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Negative impedance converter
About: Negative impedance converter is a research topic. Over the lifetime, 5801 publications have been published within this topic receiving 87636 citations.
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16 Feb 2010TL;DR: In this article, a circuit includes voltage supply terminals configured to provide an AC output voltage, at least two converter units, and a control circuit, each converter unit includes input terminals including an electrical charge storage unit, output terminals and a switch arrangement connected between the input and output terminals.
Abstract: In accordance with an embodiment, a circuit includes voltage supply terminals configured to provide an AC output voltage, at least two converter units, and a control circuit. Each converter unit includes input terminals configured to be connected to an electrical charge storage unit, output terminals, and a switch arrangement connected between the input and output terminals. The switch arrangement is configured to receive a control signal, and provide an output voltage having a duty-cycle dependent on the control signal. The control circuit is configured to provide a set of parameter sets that are dependent on a desired output voltage waveform, define a duty-cycle, and generate the control signals for the at least two converter units such that one parameter set is selected from the set of parameter sets is assigned to one converter unit, and the assignment of parameter sets to the converter stages varies over time.
54 citations
TL;DR: In this article, a parallel-connected diode-clamped M2C (DCM2C) was proposed, in which each arm consists of two parallel connected clusters, and an equal current distribution was achieved between the two clusters.
Abstract: The modular multilevel converter (MMC or M2C) is an emerging attractive multilevel topology for medium-voltage high-power applications. The capacitor voltage balancing control and the improvement of output current rating are two challenging issues of MMC. This paper proposed a new parallel-connected diode-clamped M2C (DCM2C), in which each arm consists of two parallel-connected clusters. In this topology, the capacitor voltages can be balanced automatically without any balancing control algorithms. Theoretically, no voltage sensors are needed to measure the capacitor voltages theoretically. Thus, the control of the converter can be simplified greatly. With a simple current-sharing control, an equal current distribution can be achieved between the two clusters. Furthermore, an extended parallel-DCM2C is proposed for larger current applications, and the corresponding current-sharing control method is developed. Experimental results validated the voltage self-balancing capability of parallel-DCM2C and the effectiveness of the proposed current-sharing control.
54 citations
TL;DR: In this article, a re-lift circuit, which is a new DC-DC step-up (boost) converter, is proposed, which performs positive to positive DC voltage increasing conversion with high output voltage.
Abstract: A re-lift circuit, which is a new DC-DC step-up (boost) converter, is proposed. This converter performs positive to positive DC-DC voltage increasing conversion with high output voltage.
53 citations
TL;DR: A negative capacitance shunt is a basic, analog, active circuit electrically connected to a piezoelectric transducer to control the vibrations of flexural bodies.
Abstract: A negative capacitance shunt is a basic, analog, active circuit electrically connected to a piezoelectric transducer to control the vibrations of flexural bodies. The shunt circuit consists of a resistor and a synthetic negative capacitor to introduce a real and imaginary impedance on a vibrating mechanical system. The electrical impedance of the negative capacitance shunt modifies the effective modulus of the piezoelectric transducer to reduce the stiffness and increase the damping, which causes a decrease in amplitude of the vibrating structure to which the elements are bonded. To gain an insight into the electromechanical coupling and power output, the shunt and the electrical properties of the piezoelectric transducer are modeled using circuit modeling software. The power output of the model is validated with experimental measurements of a shunt connected to a piezoelectric transducer pair bonded to a vibrating aluminum cantilever beam. The model is used to select the passive components of the negative capacitance shunt to increase the efficiency and quantify the voltage output limit of the op-amp.
53 citations
TL;DR: In this paper, the authors proposed a simple method for choosing the measurement frequency to minimalize errors resulting from the spectral leakage and distortion caused by a lack of an anti-aliasing filter in the DDS generator.
Abstract: As it contains elements of complete digital impedance meter, the AD5933 integrated circuit is an interesting solution for impedance measurements. However, its use for measurements in a wide range of impedances and frequencies requires an additional digital and analogue circuitry. This paper presents the design and performance of a simple impedance meter based on the AD5933 IC. Apart from the AD5933 IC it consists of a clock generator with a programmable prescaler, a novel DC offset canceller for the excitation signal based on peak detectors and a current to voltage converter with switchable conversion ratios. The authors proposed a simple method for choosing the measurement frequency to minimalize errors resulting from the spectral leakage and distortion caused by a lack of an anti-aliasing filter in the DDS generator. Additionally, a novel method for the AD5933 IC calibration was proposed. It consists in a mathematical compensation of the systematic error occurring in the argument of the value returned from the AD5933 IC as a result. The performance of the whole system is demonstrated in an exemplary measurement.
53 citations