Nonlinear Effect of Deadtime in Small-Signal Modeling of Power-Electronics System Under Low Load Conditions
Berg, Matias; Roinila, Tomi (2020)
Berg, Matias
Roinila, Tomi
2020
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202009307188
https://urn.fi/URN:NBN:fi:tuni-202009307188
Kuvaus
Peer reviewed
Tiivistelmä
Deadtime is required to ensure that switches of a synchronous switching inverter leg never conduct at the same time. During deadtime, the current commutates to an anti-parallel diode that can cause a voltage error depending on the instantaneous current direction. To measure a frequency response from a system, external injections are commonly required to perturb the system. The perturbation can change the current direction at the frequency of the injection causing a voltage error at injection frequency due to the deadtime. The error depends on the perturbation amplitude, inductor current ripple and the fundamental current amplitude. This paper proposes a describing-function method to model the deadtime effect under low load conditions. It is shown that a nonlinear damping effect from the deadtime can occur under low load conditions and cannot be modeled with a resistor-like element. Real-time hardware-in-the-loop-simulation results are presented and used to demonstrate the effectiveness of the proposed method. Experimental measurements are used to verify the nonlinear deadtime effect.
Kokoelmat
- TUNICRIS-julkaisut [16983]