Choke Current Zero-Crossing Timing for Fast Converter Control
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Solution Overview
Problem
Existing control methods for active voltage converters in power electronics require immediate reaction to zero crossings of current, placing high demands on control units and lacking closed-loop control, which is challenging at high switching frequencies.
Innovation Solution
A method determining parameters based on the duration between zero crossings of choke current, allowing for indirect control and enabling plausibility checks and error detection, reducing hardware requirements and enabling use of more capable microcontrollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If direct reaction to zero crossing of current is implemented, then control dynamics is improved, but control unit complexity and computational burden increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing current values at zero crossings in a buffer memory before they are needed for control decisions. This allows the control unit to retrieve pre-processed data without performing real-time computations, thus maintaining fast control dynamics while reducing the computational burden on the control unit.
2Measurement precision
If multiple computation operations are performed within the same switching period, then control precision is improved, but available processing time decreases
Solution Approach 1:
The control device performs computation operations in advance by storing current values at zero crossings in a buffer memory during the first half of the switching period. This preliminary storage of data allows the control unit to make precise control decisions in the second half of the period without time pressure, thus maintaining control precision while effectively utilizing available processing time.
3Power
If switching frequency is increased, then power density is improved, but period duration for control operations decreases
Solution Approach 1:
The patent enables operation at high switching frequencies by performing preliminary actions during the first half of each switching period: detecting zero crossings and storing corresponding current values in buffer memory. This pre-processing approach ensures that control decisions can be made within the shortened period duration at high frequencies without compromising control accuracy or requiring increased hardware complexity.
4Reliability
If plausibility check and error correction are performed, then control reliability is improved, but control response time increases
Solution Approach 1:
The patent performs plausibility checks and error corrections as preliminary actions on the stored current values in buffer memory, before these values are used for control decisions. By validating and correcting data in advance, the system ensures high control reliability while maintaining fast response times, as no additional verification time is needed during critical control operations.
Data Source
AI summary
Disclosed is a method (100) for ascertaining a parameter (I_avg, I_N, I_P, V_c), said parameter (I_avg, I_N, I_P, V_c) characterizes a current or a voltage in a circuit arrangement (200). The circuit arrangement (200) comprises an inductor (L) through which an alternating choke current (I_L) flows. The method comprises the steps of: ascertaining (120) at least one duration (TN1) between two zero crossings (N_−, N_+)+) of the choke current (I_L), or a duration (TNE1) between a zero crossing (N_−, N_+)+) and an apex (E_−, E_+) of the choke current (I_L); ascertaining (130) the parameter (I_avg, I_N, I_P, V_c) according to the ascertained duration (TN1, TNE1).