Frequency Converter Circuit Reusing a Rectifier as Standby Inverter

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Solution Overview

Problem

In existing AC input frequency converters modified for DC input, the rectifier unit becomes idle, unable to effectively drive motors after voltage conversion from AC to DC, as it is not utilized in the circuit.

Innovation Solution

A driving circuit and method that includes a rectifier unit, an inverter unit, a first switch for mode switching, and a capacitor connected in parallel, allowing the rectifier unit to switch between series and parallel modes, thereby utilizing the rectifier unit as a standby inverter unit to fully utilize its functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the frequency converter is modified from AC input to DC input by using the rectifier unit with diode switching, then the device can operate with DC power supply, but the rectifier unit becomes idle and cannot be effectively utilized

Engineering Contradiction:
ImproveDC input capabilityVSAvoidrectifier unit utilization
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent makes the rectifier unit multi-functional by enabling it to operate in two modes: as a rectifier when AC input is detected, and as an inverter when DC input is detected. The control unit switches the connection configuration of the rectifier unit based on input type, allowing the same hardware to perform different functions and eliminating idle capacity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces dynamic switching capability where the rectifier unit's connection configuration can be changed in real-time based on the detected input type. The control unit dynamically reconfigures the circuit connections using switching elements to transform the rectifier unit between rectifier and inverter operations, maximizing its utilization regardless of input source.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the rectifier unit is completely bypassed in DC input mode, then the circuit is simplified, but the rectifier unit becomes completely idle and wasted

Engineering Contradiction:
Improvecircuit configurationVSAvoidrectifier unit utilization
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements multi-functionality by programming the control unit to switch the rectifier unit's operation mode based on input detection. The same rectifier unit hardware serves dual purposes: rectifying AC voltage when AC input is detected, and functioning as an inverter to generate AC output when DC input is detected, thereby eliminating waste while maintaining circuit simplicity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the operational parameters of the rectifier unit based on the detected input type. When DC input is detected, the control unit modifies the switching patterns and connection configurations to enable the rectifier unit to operate in inverter mode, effectively changing its functional parameters to match the input source and maximize utilization.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the rectifier unit is utilized as a standby inverter unit in DC input mode, then component utilization is maximized, but the circuit complexity increases with additional switching mechanisms

Engineering Contradiction:
Improverectifier unit utilizationVSAvoidswitching control mechanism
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent achieves maximum utilization by making the rectifier unit universal - capable of functioning as either a rectifier or an inverter. The control unit contains logic to detect the input type and automatically configure the appropriate circuit connections, using the same hardware components for both functions without requiring separate dedicated circuits for each mode.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control unit automatically detects the input type (AC or DC) and self-configures the circuit connections accordingly. The system performs self-service by autonomously determining the appropriate operational mode and switching the rectifier unit to the correct configuration without external intervention, thereby managing the increased complexity through automated control.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3920408B1Driving circuit and method, and frequency converter, device and computer-readable storage medium
Publication Date: 2023.12.13 GREE ELECTRIC APPLIANCE INC OF ZHUHAI
  • EP3920408B1 patent drawingFigure 1~2
  • EP3920408B1 patent drawingFigure 3~4
  • EP3920408B1 patent drawingFigure 5~6

AI summary

The present disclosure relates to a driving circuit and method, and a frequency converter, a device and a computer-readable storage medium. The circuit includes: a rectifier unit comprising a first input end and an output end, the output end of the rectifier unit being connected to the input end of an inverter unit, and the line between the rectifier unit and the inverter unit being connected to the second input end of the rectifier unit; a first switch disposed between the first input end of the rectifier unit and the output end of the inverter unit, and used for controlling, by means of turning off or turning on, a driving circuit to switch between a series mode and a parallel mode, the inverter unit, the output end of the inverter unit being connected to a load; and a capacitor connected in parallel between the rectifier unit and the inverter unit. By means of the present disclosure, the switching of the series and parallel modes of the driving circuit is implemented, so that the idle rectifier unit is transformed into a standby inverter unit, and thus can be fully utilized.