Injection Molding Machine Regenerative Line Circuit
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Solution Overview
Problem
Existing injection molding machines are inefficient in regenerating regenerative electric power, as both powering and regenerative electric power pass through the same AC converter circuit, leading to ineffective regeneration during motor deceleration.
Innovation Solution
The injection molding machine incorporates a regenerative line in parallel with the powering line, featuring a bridge circuit and harmonics component reducing part, utilizing PWM control to effectively regenerate electric power by converting direct to alternating current and shaping the alternating current output to reduce harmonics and improve power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If powering and regenerative electric power pass through the same A/C converter circuit, then the circuit structure is simplified, but the regenerative electric power generated at the time of decelerating the motor cannot be regenerated effectively
Solution Approach 1:
The patent divides the power conversion system into two separate functional paths: a powering line for converting AC to DC power, and a regenerative line for converting DC to AC power during motor deceleration. This segmentation allows each line to be optimized for its specific function, enabling effective regeneration of regenerative electric power while maintaining clear functional separation.
Solution Approach 2:
The patent extracts the regenerative power conversion function from the common A/C converter circuit and creates a dedicated regenerative line with its own bridge circuit and control system. This extraction enables the regenerative electric power to be processed independently without interference from the powering circuit, solving the problem of ineffective regeneration.
2Device complexity
If a common A/C converter circuit is used for both powering and regenerative power, then component ratings must accommodate peak combined loads, but this increases component ratings and costs
Solution Approach 1:
By segmenting the power supply system into separate powering and regenerative lines, each line's components only need to handle their respective power loads independently. The powering line components are sized for motor acceleration power requirements, while regenerative line components are sized for deceleration power recovery, eliminating the need for oversized components that would be required if both functions shared a common circuit.
3Object-generated harmful factors
If PWM control is applied to shape alternating current output, then harmonics are reduced and power factor improves, but the control system becomes more complex
Solution Approach 1:
The patent implements PWM control with feedback mechanisms in the regenerative line that monitor current and voltage conditions, dynamically adjusting switching signals to shape the alternating current output. This feedback-based PWM control effectively reduces harmonics and improves power factor by synchronizing the regenerative power flow with the power supply waveform, while the control complexity is managed through integrated control circuits.
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 configuration allows for effective regeneration of regenerative electric power, reducing energy consumption and enabling the selection of components based on regenerative power requirements, while improving power factor and reducing ratings compared to common powering and regenerative lines.
Implementation Method 1
a bridge circuit (104) configured to convert the direct electric power into the alternating electric power
Implementation Method 2
a harmonics component reducing part (63) configured to reduce harmonics of the alternating electric power output from the bridge circuit (104) and improve a power factor
Data Source
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AI summary
An object of the invention is to provide an injection molding machine which can effectively regenerate the regenerative electric power of the motor. An injection molding machine, comprising: a motor; a driver circuit that drives the motor; and a rectifying part 102 that supplies electric power to the driver circuit, wherein a regenerative line 82 for regenerative electric power of the motor is connected to the rectifying part in parallel, and a bridge circuit 104 and a harmonics component reducing part 63 are provided in the regenerative line 82, the converting part converting direct electric power between the driver circuit and the rectifying part into alternating electric power which is input to the harmonics component reducing part, and the injection molding machine further comprises a controller 26 that controls the operation of the bridge circuit 104 such that an electric current wave-shape of the alternating electric power converted by the bridge circuit 104 corresponds to a shape of a sine wave.