DC-DC Converter Control Using Sensorless Current Estimation
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Solution Overview
Problem
Existing direct current fast charging (DCFC) systems rely on current sensors to improve dynamic performance, which can be costly and prone to inaccuracies under varying load and battery conditions.
Innovation Solution
A controller module estimates output current without the use of current sensors by utilizing input and output voltages to generate control signals for the DC-DC converter, employing a power converter controller (PCC) to adjust charging output based on estimated current values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current sensors are used to improve dynamic performance, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces physical current sensors with a computational approach using the power converter controller to estimate output current based on voltage measurements and power calculations. This substitutes mechanical/electrical sensing components with a control algorithm that calculates current indirectly, thereby reducing device complexity while maintaining measurement capability
Solution Approach 2:
The patent introduces voltage measurements as an intermediary to indirectly determine current. Instead of directly measuring current with sensors, the system measures voltage and uses power relationships (P=VI) to calculate current, using voltage as a mediator to obtain current information without direct current sensing
2Measurement precision
If current sensors are used to improve dynamic performance, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent replaces expensive current sensor hardware with a software-based calculation approach implemented in the power converter controller. This substitution eliminates the need for additional sensor components, reducing bill of materials cost and simplifying the manufacturing process while maintaining the capability to obtain accurate current information
Solution Approach 2:
The system uses its existing voltage measurement capabilities and power control algorithms to self-determine current information without requiring external current sensing components. The controller leverages data it already collects for power regulation purposes, making the system self-sufficient in obtaining current measurements
3Speed
If current sensors are used, then dynamic performance is improved, but reliability decreases due to sensor inaccuracies under varying conditions
Solution Approach 1:
The patent implements a feedback mechanism where the power converter controller continuously monitors voltage and power information and uses this feedback to calculate and adjust current estimates in real-time. This closed-loop approach ensures that current information remains accurate under varying load and battery conditions, improving reliability compared to fixed sensor readings
Solution Approach 2:
The patent employs a dynamic calculation approach where current estimation adapts to changing operating conditions through real-time computation based on instantaneous voltage and power measurements. This dynamic method maintains accuracy across varying loads and battery states, overcoming the static nature of traditional current sensors that may drift or become inaccurate under different conditions
Data Source
AI summary
Various disclosed embodiments include illustrative controller modules, direct current (DC) fast charging devices, and methods. In an illustrative embodiment, a controller module for a DC-DC converter includes a controller and computer-readable media configured to store computer-executable instructions configured to cause the controller to receive an input voltage Vin to the DC-DC converter, receive an output DC voltage Vo from the DC-DC converter, generate control signals configured to control a charging output of the DC-DC converter responsive to the received input voltage Vin and output voltage Vo, and output the generated control signals to the DC-DC converter.