Power Supply Regenerative Converter for Injection Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power supply regenerative converters continue to draw electric power back into the AC supply after motor regeneration, leading to measurable power loss, especially in applications with frequent motor start-stop cycles like injection molding machines.
Innovation Solution
An injection molding machine with a power supply regenerative converter that includes an electric power conversion part, a direct current voltage detector, and an alternating current control part to manage the flow of alternating current based on detected direct current voltage and its variance, preventing power flow back into the AC supply once regeneration is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the power supply regenerative converter continues the power supply regenerative operation based on DC voltage threshold after motor regeneration is completed, then the DC voltage is maintained within acceptable range, but unnecessary power transfer occurs from DC link capacitor back to AC power supply causing energy loss
Solution Approach 1:
The control device monitors both DC voltage levels and motor operational state in real-time, using feedback signals to dynamically adjust the power supply regenerative operation. When motor regeneration is detected to be completed, the control device stops the regenerative operation even if DC voltage remains above threshold, preventing unnecessary power transfer and energy loss while maintaining DC voltage stability through controlled stopping.
Solution Approach 2:
The control device detects motor regeneration completion in advance and proactively stops the power supply regenerative operation before DC voltage drops to the threshold level. This preliminary action prevents the cycle of unnecessary power transfer from DC link capacitor to AC power supply, eliminating energy loss while maintaining sufficient DC voltage for subsequent operations.
2Extent of automation
If the power supply regenerative converter uses hysteresis comparator to monitor DC voltage difference, then the operation switching is automated, but chattering occurs causing frequent switching between power-running and regenerative operations
Solution Approach 1:
The control device uses comprehensive feedback including both DC voltage levels and motor operational state (regeneration completion detection) to make switching decisions. This dual-feedback mechanism prevents chattering by ensuring that operation mode changes occur only when both voltage and motor state conditions are satisfied, providing stable and reliable automated switching without frequent oscillations.
Solution Approach 2:
The control device changes the decision parameters for operation switching from solely DC voltage threshold to a combination of DC voltage level and motor regeneration state. By introducing the motor operational state as an additional parameter, the system achieves more stable switching behavior that prevents chattering while maintaining automation, as switching occurs only when both parameters indicate appropriate conditions.
3Measurement precision
If the power supply regenerative converter waits for input current information to stabilize before judgment, then accurate electric power state detection is achieved, but the response time is delayed
Solution Approach 1:
The control device performs preliminary detection of motor regeneration state using DC voltage information before waiting for input current information to fully stabilize. By detecting regeneration completion in advance through DC voltage monitoring and motor state analysis, the system prepares for timely operation switching without excessive delay, achieving both accuracy and responsiveness.
Solution Approach 2:
The control device continuously monitors DC voltage and motor operational state throughout the regeneration process, maintaining continuous useful action for detecting regeneration completion. This continuous monitoring allows the system to respond immediately when regeneration completes, eliminating unnecessary waiting time while ensuring accurate detection through ongoing measurement of both voltage and motor state parameters.
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 enables more efficient power regenerative operations by preventing unnecessary power transfer, reducing energy loss, and allowing earlier initiation of regenerative operations, thus enhancing the overall efficiency of the power supply regenerative converter.
Implementation Method 1
an electric power conversion part (11), which bidirectionally converts between alternating current electric power and direct current electric power
Implementation Method 2
a direct current voltage detector (15), which detects a direct current voltage of a capacitor (14) disposed between the inverter part (30) and the electric power conversion part (11)
Implementation Method 3
an alternating current control part (16), which outputs a control signal to the electric power conversion part (11) based on a detected value of the direct current voltage and a time variance of the direct current voltage, and controls an alternating current flowing between the alternating current power supply (20) and the electric power conversion part (11)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An injection molding machine including a power supply regenerative converter 10 connected between an AC power supply 20 and inverter parts 30 is provided with a electric power conversion part 11 which bidirectionally converts between an AC power and a DC power, a DC voltage detector 15 which detects a DC voltage of a capacitor 14 between the inverter parts 30 and the electric power conversion part 11, and an AC control part 16 which outputs a control signal, which is produced based on the DC voltage detected by the DC voltage detector 15 and time variance of the DC voltage, to the electric power conversion part 11, and controls an alternating current flowing between the AC power supply 20 and the electric power conversion part 11.