Abstract: The present application discloses a TNPC inverter device, comprising: a TNPC inverter module and a short circuit detecting module. The TNPC module at least comprises an inverting bridge arm and a bi-directional switching bridge arm. The inverting bridge arm comprises at least two switches connected in series; the bi-directional switching bridge arm comprises at least two switches. The short circuit detecting module mainly consists of two switch detecting unit corresponding to the two switches in the inverting bridge arm respectively. Increasing the voltage drop of the switches in the inverting bridge when a short circuit occurs in the TNPC module by some way, then it could realize the short circuit detecting module is able to detect all the paths of the short circuit in the TNPC module to simplify the peripheral circuit of the TNPC module in the TNPC inverter device.

Abstract: The present application discloses a TNPC inverter device, comprising: a TNPC inverter module and a short circuit detecting module. The TNPC module at least comprises an inverting bridge arm and a bi-directional switching bridge arm. The inverting bridge arm comprises at least two switches connected in series; the bi-directional switching bridge arm comprises at least two switches. The short circuit detecting module mainly consists of two switch detecting unit corresponding to the two switches in the inverting bridge arm respectively. Increasing the voltage drop of the switches in the inverting bridge when a short circuit occurs in the TNPC module by some way, then it could realize the short circuit detecting module is able to detect all the paths of the short circuit in the TNPC module to simplify the peripheral circuit of the TNPC module in the TNPC inverter device.

Abstract: An inverter and an active power filter system have been disclosed in the invention, so that the application range of the inverter under the occasions of different capacitor requirement can be widened, the cost can be decreased, and the efficiency can be improved. The technical scheme is: an auxiliary capacitor module can be added on the traditional inverter structure and connected in parallel selectively with the capacitor in the inverter. In a system without connecting an external auxiliary capacitor module, the value of capacitance can be designed to be smaller to satisfy the application under normal occasions. If the device operates under the occasions having large harmonic current or having large neutral line current, the ripple current on the capacitor will be larger so that large capacitance will be required to satisfy the life requirement, therefore, the problem can be solved by a method of installing an auxiliary capacitor module.

Abstract: An inverter and an active power filter system have been disclosed in the invention, so that the application range of the inverter under the occasions of different capacitor requirement can be widened, the cost can be decreased, and the efficiency can be improved. The technical scheme is: an auxiliary capacitor module can be added on the traditional inverter structure and connected in parallel selectively with the capacitor in the inverter. In a system without connecting an external auxiliary capacitor module, the value of capacitance can be designed to be smaller to satisfy the application under normal occasions. If the device operates under the occasions having large harmonic current or having large neutral line current, the ripple current on the capacitor will be larger so that large capacitance will be required to satisfy the life requirement, therefore, the problem can be solved by a method of installing an auxiliary capacitor module.

Abstract: An active isolated power supply with multiple outputs is provided. The power supply includes N transformers T1˜Tn connected to output terminals of AC source, the primary circuits of transformers T1˜Tn are connected in parallel with each other, wherein N is a positive integral number equals to or greater than 2, and N switching devices S1˜Sn or N?1 switching devices S1˜Sn?1 connected in series with the primary circuits of transformers T1˜Tn respectively, to restrict the current direction of the primary circuits of transformers T1˜Tn. Herein, N output power supplies isolated with each other are generated on the secondary sides of transformers T1˜Tn. Therefore, flow direction of current in the primary sides of the transformers is fixed by present invention, such that each transformer can accomplish magnetic reset in one operation period, thereby avoiding the occurrence of current circulation between the primary circuits.