Filter circuitry is constituted by transversal filters which are connected in parallel to each other. The transversal filters change amplitude and a phase of an input digital signal X.sub.in[n.Math.T.sub.s] and output different digital signals X.sub.1[n.Math.T.sub.s], X.sub.2[n.Math.T.sub.s], and X.sub.3[n.Math.T.sub.s] as respective resulting digital signals whose amplitude and phase have been changed. A phase frequency computer computes a phase θ.sub.X[n.Math.T.sub.s] and a frequency f.sub.X[n.Math.T.sub.s] of the input digital signal X.sub.in[n.Math.T.sub.s] by performing phase computation and frequency computation using the digital signals X.sub.1[n.Math.T.sub.s], X.sub.2[n.Math.T.sub.s], and X.sub.3[n.Math.T.sub.s] output by the transversal filters.

Filter circuitry is constituted by transversal filters which are connected in parallel to each other. The transversal filters change amplitude and a phase of an input digital signal X.sub.in[n.Math.T.sub.s] and output different digital signals X.sub.1[n.Math.T.sub.s], X.sub.2[n.Math.T.sub.s], and X.sub.3[n.Math.T.sub.s] as respective resulting digital signals whose amplitude and phase have been changed. A phase frequency computer computes a phase θ.sub.X[n.Math.T.sub.s] and a frequency f.sub.X[n.Math.T.sub.s] of the input digital signal X.sub.in[n.Math.T.sub.s] by performing phase computation and frequency computation using the digital signals X.sub.1[n.Math.T.sub.s], X.sub.2[n.Math.T.sub.s], and X.sub.3[n.Math.T.sub.s] output by the transversal filters.

A system includes an orthogonal coordinate signal generator that generates an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency. A prediction calculator calculates a predicted value of the angular frequency after a time has elapsed based on the angular frequency and a differential of the angular frequency. In a state in which the phase jump of the power system is not detected, the frequency calculator calculates the system frequency based on the angular frequency. When the phase jump of the power system is detected, the frequency calculator calculates the system frequency based on predicted value for a constant amount of time.

A system includes an orthogonal coordinate signal generator that generates an orthogonal two-phase voltage signal from a three-phase voltage signal of three-phase alternating current power of a power system; and a frequency calculator including an angular frequency calculator calculating an angular frequency of the power system based on the two-phase voltage signal, and an arithmetic unit calculating a system frequency of the power system from the angular frequency. A prediction calculator calculates a predicted value of the angular frequency after a time has elapsed based on the angular frequency and a differential of the angular frequency. In a state in which the phase jump of the power system is not detected, the frequency calculator calculates the system frequency based on the angular frequency. When the phase jump of the power system is detected, the frequency calculator calculates the system frequency based on predicted value for a constant amount of time.

The present disclosure provides an optimization method, a unit, and an electronic device of a shifted frequency (SF)-based electromagnetic transient simulation, comprising: determining a current amplitude and a voltage frequency based on a node voltage and a branch current calculated from a shifted frequency on a basis of a current time step; determining an optimal shifted frequency of the current time step based on the current amplitude and the voltage frequency; and updating the shifted frequency by adopting the optimal shifted frequency of the current time step for calculating a node voltage and a branch current of the next time step. The method, the unit, and the electronic device provided in the present disclosure may gradually update and optimize the shifted frequency in the simulation process so to enable the shifted frequency to reach the best, thus ensuring the accuracy of output current and voltage simulation results.

The present disclosure provides an optimization method, a unit, and an electronic device of a shifted frequency (SF)-based electromagnetic transient simulation, comprising: determining a current amplitude and a voltage frequency based on a node voltage and a branch current calculated from a shifted frequency on a basis of a current time step; determining an optimal shifted frequency of the current time step based on the current amplitude and the voltage frequency; and updating the shifted frequency by adopting the optimal shifted frequency of the current time step for calculating a node voltage and a branch current of the next time step. The method, the unit, and the electronic device provided in the present disclosure may gradually update and optimize the shifted frequency in the simulation process so to enable the shifted frequency to reach the best, thus ensuring the accuracy of output current and voltage simulation results.

A circuit for an inductive conductivity sensor comprises: a secondary coil having a first coil terminal and a second coil terminal, a switch having a first switch terminal, a second switch terminal, a third switch terminal, a first potential terminal, and a control unit having a first control terminal and a second control terminal, wherein the first coil terminal is connected to the first control terminal and the second coil terminal is connected to the first switch terminal, wherein the second switch terminal is connected to the first potential terminal and the third switch terminal is connected to the second control terminal.

A circuit for an inductive conductivity sensor comprises: a secondary coil having a first coil terminal and a second coil terminal, a switch having a first switch terminal, a second switch terminal, a third switch terminal, a first potential terminal, and a control unit having a first control terminal and a second control terminal, wherein the first coil terminal is connected to the first control terminal and the second coil terminal is connected to the first switch terminal, wherein the second switch terminal is connected to the first potential terminal and the third switch terminal is connected to the second control terminal.

The present disclosure provides an optimization method, a unit, and an electronic device of a shifted frequency (SF)-based electromagnetic transient simulation, comprising: determining a current amplitude and a voltage frequency based on a node voltage and a branch current calculated from a shifted frequency on a basis of a current time step; determining an optimal shifted frequency of the current time step based on the current amplitude and the voltage frequency; and updating the shifted frequency by adopting the optimal shifted frequency of the current time step for calculating a node voltage and a branch current of the next time step. The method, the unit, and the electronic device provided in the present disclosure may gradually update and optimize the shifted frequency in the simulation process so to enable the shifted frequency to reach the best, thus ensuring the accuracy of output current and voltage simulation results.

The present disclosure provides an optimization method, a unit, and an electronic device of a shifted frequency (SF)-based electromagnetic transient simulation, comprising: determining a current amplitude and a voltage frequency based on a node voltage and a branch current calculated from a shifted frequency on a basis of a current time step; determining an optimal shifted frequency of the current time step based on the current amplitude and the voltage frequency; and updating the shifted frequency by adopting the optimal shifted frequency of the current time step for calculating a node voltage and a branch current of the next time step. The method, the unit, and the electronic device provided in the present disclosure may gradually update and optimize the shifted frequency in the simulation process so to enable the shifted frequency to reach the best, thus ensuring the accuracy of output current and voltage simulation results.