Study of HV dielectric ceramics for applications in compact pulsed power

Abstract

The scientific interest of this paper consists of the study of ceramic dielectrics for applications in compact pulsed power systems. The reason for this is that ceramic dielectrics with large dielectric constant and high breakdown strength have great potential for decreasing the volume required for pulsed power supplies in future envisioned pulsed power-driven systems on mobile platforms. In particular, the main idea here is to check the dielectric properties of PZT (Lead Zirconate Titanate) ceramics for use in storage systems because of their high dielectric constant (300-3000) and excellent performance in HV explosive-driven ferroelectric generators.

Characterization of Ceramic Dielectrics for Sub-GHz Applications in Nonlinear Transmission Lines

“…9. According to (9), the capacitances are given as a function of frequency and exhibit the same behavior observed for the dielectric permittivity (Figs. 6 and 7), increasing near resonance frequency, except for the SMD capacitor.…”

“…In principle, NLTLs could provide submicrowave peak power of tens of megawatts at a pulse repetition rate (0.1-1 kHz) with dielectric requirements of high-voltage breakdown (BD, tens of kV/cm) strength and low loss tangent (<1%). As shown elsewhere [9], [10] the capacitors based on lead-zirconate-titanate (PZT) and BT dielectrics have dielectric BD strength of the order of 50 and 100 kV/cm, respectively. Nevertheless, the suppliers do not furnish the loss tangent of these components at sub-GHz frequencies.…”

Prospects of building capacitive nonlinear lines using ceramic PZT for high-frequency operation

“…A capacitance meter connected in series with the device and isolated from the HV DC power supply using a HV linear blocking capacitor of higher capacitance (at least 1.0 ʅF) measured the nonlinear capacitance under test. More details of the circuit can be found in [4]. With the P×E polarization measurement the well-known Sawyer-Tower circuit [5] was used.…”

“…In this measurement system, the voltage across the transformer output is proportional to the electric field applied in the dielectric whereas the voltage across the linear capacitor is proportional to the polarization P or the accumulated charged q (since P=q/A, where A is the area of the dielectric). Finally, for the HV BD tests an LC oscillatory half sine wave discharge circuit was built [4]. This circuit comprised basically a 1 kV capacitor bank that is discharged via the closing of a mechanical normally open switch through the primaries of two 12 V ignition coils connected in parallel and in anti-phase in order to generate a maximum HV differential output pulse of about 60 kV across the electrodes of the PZT sample or of the capacitor tested.…”

“…Moreover, other important characteristic to be considered for use in NLTLs is the assessment of their nonlinearity [4], since for nonlinear applications polar dielectric materials (such as BST and BT ceramics) are normally employed because their dielectric constant varies with the applied voltage, temperature, frequency, etc. Therefore, the main objective of this paper is to show the characterization of PZT material in terms of their nonlinearity, losses and BD strength to assess their possible use in NLCLs at higher frequencies.…”