Abstract: A control device includes a power generator simulation unit to generate a voltage command value, and a signal generation unit to generate a control signal for the power converter. The power generator simulation unit includes a first integrator to time-integrate a first difference between effective power and a target value of the effective power and output a first angular frequency, a second integrator to time-integrate the first angular frequency and output a phase of an AC voltage, and a voltage command generation unit to generate the voltage command value based on the AC voltage, a target value of the AC voltage, and the phase. When a voltage difference between the AC voltage and the target value of the AC voltage is greater than a threshold, the first integrator outputs a difference between an angular frequency of the AC voltage and a reference angle frequency as the first angular frequency.

Abstract: In a power grid stabilization system, a second energy storage system has a larger energy storage capacity than a first energy storage system. A bidirectional AC/DC converter is connected between an AC power grid and a pair of input and output terminals of the first energy storage system. A first bidirectional DC/DC converter is connected between the pair of input and output terminals of the first energy storage system and a pair of input and output terminals of the second energy storage system.

Abstract: An electric power control system includes a plurality of power converters connected in parallel. Each power converter, among the plurality of power converters, converts a direct-current power of an electricity storage device connected to the power converter into an alternating-current power, and outputs the alternating-current power to the power system. The electric power control system further includes: a power generator simulation unit to simulate characteristics of the synchronous generator based on an aggregate active power to generate a phase of the alternating-current voltage; a signal generation unit to generate a control signal for the power converter, based on the phase of the alternating-current voltage. The power generator simulation unit generates a first angular frequency based on a first difference between the aggregate active power and a target value for the aggregate active power, and generates, based on the first angular frequency, the phase of the alternating-current voltage.

Abstract: A power conversion device includes a power converter connected between a multi-phase alternating-current circuit and a direct-current circuit, and a control device to control the power converter. The control device detects an unbalanced component indicating a voltage unbalanced component or a current unbalanced component of the alternating-current circuit and limits a magnitude of an alternating current flowing between the power converter and the alternating-current circuit based on the unbalanced component.

Abstract: A method of and system for cleansing a toilet or urinal are proposed which require less maintenance work and are safer to users than conventional methods using acid substances, and which can prevent the formation of stain on the toilet or urinal effectively and suppress the generation of ammonia sufficiently, thus accomplishing a sufficient countermeasure to the stench. A urinal (A1) is provided with a continuous electrolytic cell (1) having at least a pair of electrodes, a passage formed between the electrodes, and an inlet and an outlet that lead to the passage. Tap water is electrolyzed by the continuous electrolytic cell (1), whereby free chlorine is produced. Then the water containing free chlorine produced is supplied to the urinal (A1), and the water containing free chlorine sterilizes the inside of the urinal, thus preventing urease, an enzyme carried by bacteria, from acting to decompose urea.

Abstract: An electrolyzing apparatus for flowing water containing chlorine ions has an electrolytic cell provided with at least one pair of electrodes, a passage formed between the electrodes, an inlet port and an outlet port communicating the passage, and a power supply for applying voltage across the electrodes.