| 摘要 |
A power converting apparatus with dynamical driving adjustment includes a rectifying unit, a power factor correction unit, a power conversion unit and a feedback unit. The rectifying unit rectifies an AC input power to generate and transfer a DC power to the power factor correction unit for performing power factor correction. A power factor correction power is generated and transferred to the power conversion unit. The feedback unit is electrically connected to the power conversion unit to form a closed control loop. A PWM driving controller of the power conversion unit performs an adjustment process to control a switching transistor based on a feedback signal from the feedback unit, and the power conversion unit converts the power factor correction power into an output power supplied to an external load. Thus, the margin for electromagnetic interference is increased, and both switching loss and conduction loss are considerably reduced. |
| 主权项 |
1. A power converting apparatus with dynamical driving adjustment for converting an AC (alternative current) input power with an input voltage into an output power with an DC (direct current) output voltage supplied to an external load, comprising:
a rectifying unit for receiving and rectifying the AC input power to generate and transfer a DC power; a power factor correction unit for receiving the DC power and performing a process of power factor correction to generate and transfer a power factor correction power; a power conversion unit for receiving the power factor correction power and performing a process of power conversion to generate the output power; and a feedback unit electrically connected to the power conversion unit for generating and transferring a feedback signal based on the DC output voltage of the output power to the power conversion unit, wherein the power conversion unit comprises a transformer, a pulsed width modulation (PWM) driving controller, a switch transistor, an auxiliary diode, an output inductor, an output diode and an output capacitor, the transformer comprises a first side coil and second side coil, a positive end of the output diode is connected to an end of the second side coil, a positive end of the auxiliary diode is connected to an another end of the second side coil, a negative end of the output diode and a negative end of the auxiliary diode are connected to an end of the output inductor, an another end of the output inductor is connected to an end of the output capacitor, an another end of the output capacitor is connected to the another end of the second side coil, the load is connected to the output capacitor in parallel, the switch transistor is connected to an end of the first side coil, the PWM driving controller performs an adjustment process based on the feedback signal to generate a PWM driving signal for controlling the switch transistor to turn on and turn off, the output capacitor generates the output power, the switch transistor is an N type switch element selected from an NMOS transistor or an NPN bipolar transistor, and the adjustment process performed by the PWM driving controller comprises steps of:
during a first rising period, increasing a driving voltage of the PWM driving signal from zero voltage to a first voltage for beginning to turn on the switch transistor such that a drain-source voltage (Vds) of the switch transistor is lowered;during a second rising period, increasing the driving voltage from the first voltage to a second voltage or more than the second voltage which is larger than the first voltage, for beginning to turn on the switch transistor such that a drain-source voltage (Vds) of the switch transistor is lowered;sustaining the driving voltage for a preset period;lowering the driving voltage from the second voltage or more than the second voltage to the first voltage during a first falling period; andlowering the driving voltage from the first voltage to zero voltage during a second falling period,wherein the first voltage is about Miller plateau for the switch transistor, the Miller plateau is referred to a specific constant gate-source voltage (Vgs) lasting for a period of time when the switch transistor shifts from a turn-off state to a turn-on state or from the turn-on state to the turn-off state, the first rising period is prolonged as much as possible to minimize electromagnetic interference, and the second rising period, the first falling period and the second falling period are shortened as much as possible to reduce switching loss and conduction loss. |
