The invention relates to a method for determining a state of at least one cell of a battery, wherein the battery has a plurality of cells, which are connected in series with each other, the method comprising at least the following steps: a) applying an alternating current to the plurality of cells; b) measuring the alternating voltage produced thereby at at least a first cell and a second cell; c) analyzing a phase position of the measured alternating voltage of each cell; wherein a difference at least between a first phase position of a first alternating voltage measured at the first cell and a second phase position of a second alternating voltage measured at the second cell forms a conclusion about a difference between the states of at least the first cell and the second cell.

Systems and methods associated with phase frequency detection are disclosed. In one illustrative implementation, a phase frequency detection (PFD) circuit device may comprise first circuitry and second circuitry having a set input, a reset input, and an output, wherein the set input has a higher priority than the reset input, and additional circuitry arranged and operatively coupled to provide advantageous operation of the PFD circuit device. According to some implementations, for example, systems and methods with clock edge overriding reset features, extended detection range(s), and/or reduction of reverse charge after cycle slipping are provided.

A wideband digital phase meter and phase detection method are disclosed. The device measures a phase difference between 2 signals and is suitable for integration into a single MMIC. The input signals are compared digitally by using two EXOR gates and integrated over a phase comparison period. The resultant analogue signals are digitised using an Analogue to Digital convertor. Additionally, 2×D-Type registers are used to resolve the (0° to 180°) or (180° to 360°) ambiguity of the EXOR phase detector.

Current transducers are widely used in current measuring systems. They provide good isolation between the supply voltage and the measurement equipment. However they can introduce small phase errors which can become significant sources of error if the current to a load is out of phase with the supply voltage for the load. This disclosure discusses a robust measurement apparatus and method that can be used in situ to monitor for and correct phase errors.

Current transducers are widely used in current measuring systems. They provide good isolation between the supply voltage and the measurement equipment. However they can introduce small phase errors which can become significant sources of error if the current to a load is out of phase with the supply voltage for the load. This disclosure discusses a robust measurement apparatus and method that can be used in situ to monitor for and correct phase errors.

The present disclosure relates a reactive power compensation system including a detection unit for acquiring loading state information of a plurality of loads, a reactive power compensation unit for compensating reactive power, and a controller for controlling the reactive power compensation unit to perform flicker compensation or power factor compensation based on a control signal according to the loading state information.

The present disclosure relates a reactive power compensation system including a detection unit for acquiring loading state information of a plurality of loads, a reactive power compensation unit for compensating reactive power, and a controller for controlling the reactive power compensation unit to perform flicker compensation or power factor compensation based on a control signal according to the loading state information.

A method includes obtaining electrical measurements of an input signal of a power system. The electrical measurements are obtained at a sampling frequency and the input signal is indicative of an operating frequency of the power system. The method includes generating an intermediate signal from the input signal. The intermediate signal has a direct current (DC) component indicative of a magnitude and a phase of the input signal. The method includes filtering the intermediate signal using an adjustable length filter to obtain the magnitude and the phase of the input signal. The length of the adjustable length filter varies based at least in part on a period measurement of the power system.

A method includes obtaining electrical measurements of an input signal of a power system. The electrical measurements are obtained at a sampling frequency and the input signal is indicative of an operating frequency of the power system. The method includes generating an intermediate signal from the input signal. The intermediate signal has a direct current (DC) component indicative of a magnitude and a phase of the input signal. The method includes filtering the intermediate signal using an adjustable length filter to obtain the magnitude and the phase of the input signal. The length of the adjustable length filter varies based at least in part on a period measurement of the power system.

The present disclosure relates to systems and methods for detecting a winding fault and the winding fault severity in a brushless direct current motor before motor failure. Methods for detecting a winding fault include time domain based sequence component analysis, fast Fourier transform analysis, or Hilbert analysis. Methods for detecting the severity of a winding fault include analysis of the standard deviation of real mean squared values determined using motor currents.