Chaos in Power Electronics & Power Supplies (2 of 5)

Relevance

Chaos can exist in a wide variety of power electronics circuits including:

• PWM regulators,
• ripple regulators,
• current-mode controllers,
• overcurrent protection circuits,
• series resonant circuits,
• rectifier-filter circuits,
• ferro-resonant circuits,
• snubbers with nonlinear inductors,
• magnetic amplifiers,
• circuits with a combination high-gain and low-gain loop, etc.

Nonlinear Systems
Chaos occurs in nonlinear circuits of second order or higher.

Autonomous Systems
In autonomous circuits (no external driving function) such as a ripple regulator, the circuit must be a third order (three or more energy storage elements) or higher. Energy storage elements that increase the circuit order can include parasitic capacitance and stored charge in diodes and transistors. Autonomous systems whose only periodic solutions are limit cycles do not exhibit chaos. Single and second order autonomous systems are not chaotic. [BROC84A]

Driven Systems
In driven circuits, such as the buck converter with PWM voltage-mode control, chaos can occur in second order systems. The driving element in this circuit is the external PWM sawtooth ramp. [DEAN90B]

Use
Chaos is usually bounded and non-destructive and therefore may be useful, although presently it is usually considered undesirable. As it is understood and controlled, it may provide useful in design, for example, smearing discrete harmonics to broadband noise.

Do not use this information for design without independent verification of the information.

Editor: Jerrold Foutz