Description of the offer

The invention relates to an improved sequential switching shunt regulator cell, and to a solar power regulator comprising a plurality of said cells.

In many applications it is essential to ensure that a single failure cannot result in a significant loss of operation. A short-circuit of the diode of a single sequential switching shunt (S3R) sequential switching shunt series regulator (S4R) cell would result in a total loss of operation. Therefore, two diodes connected in series are generally used, but unfortunately, reduces the power efficiency of the system. The increase in power dissipation hinders miniaturisation of the regulator and requires bulky and heavy heat sinks. The offered technology aims at avoiding this major drawback by providing a sequential switching shunt regulator cell comprising a power line connecting a power source to a power bus including a shunting switch with driving means. The cell furthermore comprises a non-redundant rectifier connected in series to the power line for disconnecting the power bus from the shunting switch if closed. A fault detector is included to detect short-circuit conditions in the non-redundant rectifier and to open the shunting switch in such a case.

Innovations and advantages of the offer:

The offered technology:

• Provides several different embodiments of the fault detector, which is able to monitor the voltage levels of the power line and driving means in order to detect a short-circuit fault.
• Obtains an ever greater increase in power efficiency by the use of a synchronous rectifier which replaces the diode.
• Solved the difficulty to distinguish between a failure condition and a transient which can occur in nominal operation by providing a solution based on the observation that it is not necessary to activate the fault detector within a single cycle of the shunting switch.

Considering a typical power system comprises several cells, and several generators, the efficiency gain provided by the offered technology can be quite substantial.

Domain of Application:

Although S3R (S4R) regulators are widely spread in the space sector for solar cells and arrays in satellites, the offered technology may also be applied, among others, to power supplies in the automotive sector and the terrestrial solar energy sector.

• Power Supplies
• Solar Energy
• Photovoltaic Solar
• Other Energy

Energy Management

Description of the offer:

This solar array regulator (SAR) is based on a step-up and step-down converter. The control loop of the boost power cell is highly stable, the control system ensures smooth transition between different operation modes (step-up, step-down, Direct Energy Transfer, DET) and it is stable in all operation modes, e.g. In battery management mode, but also when operating on the voltage and current region of the solar array in MPPT (Maximum Power Point Tracking) mode, in the event of a failure, simultaneous operation of the step-up and step-down cells is avoided, the complexity of the system is low, particularly in case of analog implementation.

Innovations and advantages:

With this invention you will get next benefits:

• Increase the efficiency of the solar array, with less cost and less dissipation.
• Increase the flexibility of Solar array design
• As this inventions applies to any configuration, it would be recurrent, what means less cost. 

Commercialisation aspects:

Applications and Markets

The main applications are in solar power generation stations, off-shore or remote facilities or equipments powered by solar energy. It can also be applied to DC-DC converters when the input offers instability such as in power grids, batteries, buildings, electric vehicles, etc.

Intellectual property status

Currently patented and looking for license agreements.

Description

Improving the efficiency, consumption, dissipation and/or linearity of radio-frequency (RF) solid state power amplifiers (SSPAs) is a high priority for manufacturers of ground mobile telephony network infrastructures due to the very demanding requirements for 3G-UMTS.  The very high linearity required dramatically impacts the efficiency of power amplifiers used in base stations.  Similar requirements arise in in space applications.

Linearity and energetic efficiency are seen as contradictory requirements and therefore the “flexible amplifier” concept consists in adjusting the power supply to the average RF power in order to achieve both high linearity and high efficiency.  “Envelope tracking” is an evolution of this approach, wherein the power supply is dynamically adjusted, following the RF signal envelope.

The invention solves the problems of existing SoA through a device consisting of a radio-frequency power amplifier with envelope tracking, comprising:

• A power RF amplifying device
• A fast DC/DC converter for envelope tracking using two RF power transistors for implementing both the switching element and rectifier.
• An optional low-pass filter for reducing the bandwidth of the envelope signal on which the PWM signal driving the DC/DC converter depends.

As an advantage, the switching device, the rectifying device and the power RF amplifier can be identical transistors.

An RF power transistor connected as a rectifier enables a high commutation speed to be achieved, whilst dealing with comparatively high currents (>1A) and powers (several Watts).  This is not possible using commercial diodes and therefore a transistor connected as a two terminal device avoids “diode bottlenecks” seen with current technology.

Innovations and advantages

The technology offers better efficiency, wider bandwidth, better integration, better linearity and power flexibility. Monolithic integration of the envelope tracking circuit and the main RF power amplifier is possible. A single power supply to the envelope tracking circuit is sufficient.

Commercialisation aspects

Applications and Markets

This power amplifier may be used in any field where a modulated signal (most efficient case) is used. 

Examples include:

• General telecom applications (L, S, C band) such as telephony, radio, TV or radio links
• GNSS communications
• Ground applications that use an SSPA transmitting device (e.g. SAR imaging)
• Radar
• Sensors (ultrasonic, infrared or laser) which use a modulated signal for increasing their range.

Description

The present invention consists in extending average current mode control with symmetrical sawtooth beyond its limit to reach peak current mode control “with symmetrical compensation ramp”. The symmetrical compensation ramp necessary to implement such peak current mode control shall consist in two asymmetrical compensation ramps. This is the essence of the invention, as illustrated on the figure below.

By substituting the upper (in blue) and lower (in violet) compensation ramps to the symmetrical sawtooth (dotted line) relevant to symmetrical Average Current Mode control, the current waveform is allowed to move from low gain (in green) to higher, optimal, gain (in red) relevant to Peak and valley Current Mode control.

Innovations and advantages:

As yet, current mode control would resort to average control with asymmetrical sawtooth, or peak control with asymmetrical compensation ramp or average control with symmetrical sawtooth. Considering that average current control (with negligible integral loop gain) is a subset of peak current control, the missing link was peak current control with symmetrical compensation ramp. It constitutes the ultimate control strategy because peak current control has superior dynamics with respect to average current control and because symmetrical sawtooth or compensation ramp offers a factor 2 on the bandwidth performance with respect to asymmetrical sawtooth or compensation ramp. In turn, power supply products can have implemented with reduced mass and cost.

Domain of application:

The scope of applications of the invention is quite extensive as it concerns not only DC/DC power supplies for space, but also AC/DC, DC/AC and AC/AC power supplies for terrestrial (50 Hz) or aeronautical (400 Hz) applications.