Chen Guozhu

A novel hybrid active power filter with two passive channels for high power application

This paper proposes a new structure of serial hybrid active power filter which can reduce the power rating of the active power filter dramatically, and has good performance for harmonic suppression. The principle and designing rules are analyzed. The proposed structure is rational and feasible for high kVA applications. Simulation results are presented too.

The design and implement of series hybrid active power filter for variable nonlinear loads

The paper discusses the design and implementation of a series hybrid active power filter (SHAPF) when its nonlinear load is varied in a wide range. The specially designed passive filter and adaptive control methods of SHAPF are discussed. With these methods, the SHAPF is stable with good performance and causes small capacitive reactive current. The simulation and experimental results are accorded with the theoretical analysis.

A hybrid solution to active power filter for the purpose of harmonic suppression and resonance damping

Active power filters (APFs) have been intensively explored over the past decade. Various topologies and control schemes have been documented aiming at reducing the cost and improving the performance of the harmonic compensation system. This paper highlights the essence of the mechanisms of diverse APFs by using the concepts of controllable sources. Four basic active units for comprehensive APFs can be employed in the circuit branch to control the impedance of the branch. This paper also presents a general principle for constructing new hybrid APFs to suppress harmonics. The principle can be easily used to find new approaches for cost-effective hybrid APFs. One hybrid solution is provided in this paper.

A novel control algorithm for magnetically controlled reactor

In order to reduce the response time and solve the problem of reactive power overcompensation of the magnetically controlled reactor (MCR), a novel compensation algorithm is proposed in this paper. The algorithm is based on the principles and algorithms of unbalanced load compensation and via modifying the compensation conditions of the Steinmetz principle. The general formula of the compensatory algorithm is derived from instantaneous reactive power theory. The algorithm can be used as the control strategy to balance the three-phase active power, but also can compensate loads to specified power factor and effectively prevent reactive power feeding inversely that caused by overcompensation. The results of simulations are coincided with the theory analyses, which demonstrate that the algorithm proposed by this paper has high precision and good dynamic characteristics.

A new control strategy and compensation method on hybrid system of combining APF with shunt capacitors

Aiming at reactive power and harmonic current in the low-voltage distribution grid, a hybrid comprehensive dynamic reactive power and harmonic current compensator is designed. The shunt capacitors compensate the fundamental reactive power, the shunt APF eliminates the harmonics and the small amounts of load reactive power. But when they work in the same electric utility there exists resonance problem, in order to avoid resonance, the compensation character of hybrid compensation device under traditional strategies for current type nonlinear load were well studied theoretically and quantitatively by establishing mathematic model. A new current control strategy, which not only suppress line-side harmonic current and reactive power but also avoid resonance between shunt capacitors and line-side impedance, was put forwards. And a new compensator method which the APF only compensates 1/2 reactive power of each shunt capacitor was provided, due to the APF could compensate both inductive and capacitive reactive power. It lower the capacity of APF, and reduce the cost. Simulation show that the new control strategy and the new compensation method work stable, fleetly and effectively eliminates most harmonics and compensates majority reactive power.

The special design considerations for series hybrid active power filter

Some important factors of a series hybrid active power filter are presented in this paper for the case when the load is varied in a wide range and/or the source voltage is seriously distorted. Special designs of passive filters, adaptive control of parameter and multi variant control are discussed in detail. The filter is stable, has good performance, and causes small, capacitive reactive current. The simulation and experimental results accorded with the theoretical analysis results.

Design considerations for series hybrid active power filter

Some important factors for designing a series hybrid active power filter (SHAPF) are presented in this paper for the case when the load is varied in a wide range and/or the source voltage is seriously distorted. Special design of passive filters, adaptive control of parameter and multi variant control are discussed in detail. The filter is stable, has good performance, and causes small capacitive reactive current. The simulation and experimental results accorded with the theoretical analysis results.

Probability approach for harmonic analysis of multi-converter system

In this paper, the sum harmonic currents of a multi-converters power system are analyzed by means of probability because of its random feature. A series of formulae to calculate the five important parameters of the normal distribution are presented, provided that the firing angle of each converter follows mean distribution. The study found that the random property of the sum harmonics becomes more evident as the number of converters, the harmonic order increases and the distribution range of the firing angle widens.