Power to an electrical device is controlled using a phase control that changes a cutoff phase of an alternating current (AC) electrical signal delivered to the electrical device. The power delivered to the electrical device is increased to an operational level using the phase control. A level of the power delivered to the electrical device is maintained at the operational level using an integral half cycle control that selectively removes a plurality of half cycles from the AC electrical signal delivered to the electrical device such that a plurality of remaining half cycles in the AC electrical signal delivered to the electrical device have a frequency outside a range of sub-harmonic frequencies.

Power to an electrical device is controlled using a phase control that changes a cutoff phase of an alternating current (AC) electrical signal delivered to the electrical device. The power delivered to the electrical device is increased to an operational level using the phase control. A level of the power delivered to the electrical device is maintained at the operational level using an integral half cycle control that selectively removes a plurality of half cycles from the AC electrical signal delivered to the electrical device such that a plurality of remaining half cycles in the AC electrical signal delivered to the electrical device have a frequency outside a range of sub-harmonic frequencies.

A method, device, and system for managing a mining facility including a plurality of systems. The method includes generating, on a simulation unit, system models for one or more systems from the plurality of systems of the mining facility. The system models are generated based on one of input signal, sensor data and output signal from the plurality of systems at the mining facility. The method further includes generating a facility model of the mining facility based on dependencies between the system models and managing the mining facility by simulating operation of the mining facility using the facility model.

An electrical power distribution network includes: a plurality of electrical power control apparatuses, each of which include one or more signal conversion components receiving electrical power in the form of a first signal and generating a corresponding second signal, a controller that controls operation of the signal conversion components, electrical power generation components acting as sources of electrical power to at least some of the electrical power control apparatuses, and electrical power consumption components acting as sinks of electrical power from at least some of the electrical power control apparatuses. The electrical power control apparatuses operate autonomously but are interconnected so that the electrical power control apparatuses collectively maintain the voltages and frequencies of electrical power signals flowing through the electrical power distribution network at target values to compensate for variations in the sinks and/or sources of electrical power.

An electrical power distribution network includes: a plurality of electrical power control apparatuses, each of which include one or more signal conversion components receiving electrical power in the form of a first signal and generating a corresponding second signal, a controller that controls operation of the signal conversion components, electrical power generation components acting as sources of electrical power to at least some of the electrical power control apparatuses, and electrical power consumption components acting as sinks of electrical power from at least some of the electrical power control apparatuses. The electrical power control apparatuses operate autonomously but are interconnected so that the electrical power control apparatuses collectively maintain the voltages and frequencies of electrical power signals flowing through the electrical power distribution network at target values to compensate for variations in the sinks and/or sources of electrical power.

A motor control method includes the following steps: receiving a frequency command and an excitation current setting value as a motor speed command; running a magnetic flux calculation program to generate a magnetic flux voltage command; generating a synchronous coordinate voltage command, and providing a three-phase current to a sensorless motor; calculating a synchronous coordinate feedback current based on the three-phase current, and calculating an effective current value of three-phase current; calculating a reactive power feedback value based on synchronous coordinate voltage command and the synchronous coordinate feedback current; running a steady state calculation program to calculate a reactive power command based on frequency command and the effective current value; calculating a reactive power error value between the reactive power command and the reactive power feedback value; and adding magnetic flux voltage command and reactive power error value to adjust synchronous coordinate voltage command and change three-phase current.

A circuit and method for converting an input AC voltage of a source to an output AC voltage of a destination is disclosed. The circuit may include a main switch cell coupled to the source, a freewheeling switch cell coupled to the main switch cell, a first inductor coupled to the main switch cell, the freewheeling switch and the destination, and a second inductor coupled to the first inductor, the main switch cell, the freewheeling switch and the destination. The circuit may also include a plurality of current paths when at least one of the main switch cell and/or the freewheeling switch cell is on. In some implementations, the main switch cell and the freewheeling switch cell are controlled using a switching method.

A multi-phase power converter comprising a plurality of phases for generating an output voltage according to a switching signal and an input voltage, each phase of the plurality of phases comprising a switching element and inductance; wherein the plurality of phases is connected to a common star point, wherein an output capacitor is connected to the common star point. The phases of the multi-phase power converter are not identical in terms of their inductance. Therefore, at least one phase may be optimized for a low current such that, in low power operation, said at least one phase is optimal for lower current levels.

An AC-to-AC modular multilevel converter (MMC) is configured to be connected between a three-phase AC system and a single-phase AC system. The MMC includes a number of converter arms connected in a ring to allow a circulating current to be circulated in the ring through each of the converter arms. Each converter arm includes series-connected converter cells. Phase terminals are arranged in the ring between the converter arms such that each of the converter arms is separated from neighboring converter arms by at least one of the phase terminals. The phase terminals include respective terminals for each of a first phase, a second phase and a third phase of the three-phase AC system and respective terminals for each of a positive conductor and a negative conductor of the single-phase AC system.

An operating circuit and a method for operating a synchronous machine on a voltage supply network is disclosed. The operating circuit has a converter circuit with controllable converter switches and a controllable switching arrangement to switch the converter circuit between a start converter configuration and a direct converter configuration. The power supply network is connected to a converter output and the synchronous machine is connected to a converter input of the converter circuit. In the direct converter configuration, an AC voltage is provided at the converter output with a preset AC voltage frequency. In the direct converter configuration, the switching of the AC voltage between the converter input and the converter output takes place without intermediate rectification.