Direct-current power supply apparatus, motor drive control apparatus, blower, compressor, and air conditioner
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Solution Overview
Problem
The existing direct-current power supply apparatuses employing both diode rectification and high-speed switching have a lower power factor, leading to higher reactor loss, particularly in the high-load operation region, as they do not consider optimal inductance values for minimizing losses.
Innovation Solution
A direct-current power supply apparatus with a reactor that dynamically adjusts its inductance based on the alternating current, switching to a lower inductance when the current exceeds a threshold, and a bridge circuit that operates actively at high currents and passively at low currents to reduce reactor loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed inductance reactor is used to comply with harmonic regulations at light load, then the reactor size is limited, but reactor loss increases at high load
Solution Approach 1:
The reactor's inductance is made dynamically adjustable based on load conditions. The control unit switches between first and second inductance values depending on whether the load is light or high, optimizing performance across different operating regions while reducing overall energy loss.
Solution Approach 2:
The inductance parameter of the reactor is changed according to operating conditions. By switching between different inductance values (first inductance for light load, second inductance for high load), the system adapts to varying load requirements and minimizes reactor loss at high load while maintaining compliance at light load.
2Device complexity
If diode rectification is used at light load, then the circuit is simple, but power factor is lower and reactor loss is higher
Solution Approach 1:
The rectification method is dynamically switched based on load conditions. The control unit selects between diode rectification (simple circuit) for light load and active rectification with switching elements (higher complexity) for high load, optimizing the balance between circuit simplicity and energy efficiency across different operating regions.
Solution Approach 2:
The rectification process is segmented into different modes based on load conditions. Light load operation uses diode rectification while high load operation uses active rectification with switching elements, allowing each mode to be optimized independently for its specific operating region.
3Object-generated harmful factors
If high speed switching operation mode is used at high load, then harmonic compliance is improved, but power factor is lower leading to higher reactor loss
Solution Approach 1:
The inductance parameter is specifically adjusted for high load conditions by switching to the second inductance value, which is optimized for active rectification operation. This reduces the reactive power demand and minimizes reactor loss while maintaining harmonic compliance through active rectification control.
Solution Approach 2:
The control unit monitors load conditions and switches between rectification modes and inductance values based on detected operating region. This feedback mechanism ensures optimal performance by adapting the system parameters to match actual load conditions, reducing reactor loss while maintaining harmonic compliance.
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 approach significantly reduces reactor loss, especially in the high-load operation region, improving the overall efficiency and compliance with harmonic regulations.
Implementation Method 1
The reactor has a characteristic of reducing an inductance in accordance with an increase of the alternating current and causing, when the alternating current exceeds a first current, an inductance to be lower than one third of an inductance when a current does not flow in the reactor
Data Source
AI summary
A direct-current power supply apparatus includes: a reactor having one end connected to an alternating-current power supply; a bridge circuit, connected to an opposite end of the reactor, converting an alternating-current first voltage output from the alternating-current power supply into a direct-current voltage; and a current detector detecting an alternating current flowing between the alternating-current power supply and the bridge circuit. The reactor reduces an inductance in accordance with an increase of the alternating current and, when the alternating current exceeds a first current, has an inductance lower than one third of an inductance at which a current does not flow in the reactor. The bridge circuit performs an active operation when the detection value of the alternating current is larger than or equal to the first current and performs a passive operation when the detection value of the alternating current is lower than the first current.