A method comprising: detecting a voltage signal of a three-level power converter, the voltage signal indicative of a capacitor voltage balancing in the three-level power converter; and dynamically adjusting an operating variable to adjust the voltage signal until the capacitor voltage balancing in the three-level power converter satisfies a criteria, wherein the three-level power converter includes: a first switch, a second switch, a third switch and a fourth switch connected in series between an input voltage Vin bus and ground; a flying capacitor (Cb) connected between a common node of the first switch and the second switch, and a common node of the third switch and the fourth switch; and an output filter connected between a common node of the second switch and the third switch, and ground, wherein the voltage signal is a voltage Vcb across the flying capacitor, and the operating variable is a duty cycle of the second switch, the method further comprising: determining a duty cycle through a main control loop; determining a duty cycle variation Δton through a local control loop; and configuring the first switch to operate with the duty cycle, and configuring the second switch to operate with a sum of the duty cycle and the duty cycle variation Δton; wherein a try-and-error based control process functions as the local control loop, the try-and-error based control process comprising a parameter (Sgn) indicating a try-and-error direction depending on the voltage Vcb across the flying capacitor; and a predetermined time duration (tstep); and wherein the duty cycle variation Δton is determined based on the parameter, the predetermined time duration and the duty cycle variation Δton in a previous one switching cycle or multiple switching cycles. detecting a voltage signal of a three-level power converter, the voltage signal indicative of a capacitor voltage balancing in the three-level power converter; and dynamically adjusting an operating variable to adjust the voltage signal until the capacitor voltage balancing in the three-level power converter satisfies a criteria, wherein the three-level power converter includes: a first switch, a second switch, a third switch and a fourth switch connected in series between an input voltage Vin bus and ground; a flying capacitor (Cb) connected between a common node of the first switch and the second switch, and a common node of the third switch and the fourth switch; and an output filter connected between a common node of the second switch and the third switch, and ground, a first switch, a second switch, a third switch and a fourth switch connected in series between an input voltage Vin bus and ground; a flying capacitor (Cb) connected between a common node of the first switch and the second switch, and a common node of the third switch and the fourth switch; and an output filter connected between a common node of the second switch and the third switch, and ground, wherein the voltage signal is a voltage Vcb across the flying capacitor, and the operating variable is a duty cycle of the second switch, the method further comprising: determining a duty cycle through a main control loop; determining a duty cycle variation Δton through a local control loop; and configuring the first switch to operate with the duty cycle, and configuring the second switch to operate with a sum of the duty cycle and the duty cycle variation Δton; wherein a try-and-error based control process functions as the local control loop, the try-and-error based control process comprising a parameter (Sgn) indicating a try-and-error direction depending on the voltage Vcb across the flying capacitor; and a predetermined time duration (tstep); and wherein the duty cycle variation Δton is determined based on the parameter, the predetermined time duration and the duty cycle variation Δton in a previous one switching cycle or multiple switching cycles. determining a duty cycle through a main control loop; determining a duty cycle variation Δton through a local control loop; and configuring the first switch to operate with the duty cycle, and configuring the second switch to operate with a sum of the duty cycle and the duty cycle variation Δton; wherein a try-and-error based control process functions as the local control loop, the try-and-error based control process comprising a parameter (Sgn) indicating a try-and-error direction depending on the voltage Vcb across the flying capacitor; and a predetermined time duration (tstep); and wherein the duty cycle variation Δton is determined based on the parameter, the predetermined time duration and the duty cycle variation Δton in a previous one switching cycle or multiple switching cycles. a parameter (Sgn) indicating a try-and-error direction depending on the voltage Vcb across the flying capacitor; and a predetermined time duration (tstep); and wherein the duty cycle variation Δton is determined based on the parameter, the predetermined time duration and the duty cycle variation Δton in a previous one switching cycle or multiple switching cycles.