Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 8 of 8 for “"Variable switching frequency"”.
-
Medium voltage extreme fast charger based on novel medium voltage SiC power devices
… voltage power electronic switches and soft-switching over the entire range of grid voltage has been ensured by a novel variable switching frequency double phase shift modulation technique. Experimental results validate the simulation results and show a high efficiency of 98%. A novel and …
-
DM EMI Noise Analysis for Single Channel and Interleaved Boost PFC in Critical Conduction Mode
… widely used in industry for low power offline switching mode power supplies. For the CRM PFC, the main advantage is to reduce turn-on loss of the main switch. However, the large inductor current ripple in CRM PFC creates huge DM EMI noise, which requires a big EMI filter. The switching …
-
Novel Voltage Control Methods for quasi-Z-source Network Converters with Focus on Fixed DC-Link Voltage, Constant- Frequency and Soft-Switching Operation
… degrade efficiency, and disrupt consistent soft switching. Conventional pulse-width-modulated (PWM) qZS converters often rely on variable switching frequency or auxiliary circuits to achieve soft switching, which increases cost and control complexity. Resonant qZS converters can enhance gain and …
-
Improvements in direct torque control of induction motors
… control of the electrical motor by means of a variable speed drive incorporating sophisticated control strategies. Besides the expectations that have to be met concerning the motion control, other aspects such as efficiency, reliability, generation of electromagnetic pollution, etc. have become …
-
A High Power Density Three-level Parallel Resonant Converter for Capacitor Charging
This dissertation proposes a high-power, high-frequency and high-density three-level parallel resonant converter for capacitor charging. DC-DC pulsed power converters are widely used in military and medical systems, where the power density requirement is often stringent. The primary means for …
-
Zero Voltage Switching (ZVS) Turn-on Triangular Current Mode (TCM) Control for AC/DC and DC/AC Converters
… of these filters can be reduced by pushing the switching frequency higher. High frequency operation (> 300 kHz) leads to a size in reduction of EMI filters though it also leads to an increase in switching losses thus compromising on efficiency. Thus, soft switching becomes necessary to reduce …
-
Digital control of a multi-channel boundary-conduction-mode boost converter for power-factor-correction applications
… all line voltages. BCM boost converters have a variable switching frequency. Hence, a phase-shift control scheme is used to allow interleaving between the different boost-converter channels. It is important that the phase-shift control scheme requires minimal microcontroller computational …
-
Digital-Based Zero-Current Switching (ZCS) Control Schemes for Three-Level Boost Power-Factor Correction (PFC) Converter
… low-cost system in the PFC stage, zero-current switching (ZCS) control schemes are highly employed in control principles. Representative schemes are discontinuous conduction mode (DCM) and critical conduction mode (CRM). Both modes can realize ZCS turn-on without diode reverse recovery so that …