CN100462727C - Alternating current electronic load simulation device suitable for any alternating current signal waveform - Google Patents

Abstract

The AC electronic load simulator suitable for any AC signal waveform includes one automatic gain control amplifier with input end for inputting AC power source to be measured as signal source and output end capable of sending gain regulated gain output signal. An RMS conversion circuit for obtaining a gain output signal from the output terminal of the AGC amplifier and generating an RMS feedback signal to be sent to the feedback signal input terminal of the AGC amplifier. When any AC signal waveform is sent to the input end of the automatic gain control amplifier, the gain output signal output by the output end of the automatic gain control amplifier can constantly keep a preset value under the control of the automatic gain control amplifier and the RMS value conversion circuit, and the electronic load circuit can be controlled according to the gain output signal. The AC electronic load simulator also comprises a level adjusting circuit used for adjusting the output signal level of the automatic gain control amplifier.

Description

AC electronic load simulation device suitable for arbitrary AC signal waveforms

technical field

The invention relates to an AC electronic load simulation device, in particular to an AC electronic load simulation device applicable to arbitrary AC signal waveforms.

technical background

AC power supply equipment is required in modern industrial instruments, electrical equipment, and computer equipment. For example, the AC power equipment that is often used in the industry at present includes uninterruptible power supply (UPS), inverter (INVERTER), voltage regulator (VOLTAGE REGULATOR) and so on. After the design and assembly of these various AC power supply equipment is completed, in order to understand the various electrical characteristics of the power supply, it is often necessary to connect the actual electrical load to test, record and improve the various electrical characteristics. Since it is necessary to prepare various electrical loads in order to actually connect to the AC power supply device, it is extremely inconvenient during testing and the work efficiency cannot be improved.

Therefore, in order to overcome the inconvenience of using physical load connection in the conventional technology, there is research and development of an AC electronic load simulation device.

However, commonly used AC electronic load simulation devices are generally only suitable for typical AC signal waveforms, and good simulation effects cannot be achieved for other waveforms of AC signals. The load characteristics of general electronic and electrical products (such as personal computers or UPS uninterruptible power supplies, televisions, audio equipment, etc.) are electronic rectification, and their current waveforms are pulse waveforms. When simulating such waveform signals, it is often A good simulation effect cannot be obtained.

For example, in the conventional uninterruptible power supply system (UPS) technology currently used, the output voltage waveform generated by it can be divided into sine wave and square wave. In testing the load of the uninterruptible power supply system (UPS), in addition to the actual equipment used, the test equipment can be divided into constant current type and constant resistance type load. In the constant current type, the current waveform cannot be well controlled when the UPS switches between mains power and battery power. When the mains power supply is converted to an inverter (Inverter), the phase shifts and is not at the originally expected angle. Furthermore, in the square wave output voltage supplied by the uninterruptible power supply currently available in the market, there is no current signal in the section other than the square wave. This phenomenon will cause a very large error in the actual simulation test. Although the waveform generated by the constant resistance type is good, the load current varies with the voltage, which cannot achieve the purpose of constant current and cannot meet the test conditions.

Contents of the invention

The main purpose of the present invention is to provide an AC electronic load simulation device suitable for any AC signal waveform, so that when any AC signal waveform is input, the function of electronic load simulation can be achieved, and it is not only suitable for typical sinusoidal AC Signal.

Another object of the present invention is to provide an AC electronic load simulation device with an automatic gain control function, which receives an AC power source to be tested as a signal source through an automatic gain control amplifier, and can send a gain through the output terminal Adjusted gain output signal. Furthermore, a root mean square value conversion circuit obtains a gain output signal from the output terminal of the automatic gain control amplifier, and generates a root mean square value feedback signal and sends it to the feedback signal input terminal of the automatic gain control amplifier, Through the design of the circuit, the gain output signal output from the output terminal of the automatic gain control amplifier can be kept at a predetermined value, and the electronic load circuit can be controlled according to the gain output signal.

The technical means adopted by the present invention to solve the problems of the prior art is to combine an automatic gain control amplifier in the electronic load circuit of the AC electronic load simulation device. The output terminal can send out a gain output signal after gain adjustment. A root mean square conversion circuit obtains a gain output signal from the output terminal of the automatic gain control amplifier, and generates a root mean square value feedback signal and sends it to the feedback signal input terminal of the automatic gain control amplifier. When any AC signal waveform is sent to the input terminal of the automatic gain control amplifier, the gain output signal output from the output terminal of the automatic gain control amplifier can be kept constant through the control of the automatic gain control amplifier and the root mean square conversion circuit. Keeping the predetermined value, the output signal can be used to control the electronic load circuit according to the gain. The AC electronic load simulation device further includes a level adjustment circuit for adjusting the output signal level of the automatic gain control amplifier.

Through the technical means adopted in the present invention, the AC electronic load simulation device of the present invention can be applied not only to the electronic load simulation function of typical sinusoidal AC signals, but also to the electronic load simulation function of any AC signal. The traditionally used AC electronic load simulation device has more practical functions. And when carrying out load simulation, by the automatic gain control function among the present invention and the conversion of root-mean-square value signal, and can output a control signal that keeps predetermined value constantly at the output end of an automatic gain control amplifier, according to this gain output The signal can be used to control the action of the electronic load circuit in the AC electronic load simulation device.

Description of drawings

Fig. 1 is a circuit diagram showing a preferred embodiment of the present invention;

Fig. 2 is a list of AC power signals of various waveforms to which the present invention is applicable.

11 Automatic Gain Control Amplifier

12 RMS conversion circuit

13 Reference signal unit

14 Level adjustment circuit

15 Microcontroller

2 Electronic load circuit

21 Operational Amplifier

22 Power crystal

23 Testing the Current Sensing Element

24 rectifier circuit

s1 Level-adjusted output signal

Vin Signal Source

Vout Gain output signal

Vf RMS Feedback Signal

ACV AC Power

Vdc DC power supply

IL Test current

Detailed ways

Referring first to FIG. 1 , it is a circuit diagram showing the present invention. As shown in the figure, the present invention includes an automatic gain control amplifier 11, and the input terminal of the automatic gain control amplifier 11 can be connected to various signal sources Vin with different waveforms.

The output terminal of the AGC amplifier 11 can send a gain-adjusted gain output signal Vout. The gain output signal Vout can generate an RMS feedback signal Vf to the feedback signal input terminal of the automatic gain control amplifier 11 through an RMS conversion circuit 12 .

The root mean square value conversion circuit 12 can obtain a root mean square value signal from the output terminal of the automatic gain control amplifier 11, and convert the root mean square value signal into a DC level root mean square value feedback signal Vf as the The feedback signal of the automatic gain control amplifier 11 when performing gain control. The root mean square value conversion circuit 12 is connected with a reference signal unit 13, which can provide a reference signal Vref to the root mean square value conversion circuit 12, as the root mean square value conversion circuit 12 in the implementation of the root mean square value signal to DC When the root mean square value feedback signal Vf is converted, it is used as a reference value.

Through the control of the automatic gain control amplifier 11 and the root-mean-square value conversion circuit, the gain output signal Vout output by the output terminal of the automatic gain control amplifier 11 can be kept at a predetermined value, and will not be affected by the automatic gain control amplifier 11 input terminal. It varies depending on the difference in the signal waveform of the input signal source Vin.

The gain output signal Vout output by the output terminal of the automatic gain control amplifier 11 has to be adjusted by a level adjustment circuit 14 to adjust the output signal level, and finally the level adjustment circuit 14 sends out a level-adjusted output signal s1.

In a preferred embodiment of the present invention, the level adjustment circuit 14 can be a digital to analog converter (Digital to Analog Converter), and the digital to analog converter can be controlled by a microcontroller 15 . The level adjustment circuit 14 can also be an adjustable resistor, and the purpose of signal level adjustment can also be achieved by adjusting the adjustable resistor.

The output signal s1 sent by the level adjustment circuit 14 can be used to control an electronic load circuit 2. The electronic load circuit 2 includes an operational amplifier 21, a power crystal 22 (for example, an N-channel power metal oxide field effect power crystal N-MOSFET), a test current sensing element 23, and a rectification circuit 24.

The rectifier circuit 24 is a known bridge-type full-wave rectifier circuit, and its power input terminal is connected to the AC power supply ACV to be tested. After the AC power supply ACV to be tested is rectified by the rectifier circuit 24, a DC power supply can be sent out. Vdc. The operational amplifier 21 is used as a driving circuit for driving the power crystal 22 to consume the connected AC power on the power crystal 22 . When the test current IL passes through the power crystal 22 , the current sensing element 23 can detect the current value of the test current IL, and feed back the detected current value signal to the inverting terminal (−) of the operational amplifier 21 .

When an AC power supply ACV is sent into the electronic load circuit 2, in addition to the rectification of the AC power supply ACV through the rectification circuit 24 and the control of the operational amplifier 21, power crystal 22, and test current sensing element 23, the AC power supply ACV is also At the same time, it is sent to the automatic gain control amplifier 11 as the signal source Vin of the automatic gain control amplifier 11 . After the automatic gain control amplifier 11 cooperates with the RMS conversion circuit 12 for gain adjustment, the level adjustment circuit 14 is used to adjust the output signal level, and finally the level adjustment circuit 14 sends out a level-adjusted output signal s1. The output signal s1 sent by the level adjustment circuit 14 is also used as the non-inverting input terminal (+) of the operational amplifier 21 in the electronic load circuit 2 , thereby achieving the function of AC electronic load simulation.

In addition to the standard sine wave AC power supply, the AC power supply ACV applicable to the AC electronic load simulation function of the present invention can also be other different types of AC power supply signals. Various AC power signals of different waveforms shown in Figure 2 are applicable to the present invention, wherein the first AC power signal ACV1 is a standard sine wave AC power signal, while the other AC power signals ACV2 ^- ACV5 have different waveforms AC power signal. After the AC power signals of these different waveforms are sent to the automatic gain control amplifier 11, the automatic gain function of the automatic gain control amplifier 11 and the RMS value conversion of the signal RMS value of the root mean square value conversion circuit 12 make the automatic gain control amplifier 11 The gain output signal Vout output from the output terminal can maintain a predetermined value, and will not change due to the difference in the signal waveform of the signal source Vin input to the input terminal of the automatic gain control amplifier 11 .

In summary, the AC electronic load simulation device provided by the present invention is indeed applicable to the electronic load simulation function of any AC signal waveform, and through the automatic gain control function and the conversion of the RMS signal in the present invention, it can An automatic gain control amplifier outputs a control signal with a constant predetermined value, and the gain output signal can be used to control the action of the electronic load circuit in the AC electronic load simulation device. This feature has great practical value for the industry.

The above are only descriptions of preferred embodiments of the present invention, rather than limiting the present invention. Therefore, those skilled in the art can make various improvements and modifications to the present invention, but these changes should still belong to the creative spirit of the present invention and the patent scope defined by the claims.

Claims (6)

1. alternating current electronic load analogue means that is suitable for any AC signal waveform is characterized in that including:

One electronic load circuit after one AC power to be measured is sent into this electronic load circuit, gives rectification by the rectification circuit in this electronic load circuit;

One automatic gain control amplifier, its input end are to supply this AC power to be measured of input as signal source, and its output terminal can be sent the gain output signal that a process gain-adjusted is crossed;

One root-mean-square value change-over circuit is obtained a gain output signal by the output terminal of this automatic gain control amplifier, and is produced the feedback signal input end that a root-mean-square value feedback signal is delivered to this automatic gain control amplifier;

When any AC signal waveform is sent into the input end of this automatic gain control amplifier, control by this automatic gain control amplifier and root-mean-square value change-over circuit, the gain output signal that makes the output terminal of this automatic gain control amplifier export is able to the permanent predetermined value that keeps, can be in order to control this electronic load circuit according to this gain output signal.

2. be suitable for the alternating current electronic load analogue means of any AC signal waveform according to claim 1, it is characterized in that: this root-mean-square value change-over circuit is connected with a reference signal unit, this root-mean-square value change-over circuit is converted to the feedback signal of the root-mean-square value signal of the accurate position of predetermined direct current as this automatic gain control amplifier with this gain output signal after obtaining the gain output signal by the output terminal of this automatic gain control amplifier.

3. be suitable for the alternating current electronic load analogue means of any AC signal waveform according to claim 1, it is characterized in that also including a level regulator circuit, it is the output terminal that is connected in this automatic gain control amplifier, make gain output signal that the output terminal of this automatic gain control amplifier exports do the adjusting of the accurate position of output signal, send once adjusted this electronic load circuit that outputs signal in accurate position by this level regulator circuit again via this level regulator circuit.

4. as being suitable for the alternating current electronic load analogue means of any AC signal waveform as described in the claim 3, it is characterized in that: this level regulator circuit is a digital to analog converter.

5. as being suitable for the alternating current electronic load analogue means of any AC signal waveform as described in the claim 4, it is characterized in that: this digital to analog converter is controlled by a micro controller.

6. be suitable for the alternating current electronic load analogue means of any AC signal waveform according to claim 1, it is characterized in that: this electronic load circuit is to include an operational amplifier, a power crystal, a measuring current sensing element, a rectification circuit, wherein this operational amplifier is as driving circuit, in order to driving this power crystal, with the AC power power consumption that will connect on this power crystal.

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