The present invention discloses a parameter tuning approach for bypass damping filter to suppress subsynchronous resonance in power systems, namely determining the parameters of capacitor, inductor and damping resistor in BDF. Using this approach, the parameters of capacitor and inductor in BDF can be adjusted, so that the frequency where the negative electrical damping of generator reaches minimum can be away from the frequency range of low frequency oscillation mode and typical frequencies of each torsional mode; the parameter of damping resistor in BDF can be further adjusted so that the minimum value of negative electrical damping is in reasonable range. The application of BDF with parameters tuned by the present invention contributes to the suppression of both the torsional interaction effect and the transient torque amplification effect.

The present invention discloses a parameter tuning approach for bypass damping filter to suppress subsynchronous resonance in power systems, namely determining the parameters of capacitor, inductor and damping resistor in BDF. Using this approach, the parameters of capacitor and inductor in BDF can be adjusted, so that the frequency where the negative electrical damping of generator reaches minimum can be away from the frequency range of low frequency oscillation mode and typical frequencies of each torsional mode; the parameter of damping resistor in BDF can be further adjusted so that the minimum value of negative electrical damping is in reasonable range. The application of BDF with parameters tuned by the present invention contributes to the suppression of both the torsional interaction effect and the transient torque amplification effect.

A high-frequency oscillator includes an electric resonant circuit, and a high-frequency welding system and a method for controlling the frequency uses a high-frequency oscillator, in particular in a high-frequency welding system. The electric resonant circuit includes at least one electronic component having an inductance and at least one capacitor having a capacitance. At least one additional magnetic coil is associated with the electronic component and can electronically influence the inductance of the electronic component.

A high-frequency oscillator includes an electric resonant circuit, and a high-frequency welding system and a method for controlling the frequency uses a high-frequency oscillator, in particular in a high-frequency welding system. The electric resonant circuit includes at least one electronic component having an inductance and at least one capacitor having a capacitance. At least one additional magnetic coil is associated with the electronic component and can electronically influence the inductance of the electronic component.

A method includes receiving a series of radio frequency (RF) signals, where, from RF signal to RF signal of the series of RF signals, a carrier frequency is changed in accordance with a frequency hopping pattern. The method further includes, while receiving the series of RF signals, sensing an environmental condition by, for a frequency hop of at least some frequency hops of the frequency hopping pattern, adjusting a characteristic of a wireless sensor to maintain proximal alignment of a resonant frequency of the wireless sensor with the carrier frequency corresponding to a present frequency of the at least some frequency hops and generating a value to represent the adjustment of the characteristic, where a set of values is generated for the at least some frequency hops and where the set of values is used to determine a sensed value of the environmental condition.

A method includes receiving a series of radio frequency (RF) signals, where, from RF signal to RF signal of the series of RF signals, a carrier frequency is changed in accordance with a frequency hopping pattern. The method further includes, while receiving the series of RF signals, sensing an environmental condition by, for a frequency hop of at least some frequency hops of the frequency hopping pattern, adjusting a characteristic of a wireless sensor to maintain proximal alignment of a resonant frequency of the wireless sensor with the carrier frequency corresponding to a present frequency of the at least some frequency hops and generating a value to represent the adjustment of the characteristic, where a set of values is generated for the at least some frequency hops and where the set of values is used to determine a sensed value of the environmental condition.

A voltage controlled oscillator comprises a negative resistance, a first inductor, a fixed capacitor, and a frequency control component. The frequency control component comprises at least one varactor and at least a second inductor connected in series with the at least one varactor. A magnitude of an inductance of the second inductor is selected such that the frequency control component has an effective capacitance range larger than a capacitance range of the at least one varactor.

A voltage controlled oscillator comprises a negative resistance, a first inductor, a fixed capacitor, and a frequency control component. The frequency control component comprises at least one varactor and at least a second inductor connected in series with the at least one varactor. A magnitude of an inductance of the second inductor is selected such that the frequency control component has an effective capacitance range larger than a capacitance range of the at least one varactor.

A high-frequency oscillator includes an electric resonant circuit, and a high-frequency welding system and a method for controlling the frequency uses a high-frequency oscillator, in particular in a high-frequency welding system. The electric resonant circuit includes at least one electronic component having an inductance and at least one capacitor having a capacitance. At least one additional magnetic coil is associated with the electronic component and can electronically influence the inductance of the electronic component.

A high-frequency oscillator includes an electric resonant circuit, and a high-frequency welding system and a method for controlling the frequency uses a high-frequency oscillator, in particular in a high-frequency welding system. The electric resonant circuit includes at least one electronic component having an inductance and at least one capacitor having a capacitance. At least one additional magnetic coil is associated with the electronic component and can electronically influence the inductance of the electronic component.