Complex Foc_LimitVqVd Function for Field-Oriented Control

This function takes in two pointers to TPic structures (Pic_d and Pic_q), a Complex variable (mdq), and a float32 variable (Limit). It calculates the modulus of mdq and stores it in ModIndex. If ModIndex is less than the Limit, it scales mdq by dividing its real and imaginary parts by ModIndex. It then updates the 'uk' values of Pic_d and Pic_q with the scaled values of mdq, and returns mdq. The purpose of this function is to limit the voltage output of a field-oriented control algorithm to prevent overloading the motor or inverter.