Unlock instant, AI-driven research and patent intelligence for your innovation.

DC power supply unit and air conditioner equipped with the same

A technology of DC power supply and AC power supply, which is applied in the direction of output power conversion device, conversion of AC power input to DC power output, electrical components, etc., and can solve the problem of increased short-circuit current and short-circuit time without consideration of DC power supply. and other issues, to achieve the effect of high efficiency, high circuit efficiency, and a small number of components

Active Publication Date: 2019-01-11
HITACHI JOHNSON CONTROLS AIR CONDITIONING INC
View PDF6 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, in the synchronous rectification rectification circuit disclosed in Patent Document 1, MOSFETs and diodes are connected in parallel, and circuit efficiency can be improved. However, since components are configured in parallel, there is a problem that the number of circuit components increases and miniaturization cannot be achieved.
[0005] In addition, there is a problem that a rectifier circuit that can obtain a high output voltage of a DC output power supply cannot be realized due to the limited range of output voltage that can be boosted by controlling the MOSFET on / off once during the half cycle of the AC power supply.
[0006] In addition, the high-order harmonic current component included in the AC power supply current is also high, so there is a problem that the power factor of the input power supply is low
[0007] In addition, a method of using a parasitic diode of a MOSFET as a diode connected in parallel with the MOSFET is also disclosed. However, in general, the switching speed of the parasitic diode is slow, so there is a problem that when performing the switching operation of turning on / off each MOSFET , resulting in MOSFET short circuit and overcurrent flowing through the DC output power supply
[0008] Therefore, there is a problem that when switching operations are performed multiple times during a half cycle of the AC power supply or when switching operations are repeatedly performed at frequencies exceeding audible frequencies, for example, 15 kHz or more, the switching loss increases and the circuit efficiency of the rectifier circuit increases. low
[0009] Furthermore, when the switching operation is performed multiple times during the half cycle of the AC power supply, a current flows through any one of the two MOSFETs, and there is a possibility that the heat generated by the MOSFET is larger than that in the case where a diode is separately connected in parallel. question
[0010] In addition, there is no consideration that when a gate signal is applied and a channel current flows while a current is flowing in the parasitic diode, the function as a diode will be lost. Compared with the case of connecting a diode connected in parallel with the MOSFET, there are the following problems , that is, the reverse recovery time increases so that the short-circuit current of the DC power supply increases, and the short-circuit time increases, which may damage the components

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • DC power supply unit and air conditioner equipped with the same
  • DC power supply unit and air conditioner equipped with the same
  • DC power supply unit and air conditioner equipped with the same

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach

[0028] A DC power supply device according to a first embodiment of the present invention will be described with reference to the drawings.

[0029] figure 1 It is a figure which shows the structural example of the DC power supply apparatus which concerns on the 1st Embodiment of this invention, (a) shows the structure of a DC power supply apparatus, and the connection relationship between an AC power supply and a load, (b) shows MOSFET (Q1, Q2) and association of parasitic diodes.

[0030]

[0031] exist figure 1 In (a), the DC power supply device 100 is composed of an n-type MOSFET (Q1: the first MOSFET), an n-type MOSFET (Q2: the second MOSFET), a diode D1 (the first diode), and a diode D2 (the second and second MOSFETs). pole tube), reactor 12, smoothing capacitor 13, AC power supply voltage detection circuit 11, DC output voltage detection circuit 15, current detection circuit 14, and control circuit 16.

[0032] The outline of the functions and operations of the DC p...

no. 2 approach

[0191] A DC power supply device according to a second embodiment of the present invention will be described with reference to the drawings.

[0192] Figure 7 It is a diagram showing a configuration example of a DC power supply device 100B according to the second embodiment of the present invention, (a) shows the configuration of the DC power supply device, the connection relationship between the AC power supply and the load, and (b) shows MOSFETs (Q1, Q2, Q3, Q4) control signals and associated signals.

[0193] exist Figure 7 (a), with figure 1 (a) The difference is that instead of figure 1 The diode D1 and the diode D2 in (a) are replaced with a MOSFET (Q3: third MOSFET) and a MOSFET (Q4: fourth MOSFET), respectively.

[0194] In addition, the MOSFETs ( Q3 , Q4 ) are controlled by the control circuit 16 .

[0195] Figure 7 Other structures of (a) with figure 1 Since the structure of (a) is the same, repeated explanation is omitted.

[0196] In addition, in Figure...

no. 3 approach

[0205] An air conditioner according to a third embodiment of the present invention will be described. A third embodiment is an air conditioner equipped with the DC power supply device of the first embodiment.

[0206]

[0207] Figure 8 It is a figure which shows the structural example of the air conditioner 300 which concerns on 3rd Embodiment of this invention.

[0208] exist Figure 8 In the air conditioner 300, the DC power supply device 100 of the first embodiment ( figure 1 ) includes an inverter circuit 81 , a compressor 82 , heat exchangers 83 and 85 , and a pressure reducer 84 .

[0209] Inverter 81 and DC power supply device 100 ( figure 1 ) is connected to the output portion of the smoothing capacitor 13 to generate a three-phase AC voltage (electric power) from the DC voltage (electric power).

[0210] A compressor 82 including a motor (not shown) is operated by the three-phase AC voltage (electric power) output from the inverter circuit 81 .

[0211] In ad...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a DC power supply unit and an air conditioner using same. A DC power supply unit is provided that allows for improving efficiency and reducing harmonic currents. A DC power supply unit includes: a bridge rectification circuit having diodes and MOSFETs; a reactor that is arranged between the AC power supply and the bridge rectifier circuit; a smoothing capacitor that is connected to an output side of the bridge rectifier circuit and smoothes a voltage; and a converter control unit that executes, based on predetermined threshold values, a diode rectification control that uses diodes and parasitic diodes of the MOSFETs, a synchronous rectification control that switches the MOSFETs in synchronization with a polarity of the voltage of the AC power supply, a partial switching control that repeats partially short-circuiting the reactor multiple times in a half cycle of the AC power supply, or a fast switching control that short-circuits the reactor at a predetermined frequency over a full AC cycle.

Description

technical field [0001] The present invention relates to a DC power supply device which converts an AC voltage of an AC power supply into a DC voltage and outputs it, and an air conditioner equipped with the DC power supply device. Background technique [0002] There is a method called synchronous rectification, in which the diode is replaced on the side of the bridge rectification circuit composed of four diodes connected to the reactor, or a MOSFET (metal-oxide-semiconductor field-effect transistor : metal-oxide-semiconductor field-effect transistor) to carry out predetermined control and improve the efficiency of the rectifier circuit. [0003] In addition, there is a method in which a diode connected in parallel to a MOSFET is a parasitic diode of the MOSFET (Patent Document 1). [0004] However, in the synchronous rectification rectification circuit disclosed in Patent Document 1, MOSFETs and diodes are connected in parallel to improve circuit efficiency. However, since...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/217H02M1/12
CPCH02M1/12H02M7/217
Inventor 北山亨奥山敦黑川勉田村建司田村正博
Owner HITACHI JOHNSON CONTROLS AIR CONDITIONING INC