Power Supply Bridge Circuit Zero-Crossing Control
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Solution Overview
Problem
Conventional non-contact power supply devices face challenges in reducing size and cost while maintaining efficiency due to high switching losses and power factor issues, particularly when dealing with regenerative loads and detection errors in zero crossing points.
Innovation Solution
A power supply device with a bridge circuit configuration that includes switching arm series circuits with inverse parallel semiconductor switches and diodes, along with a control unit that adjusts semiconductor switch operation to optimize voltage and current phases, ensuring a power factor of 1 and reducing switching losses by minimizing unnecessary switching events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the frequency of the current supplied through the coil is increased to reduce excitation inductance and device size, then the size of the coil and core can be reduced, but the switching loss of the semiconductor switch increases and power supply efficiency decreases
Solution Approach 1:
The patent employs periodic action by utilizing the natural zero-crossing points of the input current to timing the switching operations. The semiconductor switches are controlled to switch at specific intervals synchronized with the AC current waveform, performing switching actions only when necessary (at zero-crossings) rather than continuously. This periodic switching strategy reduces the frequency of switching events, thereby minimizing switching losses while still achieving the desired power factor correction and voltage control.
2Reliability
If conventional full-wave rectifier circuit and constant voltage control circuit are used to control DC output voltage, then the DC output voltage can be maintained constant, but the circuit size becomes large and installation space increases
Solution Approach 1:
The patent extracts and eliminates unnecessary circuit components from the conventional full-wave rectifier configuration. By removing redundant diodes and simplifying the circuit topology, the design achieves constant DC output voltage control with fewer components. The control unit directly manages the semiconductor switches in a simplified bridge circuit configuration, taking out the complex constant voltage control circuitry while maintaining voltage stability through intelligent switching control.
Solution Approach 2:
The semiconductor switches in the patent serve multiple functions simultaneously: they perform rectification, voltage control, and power factor correction all within a single circuit configuration. The control unit provides universal control that adapts to different operating conditions, making the circuit compact while maintaining reliable DC output voltage. This multi-functionality eliminates the need for separate dedicated circuits for each function, reducing overall circuit size.
3Manufacturing precision
If semiconductor switches are switched frequently to control voltage, then voltage control precision improves, but switching losses increase and power supply efficiency lowers
Solution Approach 1:
The control unit performs preliminary action by pre-planning the switching timing based on the detected zero-crossing points of the input current. Instead of reacting to voltage deviations and making frequent corrective switching, the system anticipates the optimal switching moments in advance by synchronizing with the AC waveform. This preliminary timing strategy achieves precise voltage control with minimal switching events, as the switches are activated only when most beneficial, reducing switching losses while maintaining control precision.
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
The solution enhances power factor correction, reduces switching losses, and minimizes the size and cost of the device, while maintaining stable power delivery even with detection errors, thus inhibiting overall losses and enabling efficient operation.
Implementation Method 1
a coil configured to exchange power by an external magnetic coupling
Data Source
AI summary
In a power supply device the bridge circuit is configured such that a plurality of series circuits of two inverse parallel connection circuits of a semiconductor switch and a diode are connected in parallel. The power supply device includes a control unit configured to control the semiconductor switch such that a voltage between AC terminals of the bridge circuit becomes a zero voltage only during a prescribed time period before and after two zero crossing points in one cycle of the input current and such that the voltage becomes a positive-negative voltage in which the output voltage is a peak current value during other time periods. Consequently, a power factor of the power receiving circuit is improved and a loss of an entire device is inhibited, and a size and a cost of the entire device may be reduced.