Precision Corporation
Digital multimeter
B&K Precision Corporation
Digital storage oscilloscope
Tektronix
Experiments
Description: In this experiment, a pre-built buck converter open-loop control model is run in real time as an introduction to the components mentioned above. The following section gives a brief overview of the various components used to run the buck converter model. This will be followed by running the system in real time using the GaN/Si power electronics platform.
Description: The objective of this experiment is study the switching characteristics of power MOSFETs and power diodes using a buck converter. The circuit will be operated in open loop conditions (without feedback). The primary objective is to understand the switching behavior of these two power devices.
Description: The objective of this experiment is to study the characteristics of a buck converter. The circuit will be operated under continuous-conduction mode (CCM) and open-loop conditions (without feedback).
Description: In the previous experiment, Buck converter - Continuous conduction mode (CCM) was analyzed in continuous-conduction mode (CCM), i.e., the inductor current was always greater than 0. In this experiment, the buck converter operation under discontinuous-conduction mode (DCM) is analyzed. Unlike CCM, under DCM the inductor current briefly goes to 0 during each switching cycle.
Description: The objective of this experiment is to study the characteristics of a boost converter. The circuit will be operated under continuous-conduction mode (CCM) and open-loop conditions (no feedback).
Description: In the previous experiment, Boost converter - Continuous conduction mode (CCM) was analyzed in continuous-conduction mode (CCM), i.e., the inductor current was always greater than 0. In this experiment, the boost converter operation under discontinuous-conduction mode (DCM) is analyzed. Unlike CCM, under DCM the inductor current briefly goes to 0 during each switching cycle.
Description: The objective of this experiment is to study the characteristics of a buck-boost converter. The circuit will be operated under continuous conduction mode (CCM) and open loop conditions (no feedback).
Description: In the previous experiment, Buck-boost converter - Continuous conduction mode (CCM) was analyzed in continuous-conduction mode (CCM), i.e., the inductor current was always greater than 0. In this experiment, the buck-boost converter operation under discontinuous-conduction mode (DCM) is analyzed. Unlike CCM, under DCM the inductor current briefly goes to 0 during each switching cycle.
Description: In voltage-mode control, the objective is to regulate the output voltage of the buck converter with fast dynamic response and adequate stability margins..
Description: The objective of this experiment is to study the characteristics of a flyback converter. The circuit will be operated under both continuous conduction mode (CCM) and discontinuous conduction mode (DCM).
Description: The objective of this experiment is to design a snubber circuit for flyback converter to clamp the voltage across the switch.
Description: The objective of this experiment is to study the characteristics of a forward converter. The circuit will be operated under continuous conduction mode (CCM) and open loop conditions (no feedback).
Description: The objective of this experiment is to study the characteristics of a full-bridge converter. The circuit will be operated under continuous conduction mode (CCM) and open-loop conditions (no feedback).
Resources
Safety considerations when working in power electronics
Open resource →Textbook
Power Electronics: A First Course
Ned Mohan, Siddharth Raju · Wiley