38results about How to "Reduce heat source" patented technology

The application discloses a kind of no sampling resistance square wave control overcurrent protection method, method includes: real-time acquisition digital sampling sequence of direct current bus voltage, synchronous analysis logic state combination of three-phase PWM driving signal;According to the mapping table of pre-stored commutation state machine, the logic state combination is converted into current effective conduction phase identification, and the signal of corresponding current detection enable window is generated, and enable window is limited to the interval of voltage oscillation attenuation completion after PWM opening to before off before freewheeling protection;During the effective period of enable window, the digital band-pass filtering is carried out to bus voltage digital sampling sequence, the voltage drop component of characteristic frequency band is extracted, and the time-domain integral value and the rate differential value of voltage drop component are calculated.The application is reconstructed by the current of no sampling resistance technology and dynamic protection strategy, while reducing hardware cost, significantly improve system reliability, effectively solve the protection failure problem of traditional scheme under commutation interference, high-speed working condition and transient impact.