Autonomous Power Supply Monitoring to Prevent Reset Oscillation

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Solution Overview

Problem

In safety-relevant systems, voltage regulators experience repeated RESET pulses due to synchronous load reduction, leading to unstable output voltage and potential errors in consumers, especially when energy storage is depleted, causing periodic fluctuations in supply voltage.

Innovation Solution

An energy supply unit with a monitoring unit that sets a monitoring signal to an active state if the output voltage falls below a threshold and deactivates it when the input voltage rises above a reset threshold, incorporating delay timers to stabilize the signal transitions and prevent repeated activations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the output voltage is monitored and load is reduced when voltage falls below minimum regulator input voltage, then the regulator output voltage stability is improved, but multiple RESET pulses are generated causing system instability

Engineering Contradiction:
Improveregulator output voltage stabilityVSAvoidsystem stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary anti-action by detecting the undervoltage condition and activating the monitoring signal before the output voltage actually drops below the minimum regulator input voltage. This preventive approach stops the load current from causing the voltage drop in the first place, thereby preventing the sequence of events that leads to multiple RESET pulses and system instability.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The monitoring signal is activated in advance when the output voltage approaches the critical threshold, allowing the system to take preparatory actions (such as load shedding) before the undervoltage condition actually occurs. This preliminary action prevents the harmful oscillation cycle from starting.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If synchronous load reduction is triggered by undervoltage monitoring, then regulator output voltage is stabilized, but repeated RESET pulses cause consumer errors

Engineering Contradiction:
Improveoutput voltage regulationVSAvoidconsumer errors
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system activates the monitoring signal preemptively when voltage approaches the threshold, preventing the undervoltage condition and subsequent RESET pulse generation before they occur. This eliminates the harmful effect of consumer errors caused by repeated RESET pulses.

Inventive Principle:
Principle #9Preliminary anti-action

3Duration of action of stationary object

If energy storage is depleted causing input voltage to decrease, then autonomous operation is maintained, but periodic voltage fluctuations occur

Engineering Contradiction:
Improveautonomous operation durationVSAvoidsupply voltage stability
Core Design Contradiction:
Duration of action of stationary objectVSStability of the object's composition

Solution Approach 1:

The monitoring signal provides early warning when the output voltage approaches the critical threshold during energy storage depletion. This allows the system to take preventive measures (such as reducing load) before the undervoltage condition occurs, maintaining stable operation throughout the autonomous duration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The monitoring signal creates a feedback mechanism that continuously monitors the output voltage and triggers load reduction when the voltage approaches the minimum threshold. This feedback loop prevents the periodic fluctuations that would otherwise occur as energy storage depletes, maintaining stable supply voltage throughout the autonomous operation period.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2951596B1Energy supply unit and method for operating an energy supply unit for autonomously supplying a load
Publication Date: 2024.06.12 ROBERT BOSCH GMBH
  • EP2951596B1 patent drawingFigure 1A~1B
  • EP2951596B1 patent drawingFigure 2A
  • EP2951596B1 patent drawingFigure 2B

AI summary

The invention relates to an energy supply unit (200) for autonomously supplying a load (140). The energy supply unit (200) comprises an energy store (ER) which is designed to deliver electrical energy to a load (140) when the electrical load (140) is decoupled from an energy supply network (115). The energy supply unit (200) also comprises an energy supply controller unit (100) having an input (110), which is coupled to the energy store (ER), in particular via a diode, and is intended to receive electrical energy, and an output (130) for delivering electrical energy to the load (140). The energy supply unit (200) finally comprises a monitoring unit (230) for outputting a monitoring signal (150, RESET), wherein the monitoring unit (230) is designed to set the monitoring signal (150, RESET) to an active state ("0") if an output voltage (Uout) applied between the output (130) and a reference potential (120) is less/greater than a predefined activation threshold value (Uout_ru / Uout_ro), and wherein, if an excessively low input voltage between the input (110) and the reference potential (120) of the energy supply controller unit is detected, in particular combined with an excessively low output voltage Uout (130), the monitoring unit (230) is also designed such that the monitoring signal (150, RESET) is switched to be inactive again only when both the input voltage is above a reset threshold and the output voltage of the controller is in the monitoring band.