| |
|
|
Power Factor
Correction Patent |
| Illustrated here is a low cost DC power circuit capable of sufficiently
improving a power factor and attaining the inhibition of higher harmonic
distortions in spite of small-sized and light-weight constitution. |
Conventionally, there are two type of power factor correction means
: One method is to include a choke coil at the AC input section or
the output of rectification circuit. Another is to provide the boosting
coverter. When the harmonic distortion is large, the high harmonics
with high frequency is getting bigger and excessive current flows
at the AC input, the effective power delivered from the source decreases.
At the same time, the higher harmonics will adversely affect other
electronics equipment. Thefore, the world regulation agencies are
adopting various higher harmonic restricting rules by limiting the
max value of harmonics. |
| The Subject to be resolved
by the invention |
By the choke coil method, to get the
good power factor and in order for the system to meet the high harmonic
regulation, relatively large inductance is needed and therefore, the
coil is becoming large and this will make the system bigger and the
power consumption larger.
On the other hand, in the later voltage boosting converter case, the
power loss of the coverter itself shall be counted and thus the overall
efficiency is decreased. Furthermore, large current is switched by
swithcing semiconductor, and the large power device is needed and
the noise countermeasure becomes complicated and expensive.
Therfore, this invention is aimed to get the high power conversion
efficiency and at the sametime, good power factor correction and the
low cost at the subject AC-DC power source. |
|
| The means to solve the subject |
| AC input voltage Vin is rectified by a main rectifier
6, and smoothed by a smoothing circuit 18, thus acquiring output voltage
Vo. A sub- rectifier 7 is connected to the AC-side both input terminals
of the main rectifier 6. The pulsating current output of the sub-full-wave
rectifier 7 is converted into auxiliary currents 12 by a current adjusting
circuit 8 while the auxiliary currents 12 are overlapped to main currents
11 output from the main rectifier 6, thus obtaining synthetic currents
13. Accordingly, insufficient sections for enhancing a power factor
and higher harmonic distortions by main currents 11 are supplied by
auxiliary currents 12, thus realizing sufficient improvement in the
power factor and the attainment of a higher-harmonic control reference. |
|
