A Passive Filter Building Block for Input or Output Current Ripple Cancellation in a Power Converter

This paper discusses applying various switching strategies such as conventional complementary and proportional methods on a specific converter. This converter was recently presented and it can provide high voltage gain and has current ripple cancelation ability at a preselected duty-cycle. The input current ripple is zero when the converter works at a special duty-cycle. But load disturbance leads to output voltage changes that maybe cause the duty-cycle to deviate from its preselected value. In this situation, the input current ripple cannot be completely canceled. The proposed proportional strategy is an optimized method for minimizing input current ripple at other operating duty-cycles and also it provides a voltage gain lower than conventional complementary strategy. Here, the converter's performance is analyzed under two switching strategies and the effect of various strategies has been investigated on converter parameters including output voltage and input current ripple. These considerations are verified by implementing a 100-W prototype of the proposed converter in laboratory.

This paper proposes an optimal methodology based on the Differential Evolution algorithm for obtaining the set of duty cycles of a recently proposed power electronics converter with input current ripple cancelation capability. The converter understudy was recently introduced to the state-of-the-art as the interleaved connection of two unequal converters to achieve low input current ripple. A latter contribution proposed a so-called proportional strategy. The strategy can be described as the equations to relate the duty cycles of the unequal power stages. This article proposes a third switching strategy that provides a lower input current ripple than the proportional strategy. This is made by considering duty cycles independently of each other instead of proportionally. The proposed method uses the Differential Evolution algorithm to determine the optimal switching pattern that allows high quality at the input current side, given the reactive components, the switching frequency, and power levels. The mathematical model of the converter is analyzed, and thus, the decision variables and the optimization problem are well set. The proposed methodology is validated through numerical experimentation, which shows that the proposed method achieves lower input current ripples than the proportional strategy.

A ripple current cancellation technique injects AC current into the output voltage bus of a converter that is equal and opposite to the normal converter ripple current. The output current ripple is ideally zero, leading to ultra-low noise converter output voltages. The circuit requires few additional components, no active circuits are required. Only an additional filter inductor winding, an auxiliary inductor, and small capacitor are required. The circuit utilizes leakage inductance of the modified filter inductor as all or part of the required auxiliary inductance. Ripple cancellation is independent of switching frequency, duty cycle, and other converter parameters. The circuit eliminates ripple current in both continuous conduction mode and discontinuous conduction mode. Experimental results provide better than an 80/spl times/ ripple current reduction.

The Weinberg converter is a suitable choice for the battery discharge regulator of a geostationary satellite due to its high efficiency, continuous input and output current, and soft switching of switches and diodes. Nevertheless, this converter has high output current ripple during the commutation period of its output diodes. Therefore, the output RMS current and output voltage ripple are high, which may directly affect the lifetime and total capacitance of bus capacitors and hence, the lifetime and volume of the geostationary satellite. Thus, reducing the output current ripple is important to the design of the geostationary satellite. An improved Weinberg converter with an additional inductor and capacitor is proposed in this paper to reduce the output current and voltage ripple. It features soft switching of all switches, no reverse recovery problems of the diodes, and reduced magnetizing offset current in the coupled inductor. The proposed converter is verified with experimental results from a 750W, 100kHz, 36-50Vdc prototype.

A high gain bidirectional DC-DC converter is described in this paper. This converter consist of a buck-boost topology which has continuous input current followed by a high gain switched-capacitor based boost converter [11]. The modified converter has six switches with their body diodes. The operation of switches is in such a way that three switches requires gate pulse from each side of operation. The current ripple cancellation at low voltage side and low switches voltage stress are the main feature of this modified converter. Compared to other buck-boost converters, the converter's voltage gain is more in boosting mode. The simulation study is carried out and presented for validation of the modified converter effectiveness.

This work presents a single stage converter for a high bandwidth and a high efficiency envelope amplifier. The current ripple cancellation technique is applied to a synchronous buck converter to cancel the output current ripple and to decrease the switching frequency without a reduction in the large signal bandwidth. The converter is modeled and the new design with ripple cancellation circuit is detailed. The advantages of the proposed design are presented and validated experimentally. The transfer function of the output filter of the buck converter with ripple cancellation circuit has been modeled and compared to measurements, showing a good correspondence. Experimental validation is provided at 4MHz of switching frequency for DC and variable output voltage for a sinusoidal and a 64QAM signal. Additional experimental validation of the efficiency improvement is provided, compared to the equivalent design (same bandwidth and output voltage ripple) of the conventional buck converter.

Analysis and minimization of input current and voltage ripples of five-phase PWM inverters are presented in this paper. The analytical expressions for the RMS value of input current and voltage ripples as a function of the PWM reference signal are derived. Different to three-phase PWM inverters, it is shown that pure sinusoidal is the optimum reference signal that produces minimum input voltage ripple. Input current ripple does not depend on the employed reference signal so the ripple canpsilat be minimized by changing reference signal. Simulation and experimental results verify the analysis.

A New Topology of Bidirectional Buck-Boost dc/dc Converter with Capability of Soft Switching and input Current Ripple Cancellation

This brief proposes a thorough methodology for the steady-state characterization of input and output current ripples in discontinuous conduction mode (DCM) interleaved power converters, under inductance mismatch. The proposal analyzes total ripple for any number of phases, any inductance ratio and operating point. Furthermore, calculation of amplitude, rms value and harmonic content of total input and output current ripples is presented. Experimental tests on a 5-phase boost converter are conducted under different conditions to verify the presented method.

SummaryThis paper proposes a power electronics converter capable of canceling the input current ripple at preselected duty cycle. The proposed converter is an extended topology of a buck–boost converter aided by a boost‐type converter that improves the quality of the current drawn from the direct current source. The voltage gain of the proposed converter is increased as well, with a minimum of extra component added to the original buck–boost power converter. These features make the proposed converter ideal for low voltage generation sources, such as photovoltaic panel and fuel cell applications. Along this paper, the state space mathematical model is developed to provide the key design guidelines. The theoretical analysis is validated through computer simulation and hardware prototyping.

In this article, a novel high-power-factor electrolytic-capacitorless light-emitting diode (LED) driver based on the use of a ripple port is presented. The ripple port consists of adding an extra power processing circuit at the output of the converter that injects energy to compensate for the output current and voltage ripples. In this work, the main converter is built by using a flyback converter operating in the discontinuous conduction mode (DCM). The ripple port is implemented by adding an extra winding to the flyback coupled inductors, together with an extra switch, a capacitor, and an inductor. The additional switch is used to inject energy to the output in the time intervals, in which the flyback output current is low, thus reducing the output current ripple. The proposed converter is analyzed in detail, and a design methodology is proposed. A design example for a 27-V/1-A LED lamp is presented. Simulation and laboratory experiments have also been carried out. It is demonstrated that the proposed solution can achieve a reduction on the output current ripple of around 65% compared to the solution without ripple port for the same total capacitance and maintain a high power factor of 0.994.

In a high power converter design for fuel cell applications, the usefulness of interleaving power converter module has become apparent. The benefits of interleaving include: reduced rms current in the do bus capacitors; ripple current cancellation in the input and output waveforms; reduction of size and volume of input inductors, enabling the simplicity to obtain Ferrite-core and Litz wire size; improved transient response as a result of reduced input inductance and higher input and output ripple frequency; separation of heat generating components; and power converter segmentations, enabling the superior reliability. So, this paper presents a fuel cell current control loop of the proposed 4-phase interleaved boost converter for high power fuel cell applications. Experimental results of the proposed FC converter (1.2-kW) at 25-kHz PWM switching frequency connecting with a Nexatrade PEM fuel cell (1.2-kW, 46-A,) collaborate the excellent performances: static and transient states of the design system.

In this article we provide an analysis, design, and implementation of a universal input 150-Watt boost power factor correction converter with a ripple current cancellation circuit for lighting industry. A simulation and experimental bench test model of the 150-Watt boost power factor converter with the ripple current cancellation circuit is presented. The results obtained from the simulation and experimental model are presented. The EMI results of the ripple current cancellation circuit are compared with the traditional filtering method used for the EMI suppression on the 150-Watt boost power factor correction converter. Advantages of the proposed ripple current cancelation circuit are discussed.

This paper presents a current ripple analysis of new double-stator AC drive system. At first, a new double-stator AC drive system is proposed. The aim is to combine the benefits both the multilevel and multiphase system to provide the better performance to drive AC motor. The input and output current ripples of the proposed AC drive system are then analyzed. The current ripples of the proposed AC drive system are then compared to the ones of conventional double-stator AC drive system. Under the same DC input voltage, it is shown that the proposed results in less output current ripple. Under the same output voltage, the proposed AC drive system results in smaller input current and, therefore, fewer losses on the DC power supply. Experimental results are included to show the validity of the proposed concept.

This article introduces a nonisolated bidirectional converter with high-voltage conversion ratio. In the proposed converter, by integrating the two-phase low-voltage-side (LVS)-parallel high-voltage-side (HVS)-series bidirectional converter with the coupled inductors, features, such as high voltage gain, low voltage stresses, current sharing, and current ripple cancelation, are achieved. Due to the proposed converter's operation in triangular conduction mode, the desirable benefits of zero voltage switching, diode reverse recovery elimination, and reduction of converter filter inductors and, consequently, leakage inductors are obtained. To recycle the leakage inductors' energy and to solve the related difficulties for both operation modes, a simple passive clamp with the minimum number of elements is utilized. Also, to improve the light-loads' efficiency, the variable frequency control is developed. The proposed converter is comprehensively analyzed, and to verify the analysis, the experimental results are provided.