Control device for maintaining balance of bus midpoint voltage of T-shaped three-level photovoltaic inverter

The utility model discloses a control device for maintaining balance of the bus midpoint voltage of a T-shaped three-level photovoltaic inverter. The control device comprises a DC filter, a boost circuit, a three-level inversion circuit, a low pass filter, an AC filter, and a control circuit based on a DSP. The control device also comprises a sampling unit for inversion current and power grid voltage signals. In terms of hardware, hardware circuits need not to be additionally provided, the hardware cost and expenditure will not increased, a hardware circuit is easy to debug, and the normal operation of an MPPT function on a DC side will not be affected. In terms of software, the time will not increase additionally, and many operands are processed and completed by an original interrupt program to make the program run stably within a reasonable control range. The control device can achieve balance of the midpoint voltage of a three-level photovoltaic inverter.