Driving System Voltage Variation Suppression via Fourier Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing driving systems fail to adequately suppress voltage variations of the smoothing capacitor and torque variations of the motor due to difficulties in removing electrical second and sixth variation components using band pass filters.
Innovation Solution
The driving system employs Fourier series expansion to calculate the electrical first variation component of the smoothing capacitor's voltage and controls the inverter to set this component to zero, effectively removing higher-order variation components and improving voltage and torque stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a band pass filter is used to extract the voltage component of identical frequency, then the voltage component can be extracted, but the electrical second and sixth variation components cannot be sufficiently removed
Solution Approach 1:
The patent segments the voltage signal into multiple frequency components using Fourier series expansion, separating the electrical first variation component from the electrical second and sixth variation components. This allows selective processing of each component to achieve both accurate extraction and effective suppression of unwanted components.
Solution Approach 2:
Instead of attempting to filter out all unwanted components simultaneously (which is insufficient with BPF), the patent applies partial action by specifically targeting and eliminating only the electrical first variation component through controlled adjustment, while other components are naturally suppressed through the correction process.
2Measurement precision
If the detected value of the current sensor is corrected to equalize the voltage value, then the voltage component can be corrected, but the voltage variation and torque variation cannot be sufficiently suppressed
Solution Approach 1:
The patent implements feedback control by detecting the electrical first variation component of the smoothing capacitor voltage and using this information to correct the phase current commands. The control device continuously monitors the voltage variation and adjusts the current commands to eliminate the first variation component, thereby suppressing both voltage and torque variations.
Solution Approach 2:
The patent changes the parameters of the phase current commands by adding correction amounts based on the detected electrical first variation component. This parameter modification allows the system to compensate for sensor detection errors and suppress voltage and torque variations without changing the physical hardware.
Data Source
AI summary
There is provided a driving system including a motor; an inverter configured to drive the motor; a power storage device connected with the inverter via a power line; a smoothing capacitor mounted to the power line; a voltage sensor configured to detect a voltage of the smoothing capacitor; a current sensor configured to detect an electric current of each phase of the motor; and a control device configured to control the inverter, based on a detected value of the current sensor. The control device performs Fourier series expansion of a detected value of the voltage sensor to calculate an electrical first variation component of the voltage of the smoothing capacitor. The control device controls the inverter, such that the electrical first variation component of the voltage of the smoothing capacitor becomes equal to a value 0.