Ripple current cancellation circuit
ABSTRACT 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× ripple current reduction.
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ABSTRACT: In this paper, a passive ripple cancelling circuit (PRCC) is proposed to eliminate the output power reduction effect of PV systems caused by the current ripple of the PV converters. Special features of the proposed PRCC include low cost, simple, modular structure, and independent of the duty ratio control of the main power circuit. Hence, it can be easily integrated to the main power circuit to achieve zero input current ripple yielding less filter size, loss, and fast response. Meanwhile, the linear line maximum power point tracking (MPPT) control is also integrated with the proposed MIC to achieve instantaneous tracking response. Finally, a 90W laboratory prototype is constructed to verify the effectiveness of the proposed principle. It is seen that the resulting peak to peak input current ripple is reduced to about 2% of the original DC converter input ripple. In other words, the input current ripple is almost zero. As a result, the harvested power of the proposed MIC can be increased by 7% as compared with that of the MIC without the proposed PRCC.Power Electronics and Drive Systems (PEDS), 2013 IEEE 10th International Conference on; 01/2013
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ABSTRACT: Design of a ripple free switching mode power converter is a challenging task in power electronics industry. The conventional method for ripple reduction is to use passive filters, which makes the system bulky. Hybrid structured converters are introduced to reduce the ripple without using bulky output capacitors. In this type of converters, to cancel the ripple, opposite current / voltage of the ripple is injected to the output of converter. However the efficiency of the hybrid structure is poor due to the series resistor used for current sensing. This paper proposes a modified hybrid structure converter with improved efficiency as well as desirable ripple performance. The proposed circuit uses DCR current sensing method and reduces the losses. The modified structure gives 4.14 percent efficiency improvement at a load current of 2A compare to conventional hybrid converter. The ripple voltage is just 3mV even without output capacitor.2013 Annual IEEE India Conference (INDICON); 12/2013
Conference Paper: A hybrid binary harmony search algorithm inspired by ant system[Show abstract] [Hide abstract]
ABSTRACT: Harmony Search (HS) algorithm, which mimics music improvisation process, has been used to solve various optimization problems. However, the standard HS algorithm is not suitable for settling binary-coded problems as the pitch adjusting operator is degraded and cannot efficiently perform the local search in the binary space. To extend HS to solve the binary-coded problems more effectively and efficiently, a novel binary Ant System Harmony Search (BASHS) algorithm is proposed in this paper which is inspired by the search mechanism of Ant System. The new harmony memory consideration operator and pitch adjustment operator are developed to execute the global search and local search with the current iteration best solution and the global best solution. The experiment results demonstrate that the proposed BASHS algorithm is a powerful optimization tool and outperforms binary HS, binary Ant System and Discrete Binary Particle Swarm Optimization algorithm in terms of search accuracy and convergence speed.Cybernetics and Intelligent Systems (CIS), 2011 IEEE 5th International Conference on; 01/2011