Other

Queen's University at Kingston

Hongliang Wang

Yan-Fei Liu

Yang Chen

Zhanming Li

Yue Fu

Yanfei Liu

Resonant converters may be operated according to selected working modes to achieve voltage doubler or non-voltage doubler functions. Embodiments may be based on two-phase resonant converters. Embodiments may implement primary side switching, secondary side switching, or both, to achieve the selected working modes and voltage doubler and non-voltage doubler function. Embodiments are suitable for applications requiring wide input and output voltage ranges, such as low-voltage charging circuits for personal electronic devices, and high voltage charging circuits for electric vehicles.

Power converter topologies and control methods for wide input and output voltage ranges

A single-phase five-level active clamping converter unit and a converter. The single-phase five-level active clamping converter unit has three input ends and one output end, and also comprises: a suspension capacitor and a topological control portion. The topological control portion is connected to the suspension capacitor and the three input ends and one output end of the single-phase five-level active clamping converter unit, is connected to a plurality of control ends, and is suitable for the supply of at least eight operating modes under the control of a control signal accessing the control ends. In the single-phase five-level active clamping converter unit, a topological structure is easy to design, and is simple and convenient to control.

Single-phase five-level active clamping converter unit and converter

A single-phase four-level inverter circuit topology and a three-phase four-level inverter circuit topology. The single-phase four-level inverter circuit topology is adapted to be used with two series-connected direct current power sources, so as to enable a first direct current power source or a second direct current power source to supply power to a load of the four-level inverter circuit topology, alternatively, any one of two direct current power sources is first algebraically superimposed with a flying capacitor and then supplies the power to the load of the four-level inverter circuit topology (M), thereby making the four-level inverter circuit topology output four different levels. The single-phase and three-phase four-level inverter circuit topologies reduce the system cost and volume by using a flying capacitor, the voltage utilization rate is three times that of the existing four-level inverter circuit topology under the same operating conditions, and the direct current side neutral point voltage can be balanced without requiring additional circuits.

Single-phase four-level inverter circuit topology and three-phase four-level inverter circuit topology

A single phase five-level inverter topology comprising a half-bridge inverter circuit with a floating capacitor which outputs five mutually different voltage levels including zero, wherein both the system cost and the size is reduced, the leakage current is eliminated substantially and high efficiency is achieved by using five-level half-bridge structure with only one AC filtering inductor. A three-phase five-level inverter topology wherein the voltage utilization is twice that of the present three-phase five-level half-bridge inverter under the same operating conditions; the AC filtering inductance is smaller than that of the three-level half-bridge inverter; the DC link mid-point voltage can be balanced without additional circuitry.

Five-level half bridge inverter topology with high voltage utilization ratio

Disclosed are half bridge inverter unit and inverter thereof. The half bridge inverter unit includes an inverter controlling module and inductors. The inverter controlling module provides different connection modes based on different operation modes so that the inverter meets the requirement of wide input voltage range as it can work in either voltage step-up mode or voltage step-down mode. The mid-point voltage between the DC series capacitors connected in parallel with DC power supply can be balanced automatically by taking advantage of the grid voltage symmetry with regard to positive and negative half cycles. The inverter is of single stage structure. It has advantages of low power loss, low cost, high efficiency and reliability.

Half bridge inverter units and inverter thereof

A five-voltage level inverter topology circuit and a three-phase five-voltage level inverter topology circuit, suitable for use with two series-connected direct current (DC) power sources, include a half-bridge inverter circuit having a first circuit module and a second circuit module. The half-bridge inverter circuit outputs five voltage levels including a 0V level. The five-voltage level inverter topology circuit has a five-voltage level half-bridge structure, and only requires an alternating current (AC) filtering inductor, thereby reducing system cost and size, removing leakage current, and providing high efficiency.

Five-level inverter topology with high voltage utilization ratio

A hybrid rectifier that works as either a hybrid full bridge or a voltage doubler. Under 220 V AC input condition, the hybrid rectifier operates in full bridge mode, while at 110 V AC input, it operates as voltage doubler rectifier. The hybrid rectifier may be used with a DC-DC converter, such as an LLC resonant converter, in a power supply. With this mode switching, the LLC converter resonant tank design only takes consideration of 220 V AC input case, such that the required operational input voltage range is reduced, and the efficiency of the LLC converter is optimized. Both the size and power loss are reduced by using a single stage structure instead of the conventional two-stage configuration.

Hybrid full bridge-voltage doubler rectifier and single stage LLC converter thereof

Hybrid modulation strategies are provided for single phase and three phase inverter topologies. According to hybrid modulation strategy embodiments, one line frequency period is divided into two operation modes based on the polarities of output voltage and output current. When polarities of the output voltage and output current are the same, a nominal voltage level modulation is used to generate the output voltage. When polarities of the output voltage and output current are opposite, a lower voltage level modulation is used to generate the output voltage. In one embodiment, a nominal voltage level modulation is five voltage level modulation, and a lower voltage level modulation is three or two voltage level modulation. Embodiments allow inverters to be constructed with fewer switches, and improve performance of multilevel inverters. The hybrid modulation strategies may be implemented in multilevel inverters such as active neutral point clamped (ANPC) and neutral point clamped (NPC) inverters.

Hybrid modulation strategy for multilevel inverters

Five-level topology units and inverters based on the five-level inverter units without a boost circuit. Cost is reduced by using only one AC filtering inductor and high efficiency is achieved in the absence of an extra boosting circuit. Leakage current is eliminated substantially by using a half-bridge inverter module. A five-level inverter including a five-level topology unit without a boost circuit to raise the input voltage is able to output the same AC power as a five-level full bridge inverter under the same working condition.

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Hefei, China

Hongliang Wang