Inverter Control via Bidirectional Communication for Food Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing food processing machines face issues with motor mixer speed control due to electromagnetic disturbances, limited rotation rate selection, instantaneous velocity changes, lack of bidirectional communication, and vulnerability to errors, which affect the precision and quality of food products like ice-cream.
Innovation Solution
A machine with a microprocessor-driven inverter using a bidirectional communication circuit for precise control of motor speed with infinitesimal frequency changes, gradual acceleration/deceleration, and error-immune communication, allowing continuous monitoring and control of the inverter's state for optimal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DAC and inverter system is used to control motor speed, then the system can provide continuous analog control, but electromagnetic disturbances from the inverter cause communication errors and voltage spikes
Solution Approach 1:
The patent introduces an intermediary communication system between the microprocessor card and inverter that converts analog control signals into digital communication protocols. This intermediary layer isolates the sensitive communication circuitry from the electromagnetic disturbances generated by the inverter, allowing reliable data exchange while maintaining precise motor speed control capability.
Solution Approach 2:
The patent replaces the direct analog voltage control system with a digital communication-based control system. Instead of using analog voltage signals that are susceptible to electromagnetic interference, the system uses digital communication protocols to transmit control commands, thereby eliminating the vulnerability to voltage spikes and communication errors caused by inverter-generated electromagnetic disturbances.
2Adaptability or versatility
If quantized voltage variations are used for motor control, then the system is simpler to implement, but the selection scale of rotation rates is limited
Solution Approach 1:
The patent replaces the simple but limited quantized voltage control system with a digital communication-based control system. The microprocessor card communicates with the inverter using digital protocols, enabling continuous and precise control of motor speed across a wide range of rotation rates without the constraints of fixed voltage steps.
Solution Approach 2:
The patent changes the control parameter from quantized voltage levels to digital frequency commands. The inverter receives digital signals that specify exact rotation rates, allowing for continuous adjustment of motor speed rather than being restricted to discrete voltage-based speed levels. This enables precise control adapted to different recipe requirements.
3Reliability
If instantaneous velocity change is used for safety response, then the motor stops quickly when lid is opened, but the acceleration/deceleration variation dynamism required for different processing phases is lost
Solution Approach 1:
The patent implements a dynamic control system that adjusts acceleration and deceleration rates based on the current processing phase and safety requirements. During normal operation, the system uses gradual speed transitions adapted to each recipe's needs. When safety conditions are triggered (such as lid opening), the system dynamically switches to instantaneous stopping mode, providing both adaptability for processing and reliability for safety responses.
Solution Approach 2:
The patent changes the control parameters dynamically based on operational context. The acceleration and deceleration time constants are adjusted according to the processing phase and safety conditions. During normal mixing phases, longer acceleration times are used for gentle mixing, while safety-critical moments trigger immediate parameter changes for rapid stopping, thus achieving both adaptability and safety.
4Device complexity
If unidirectional analog communication is used from DAC to inverter, then the system is simpler, but the inverter cannot communicate back to verify effective actuation
Solution Approach 1:
The patent implements a bidirectional communication system where the inverter sends feedback signals back to the microprocessor card to confirm receipt and execution of control commands. This feedback mechanism allows the system to verify effective actuation, detect errors, and adjust control parameters accordingly, significantly improving the reliability of the control system while maintaining manageable complexity through standardized communication protocols.
Data Source
Figure 1
Figure 2
AI summary
A machine for processing food products in at least one basin (12a, 12b) with the use of a mixer (13a, 13b) activated by a motor (11a, lib) controlled by an inverter (10a, 10b), in turn in communication with an electronic card with a micro-processor (1), equipped with an electronic bidirectional communication circuit (9) with serial transmission and protocol of the Modbus, Canbus or Profibus type, suitable for revealing the instantaneous state of said inverter (10a, 10b). The process and machine of the invention offer the advantage of controlling the effective execution of each processing phase of the product, repeating it automatically if this is not so.