Benedikt Sanftl

Implementation of simultaneous energy and data transfer in a contactless connector

This paper presents a contactless near field energy and data transfer system, which uses one common pair of coils for both transmission purposes. Though a contactless connector for harsh environments proves an exemplary application, the concept can be adapted to several other applications. The challenge is to transmit the data simultaneously to a large energy signal. The system concept, simulation, as well as measurement results of a hardware demonstrator will be presented in this paper. It will be shown that a robust data transmission system can be realized featuring superior SNR and nearly noise free operation even with a simultaneous energy transfer of several kilowatts.

A novel approach for reliable communications within inductive power transfer systems

This paper presents a novel approach for simultaneous inductive power transfer (IPT) and communication in one system. The communication part is using the coupled pair of coils of the IPT system as transmitting medium. The proposed architecture is applicable to new and existing IPT systems with operating frequencies above 100 kHz. The challenge is to enable robust and reliable communication in the noisy environment of the power transfer. High reliability is necessary as it shall transmit sensor data error free. For example, this data link can be used for closed-loop operation of the IPT system. Through its fully digital implementation it can be quickly adapted for various other applications. It will be shown that a reliable communication system with joint power transfer and continuous data transmission over the same pair of coupling coils can be realised. Even during high power transfers it features a robust communication channel with outstanding signal to noise ratio and advantageous error vector magnitude. For proof of concept the key performance values of the proposed communication architecture are measured in a 20W IPT system.

Reliabe data link for power transfer control in an inductive charging system for electric vehicles

This paper presents a novel data link for electric vehicles charged through inductive power transfer (IPT) systems. The data link uses the magnetically coupled coils as transmission medium. The data link is intended to transfer the instantaneous current and voltage values in the power receiving circuitry on the electric vehicle (EV) platform. One key goal is to enable robust and reliable communication for closed-loop operation of the IPT system. By careful system design the data link can be used in the noisy environment of the power transfer. For the communication architecture a fully digital approach is considered. The digital signal processing is done in an industrial controller thus, the data link can be implemented into existing systems with minimum changes. For proof of concept the communication system is connected to a 3kW IPT system and evaluated. These key performance values for simultaneous power transfer and communication will be presented. The data link stands out with its high signal to noise ratio and error vector magnitude, consequently high reliability can be guaranteed.

A direct RF-to-baseband quadrature subsampling receiver using a low cost ADC

This paper presents a novel receiver using direct complex subsampling. In this approach no frequency conversion is used, but therefore bandpass sampling in combination with nonuniform sampling. A special sampling pattern for the analog to digital conversion is used. The resulting sampling frequency is below the carrier frequency, like in standard bandpass sampling receivers. Therefore the requirements for the analog-digital converter (ADC) and digital signal processor (DSP) are decreased. The sample and hold stage of the ADC still has to meet the requirements for the carrier frequency. The corresponding sampling scheme and its signal processing are described. A simulation of a QPSK receiver is presented. The proposed architecture is validated using a low cost commercial-off-the-shelf (COTS) ADC along with some testing and measurements. The receiver works for the industrial, scientific and medical band (ISM) carrier frequency at 13.56 MHz, which is commonly used for short range devices like radio-frequency identification (RFID) applications.

Dimensioning and comparison of common compensation topologies for IPT systems

This paper presents the dimensioning as well as the comparison of common compensation topologies for inductive power transfer (IPT) systems. A compensation is needed on the primary as well as the secondary side. It consists of a capacitor (parallel or series) in the simplest case or a combination of reactive components (like LCC). This work is the first compilation of the dimensioning, considering all potential combinations of these three compensation possibilities. The five most promising solutions are simulated and the results are compared for constant current- and voltage-operation with varying loads as well as different coupling factors. Finally the different topologies are compared by selected criteria and evaluated accordingly.

Increased data rate using higher-order digital modulation for simultaneous inductive data and power transfer systems

This paper presents an improved communication architecture with increased data rate for inductive power transfer (IPT) systems. The main challenge is to enable robust and reliable communication within the noisy environment of the power transfer. Therefore, the communication channel, consisting of the coupled pair of coils of the inductive power transfer system is analysed. From this, a frequency band with an excellent available signal to noise ratio has been identified. It is exploited using phase shift keying or higher-order digital modulation schemes as n-th quadrature amplitude modulation to increase the data rate. Furthermore the bandwidth of the system shall be extended by the utilisation of an equalizer. The implementation using a software defined radio will be presented in this paper and it will be shown that reliable and fast communication is possible in a harsh industrial environment.

Frequency separation stage design for a reliable data link in an IPT system for electric vehicles

This paper presents the hardware design of a novel and reliable data link for charging electric vehicles by an inductive power transfer (IPT) system. The simultaneous transmission uses the contactless near field of one common pair of coils. The data link can amongst others exchange the status information between the vehicle and the charging station. Due to its structure, most existing systems can be upgraded by this highly integrated data link without significant changes. One key component for the data link is the frequency separating filter (FSF). Its structure and design as part of the communication system as well as the interaction with the IPT system will be presented.