Switching Mode DC/DC Converter for Radar Pulse Currents

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Solution Overview

Problem

Radar systems face energy losses and interference due to pulsating loads from RF transmitters, which cause current modulation and mechanical wear in AC generators, requiring complex filtering and regulation to manage voltage and current effectively.

Innovation Solution

A switching mode DC/DC power converter with a high switching frequency and control parameters that introduce high impedance, allowing capacitors to provide a low impedance path for pulse currents, ensuring a constant current draw close to the transmitters, thus simplifying regulation and reducing the need for additional filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If passive LC-filters are used to filter pulsating loads at higher PRF (>5 kHz), then filtering effectiveness is improved, but the filters become bulky and require too much space at lower PRF

Engineering Contradiction:
Improvepulsating load filteringVSAvoidfilter size
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent changes the operating parameters of the DC/DC converter (switching frequency, duty cycle) to match the radar pulse repetition frequency, enabling the converter itself to act as an active filter that adapts to different PRF conditions without requiring bulky passive filters

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a current regulation loop is included in the DC/DC converter to charge capacitors with limited current, then voltage regulation performance is improved, but device complexity increases

Engineering Contradiction:
Improvevoltage regulationVSAvoidregulation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the voltage regulation function and current filtering function into a single DC/DC converter circuit by coordinating the switching frequency and duty cycle with the radar pulse repetition frequency, eliminating the need for separate current regulation loops and capacitive filtering circuits

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The DC/DC converter is designed to perform multiple functions simultaneously: voltage regulation, current filtering, and pulse train generation, thereby reducing overall system complexity while maintaining reliable voltage regulation

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If advanced regulation techniques are implemented to improve voltage regulation and filter pulse currents, then voltage regulation performance is improved, but device complexity and control difficulty increase

Engineering Contradiction:
Improvevoltage regulationVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The DC/DC converter is controlled to automatically synchronize its switching frequency and duty cycle with the radar pulse repetition frequency, enabling the system to self-regulate and filter pulse currents without requiring complex external control systems or additional input signals about radar operation

Inventive Principle:
Principle #25Self-service

4Productivity

If capacitors are placed on the voltage supply close to the transmitter and on the output of the DC/DC-converter, then pulse current supply capability is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvepulse current supplyVSAvoidsupply system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts the pulse current supply function from the traditional capacitor-based filtering approach and implements it directly within the DC/DC converter circuitry, eliminating the need for separate capacitor banks while maintaining the ability to supply pulse currents

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution reduces complexity, minimizes pulsating currents in distribution cables, and enhances spectral purity by maintaining proper voltage regulation with fewer components and smaller inductance, minimizing the need for central power supply filtering.

Implementation Method 1

A switching mode DC/DC power converter with a high switching frequency and control parameters that introduce high impedance, allowing capacitors to provide a low impedance path for pulse currents

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

allowing capacitors to provide a low impedance path for pulse currents, ensuring a constant current draw close to the transmitters

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3097431B1Radar system with a switching mode DC/DC power converter for delivering a direct current to a pulse radar unit
Publication Date: 2021.11.03 SAAB AB
  • EP3097431B1 patent drawingFigure 1
  • EP3097431B1 patent drawingFigure 2

AI summary

The present invention relates to a switching mode DC/DC (Direct Current/Direct Current) power converter for delivering a direct current to a pulse radar unit configured to transmit RF pulses with pulse duration. The switching mode power converter comprising: a first switching element configured to connect and disconnect the switching mode power converter from a power source in each cycle of the power converter. An inductor configured to charges and discharges in each cycle of the power conversion.A capacitor configured to maintain a DC output voltage as the inductor charges and discharges in each cycle.A second switching element configured to transfer energy from the inductor to the capacitor when the first switch disconnects the switching mode power converter from the power source. A control loop regulating the voltage with a time constant, to a predetermined value by means of controlling the first switching element. An on time for the first switching element in each cycle is chosen to allow the current through the inductor to fall to zero in each cycle. The cycle is shorter than RF the pulse duration and that the time constant of the control loop is longer than the RF pulses.