The subject of the application is a power electronic tap changer module for transformer using power electronic elements connected to sections of a primary winding of the transformer. The power electronic tap changer module is equipped with valves having a pair of a thyristor or transistors connected with a controller and the valves are connected in series with the fuses, respectively. The module is equipped with an additional oversized tap line having an oversized valve rated for short circuit current, which valve is connected with an overvoltage triggering circuit. The oversized valve is equipped with a pair of thyristor or transistors connected with a thermally protected voltage suppressing device.

Provided is a signal isolator with reduced power loss. The signal isolating circuit comprises an input stage and an output circuit that is connected downstream thereof and which includes a linear regulator. The linear regulator comprises an operational amplifier and a switching regulator, wherein an input of the switching regulator is connected to an output of the operational amplifier and an output of the switching regulator is fed back to a first input of the operational amplifier. The operational amplifier regulates the switching regulator such that the switching regulator provides at its output an output measuring signal for a load that corresponds to the input measuring signal.

A semiconductor chip includes a hardware performance monitor (HPM) unit and an HPM controller. The HPM unit is driven during an initial operation period, a first operation period, and a second operation period, outputs initial HPM data, first HPM data, and second HPM data in the initial operation period, the first operation period, and the second operation period, respectively. The HPM controller performs a first compensation operation of compensating a driving voltage of the semiconductor chip using the initial HPM data and the first HPM data, and a second compensation operation of compensating the driving voltage using the initial HPM data and the second HPM data. The HPM unit provides the initial HPM data, the first HPM data, and the second HPM data, which are correlated with performance of the semiconductor chip, to the HPM controller in a first mode, and does not provide this data in a second mode.

Unique systems, methods, techniques and apparatuses of a modular power transformer are disclosed. One exemplary embodiment is a matrix power transformer including a plurality of block assemblies each including a plurality of transformer modules, each transformer module including a primary winding coupled to an input and a secondary winding coupled to an output, the inputs of each transformer module in one block assembly being coupled together and the outputs of each transformer block being coupled together. One of the secondary windings includes a plurality of taps structured to be selectively coupled to the output of the associated transformer module assembly or another secondary winding of the associated module assembly.

A method and a circuit dynamically adjust a frequency of a clock signal that drives the operations of a power converter. The method includes (a) detecting a change from a predetermined value in an output voltage of the power converter; and (b) upon detecting the change, changing the frequency of the clock signal so as to restore the output voltage. The change, such as a load step-up, may be detected by comparing a feedback signal generated from the output voltage and a predetermined threshold voltage. In one implementation, changing the switching frequency is achieved in increasing (e.g., doubling) the frequency of the clock signal, as needed. The frequency of the clock signal need only be changed for a predetermined time period.

The invention relates to an on-load tap changer (1) for controlling voltage, comprising semiconductor switching elements (61, 62, 71, 72), and to a method for controlling voltage for a variable transformer (2). The on-load tap changer (1) has a first load branch (6) and a second load branch (7) arranged parallel thereto. A partial winding (8) is arranged between the first and second load branches (6, 7). In the first load branch (6), a first semiconductor switching element (61) is provided upstream of the partial winding (8) and a second semiconductor switching element (62) is provided downstream of the partial winding (8). In the second load branch (7), a first semiconductor switching element (71) is provided upstream of the partial winding (8) and a second semiconductor switching element (72) is provided downstream of the partial winding (8). The on-load tap changer (1) consists of at least one switching module (5), which comprises the first load branch (6) and the second load branch (7) of the on-load tap changer.

The invention relates to an on-load tap changer (1) for controlling voltage, comprising semiconductor switching elements (61, 62, 71, 72), and to a method for controlling voltage for a variable transformer (2). The on-load tap changer (1) has a first load branch (6) and a second load branch (7) arranged parallel thereto. A partial winding (8) is arranged between the first and second load branches (6, 7). In the first load branch (6), a first semiconductor switching element (61) is provided upstream of the partial winding (8) and a second semiconductor switching element (62) is provided downstream of the partial winding (8). In the second load branch (7), a first semiconductor switching element (71) is provided upstream of the partial winding (8) and a second semiconductor switching element (72) is provided downstream of the partial winding (8). The on-load tap changer (1) consists of at least one switching module (5), which comprises the first load branch (6) and the second load branch (7) of the on-load tap changer.

A control system configured to control switching of taps of an on-load tap changer provided on an electric power transformer. The on-load tap changer includes switches that are controllable to switch between transformer taps. The control system includes a detector configured to detect an indication of a zero crossing of a transformer voltage of the transformer and a control signal generator configured to generate a control signal that controls a switching of the switches for performing a tap change to a new transformer tap. The control signal generator is configured to determine the timing of the control signal for changing the transformer tap based on the detected indication of the zero crossing of the transformer voltage such that the switching of at least one of the switches for performing the tap change occurs a predetermined time prior to a zero crossing of a tap voltage at the new transformer tap.

A method of switching taps of an on-load tap changer includes providing a main finger, a first side finger including a first solid state switch and a second side finger including a second solid state switch. The main finger, the first side finger and the second side finger are utilized to provide a connection between the taps and a power terminal of the on-load tap changer. The method also includes triggering the on-load tap changer to shift the fingers from a first tap to a second tap of the on-load tap changer when a tap change signal is received and utilizing the first solid state switch and the second solid state switch to commutate a current during the tap change operation.

A method of switching taps of an on-load tap changer includes providing a main finger, a first side finger including a first solid state switch and a second side finger including a second solid state switch. The main finger, the first side finger and the second side finger are utilized to provide a connection between the taps and a power terminal of the on-load tap changer. The method also includes triggering the on-load tap changer to shift the fingers from a first tap to a second tap of the on-load tap changer when a tap change signal is received and utilizing the first solid state switch and the second solid state switch to commutate a current during the tap change operation.