Current Compensation with Circulating Current Control Circuit in Vibration Generator

Improvement in output power of vibration generators based on piezoelectric elements by using internal capacitor cancel control rectifier

“…Figure 5 shows C3 circuit proposed in previous research. 15 C3 circuit is configured as a full-bridge inverter with inductor connected to its output. In the circuit shown in Figure 6, C3 circuit is connected in parallel to piezoelectric element.…”

“…C3 circuit produces current i L to compensate for i c . Using the current i L , charge-discharge time of the internal capacitor C p can be shortened, which is equivalent to reducing capacitance 15 [Color figure can be viewed at wileyonlinelibrary.com] F I G U R E 6 Conventional circuit with C3 circuit for vibration generator. 15 [Color figure can be viewed at wileyonlinelibrary.com] circuit for such current exchange.…”

“…Using the current i L , charge-discharge time of the internal capacitor C p can be shortened, which is equivalent to reducing capacitance 15 [Color figure can be viewed at wileyonlinelibrary.com] F I G U R E 6 Conventional circuit with C3 circuit for vibration generator. 15 [Color figure can be viewed at wileyonlinelibrary.com] circuit for such current exchange. In a period when the internal capacitor C p is charged, current i L must be supplied; as a result, voltage at C a decreases.…”

“…After that, we present a conventional circuit (diode rectifier) for vibration‐driven generator. Then, we describe the principle and drawbacks of LC resonant circuit proposed on a previous study, 13 present C3 circuit to overcome the drawbacks, 15 and propose an ICCC rectifier with modified C3 circuit.…”

“…In real‐world vibrations, frequency changes and includes harmonics so that the effect of LC resonance can be hardly be maintained. Thus, a circulating current control circuit (below referred to as C3 circuit) was proposed 15 to respond to frequency changes and to reduce inductor size. The proposed C3 circuit is connected in parallel to piezoelectric elements to generate electric current that is necessary to achieve same effect as with LC resonant circuit 13,14 .…”