CN211321010U

CN211321010U - EPS fast switching circuit based on sine real-time comparison principle

Info

Publication number: CN211321010U
Application number: CN201922328112.0U
Authority: CN
Inventors: 周奎; 刘山林; 张代军
Original assignee: Chongqing Hwyton Electric Co ltd
Current assignee: Chongqing Hwyton Electric Co ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2020-08-21
Anticipated expiration: 2029-12-23

Abstract

EPS fast switch over circuit based on sine compares principle in real time, including the AD converter, the AD converter input passes through sampling circuit and is connected with three-phase commercial power and three-phase emergency power supply, the output and the main control chip signal connection of AD converter, main control chip output signal passes through opto-coupler switch and change over switch control connection, change over switch includes two inputs and an output, and three-phase commercial power and three-phase emergency power supply are connected respectively to two inputs. The utility model discloses can real-time detection input mains supply signal whether unusual and EPS power and the synchronous condition of commercial power to accessible silicon controlled rectifier device switches commercial power output into emergent output fast, thereby realizes commercial power and emergent fast switch-over.

Description

EPS fast switching circuit based on sine real-time comparison principle

Technical Field

The utility model belongs to the electronic circuit field relates to stand-by power supply technique, concretely relates to EPS fast switch over circuit based on sine compares principle in real time.

Background

An EPS (Emergency Power Supply) Power Supply is an Emergency Power Supply used for Emergency lighting, and fire fighting facilities in important buildings today. The general practice is to replace the EPS with a UPS (Uninterruptible Power System/Uninterruptible Power supply), although the UPS switching time meets the requirements, the Power efficiency of the UPS is greatly reduced, which results in a great deal of waste of Power, and the maintenance cost of the UPS is much higher than that of the EPS.

SUMMERY OF THE UTILITY MODEL

For overcoming the technical defect that prior art exists, the utility model discloses a EPS fast switch over circuit based on sine compares the principle in real time.

EPS fast switch circuit based on sine compares principle in real time, including the AD converter, the AD converter input passes through sampling circuit and is connected with three-phase commercial power and three-phase emergency power supply, the output and the main control chip signal connection of AD converter, main control chip output signal passes through opto-coupler switch and is connected with change over switch control, change over switch includes two inputs and an output, and three-phase commercial power and three-phase emergency power supply are connected respectively to two inputs.

Preferably, the power supply system further comprises a power supply management chip, and an output end of the power supply management chip is connected with the main control chip and a power supply end of the AD converter.

Preferably, the sampling circuit includes a plurality of sampling units, and each sampling unit is connected with three-phase commercial power and three-phase emergency power supply's a single-phase output, the sampling unit is including parallelly connected first resistance and the voltage division branch road between single-phase output and N end, the voltage division branch road is including the second resistance that connects gradually in series, sampling electric capacity and third resistance, the common port of second resistance and sampling electric capacity is as the output of sampling unit.

Preferably, the AD converter is AD7606, and the master control chip is M0516 LBN.

Preferably, the system further comprises a communication chip in signal connection with the main control chip.

Preferably, the change-over switch is a silicon controlled optocoupler controlled by a main control chip.

EPS fast switch circuit and switching method based on sine compares principle in real time, can real-time detection input mains signal whether unusual and EPS power and the synchronous condition of commercial power to accessible silicon controlled rectifier device switches commercial power output into emergent output fast, thereby realizes commercial power and emergent fast switch-over, satisfies the not power-off switching condition of special lamps and lanterns such as metal halide lamp, high-pressure sodium lamp.

Drawings

Fig. 1 is a schematic structural diagram of a specific embodiment of the fast switching circuit of the present invention;

fig. 2 is a schematic diagram of an embodiment of the sampling unit according to the present invention;

fig. 3 is a schematic diagram of a specific connection mode of the power management chip according to the present invention;

fig. 4 is a schematic diagram of an embodiment of the switch of the present invention;

fig. 5 is a schematic diagram of comparing the standard waveform with the input waveform according to the present invention;

the reference numbers in the figures refer to: IN: the input end, R1-first resistor, R2-second resistor, C-capacitor, R3-third resistor, OUTP-positive phase output end, OUTN-negative phase output end, VIN 12-input 12V direct current voltage, V5-output 5V direct current voltage, G-optical coupler switch, K-change-over switch and VO-output power supply.

Detailed Description

The following describes the present invention in further detail with reference to the accompanying drawings.

EPS fast switch over circuit based on sine is compared principle in real time, including the AD converter, the AD converter input passes through sampling circuit and is connected with three-phase commercial power and three-phase emergency power supply, the output and the main control chip signal connection of AD converter, main control chip output signal passes through opto-coupler switch G and change over switch K control connection.

The AD converter samples the ac mains and the EPS three-phase emergency power supply, as shown in fig. 1, wherein R, S, T and U, V, W respectively represent the three phases of the ac mains and the three phases of the EPS power supply, and each phase is firstly divided by a sampling unit in the sampling circuit and then input to the AD converter after the output voltage is reduced. The sampling circuit comprises a plurality of sampling units, and each sampling unit is connected with a single-phase output end of the three-phase commercial power and the three-phase emergency power supply.

One embodiment of the sampling unit is shown in fig. 2, the sampling unit includes a first resistor and a voltage dividing branch connected in parallel between the single-phase output terminal and the N terminal, the voltage dividing branch includes a second resistor, a sampling capacitor and a third resistor connected in series in sequence, and a common terminal of the second resistor and the sampling capacitor is used as an output terminal of the sampling unit.

After a signal enters from the input terminal IN, the signal is divided by the second resistor, the capacitor and the third resistor, and then is output from the positive phase output terminal OUTP and the negative phase output terminal OUTN respectively and connected to the AD converter. The sampling unit is adopted to divide the voltage of the alternating sine wave signal and can directly capture the waveform for subsequent detection.

Still include the power management chip among the switching circuit, the power management chip output with the power supply end of main control chip and AD converter is connected, as shown in fig. 3, adopts power management chip LM7805 to change input 12V direct current voltage VIN12 into output 5V direct current voltage V5 and supplies main control chip and AD converter to use. In the specific embodiment shown in fig. 1, the display device further includes a communication chip MAX485 in signal connection with the main control chip, and RS485 communication is adopted to transmit data information to an external display unit.

One specific embodiment is as follows: the AD converter adopts 16-bit AD7606, sampling channels of a three-phase commercial power supply and a three-phase emergency power supply are respectively R + R-, S + S-, T + T-, U + U-, V + V-, W + W-to perform bipolar input and synchronous sampling, a sampling result is input into a main control chip, and the main control chip can adopt M0516 LBN.

According to the specification of the AD7606 product, the AD converter usually uses 12 of the 49 th to 64 th pins as the signal input of each phase sampling channel of the three-phase commercial power and the three-phase emergency power supply, uses 16 of the 16 th to 33 th pins as the converted signal output, and is connected to sixteen pins such as the 1 st to 3 th, 19 th to 23 th, 25 th to 27 th, 43 th to 47 th pins marked in the specification of the M0516LBN of the main control chip.

After the main control chip inputs AC mains and the EPS three-phase emergency power supply at the same time, the main control chip can directly and simply compare whether the waveforms of the AC mains and the EPS three-phase emergency power supply are both overlapped with the waveform of the standard mains, thereby simply judging whether the waveform of the input mains is normal, whether the waveform of the EPS three-phase power supply is normal and whether the waveform of the EPS three-phase power supply is the same as the waveform of the input.

The waveform can also be repeatedly compared with the waveform of the previous period, and the waveform is considered to be normal if the waveforms are basically overlapped.

The judgment and comparison can also be carried out in the following way:

the main control chip simultaneously inputs alternating current commercial power and an EPS three-phase emergency power supply for sampling and carries out comparison as follows:

s1, comparing the AC mains waveform with a pre-stored standard mains waveform, and judging whether the AC mains waveform is normal according to the comparison result;

s2, comparing the AC mains supply waveform with the EPS three-phase emergency power supply, and judging whether the phase error of the AC mains supply waveform and the EPS three-phase emergency power supply meets the standard or not according to the comparison result;

in step S1, it is necessary to collect a standard mains waveform, take a complete sine wave periodic waveform, select a plurality of points on the complete sine wave periodic waveform, and store the voltage amplitude and time interval of each point; as shown in fig. 5, the abscissa is time and the ordinate is voltage amplitude.

For example, four points a1, a2, A3 and a4 are selected on the standard waveform, the time intervals are T1, T2 and T3 respectively, the voltage value is zero and is taken as the time origin, and the time difference between the point a1 and the origin is T0.

When an input waveform is detected, the voltage value is zero as the time origin, when the time difference reaches T0, the voltage amplitudes of a point B1 and a point A1 on the input waveform are compared, whether the difference value of the two points exceeds a preset threshold value is checked, interval time T1, T2 and T3 are continued if the difference value does not exceed the threshold value, B2, B3 and B4 on the input waveform are respectively detected, point-by-point check is continued, whether the voltage amplitude difference values of the point A2, the point A3 and the point A4 on the standard waveform exceed the preset threshold value is continued, and the AC mains supply waveform is judged to be abnormal if any point exceeds the threshold value; the preset threshold is determined according to the accuracy required by the power supply equipment, and can be in the range of 10-100 millivolts or within 1% of the peak voltage value.

In actual detection, instantaneous voltage values of all time points on the current commercial power can be directly detected, the AC maximum value Um can be converted according to the mathematical conversion relation between the AC instantaneous voltage values and the maximum value Um, and then the AC maximum value Um is converted into an effective value

And then the judgment can be carried out by comparing the voltage value with the voltage value on the standard waveform.

For the ac phase determination, generally, the phase zero point determination is performed with the ac instantaneous value being zero and the current voltage variation trend, and in step S2, the phase error determination between the ac mains waveform and the EPS three-phase emergency power supply may be performed as follows:

firstly, determining a time point when any voltage is zero, such as an original point in fig. 5, comparing whether the time points when the voltages of the alternating current commercial power and the latest EPS three-phase alternating current are zero are overlapped or have an error smaller than a preset time threshold, if so, continuously detecting whether the time points when the voltages of the alternating current commercial power and the latest EPS three-phase alternating current are zero are overlapped or have an error smaller than a threshold, and if still, taking whether the voltage values of two time median values of the zero time points are equal or the difference between the two voltage values is smaller than a preset threshold, wherein the threshold can be set by referring to the voltage preset threshold; and if the three steps are judged to be in accordance, the phases are considered to be the same, and if any one step is not in accordance, the phases are considered to be different. The time threshold is determined according to comprehensive judgment such as sampling precision and power grid stability, and can be generally set within 1-50 microseconds.

As shown in fig. 5, it may be determined whether the ac utility power and the EPS three-phase ac power are temporally coincident or smaller than a time threshold by using a time zero point as a time point when the voltage is zero;

then, continuing to search for the time points when the next nearest voltage of the relative zero point of the alternating current commercial power and the EPS three-phase alternating current is zero, as shown in fig. 5, which are respectively a4 point and a B4 point, and judging whether the time points of a4 point and the B4 point coincide with each other or are smaller than a time threshold;

finally, the time middle point between the origin and the point A4 and the time middle point between the origin and the point B4 are determined, as shown in FIG. 5, whether the voltage values at the points A2 and B2 are equal or whether the difference between the two values is less than the preset threshold value

One specific embodiment is as follows: the sampling frequency is set to be 3Khz in steps S1 and S2, in a half alternating current period, 30 sampling alternating current instantaneous voltage values are obtained, the sampling point time interval is 0.3333ms, the smaller the sampling time interval is, the more accurate the sampling time interval is, but the requirement on the sampling operation speed of a device or an algorithm is higher.

When step S1 detects that the input mains waveform is inconsistent with the standard waveform, it detects whether the input mains waveform is consistent with the phase of the EPS three-phase emergency power supply, if so, the switching is performed, if not, the phase of the EPS three-phase emergency power supply can be adjusted, and then the power supply switching is performed, and the EPS three-phase emergency power supply is output to the output power supply VO through the change-over switch K.

The change over switch is the silicon controlled rectifier opto-coupler device who receives the control chip control specifically, when selecting the commercial power operation, a set of silicon controlled rectifier opto-coupler device with mains connection switches on, a set of silicon controlled rectifier opto-coupler with UPS power connection cuts off, the signal of silicon controlled rectifier opto-coupler device comes from the main control chip, as shown in fig. 4, main control chip and ground are connected respectively to first foot P1 and second foot P2, commercial power or UPS power and output power are connected respectively to third foot P3 and fourth foot P4, through the high-low level of main control chip output signal, make the opto-coupler device switch on or close, the resistance in the picture is current limiting resistor.

In the foregoing, the preferred embodiments of the present invention, if not obviously contradictory or based on a certain preferred embodiment, can be combined and used by any superposition, the specific parameters in the embodiments and examples are only for clearly expressing the utility model verification process of the utility model, and are not used for limiting the patent protection scope of the present invention, the patent protection scope of the present invention is still based on the claims, and all the equivalent structural changes made by the contents of the specification and the drawings of the present invention should be included in the protection scope of the present invention.

Claims

1. EPS fast switch over circuit based on sine compares principle in real time, a serial communication port, including the AD converter, the AD converter input passes through sampling circuit and is connected with three-phase commercial power and three-phase emergency power supply, the output and the main control chip signal connection of AD converter, main control chip output signal passes through opto-coupler switch and is connected with change over switch control, change over switch includes two inputs and an output, and three-phase commercial power and three-phase emergency power supply are connected respectively to two inputs.

2. The fast switching circuit of claim 1, further comprising a power management chip, wherein an output terminal of the power management chip is connected to the main control chip and a power supply terminal of the AD converter.

3. The fast switching circuit according to claim 1, wherein the sampling circuit comprises a plurality of sampling units, each sampling unit is connected to a single-phase output terminal of a three-phase commercial power supply and a three-phase emergency power supply, the sampling unit comprises a first resistor and a voltage dividing branch connected in parallel between the single-phase output terminal and an N terminal, the voltage dividing branch comprises a second resistor, a sampling capacitor and a third resistor connected in series in sequence, and a common terminal of the second resistor and the sampling capacitor serves as an output terminal of the sampling unit.

4. The fast switching circuit of claim 1, wherein the AD converter is AD7606 and the master chip is M0516 LBN.

5. The fast switching circuit of claim 1, further comprising a communication chip in signal connection with the master chip.

6. The fast switching circuit of claim 1, wherein the switch is embodied as a thyristor optocoupler controlled by a master chip.