Buck Converter Simulation

Design digital controllers for buck converters using simulation

Designing a digital controller with simulation can help ensure that a DC-DC buck converter will properly regulate voltage as load current and source voltage change. Simulation guides the proper choice of power stage components to ensure minimized output voltage ripple and acceptable power losses. Closed-loop simulation of the power stage and controller enables power electronics engineers to evaluate and verify their design choices before a controller is implemented and hardware is built.

When designing a power converter, you should consider simulation for performing the following tasks:

Designing a feedback controller for voltage regulation

  • Optimizing RLC components concurrently with the controller design
  • Estimating the steady-state and dynamic characteristics of the semiconductor switches
  • Analyzing dynamic performance and power quality
  • Prototyping and implementing the digital controller on an embedded microprocessor or an FPGA

Control system design using simulation with Simulink® lets you design, validate, and implement your converter knowing that it will work as intended when you begin hardware testing. You can:

  • Model the power stage using standard circuit components, or use a prebuilt Buck Converter block.
  • Simulate the converter model at different levels of fidelity: average models for system dynamics, behavioral models for switching characteristics, and detailed nonlinear switching models for parasitics and detailed design.
  • Design, simulate, and compare different controller architectures, including voltage mode control and current mode control.
  • Apply classical control techniques such as interactive loop shaping with Bode and root-locus plots on nonlinear converter models that include switching effects using methods such as AC frequency sweeps or system identification.
  • Autotune controller gains in a single or multiple feedback loops using automated tuning tools. Design nonlinear controllers such as sliding mode control or gain scheduling.
  • Model and assess the impact of component tolerances and fault events on the operation of a switching power supply.
  • Evaluate buck converter power quality by simulating it as part of a larger system where a DC-DC power converter is one of the components—for example, a rectifier or a starter generator.
  • Generate C or HDL code from control algorithms for rapid prototyping using a real-time target computer or for implementing them on a microcontroller or FPGA.
  • Generate C or HDL code from circuit models to a real-time target computer for validating a controller using hardware-in-the-loop simulation.

Software Reference

See also: boost converter, MPPT algorithm, Simscape Power Systems, Simscape Electronics, PID control, pulse-width modulation, motor control design with Simulink, motor and power control design with Simulink, power electronics simulation, field-oriented control, BLDC motor control, Clarke and Park transforms

10 Ways to Speed Up Power Conversion Control Design with Simulink