Half-bridge zvs full-bridge driver

In the proposed … Expand. This paper describes the development of a new generation of DC converter used to supply power to telecommunications equipment.

Traditional topologies have been single-phase two-stage designs. As a … Expand. View 1 excerpt, cites background. Materials Science, Engineering. For this improved topology, the main devices are switched on under zero-voltage ZVS … Expand. View 1 excerpt, references background. Engineering, Materials Science. Soft-switching is achieved for a wide load range.

A full-bridge converter which employs a coupled inductor to achieve zero-voltage switching of the primary switches in the entire line and load range is described. Because the coupled inductor does … Expand. Gate drive circuit for zero-voltage-switching half- and full-bridge converters. Formerly Power Conditioning Specialists Conference Power Processing and Electronic Specialists Conference The proposed power supply is based on a modified version of the zero … Expand.

View 1 excerpt, references methods. The authors present the analysis, design, and applications of a high-voltage, high-power, zero-voltage switched ZVS , full-bridge FB pulse-width-modulated PWM converter with an active snubber in … Expand.

Design considerations for high-voltage high-power full-bridge zero-voltage-switched PWM converter. A steady-state analysis is presented with complete characterization of the converter operation. A small-signal model of the converter is established. An H-bridge can also be used to control speed and direction of a DC motor.

In this, as in the applications mentioned above, much of the performance is predicated on the modulation strategy. Two such methods are illustrated below by way of example. Two switches are always gated on and apply a defined voltage to the motor, as determined by the control board. Change in direction is as natural as a change in duty cycle. Current can flow in both direction and the motor can motor or regenerate.

Notice that, during the first part of the cycle transistor current , power is delivered to the motor. During the remainder of the cycle power is returned to the supply.

The first method gives better servo performance while the second method gives much lower ripple current in the motor for the same operating frequency. With this modulation method power is not returned to the supply. Current free-wheels in the top devices and decays, as determined by the losses. Figure 17a. Q1 and Q4 are gated on at the same time while Q2 and Q3 are gated on for the remainder of the cycle.

The motor has a net positive voltage across its terminals. Reactive power is returned to the supply through Q2 and Q3 in the remainder of the cycle.

Since the full rail voltage is applied to the motor with one polarity or the other, ripple current in the motor can be significant. Figure 17b. Q2 and Q4 set the direction of rotation while Q1 and Q3 determine the speed. Reactive power is not returned to the supply but free-wheels in the top devices and decays very slowly. This topology Figure 18 is used almost exclusively to drive three-phase motors with different modulation strategies.

The two most common types of motors are permanent-magnet and induction motors. They require different modulation strategies. In fact, the same type of motor could be driven with different modulations: some modulations enhance motor performance at the expenses of semiconductor losses, others do the opposite.

This is a specialized topic that goes beyond the scope of this short write-up. Three-phase bridge, commonly used to drive motors with different types of modulation. The waveforms shown here represent the line-to-line voltage and line current of a sine modulation for an induction motor. Over the years many such topologies have been devised, some to overcome the limitations of the MOSFET diode, some to reduce the switching losses of IGBTs, some to reduce switching losses in general.

The reduction in switching losses is commonly achieved by some form of resonance, as we will see in some of the examples below. As we have mentioned in Section 3. One topology that is commonly used to take advantage of its conduction capabilities without paying the price in terms of switching losses is the series resonant half-bridge, shown in Figure Two capacitors have been added in parallel with the IGBTs.

This simple addition causes a fundamental change in the way this topology operates. The resulting current blue trace is quasi-triangular. Notice that when one IGBT is turned on the voltage at its terminal is a negative diode drop, hence its turn-on losses are virtually zero. When the anti-parallel diode stops conducting, the voltage at its terminals is the voltage drop across the IGBT.

In this circuit there are no reverse recovery losses. The Series Resonant Half Bridge converter. Notice the difference with the half-bridge shown in Figure the load is mostly inductive and two capacitors have been added in parallel with the IGBTs. The power switches commutate in ZVS zero voltage switching at turn-on, which eliminates turn-on losses. The anti-parallel diodes also commutate at ZVS at turn-off, which eliminates recovery losses. As have seen in Section 3.

If voltage is applied to the gate while diode current is flowing, the equivalent circuit becomes that of a resistor in parallel with a diode Figure As long as the voltage drop across the resistive part is lower than a diode drop 0.

It is widely used in very low voltage regulators V. Figure 20 shows a forward converter where the two output diodes have been replaced by MOSFETs with no other gate drive circuitry than the output of the transformer. This gate drive method is used for illustration only because no gate drive is available when the output of the secondary falls to zero. In practice, specialized ICs are used to drive the gates in synchronous rectification. Forward converter with synchronous rectification.

As long as gate voltage is applied the current will chose the path with lower voltage drop. The self-driven method shown in the picture is not used in practice: specialized gate drive ICs are used for this purpose. Electronics 1. Introduction 2. Passive Components 3. Active Components 4. Topology Fundamentals and Their Basis Waveforms The function of a power circuit is to make whatever power is available suitable to the needs of the load. We will briefly analyze the buck, the boost and few other commonly used topologies.

The performance of this converter is determined by three design choices: The sizing of the reactive components The control method: fixed or variable frequency Operating frequency or frequency range. These design choices determine: The rms component of the input current, hence the size of the input capacitor The amount of ripple in the output voltage waveform The dynamic response to load changes or input voltage changes in closed loop conditions.

As in the buck converter, the performance is determined by three design choices: The sizing of the reactive components The control method: fixed or variable frequency Operating frequency or frequency range. These design choices determine: The rms component of the input current The amount of ripple in the output voltage waveform The dynamic response to load changes or input voltage changes.

The full bridge Two half-bridges can generate an AC output from a single voltage source with no need for a neutral. This topology is most commonly used in three classes of applications: 4. Switched-mode power supplies SMPS and welders As shown in Figure 14, the bridge is used to generate a high-frequency square wave that is fed to an isolation transformer.