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**Quasi-square-wave ZVS converters**

A quasi-square-wave ZVS buck Resonant transitions but transistor and diode conduction intervals are similar to PWM Tank capacitor is in parallel with all semiconductor devices, hence all semiconductors operate with ZVS Peak currents are increased, and are similar to DCM Peak voltages applied to semiconductors are same as PWM Magnetics are small, and are similar to DCM

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**Interleaved quasi-square-wave buck converters as VRM**

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**Quasi-square-wave versions of other converters**

Flyback Boost Single transistor version of switch is restricted to 0.5 < µ < 1 So for boost, M > 2 For flyback, M > n Boost inductor and flyback transformer are very small, and are similar to DCM devices

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**Quasi-square-wave ZVS converters**

A quasi-square-wave ZVS buck Resonant transitions but transistor and diode conduction intervals are similar to PWM Tank capacitor is in parallel with all semiconductor devices, hence all semiconductors operate with ZVS Peak currents are increased, and are similar to DCM Peak voltages applied to semiconductors are same as PWM Magnetics are small, and are similar to DCM

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Goal: Find steady-state solution for this resonant switch cell Approach: State plane analysis followed by averaging of terminal waveforms

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**Interval 1 Q1 conduction Begins when Q1 starts to conduct**

For ZVS operation, this occurs when D1 had been previously conducting Circuit Initial conditions Dynamics What ends interval Endpoints Length of interval

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State plane

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**Interval 2 Dead time Circuit Initial conditions Dynamics**

What ends interval Endpoints Length of interval

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**Interval 3 D2 conduction Circuit Initial conditions Dynamics**

What ends interval Endpoints Length of interval

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**Interval 4 Dead time Circuit Initial conditions Dynamics**

What ends interval Endpoints Length of interval

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**Interval 5 (1) D1 conduction**

Circuit Initial conditions Dynamics What ends interval Endpoints Length of interval

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Waveforms

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**Average switch input current**

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**Average output current**

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**Average output current, p. 2**

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**Control input: transistor/diode conduction angle **

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**A way to solve and plot the characteristics**

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Solving, p 2

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**Results: Switch conversion ratio µ vs. F**

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**Switch conversion ratio µ vs. **

Course website contains Excel spreadsheet (with function macros) that evaluates the above equations and can plot the above characteristics.

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