Produce lateral constant improvement with China’s science and technology, the requirements for power supply quality of all trades and professions are higher and higher, and the high-frequency switching power supply of intelligence, as a kind of timing relay protective device and control loop device, the reliability of power supply when the life and produced has offered the strong guarantee. Can also be regarded as the backup power as the power interruption of city power, thus the high-frequency switching power supply of intelligence is one of the important constituent elements of the quality assurance to supplying power. It has the characteristics that it is made up, controlled independently that highly flexible, in addition highly reliable, good stability, and little noise low to have volume and energy-conservation a great advantage of it too in high-efficient, convenient maintenance,etc..
We can say the high-frequency switching power supply of intelligence is a kind of high-tech products incorporating computer technology, control technique, communication skill into an organic whole, but the automatic diagnosis, automatic test and automaticallying control of the implementation system. What this text mainly explained is the cipher scheme of the Rectifier Module of high-frequency switching power supply of intelligence.
Introduction to ensemble architecture of the zero-one system
The overall structure of the high-frequency switch power system of intelligence is mainly made up of main monitoring unit, electricity distribution module, AC distribution unit, Rectifier Module,etc., the total structure chart of system is shown as in Fig. 1. Management and controlling of acceptor’s monitoring unit of each monitoring unit in the system, mainly control the information that each monitoring unit is gathered in unison and manage through the communication line. Main the intersection of monitor display and direct-flow the intersection of system and various information, user may the touch screen inquire message and operation too, the system information can also insert in the long-range monitor system. Except basic unit of exchanging controlling, direct current supervision, switch quantity and controlling etc. of system, have also disposed functional units such as insulating monitoring, dropping equipment, battery polling,etc., in order to achieve the goal of controlling to the direct-flow system in an all-round way.
Pursue the control scheme of zero-one system
Two-way city power exchange while working Import one route to exchange through exchanging the shifter, supply power for each Rectifier Module. The Rectifier Module will be imported the back up supply the storage battery to the three-phase alternating current and changed Charge, support and supply power for the bus wire of switching-in at the same time, in addition the bus wire of switching-in gives and controls the bus wire to supply power through the dropping equipment. The Rectifier Module that thus this text designs will commutated and charged two functions and combined in integrative a new kind of Rectifier Module.
Design of 2 Rectifier Module
The Rectifier Module is a chief in the high-frequency switch power system of the intelligence, concern the steady state of voltage output when systematic direct-current volts is exported and worked. The design herein is mainly improvement and completion to that the module commutated the principle, utilize the principle of the converter of passive PFC and DC/DC, make the module after improving finish the rectified action effectively.
The job functional block diagram of Rectifier Module that this text designs is shown as in Fig. 2, while working, the module is dealt with through passing lightning protection at first and filters and deal with the three-phase alternating current input, could guarantee the security of the circuit of module final-stage in this way; While converting to the high voltage direct current after the treated three-phase alternating current is through commutating and passive PFC, the high voltage direct current changed at this moment should be converted to the convertible direct-current volts and exported again through DC/DC converter; In addition the module control box is still responsible for function such as pressing, excessive load and short circuit protection, could guarantee the stability of the output voltage in this way, can protect every part of the module at the same time too. The module has also offered four in controlling long-rangely distantly remote control, remote regulating, remote measurement, remote signaling Interface.
Working principle diagram of the ones that pursue 2 Rectifier Module
Namely power factor correction Power Factor Correct ion, PFC Refer to effective power and total electric consumption apparent power Between relation,it is for effective power divided by total for electric consumption apparent power Ratio. Passive PFC means that does not use some active device constituent calibration channel such as transistor-resistor logic, generally speaking is made up of passive apparatus such as the diode, resistance, electric capacity and inductor. PFC herein mainly adds a inductance between commutating the Bridge Rectifiers and Filtering capacitance, concrete principle show as in Fig. 3, utilize electric current at the inductor can’t abrupt change characteristic come on smoothing capacity charge strong pulsing fluctuation, improve the distortion of electric current in the circuit, and utilize the voltage on inductor to be superior to the electric current this characteristic compensate the characteristic of filtering capacitance current leading voltage, make power factor and electromagnetic disturbance all improve.
This way is only a kind of simple indemnifying measure, can only accomplish the abrupt change purpose of the curb instant, but the correction of electric current distortion and compensation ability of the power factor are very bad.
DC/DC converter transforms a stationary direct-current volts to the convertible direct-current volts, it has characteristic which accelerates steady, fast response that this kind is controlled, can achieve the result of saving the electric energy at the same time. Can save 20%~30% electric energy to replace the rheostat with the DC chopper. The DC chopper not only can play the function of voltage regulation, can also play a role in inhibiting the harmonic current noise of side of electric wire netting effectively.
Passive PFC schematic diagram of Fig. 3
DC/DC converter herein adopts the forward type DC/DC converter of two-hose sharing, its principle is shown as in Fig. 4, the voltage transformer T1 functions as isolating and voltage transformation, should add an inductor Lo the inductance of after flow on the Ausgang Play a storage and transmission of energy role, the voltage transformer is too elementary to reset the coil again, because of VD1, the feed-through of VD2 has limited the voltage born when two compensating pipes are shut off. It needs to have a kenotron VD3 and a fly-wheel diode VD4 VD3 to output the loop, VD4 preferably chooses the quick rectifier tube of recover time . The Filtering capacitance CO of the output should be chosen the low, high-capacity electric capacity, helps to reduce ripple voltage like this. The working characteristic of the forward type DC/DC converter of two-hose sharing is as follows:
1Under any working condition, do not exceed UIN for the voltage that makes two gas switching tubes bear, Ud UIN is the input voltage; Ud is VD1, forward voltage drop of VD2 ,VD1, VD2 must resume the tube soon, it is the better to be it recover time in designing and debugging actually is the shorter.
2Compared with single-ended forward type DC/DC converter, it needn’t have the reset circuit, this is favorable to design of simplified circuit and voltage transformer; Its power device can choose the lower withstand voltage value; Its power level will be very large too.
3The working condition of two gas switching tubes is unanimous, will be on-state or off-state. So use in the power of so large power level of high-frequency switching power supply of intelligence more suitable.
Circuit diagram of the forward type DC/DC converter of two-hose sharing of Fig. 4
Smooth filtering principle: The rectifying circuit turns the alternating current into the pulsation direct current, but contain a large amount of alternating component call ripple voltage among them . In order to obtain smooth direct-current volts, should add and connect the smoothing circuit behind rectifying circuit, exchange the part in order to filter. Connect a large capacity in parallel between and support on the Ausgang of the bridge rectifier circuit at this momenting, adopting the electric capacity strains the wave rear to make the time that the diode gets shorten, because the electric capacity CO charged instantaneous current is relatively great, it is apt to damage the diode to form the surge current, while choosing the diode, must leave sufficient electric current margin, in case that burning off.
Function introduction to 3 Rectifier Module
Rectifier Module except can the interchange 380V, 50Hz input into Vary into rated dc output 5A/230V Outside, also protect functions and set feature services, introduce the protection function and set feature service of the module as follows now:
3.1 Protect the function introduction
1Have exported and pressed and protected. It will be to causing the major accident to export the overtension with the electrical equipment, in order to stop the emergence of this kind of accident, there is protective circuit of overvoltage, the module self-locking after pressing within the module, the trouble lamp of the module is bright at the same time, the automatic backout working condition of the module, thus will not influence the normal operation of the overall system.
2Export currentlimiting protection. Because the output power of each Rectifier Module is limited, the electric current exported can’t be too big. So, the output current maximum to each module is limited for 1.2 times of the specified output current, if go beyond and support, the module lowers the output voltage so as to protect the function of the module automatically.
3Short circuit protection. The output characteristic of the Rectifier Module is shown as in Fig. 5, output while shorting out the module draws the output voltage low to zero in the twinkling of an eye, limit the short circuit current under the flow point of the limit, the output power of the module is very small at this moment, in order to achieve the goal of protecting the module, it is but unlikely to damage in the short-circuit condition to be in this way all right long term operation for a long time of the module, the module can resume working automatically after trouble removal at the same time.
Rectifier Module output characteristic of Fig. 5
4The module is protected in parallel. Connect the protective circuit in parallel within each module, can guarantee the automatic log down when the module breaks down, thus does not influence the work of other normal module. The module outputs the synoptic diagram in parallel and is shown as in Fig. 6.
Module of Fig. 6 outputs the synoptic diagram in parallel
5It is protected that too warm. To pass warm to protect, protect the intersection of high-power and the intersection of current transformer and device mainly module, gentle electric current overload capacity of knot of device these have safe limiting value, under the situation of normal operation, system design leaves enough excess, but under some special conditions, if ambient temperature too high and air blower stall light under the situation, module measure the heat sink temperature exceed the certain value, know the automatic shutdown to protect, just automatic actuation of the module when the temperature can reduce to the temperature value of the normal work.
6Overcurrent protection. Overcurrent protection is mainly to protect the high-power current transformer device, in every cycles of current transformer, if the electric current passed exceeds the electric current that the device bears, the module will close the power device, in order to achieve the goal of protecting the power device.
3.2 Introduction to the regulating function
1Regulating function of the voltage. The voltage regulation of the module mainly refers to the regulation of the output voltage, there are voltage regulation potentiometers on the Ausgang of the module, when the module links with the monitoring unit, the output voltage can be controlled system set-up too, the potentiometer is regulated invalid at this moment.
2Measure the function. The measurement function of the module is mainly output voltage and working condition of electric current and module of measuring the module, and reveal through LCD, understanding module and working condition of system that can make users ocular and convenient.
3Remote control function. Remote control: Mo / shut-down state of the control module, and back up supply storage battery /floating-charge state; Remote regulating: Regulation control of output voltage and output current; Remote measurement: Can measure the values of output current and output voltage when the module work; Remote signaling: Through controlling the working condition of the monitoring module long-rangely.
4 concludes the speech
This text, mainly to the design that Rectifier Module carries on and studying in the high-frequency switch power system of intelligence, utilize the principle of passive PFC circuit, improve the distortion of electric current in the circuit, add DC/DC converter and inhibit the harmonic current noise of side of electric wire netting, have reflected the advantage of Rectifier Module in the high-frequency switch power system of intelligence, suitable for power transformation places such as the railway, mine,etc.. It is exchanged and varied though this system can be accurate, it is weaker in homogeneity while charging to back up supply, the cost is higher too at the same time, the improvement in filtering lightning protection is not very complete at the same time, so will improve further in these respects. <