Bipolar Transmitter Research Articles

3-D Analytical Model of Bipolar Coils With Multiple Finite Magnetic Shields for Wireless Electric Vehicle Charging Systems

The bipolar pad is one of the most promising topologies in inductive power transfer (IPT) systems for electric vehicles. However, there is scant literature on the analytical model of the bipolar pad. In this article, a three-dimensional (3-D) analytical model of the IPT system including a bipolar transmitter and a square receiver is developed based on the superposition of two 2-D subdomain analytical models. Ferrite and the aluminum shields with finite dimension are taken into account on the transmitter and receiver sides. An analytical calculation of the mutual inductance is then carried out with respect to the main parameters of the IPT system, namely the dimension of the coils, the conductivity, and the permeability of the shield. Three study cases are demonstrated to highlight how the proposed method can accelerate speed up the pad design process. Calculation results of the proposed model are compared with both a finite-element analysis (FEA) model and experimental measurements, demonstrating that the proposed model is nine times faster than the FEA method. When comparing with the experimental results, computational error of the proposed model is less than 6% in most of the study cases.

Research on Dual-Phase Non-Salient Pole Receiver for EV Dynamic Wireless Power Transfer System

Dynamic wireless power transfer (DWPT) technology shows a vast development prospect for EV application, with advantages of reducing the demand for battery capacity and improving the user experience. However, the need to improve output performance leads to a challenge in receiver design with limited space and allowable load on the EV side. In this paper, a design of a dual-phase non-salient pole (NSP) receiver for the EV DWPT system with bipolar transmitter is proposed, aiming at providing a solution to the contradiction between reducing the volume or cost and improving the misalignment tolerance of the receiver. The coupling principle of the proposed receiver is analyzed. The structure parameters are optimized by the finite-element simulation method. Combined with specific design indexes, it is proven by comparison with the existing dual-phase receiver that the proposed receiver is 35.4% smaller in volume and needs 47.0% shorter wires. Moreover, the significant advantage of the proposed dual-phase NSP receiver in misalignment tolerance is verified by simulations and experimental comparisons.

Development of a Fit-to-Surface and Lightweight Magnetic Coupler for Autonomous Underwater Vehicle Wireless Charging Systems

A novel magnetic coupler (MC) with cross-coupling mode is proposed in this article, which has merits of fit-to-surface and lightweight in receiver, and supports stable and efficient charging for autonomous underwater vehicles (AUVs). The proposed magnetic structure employing an arc bipolar transmitter and a compact dipole-coil-based receiver utilizes horizontal flux to establish strong and stable coupling against three-dimensional misalignment; the MC structure is constructed and optimized according to the magnetic field distribution characteristics. The influence of geometric parameters on the MC's performance is obtained based on ANSYS Maxwell simulation, with which the parameters of MC are optimized. In order to fully verify the performance of the designed MC, an AUV wireless charging system circuit is also developed. A wireless charging system prototype is built and tested with a 600 g receiver, and it can deliver 1 kW at a dc-to-dc efficiency of 95.1%. The experimental results under various operating conditions indicate that the proposed MC is viable and can be used for charging the AUVs.

Space-Vector Based Excitation of a Bipolar Transmitter for Wireless Power Transfer Applications

A space-vector (SV) based excitation method for wireless power transfer systems with a bipolar transmitter is introduced in this article. Unlike traditional bipolar excitation techniques that rely on fixed transmitter current distributions, this SV approach provides an elegant analytical method of redistributing a greater magnitude of current to the transmitter coil, which is closer to a misaligned receiver. This method is shown to require a smaller transmitter current vector magnitude for a required output power compared to all other bipolar coil excitation schemes over a broad range of receiver misalignments, thereby reducing conduction losses within the system. Additionally, the gradual redistribution of transmitter current as a function of receiver misalignment achieved by the SV method causes it to be less influenced by errors in receiver position sensing compared to conventional methods. Experimental results shows that the proposed method in conjunction with single coil operation at extreme misalignments was able to achieve a coil efficiency profile with minimal variation due to misalignment (93.2% at perfect alignment to 92.7% at a misalignment of 20 cm, for 2 kW power transfer into a 200 V battery load.)

Ultrasound imaging device

An ultrasound imaging device having a bipolar transmitter to generate a bipolar voltage signal, a transducer to emit an ultrasound wave in response to the bipolar voltage signal, and a bias generator to bias the bipolar voltage signal prior to being received by the transducer so that the biased bipolar voltage signal maintains a same polarity as a poling polarity of the transducer throughout a transmit cycle of the ultrasound imaging device. By biasing the bipolar voltage signal to maintain a same polarity as the poling polarity of the transducer throughout the transmit cycle, the ultrasound imaging device prevents depoling of the transducer which could otherwise occur if the transducer is driven by a bipolar voltage signal which repeatedly has a polarity opposite to the poling polarity of the transducer.

Power minimization and technology comparisons for digital free-space optoelectronic interconnections

This paper investigates the design optimization of digital free-space optoelectronic interconnections with a specific goal of minimizing the power dissipation of the overall link, and maximizing the interconnect density. To this end, we discuss a method of minimizing the total power dissipation of an interconnect link at a given bit rate. We examine the impact on the link performance of two competing transmitter technologies, vertical cavity surface emitting lasers (VCSELs) and multiple quantum-well (MQW) modulators and their associated driver-receiver circuits including complementary metal-oxide-semiconductor (CMOS) and bipolar transmitter driver circuits, and p-n junction photodetectors with multistage transimpedance receiver circuits. We use the operating bit-rate and on-chip power dissipation as the main performance measures. Presently, at high bit rates (>800 Mb/s), optimized links based on VCSELs and MQW modulators are comparable in terms of power dissipation. At low bit rates, the VCSEL threshold power dominates. In systems with high bit rates and/or high fan-out, a high slope efficiency is more important for a VCSEL than a low threshold current. The transmitter driver circuit is an important component in a link design, and it dissipates about the same amount of power as that of the transmitter itself. Scaling the CMOS technology from 0.5 /spl mu/m down to 0.1 /spl mu/m brings a 50% improvement in the maximum operating bit rate, which is around 4 Gb/s with 0.1 /spl mu/m CMOS driver and receiver circuits. Transmitter driver circuits implemented with bipolar technology support a much higher operating bandwidth than CMOS technology; they dissipate, however, about twice the electrical power. An aggregate bandwidth in excess of 1 Tb/s-cm/sup 2/ can be achieved in an optimized free-space optical interconnect system using either VCSELs or MQW modulators as its transmitters.

A two-chip 1.5-GBd serial link interface

A silicon bipolar transmitter and receiver chip pair transfers parallel data across a 1.5-GBd serial link. A new 'conditional-invert master transition' code and phase-locked loop that provide adjustment-free clock recovery and frame synchronization are described and analyzed. The packaged parts require no external components and operate over a range of 700 to 1500 MHz using an on-chip VCO. The line code and handshake protocol have been accepted by the serial-HIPPI implementor's group for serially transmitting 800-Mb/s HIPPI data, an ANSI standard, and by SCI-FI, an IEEE standard for interconnecting cooperating computers. >

Full transmitter waveform transient electromagnetic modeling and inversion for soundings over coal measures

Modeling of transient electromagnetic soundings requires consideration of the full bipolar transmitter waveform in order to obtain full measurement accuracy from field instruments. The full‐waveform transient may be computed using existing impulse‐response forward algorithms followed by a convolution procedure with truncation and residual estimation after an even number of terms, which results in average increases in run time of about 80 percent. Simple calculations based on approximations for the behavior of transient decay over (a) a conductive layer over a resistive basement, (b) a homogeneous half‐space, and (c) a resistive layer over a conductive basement show that the effect of the full waveform is greatest at sample times near the end of the transmitter off‐time, and for the case of a conductive basement. Failure to consider the full waveform is expected to yield errors in the amplitude of the computed transient in the range of 4 to 100 percent or more, depending upon the sample time and type of earth model. Examples of soundings over moderately conductive coal measures and highly conductive cindered coal show that failure to use the full waveform yields depths and resistivities biased to erroneously high values. The bias is small in the former case, but produces substantial errors in the latter case. Depth to the electrical basement of 300 to 400 m may be estimated to accuracies of approximately 5 percent by computer inversion to three‐layer or four‐layer models.