Examples described herein include receiving current values of a power device, determining a spike situation of the power device, determining a power course for the power device, and operating the power device according to the power course. The current values may include a first current value at a first time and a second current value at a second time. The power course may be determined based on a plurality of current change values associated with the spike situation, a total number of spikes associated with the spike situation, and a duration of at least one spike out of the total number of spikes associated with the spike situation.

Examples described herein include receiving current values of a power device, determining a spike situation of the power device, determining a power course for the power device, and operating the power device according to the power course. The current values may include a first current value at a first time and a second current value at a second time. The power course may be determined based on a plurality of current change values associated with the spike situation, a total number of spikes associated with the spike situation, and a duration of at least one spike out of the total number of spikes associated with the spike situation.

A method for maintaining reliability of a distributed power system including a power converter having input terminals and output terminals. Input power is received at the input terminals. The input power is converted to an output power at the output terminals. A temperature is measured in or in the environment of the power converter. The power conversion of the input power to the output power may be controlled to maximize the input power by setting at the input terminals the input voltage or the input current according to predetermined criteria. One of the predetermined criteria is configured to reduce the input power based on the temperature signal responsive to the temperature. The adjustment of input power reduces the input voltage and/or input current thereby lowering the temperature of the power converter.

A method for maintaining reliability of a distributed power system including a power converter having input terminals and output terminals. Input power is received at the input terminals. The input power is converted to an output power at the output terminals. A temperature is measured in or in the environment of the power converter. The power conversion of the input power to the output power may be controlled to maximize the input power by setting at the input terminals the input voltage or the input current according to predetermined criteria. One of the predetermined criteria is configured to reduce the input power based on the temperature signal responsive to the temperature. The adjustment of input power reduces the input voltage and/or input current thereby lowering the temperature of the power converter.

A method for controlling a chain-link power converter including three phase legs, each of which phase legs includes a plurality of series-connected converter cells, each of the cells including a DC capacitor, the phase legs being connected in a delta configuration. The method includes detecting an unsymmetrical voltage condition at a terminal of the converter; determining a ratio between a zero sequence and a negative sequence component of a compound current to be injected into the converter, based on the detected unsymmetrical voltage condition; calculating the compound current comprising the zero sequence component and the negative sequence component in accordance with the determined ratio; and injecting the compound current into the converter to control the converter in view of the detected unsymmetrical voltage condition.

A method for controlling a chain-link power converter including three phase legs, each of which phase legs includes a plurality of series-connected converter cells, each of the cells including a DC capacitor, the phase legs being connected in a delta configuration. The method includes detecting an unsymmetrical voltage condition at a terminal of the converter; determining a ratio between a zero sequence and a negative sequence component of a compound current to be injected into the converter, based on the detected unsymmetrical voltage condition; calculating the compound current comprising the zero sequence component and the negative sequence component in accordance with the determined ratio; and injecting the compound current into the converter to control the converter in view of the detected unsymmetrical voltage condition.

The present invention relates to an inverter device. Regard to the problem in the traditional convert device that the user is difficult to obtain the information shown on the display panel in time; the state of the inverter can not be switched remotely after the user leaves; discharging or early switching-off caused by missing battery information; and the draught fan can only be at the state of ‘full-speed-start’ or switch-off, the invention provides an inverter device, it is configured with an extensible flexible wire to fix the display panel of the inverter to the place the user wants to for getting the information of the inverter in time; by virtue of wireless transmission, user can control the state of the inverter remotely; by adding a test module to the inverter device, it avoids the waste of electricity which is caused by the discharging of the battery-to-convert and switching off.

The present invention relates to an inverter device. Regard to the problem in the traditional convert device that the user is difficult to obtain the information shown on the display panel in time; the state of the inverter can not be switched remotely after the user leaves; discharging or early switching-off caused by missing battery information; and the draught fan can only be at the state of ‘full-speed-start’ or switch-off, the invention provides an inverter device, it is configured with an extensible flexible wire to fix the display panel of the inverter to the place the user wants to for getting the information of the inverter in time; by virtue of wireless transmission, user can control the state of the inverter remotely; by adding a test module to the inverter device, it avoids the waste of electricity which is caused by the discharging of the battery-to-convert and switching off.

The resonant inverter circuit includes two or more switch elements. A detector detects an output current of the switch elements. A resonance frequency determiner determines that the resonance frequency of the resonant inverter circuit is abnormal when a number of times an absolute value of a current detected by the detector at turn-off of the switch elements is equal to or greater than a threshold is equal to or greater than a predetermined number of times that is two or more during a predetermined period that is equal to or longer than two switching periods of the switch elements. A controller causes the resonant inverter circuit to stop a switching operation when the resonance frequency determiner determines that the resonance frequency of the resonant inverter circuit is abnormal.

In some embodiments, a system for driving inverters in parallel includes a master controller, a plurality of slave controllers, and a plurality of inverters controlled correspondingly by each of the slave controllers. The system may further include a control signal creation unit to create control signals for the slave controllers by using data transmitted and received between the master controller and the slave controllers to enable the plurality of inverters to create balanced output currents.