Utility model content
The utility model is in order to overcome the deficiencies in the prior art, and object aims to provide a kind of Switching Power Supply of electromagnetism interference, and it can suppress the input of Switching Power Supply and the electromagnetic interference of output, but also improves the Electro Magnetic Compatibility of Switching Power Supply.
In order to solve above-mentioned technical problem, the basic technical scheme that the utility model proposes is:
A kind of Switching Power Supply of electromagnetism interference, comprise two filter rectifier modules, anti exciting converter circuit module and power factor correction circuit module, the output of the first filter rectifier module is connected with the input of the second filter rectifier module by anti exciting converter circuit module, the output of power factor correction circuit module is connected with the input of anti exciting converter circuit module, in particular, two electromagnetic compatibility treatment circuits are also comprised; The input of described first electromagnetic compatibility treatment circuit and city's electrical connection, output is connected with the input of the first filter rectifier module; The input of described second electromagnetic compatibility treatment circuit is connected with the output of the second filter rectifier module, and output is connected with load.
Further, described electromagnetic compatibility treatment circuit comprises common mode inductance and two electric capacity; Described common mode inductance comprises two windings and magnet ring, and the first winding technique is outside magnet ring, and the second winding and described first winding are wound in magnet ring outside another in the same way; One end of described first electric capacity is connected with the Same Name of Ends of the first winding, and the other end is connected with the Same Name of Ends of the second winding; One end of described second electric capacity is connected with the different name end of the first winding, and the other end is connected with the different name end of the second winding.
Further, described magnet ring adopts iron-base nanometer crystal alloy material to make.
Further, described filter rectifier module comprises low-pass filter circuit and rectification circuit, and low-pass filter circuit is connected with rectification circuit.
Further, described power factor correction circuit module comprises current detector, RC low pass filter, regulating error device and current mode controller; Described current detector is connected with anti exciting converter and monitors the output current of anti exciting converter; Described RC low pass filter is connected with current detector and carries out filtering to current detector output current; Described regulating error device is connected with RC low pass filter and drives the output current reference value of load mutually compare and process with pre-setting the output current of RC low pass filter, obtains current difference signal; Described current mode controller and regulating error device are interconnected and control the duty cycle of switching of anti exciting converter according to current difference signal.
Further, described current mode controller adopts UCC3844 model.
The beneficial effects of the utility model are:
1, by devising electromagnetic compatibility treatment circuit at the input of Switching Power Supply and output, electromagnetic compatibility treatment circuit adopts the common mode inductance be made up of iron-base nanometer crystal alloy material, and it can suppress the electromagnetic interference caused by common mode high frequency signal widely.
2, power factor correction circuit module adopts Current Negative Three-Point Capacitance to regulate, and improves the job stability of Switching Power Supply.
Embodiment
Below with reference to attached Fig. 1 and 2, the utility model is described further, but protection range of the present utility model should not be limited with this.For convenience of description and understand the technical solution of the utility model, below illustrate that the orientation that the noun of locality used all is shown with accompanying drawing is as the criterion.
As shown in Figure 1, the Switching Power Supply of the present embodiment comprises two filter rectifier modules, anti exciting converter circuit module and power factor correction circuit module, the output of the first filter rectifier module is connected with the input of the second filter rectifier module by anti exciting converter circuit module, and the output of power factor correction circuit module is connected with the input of anti exciting converter circuit module.Adopt voltage input end filtering and voltage output end filtering, it can the high frequency ripple that causes of filtered switch power supply itself and the ripple from external electrical network effectively, thus inhibits electromagnetic interference, and also avoids bringing electromagnetic interference to ambient electronics.
As an improvement of the present utility model, the Switching Power Supply of the present embodiment also comprises two electromagnetic compatibility treatment circuits.The input of the first electromagnetic compatibility treatment circuit and city's electrical connection, output is connected with the input of the first filter rectifier module.The input of the second electromagnetic compatibility treatment circuit is connected with the output of the second filter rectifier module, and output is connected with load.As shown in Figure 1, concrete, electromagnetic compatibility treatment circuit comprises common mode inductance and two electric capacity.As shown in Figure 2, common mode inductance comprises two windings 10 and magnet ring 11, first winding 101 is wound in outside magnet ring 11, and the second winding 102 and the first winding 101 are wound in magnet ring 11 outside another in the same way.One end of first electric capacity is connected with the Same Name of Ends of the first winding 101, and the other end is connected with the Same Name of Ends of the second winding 102.One end of second electric capacity is connected with the different name end of the first winding 101, and the other end is connected with the different name end of the second winding 102.By devising electromagnetic compatibility treatment circuit at the input of Switching Power Supply and output, electromagnetic compatibility treatment circuit adopts the common mode inductance be made up of iron-base nanometer crystal alloy material, and it can suppress the electromagnetic interference caused by common mode high frequency signal widely.
As an improvement of the present utility model, the magnet ring 11 of the present embodiment adopts iron-base nanometer crystal alloy material to make, and, magnet ring 101 can be in toroidal cores, square toroidal core or oval ring magnetic core any one.Adopt iron-base nanometer crystal alloy, manganese-zinc ferrite and permalloy characterisitic parameter as shown in the table:
As shown above, common mode choke adopts the magnetic core be made up of iron-base nanometer crystal alloy, and it has
1, high saturated magnetic induction.The Bs of iron-base nanometer crystal alloy surpasses 1.3T, is more than ferritic twice.As inductance, it is saturated that important principle is that iron core can not be magnetized into, otherwise inductance value sharply reduces.And in actual applications, have the interference strength of many occasions comparatively large (such as high-power frequency conversion motor), if with common ferrite as inductance, there is saturated possibility in iron core, can not ensure the noise suppression effect under the interference of large intensity.Due to the high saturated magnetic induction of iron-base nanometer crystal alloy, its anti-saturation characteristic is obviously better than ferrite undoubtedly, makes the magnetic core of iron-base nanometer crystal alloy be highly suitable for the strongly disturbing occasion of heavy current.
2, high initial magnetic permeability.The initial magnetic permeability of iron-base nanometer crystal alloy can reach 100,000, far away higher than ferrite, therefore under downfield, has large impedance and insertion loss with the inductance of iron-base nanometer crystal alloy manufacture, has fabulous inhibitory action to weak jamming.This is for requiring that the anti-weak jamming common-mode filter of minimum leakage current is especially applicable.At some specific occasion (as Medical Devices), equipment causes leakage current by direct-to-ground capacitance (as human body), easily form common mode disturbances, and equipment itself is extremely tight to this requirement.Now using the iron-base nanometer crystal alloy of high permeability to manufacture inductance may be optimal selection.In addition, the high permeability of iron-base nanometer crystal alloy can reduce coil turn, reduces parasitic capacitance equal distribution parameter, thus the formant frequency in insertion loss spectrum caused due to distributed constant is improved.Meanwhile, the high permeability of iron-base nanometer crystal alloy makes inductance have higher inductance value and resistance value, or reduces the volume of iron core under the prerequisite of equal inductance value.
3, remarkable temperature stability.The Curie temperature of iron-base nanometer crystal alloy is up to more than 500 DEG C.When there being larger temperature fluctuation, the performance change rate of iron-base nanometer crystal alloy is starkly lower than ferrite, has excellent stability, and the change of performance is close to linearly.Usually, iron-base nanometer crystal alloy is in the temperature range of-50 DEG C-130 DEG C, and the rate of change of main magnetic property is within 10%.By contrast, ferritic Curie temperature is generally below 220 DEG C, and magnetic property rate of change reaches more than 100% sometimes, and in non-linear, not easily compensates.This temperature stability of iron-base nanometer crystal alloy in conjunction with its distinctive low loss characteristic, for device designer provides loose temperature conditions.
Filter rectifier module comprises low-pass filter circuit and rectification circuit, and low-pass filter circuit is connected with rectification circuit, the high-frequency signal on low-pass filter circuit filtering circuit, and civil power is transformed into low pressure galvanic current by rectification circuit.
As an improvement of the present utility model, the power factor correction circuit module of the present embodiment comprises current detector, RC low pass filter, regulating error device and current mode controller.Current detector is connected with anti exciting converter and monitors the output current of anti exciting converter.RC low pass filter is connected with current detector and carries out filtering to current detector output current.Regulating error device is connected with RC low pass filter and drives the output current reference value of load mutually compare and process with pre-setting the output current of RC low pass filter, obtains current difference signal.Current mode controller and regulating error device are interconnected and control the duty cycle of switching of anti exciting converter according to current difference signal.Current transformer in current detector detects the electric current of anti exciting converter circuit module, and sends this electric current to RC low pass filter.RC low pass filter sends again regulating error device to after carrying out filtering to current detector output current.The output current of RC low pass filter drives the output current reference value of load mutually compare and process with pre-setting by regulating error device, obtains current difference signal and also sends current mode controller to.Wherein, the utility model adopts UCC3844 current mode controller, it has fine-tuning oscillator, can carry out accurate Duty ratio control, the reference of temperature-compensating, high-gain error amplifier.UCC3844 current mode controller controls the duty cycle of switching of anti exciting converter according to current difference signal, and then controls the current average of anti exciting converter, indirectly controls the drive current mean value of load.
The announcement of book and instruction according to the above description, the utility model those skilled in the art can also change above-mentioned execution mode and revise.Therefore, the utility model is not limited to embodiment disclosed and described above, also should fall in the protection range of claim of the present utility model modifications and changes more of the present utility model.In addition, although employ some specific terms in this specification, these terms just for convenience of description, do not form any restriction to the utility model.