Output impedance

About: Output impedance is a research topic. Over the lifetime, 11185 publications have been published within this topic receiving 134949 citations.

Bandpass Class-F Power Amplifier Based on Multifunction Hybrid Cavity–Microstrip Filter

Abstract: This brief presents a filter-integrated high-efficiency class-F power amplifier (PA). The hybrid cavity–microstrip filtering circuit is employed not only to realize output impedance matching and the third-harmonic manipulation but also to provide high-selectivity bandpass responses. To fulfill the requirements of high-efficiency class-F PAs, cavity resonators and microstrip feeding structures are involved, and their benefits are fully exploited. The metal cavity resonator features a high $Q$ value and, thus, low loss in the passband, resulting in high efficiency. Moreover, metal walls of cavities act as heat sink for the transistor. The microstrip feeding structures are used to improve the skirt selectivity and manipulate the third harmonic. Moreover, it features easy integration with the transistor, and thus, the transition between cavity and microstrip lines is eliminated. The hybrid filter is characterized based on filter synthesis theory. Complex impedance conversion analysis is carried out to guide the impedance transformation from 50 $\Omega$ to a complex one desired by the transistor. For demonstration, a filtering PA operating at 2.4 GHz is designed and measured. It exhibits both high-selectivity bandpass responses and good PA performance with maximum power-added efficiency of 70.9% at 40.8-dBm output power.

Decentralized Control for Parallel Operation of Distributed Generation Inverters in Microgrids Using Resistive Output Impedance

Abstract: In this paper, a novel wireless load-sharing controller for islanding parallel inverters in an ac-distributed system is proposed. The paper explores the resistive output impedance of the parallel-connected inverters in an island microgrid. The control loops are devised and analyzed taking into account the special nature of a low voltage microgrid, in which the line impedance is mainly resistive and the distance between the inverters makes the control intercommunication between them difficult. In contrast with the conventional droop control method, the proposed controller uses resistive output impedance, and as a result a different control law is obtained. The controller is implemented by using a DSP board, which only uses local measurements of the unit, thus increasing the modularity, reliability, and flexibility of the distributed system. Experimental results are provided from two 6 kVA inverters connected in parallel, showing the features of the proposed wireless control.

Supply circuit with ripple compensation

Abstract: A supply circuit (1) comprising an inductor (2) coupled to switching means (7) and comprising a capacitor (4) is provided with an impedance (3) located between the inductor (2) and the capacitor (4) , with a current injector (5) and with a feedback loop comprising a converter (6) for controlling the current injector (5) for compensating a ripple in an output voltage across the capacitor (4) . The impedance (3) allows injection of acompensating current at a location different from an output location. This increases a number of possible detections of ripples in the output voltage and allows a ripple in an output voltage to be detected even in case of loads introducing much noise across the capacitor (4) . The converter (6) detects a detection signal via the impedance (3) by measuring a voltage across the impedance (3) or across a serial circuit comprising the impedance (3) and the capacitor (4) . The impedance (3) comprises a resistor or a further inductor.

Regulated dc to dc converter with regulated current source driving a nonregulated inverter

Abstract: A regulated DC to DC converter comprises a switching-type regulated current source driving a non-regulated bridge-type inverter. The output signal of the converter is regulated by pulse width modulating the switching device in the switching regulator. The output impedance of the current source is inductive. This inductive impedance, which comprises the free-wheeling or flyback inductor of the switching regulator, operates as the principal filter inductor of the converter. This regulator-inverter combination advantageously simplifies the switching control of the inverter switching devices and reduces the switching losses therein. It eliminates the switching control problems which normally occur due to switchthrough phenomena and the saturation of the inverter transformer.

Thin film resonator having stacked acoustic reflecting impedance matching layers and method

Abstract: A frequency selective component and a method for making a frequency selective component. The frequency selective component includes a substrate having at least a first surface and an acoustic impedance transformer coupled to the substrate. The acoustic impedance transformer transforms an acoustic impedance of the substrate to a second acoustic impedance. The acoustic resonator further includes a mechanical resonator disposed on the acoustic impedance transformer. The acoustic resonator provides a frequency selection function.