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A novel full-bridge converter suitable for low-voltage high-current output applications is proposed. It realizes ZVS for all switches over the entire load range with the use of voltage complementary auxiliary network on the primary side. A current-doubler rectifier is adopted on the secondary side which has no duty cycle loss and no secondary voltage spike. The operation principle and characteristic...
By integrating a novel voltage doubler rectifier with a classical current-fed converter, a current-fed push-pull boost converter with voltage doubler (CFBCVD) is presented. In addition to having a non-pulsating input current, recovery of the secondary leakage energy, low output capacitor current ripple, much lower rectifier diode voltage stress, and much higher voltage gain can be obtained. These...
This paper describes voltage balancing of all the four split dc capacitors for a five-level diode-clamped PWM inverter intended for a transformerless mediumvoltage motor drive with a three-phase diode rectifier used as the front end. A dc-voltage-balancing circuit is installed on the dc link, and introduces a new midpoint-voltage-balancing method based on phase-shift control. As a result, the dc mean...
Dynamic performances of a wind turbine generating system consisting of series connected wind generators with parallel connected bypass diodes at rectified DC output terminals and a current source thyristor inverter are discussed. It is shown that the tip speed ratio of the individual turbine can be controlled almost constant with the proposed method, making an effective operation of the system possible.
Power generation characteristics of two generator systems consisting of a permanent magnet synchronous generator and diode bridge rectifiers are discussed in this paper. One of the discussed systems has three-phase stator windings, and the other has two sets of three-phase (six-phase) stator windings to reduce pulsation in the electromagnetic torque and DC current. Experimental results reveal that...
This paper presents an approach of sparse matrix converter (SMC) using Z-source network. The SMC is implemented by connecting a controllable rectifier and the traditional inverter through a Z-source network. The Z-source can produce any desired output voltage by controlling the shoot-through time. Compare to the traditional three-phase SMC, the three-phase Z-source SMC has the same number of switches,...
In this paper, loss of a dc microgrid system for residential complex is compared with loss in an ac system. Each system has a PV system, a gas engine cogeneration and 20 residential houses. The losses are calculated from measured load data and PV output data which was estimated from global solar radiation and temperature of a PV panel. The operation of the gas engine cogeneration is determined from...
A novel current driven method for center-tapped synchronous rectifier (SR) is proposed in this paper. Compared with the previous current driven synchronous rectifier (CDSR), two SRs can be driven with only one current transformer by using the proposed CDSR. The new CDSR has the advantages such as simple structure, low power loss and good performance and so on. The performance of the proposed circuit...
In this paper, effects of the recently found mix-mode (MM) conducted electromagnetic interference (EMI) noise emissions on the boost-type power factor corrected (PFC) pulse-width modulated (PWM) rectifier are first introduced. A practical PFC EMI filter design method with consideration of the MM emissions is given. The proposed method can be easily implemented in commercially-available EMI filter...
A high efficiency, low profile, and high step-up dc-dc converter is proposed for low dc voltage renewable energy systems. The proposed converter employs an active-clamp technique with the complementary pulse width modulation (PWM) controller. Multiple transformers can be employed for a low profile design as well as multiple resonant rectifiers for the soft-switching operation of the output rectifying...
This paper extends the single-phase self-driven synchronous rectification (SDSR) technique to multiphase and multi-level AC-DC systems. Power MOSFETs with either voltage or current self-sensing and self-driven gate drives are used to replace diodes in the rectifier circuits. The generalized methodology allows multiphase SDSRs to be designed to replace multiphase diode rectifiers. Unlike traditional...
This paper describes a damping control method of power converters for suppression of the resonance in DC power networks. The resonance investigated in this paper is caused by the impedance of the DC distribution line and the DC line capacitors of the power converters. For detailed investigation, a combined system of a PWM rectifier and a PWM inverter is treated as a simplest example. To suppress the...
Instead of just transforming energy, a modern power converter should incorporate enhanced features to adapt its behavior to its environment. Stability issues in 3-phase power systems with PFC rectifiers incorporating input filters have been a problem for a long time. In this paper a new concept is presented as to how the power converter can shift filter resonances into an unproblematic frequency range...
A 12-pulse phase-controlled rectifier has been used for high power applications. It consists of two sets of 6-pulse rectifiers. Basically they operate in parallel, but they operate alternately if load is light. The commutation of the DC current between the two rectifiers is examined and it is found that harmonic distortion of the input current is automatically minimized if they operate in the boundary...
Converters using active switches can improve harmonic components of input current and power factor. Moreover, these converters contribute to the footprint downsizing. However, increase of switching losses and EMI due to high frequency switching is one challenge of these types of converters. This paper proposes a new active rectifier circuit topology, which can reduce the switching losses and EMI with...
This paper presents a unidirectional neutral-point-clamped three-level four-wire AC-DC-AC converter topology and studies how space vector modulation and vector control can be applied to the converter. It is shown that either the rectifier or inverter can utilize discontinuous modulation if the injected zero-sequence voltage is properly chosen and a method for balancing the partial DC-link voltages...
This paper proposes a new active interphase transformer for 24-pulse diode rectifier. The proposed scheme injects a compensation current into the secondary winding of either of the two first-stage interphase transformers. For only one of the first-stage interphase transformers being active, the inverter conducted the injecting current is with a lower kVA rating [1.26% pu (Po)] compared to conventional...
A single inductor three-level boost bridgeless PFC rectifier with nature voltage clamp is proposed. In the proposed converter, the operation principle is quite different from other boost bridgeless three-level converters. The charging stage is presented in the low side while the discharging stage in the high side and vice versa. As a result, nature voltage clamp is achieved. And the slow diodes are...
A novel two-phase interleaved LLC resonant converter is proposed, which can manage the number of phases by output loading. In the proposed scheme, the output load current is detected with sensing resistor in the output terminal. The measured value is compared with the threshold value for phase management and the signal is generated to trigger the gate driver. As a result, it is possible to improve...
In this paper, we describe 400-Vdc power distribution systems to be used as an energy conservation technology at telecom sites and data centers. We compared the 48-Vdc power distribution systems used at telecom sites with the AC power distribution systems used at data centers, and examined the advantages of DC. However, because of advances in the information and communication services, the 48Vdc system...
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