Multi-phase EMI and transient protection circuits and synchronous rectification control for compressors of refrigeration systems
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Solution Overview
Problem
Existing refrigeration systems in vehicles face challenges with electromagnetic interference and transient protection, particularly when handling high current levels and multiple phases, leading to noise coupling and voltage drop issues.
Innovation Solution
The implementation of multi-phase electromagnetic interference (EMI) and transient protection circuits with bi-directional synchronous rectifiers, phase-shifted outputs, and independent components to manage current and reduce noise, allowing for efficient power delivery to mobile compressors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multi-phase EMI protection circuits are implemented, then EMI filtering capability is improved, but device complexity increases
Solution Approach 1:
The system divides the EMI protection into multiple independent phases, with each phase having its own common mode choke and protection circuit. This segmentation allows each phase to handle EMI independently, improving overall filtering capability while keeping individual phase complexity manageable through modular design
Solution Approach 2:
The common mode chokes and protection circuits are designed to serve multiple functions: EMI filtering, transient protection, and noise coupling prevention across all phases. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing device complexity
2Reliability
If synchronous rectifiers with phase-shifted outputs are used, then ripple current cancellation is improved, but device complexity increases
Solution Approach 1:
The synchronous rectifiers operate with phase-shifted periodic waveforms, where each rectifier is offset by a specific phase angle (e.g., 120 degrees in a three-phase system). This periodic phase-shifting causes ripple currents to cancel each other out through constructive and destructive interference patterns, improving reliability while maintaining manageable complexity through regular timing patterns
Solution Approach 2:
The system changes the temporal parameter of the rectifier outputs by introducing phase shifts. By adjusting the phase angle parameter of each synchronous rectifier, the system achieves ripple current cancellation without fundamentally changing the rectifier topology, thus managing device complexity
3Object-affected harmful factors
If independent components are used for each phase, then EMI protection effectiveness is improved, but manufacturing cost increases
Solution Approach 1:
Each phase is equipped with independent common mode chokes and protection components, ensuring that EMI in one phase does not affect other phases. This segmentation improves protection effectiveness by isolating EMI paths, while the modular nature of the segmented design allows for standardized manufacturing of identical phase modules, reducing overall manufacturing complexity
Solution Approach 2:
While maintaining independent components for each phase, the system optimizes component parameters (such as choke inductance values and capacitor ratings) to be identical across phases where possible. This standardization of parameters enables bulk purchasing and streamlined manufacturing processes, mitigating the cost increase from using independent components
4Reliability
If common mode chokes are used in multi-phase systems, then transient protection is improved, but voltage drop increases
Solution Approach 1:
The use of separate common mode chokes for each phase isolates transient events to individual phases, preventing transients from propagating across the entire multi-phase system. This segmentation limits the impact of voltage drops to only the affected phase, maintaining better overall system voltage levels compared to a shared choke configuration
Solution Approach 2:
The system uses identical common mode choke designs across all phases, allowing for optimized choke parameters that balance transient protection and voltage drop. By copying the same proven design across phases, the system achieves consistent protection effectiveness while minimizing voltage drops through optimized component selection
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 component size and cost, eliminates noise coupling between phases, and ensures independent operation, improving EMI filtering and ripple current cancellation, thereby enhancing the reliability and efficiency of vehicle refrigeration systems.
Implementation Method 1
The common mode chokes are configured to receive a first direct current voltage and are connected to first and second grounds
Implementation Method 2
The electromagnetic interference filters include capacitors
Implementation Method 3
The transient protection components include varistors
Data Source
AI summary
A drive for a mobile compressor includes EMI and transient protection circuits, second chokes, converters and an inverter. The EMI and transient protection circuits include respectively common mode chokes and at least one component. Each of the common mode chokes is configured to receive a first direct current voltage and is connected to first and second grounds. The at least one component is connected to a third ground. The first, second and third grounds are at different voltage potentials. The second chokes are connected downstream from the common mode chokes. The converters are connected to outputs of the second chokes and are configured to collectively provide a second direct current voltage to a direct current bus. The inverter is connected to the direct current bus and configured to convert the second direct current voltage to an alternating current voltage to power the mobile compressor downstream from the inverter.