Voltage control utilizing multiple PWM patterns
摘要
說明書
However, even if cost and space considerations were not relevant, inefficiencies would still result from a power system in which many converters were delivering short pulses in short PWM cycles. When a converter switches on and off, there is a ramping time during which the converter is not functioning efficiently. As the length of time during which the converter is switched on (i.e., the pulse length) decreases, the percentage of the pulse length during which the converter is ramping up or down (and thus functioning less efficiently) increases.
Therefore, in situations during which a large voltage change is occurring, a short PWM cycle is ideal. However, in most situations (e.g., steady state operation, such as normal device performance or idling), a longer PWM cycle is more efficient, and is thus ideal.
In some embodiments of the present disclosure, multiple cyclic patterns of different lengths are maintained by the power system. For example, a cyclic measurement pattern may have a short measurement period. A first cyclic control pattern may have a short PWM period that is the same as that of the measurement period. If the short PWM period is the same as the measurement period and the two periods are in phase, the two cyclic measurement patterns may be referred to collectively as a cyclic PWM pattern. Further, the cycles of that cyclic PWM pattern may be referred to as PWM cycles, and the periods of those cycles may be referred to as PWM periods.
