Sendyne Corporation

Semtech Corporation

Usar Systems, Inc.

Other

Sensata Technologies, Inc.

Battery-Biz Inc.

Semtech New York Corporation

Usar System Inc.

Victor Marten

Ioannis Milios

Wei Wang

Nicolas Clauvelin

Andrew McKnight

Mark Vanstone

Carl Hejdeman

Aleksandar Prodic

Mahmoud Shousha

Brian J Hawkins

Aakar Patel

David M Banyai

Eran Sitnik

Joseph A Yozzo

Juan C Sanchez

Damian Glinojecki

Andrew Shafranov

Jerald Greenberg

Ofer Alon

Jennifer A Edwards

Edward Banyai

An isolation monitoring approach according to the invention is defined with respect to first and second battery connection positions, each of which is not tied to a chassis. First and second respective resistor strings, each having a first end and a second end, are each connected at their first end to the respective first and second battery connection positions. The first and second resistor strings are each connected at their second end to the chassis. In each of the first and second resistor strings, an optically-controlled MOSFET relay is connected across part of the resistor string. Connected to each of the resistor strings, at a point between the MOSFET relay and the chassis, is a respective voltage measurement circuit connected to measure voltage relative to the chassis. In operation, the MOSFETs associated with the resistor strings can be turned on and off. This brings about an excitation signal with respect to the resistor strings, and the voltage measurement circuits can measure the voltages during the time of the excitation signal, comparing them with the voltages in the absence of the excitation signal. This permits arriving at an inferred value for isolation loss along a modeled leakage path between the associated battery connection positions and the chassis. In the event of an isolation failure, the event can be annunciated.

Isolation monitoring

Switching of particular inputs in a signal processing channel permits an independent evaluation of that signal processing channel, in a system where there are at least two signal processing channels, one of which is able to be calibrated while the other of which is measuring current in a shunt. Switching a controlled current through a shunt, the controlled current being small in value compared with an overall current being measured, permits yet another independent evaluation of the shunt.

Functional safety of measurements

Wide deployment of high voltage battery systems in traction, industrial and renewable energy installations is raising the concerns for human safety. Exposure to hazardous high voltages may occur due to deterioration of insulation materials or by accidental events. It is thus important to monitor for such faults and being able to provide timely warnings to affected persons. For this purpose it has become mandatory for electrified passenger vehicles (CFR 571.305) to maintain high isolation values which can be continuously monitored by electrical isolation monitoring devices. The task of monitoring isolation resistance within the electrically noisy car environment is not a trivial task and the solution to this problem has become quickly a field of research and innovation for all affected industries.

Isolation monitoring device and method

Electrical shunt

An apparatus and method make use of a single shunt and two or more instrumentation amplifiers, switchably measuring voltages at the shunt. This permits current measurement. At times each instrumentation amplifier has its input shorted, which permits zeroing out many sources of offset in the signal path of that amplifier. Dynamic range is several orders of magnitude better than known current measurement approaches, permitting coulometry.

Current sensor

A method and a system are shown for attachment of leads for the electrical sensing of the voltage on conductive structures; connections attached per this invention have the valuable property of very low thermoelectric errors (due to Seebeck effect), among several other beneficial properties. The described method can be applied in the factory setting as well as in the field. This system is especially suitable for applications with high-precision resistive shunts utilized in the measurements of the electric current.

Attachment of leads having low thermoelectric errors

Methods and circuits for reduction of errors in a current shunt are disclosed, for example sensing lines for Kelvin sensing in which the sensing lines are of identical material to the high-resistance portions of the shunt, and welded thereto. This allows application of a current shunt with lower output voltage and thus lower power losses than the contemporary art implementations, while maintaining high accuracy with regard to temperature changes.

Current shunt

A topology is described in which each pair of cells in a string shares a single inductor. Switches permit the single inductor to selectively charge one or the other of the cells. In a variant of the topology, the inductor together with additional switches permit selectively charging multiple cells simultaneously (even one or both cells simultaneously in a pair of cells), drawing upon either an external energy source or upon one or multiple other cells in the string. In this way the number of inductors is minimized while providing isolation among the charging circuits.

Charge redistribution method for cell arrays

What is described is a battery management architecture that eliminates previously described problems of the previous solutions and compensates for the extra cost of a cell-balancing circuit. These advantages are achieved by integrating the voltage step-up and balancing functions as well as charging functions inside a single converter topology. Instead of providing the entire output voltage and power, the converter in this configuration is merely assisting the battery by providing a portion of the power delivered to the load, rather than the entirety of the power delivered to the load. This portion of power is proportional to the difference between the output and the battery pack voltages.

Assisting converter

A method, an algorithm, and circuits for implementation of a high-accuracy voltage divider are described that include a capability of fault detection. The disclosure allows for correction of non-catastrophic faults, such as significant changes of the components' values. The performance of the circuit built as described is vastly superior to operations achievable with the modern-day components utilized in previous standard and known configurations.

High precision algorithmically assisted voltage divider with fault detection

A highly accurate voltage reference and temperature sensor circuit requires only several low-cost components in addition to a general-purpose microcontroller with an analog-to-digital converter. Unlike known circuits, the circuit disclosed does not rely on matching between a pair of semiconductor devices, as only a single semiconductor junction is used. All of the signal processing may be performed digitally.

Voltage reference and temperature sensor

A system is used with a plurality of modules, each module requiring galvanic isolation from the other modules. Galvanic isolators are employed, each having an input and an output, the output galvanically isolated from the input, the output responsive to the input according to a response characteristic of the isolator. Each module has, a respective first isolator and a respective second isolator. The input of each respective first isolator and each respective second isolator for each module is disposed controllably to receive an activation signal from the module indicative of a module fault to be annunciated or to receive a test signal from the module, the test signal being smaller than the activation signal. The outputs of the respective first isolators are aggregated to a first node and the outputs of the respective second isolators are aggregated to a second node. A selection circuit selects from the first node and the second node, yielding a fault signal output when the selected node satisfies a predetermined condition. An analog-to-digital converter is coupled with each of the nodes, the analog-to-digital converter disposed to sense an output from one of the isolators indicative of its response characteristic in the event of a test signal being applied to the isolator.

Reliable signaling of fault conditions in battery systems with series-connected cells

A method, circuit, and topology are provided for utilization of this circuit in Li-Ion or any other battery that benefits from balancing between individual cells. The whole system is characterized as having high efficiency (and thus low heat losses) compared to previous art implementations. The actions of the circuit are continuous and bi-directional in respect to each cell.

Charge balancing system

A current sensing approach makes use of two shunts in series, embedded in a switching fabric, each shunt the object of a differential measurement of voltage drop across the shunt. Methodical make-before-break cycling of the switches in the switching fabric permit real-time or very near-real-time measurement of nearly all of the errors such as offset errors present in each differential-measurement path. Additional differential measurement paths can be connected with the shunts, with RFI filtering at shorter time constants to serve electronic fuse needs.

Growing community of inventors

Flushing, NY, United States of America

Victor Marten