Hungkuang University

Yuan Ze University

Rou-Yong Duan

Rong-Jong Wai

Chao-Tsung Chang

Rong-Da Luo

A power converting device converts a DC voltage input from an external power source into an AC voltage output across an output capacitor of an output circuit, and includes a coupling circuit having series first and second windings. A rectifying diode has a grounded anode coupled to an anode of a clamp diode, and a cathode coupled to the second winding. A cathode of the clamp diode is coupled to a clamp switch and the first winding. A full-bridge circuit includes a first series connection of first and second switches, and a second series connection of third and fourth switches. The first and second series connections are coupled in parallel between the first winding and ground. The output capacitor is coupled between a first common node between the first and second switches, and a second common node between the third and fourth switches.

Power converting device with high power transformation efficiency

A power converting device is adapted for converting a DC voltage input from an external power source into an AC voltage output. The power converting device includes: a transformer having first and second windings each having opposite first and second ends; a clamp unit coupled to the external power source, and including a first switch coupled between a reference node and the second end of the first winding, and a series connection of a clamp capacitor and a second switch coupled across the first winding; and an inverting unit coupled to the first end of the second winding, and operable so as to output the AC voltage output based on an induced voltage across the second winding.

DC-to-AC power converting device

A boost device boosts an input voltage to an output voltage across an output capacitor, and includes first and second output diodes coupled to the output capacitor, and a transformer coupled to first and second switches, first and second switching circuits, and to the first and second output diodes, and receiving the input voltage. The first and second switches are operated alternately in an ON-state, and have overlapping duty cycles. The first and second switching circuits are operable to suppress conduction losses for the first and second switches. The transformer has a bi-directional magnetic circuit. Electric energy is transformed through induced currents of the transformer, and a small amount of energy attributed to an exciting current of the transformer is used for voltage boosting, thereby attaining a relatively high output power.

Boost device for voltage boosting

A bidirectional power converting device coupled between first and second power storage units includes: a coupling circuit including a first winding coupled to the first power storage unit, and a second winding coupled in series to the first winding; first and second switches coupled to the first winding; a capacitor coupled between the first and second switches; a third switch coupled between the second winding and the capacitor; and a fourth switch between the second winding and the second power storage unit. The first, second, third and fourth switches are operable so that an input voltage supplied by one of the first and second power storage units is converted into an output voltage that is to be supplied to the other one of the first and second power storage units.

Bidirectional power converting device

A boost device boosts an input voltage to an output voltage across an output capacitor, and includes an output diode coupled to the output capacitor, and a transformer coupled to a first switch, a clamp circuit and a boost circuit. The clamp circuit is coupled across a first winding of the transformer, and includes a clamp capacitor coupled in series to a second switch. The output capacitor is capable of being charged through the output diode with an induced voltage across a second winding of the transformer. The boost circuit is capable of being charged with the induced voltage across the second winding, and of charging the output capacitor so as to boost the output voltage across the output capacitor.

The aim of this invention focuses on the development of a high-efficiency bidirectional converter for power sources with great voltage diversity. In traditional bidirectional converters, the circuit topology with transformer form is the common usual. Moreover, the soft-switching techniques including zero-voltage-switching (ZVS) or zero-current-switching (ZCS) are usually used for alleviating the corresponding switching losses. However, there are four and upward power semiconductor switches in these circuit schemes. By this way, it will result in the increase of production cost, and the degeneration of conversion efficiency. The coupled-inductor bidirectional scheme in the proposed converter only adopts three power semiconductor switches to accomplish the objective of bidirectional current control. Under the situation of non-isolation circuit topology, it still possesses the protection of electric safety for operators. Due to the characteristics of high step-up and step-down ratio, the battery module with low voltage could be injected into a high-voltage dc bus for the later utilization, e.g., high-voltage load, front-end of inverter. Since the techniques of voltage clamping, synchronous rectification and soft switching are manipulated in this circuit topology, and the corresponding device specifications are adequately performed, it can achieve the goal of high-efficiency bidirectional power conversion for power sources with great voltage diversity.

High-efficiency high-voltage difference ratio bi-directional converter

A current-source sine-wave voltage inverter for converting a direct current (DC) voltage to an alternating (AC) voltage includes a DC source for providing a DC voltage, a current source circuit having a primary side inductance of a transformer, a clamping circuit, an inverting circuit, and a control and driving circuit. The clamping circuit includes a first switch cascaded with a first diode, a second diode cascaded with a second switch, a first capacitor connected between an anode of the first diode and a cathode of the second diode, a secondary side inductance of the transformer cascaded with a third diode, the secondary side inductance of the transformer and the third diode connected to two ends of the DC source, and a cathode of the third diode connected to an anode of the DC source. The present invention also provides a fuel cell system.

Current source wave voltage inverter voltage-clamping and soft-switching techniques, and fuel cell system using the same

A boost converter utilizing bi-directional magnetic energy transfer of coupling inductor provides a high efficiency boost DC-DC converting with above 30 times voltage boost rate, which uses a coupling inductor and low voltage switch to absorb circuit induction voltage of a passive regenerative snubber no matter if switch is turned on or off. Such that, a much higher voltage boost rate than the turn rate of transformer and wider range of switching duty cycle is obtained. A bi-directional magnetic energy path is utilized, that is, when switch is turned on the first winding of coupling inductor stores magnetic excited high current energy, and opposite magnetic flux is induced on the second winding at the same time. When switch is turned off the magnetic excited current continues and increases the voltage on the second winding. The second winding has bi-directional magnetic current induced and fully utilizes capacity of transformer's iron core.

Boost converter utilizing bi-directional magnetic energy transfer of coupling inductor

A hybrid clean-energy power-supply framework integrates a fuel cell, solar cell, and wind energy, applies a max power tracking rule, raises the output power of a solar cell and wind energy to supply a power load and transfer the surplus electrical energy to a water-electrolyzing apparatus for producing hydrogen and oxygen, and provides a fuel for a fuel cell power generating system. Furthermore, the present invention utilizes features of each clean-energy power generating system, depends on the powerful calculation capacity of a central processing unit to monitor and dispatch each power generation and supply system, and thus ensures the reliability of supply power and reduces the power generation cost. Such a framework can selectively grid-connect with the utility power or run as a stand-alone power supply system and has a mechanism for preventing the island effect.

Growing community of inventors

Guosing, Taiwan

Rou-Yong Duan