CN216771806U - Switch electronic load - Google Patents

Abstract

The application discloses a switch electronic load, which comprises a booster circuit, a control circuit and a band elimination filter circuit; the booster circuit is provided with a first electronic switch; the output end of the control circuit is connected with the first electronic switch to control the on or off of the first electronic switch; the band elimination filter circuit comprises a filter capacitor and a second inductor which are connected in series between the first branch circuit and the second branch circuit; the first end of the filter capacitor is connected with the input side of the booster circuit, and the second end of the filter capacitor is connected with the second inductor; the other end of the second inductor is grounded; the notch frequency of the band-elimination filter circuit is the switching frequency of a first electronic switch in the booster circuit, and the impedance of a filter capacitor and a second inductor under the switching frequency is as small as possible so as to filter an alternating current component corresponding to the switching frequency in the output current of the booster circuit and allow the alternating current component under other frequencies to be output; the utility model improves the dynamic performance of the switch electronic load without increasing the current ripple value, and the power consumption of the device is lower.

Description

Switch electronic load

Technical Field

The present application relates to the field of electronic load technologies, and more particularly, to a switching electronic load.

Background

An electronic load is a device for simulating a power consumption state, and in the field of power supply testing, the electronic load can provide various test modes, and is an indispensable test device for development and manufacture of a power supply device. The principle of the electronic load is mainly to control the conduction flux of an internal power component (or power device), and the power component dissipates power to consume electric energy, so as to achieve the simulation of the power utilization environment.

The electronic load is mainly divided into a linear electronic load and a switch electronic load, and the linear electronic load converts electric energy into heat and emits the heat into air, so that the linear electronic load has high energy consumption. Linear electronic loads are also bulky for heat dissipation. And the switch electronic load feeds the electric energy back to the power grid, and the heat dissipation is far smaller than that of the linear electronic load. Therefore, the switch electronic load has low energy consumption and small volume. The dynamic response speed of switching loads is significantly slower than that of linear loads. For example, when the current change speed is required to be greater than 0.1A/us, the switch-type electronic load is difficult to meet the requirement. However, in the testing of new energy and 5G devices, the electronic load is required to meet this rate of current change.

In order to improve the dynamic response speed, one of the currently common ways is to increase the switching frequency of the power component, but the switching frequency of the power component is limited by the device performance, the switching frequency of the power component cannot be increased infinitely, and the implementation scheme of the way is complex, and increasing the switching frequency causes great loss of the equipment, and reduces the overall efficiency of the equipment; in addition, the ripple of the output current needs to be reduced while the dynamic response speed is increased, in order to reduce the ripple, a filter capacitor is usually added in the circuit, and when the switching electronic load reaches a steady state, the larger the capacitance value of the filter capacitor is, the smaller the ripple of the output current is. However, the filter capacitor filters out high-frequency current components, so that the output current only contains direct current and low-frequency components, and the dynamic response speed of the output current is caused; the larger the capacitance value of the filter capacitor is, the slower the dynamic response speed is.

SUMMERY OF THE UTILITY MODEL

In view of at least one of the drawbacks and needs of the prior art, the present invention provides a switching electronic load, which aims to improve the dynamic response speed of an output circuit while reducing output current ripple.

To achieve the above object, according to one aspect of the present invention, there is provided a switching electronic load connected to an output side of a power supply to be tested through a first branch and a second branch, the switching electronic load comprising:

the boost circuit is used for boosting the direct current power supply output by the power supply to be tested and is provided with a first electronic switch;

the output end of the control circuit is connected with the first electronic switch, and the output current of the booster circuit is controlled by controlling the on or off of the first electronic switch;

the band-elimination filter circuit comprises a filter capacitor and a second inductor which are connected between the first branch and the second branch in series; the first end of the filter capacitor is connected with the input side of the booster circuit, and the second end of the filter capacitor is connected with the second inductor; the other end of the second inductor is grounded;

the notch frequency of the band-elimination filter circuit is the switching frequency of a first electronic switch in the booster circuit, and the impedance of the filter capacitor and the second inductor under the switching frequency is as small as possible, so that alternating current components corresponding to the switching frequency in the output current of the booster circuit are filtered out, and alternating current components under other frequencies are allowed to be output.

Preferably, in the above switching electronic load, values of the filter capacitor and the second inductor in the band-elimination filter circuit satisfy the following relationship:

wherein C1 represents the capacitance of the filter capacitor; l2 represents the inductance value of the second inductor; j represents a twiddle factor over the complex field; and w is the angular velocity corresponding to the switching frequency.

Preferably, in the above switching electronic load, the band-elimination filter circuit further includes a third inductor disposed on the first branch;

and the first end of the third inductor is respectively connected with the input side of the booster circuit and the first end of the filter capacitor, and the second end of the third inductor is used as the input end of the switch electronic load and is used for connecting the anode of the power supply to be tested.

Preferably, in the above switching electronic load, an impedance value of the third inductor at the switching frequency is more than 800 times an impedance value of the band elimination filter circuit at the switching frequency.

Preferably, in the above switching electronic load, the boost circuit includes a first inductor and a freewheeling component arranged in the first branch, and a first electronic switch and an energy storage capacitor connected in series between the first branch and the second branch; the first end of the first electronic switch is connected with the output side of the first inductor and the input side of the follow current assembly respectively, and the first end of the energy storage capacitor is connected with the output side of the follow current assembly; the second ends of the first electronic switch and the energy storage capacitor are grounded.

Preferably, in the above switching electronic load, the freewheeling component is a second electronic switch;

the first end of the second electronic switch is connected with the first end of the energy storage capacitor, the second end of the second electronic switch is connected with the output side of the first inductor, and the third end of the second electronic switch is connected with the output end of the control circuit.

Preferably, in the above switching electronic load, the freewheel element is a freewheel diode;

and the anode of the freewheeling diode is connected with the first end of the energy storage capacitor, and the cathode of the freewheeling diode is connected with the output side of the first inductor.

Preferably, in the switching electronic load, an inductance value of the first branch is a preset fixed value; the sum of the inductances of the first and third inductors is the fixed value.

Preferably, in the above switching electronic load, an inductance value of the third inductor is 1uH-10 uH.

Preferably, the switching electronic load further comprises a DC/AC inverter and an isolation circuit;

the isolation circuit acquires the direct-current voltage output by the booster circuit and transmits the direct-current voltage to the DC/AC inverter, and the DC/AC inverter converts the direct-current voltage into alternating current and outputs the alternating current.

Preferably, in the above switching electronic load, the filter capacitor is a thin film capacitor.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

according to the switch electronic load provided by the utility model, the band elimination filter circuit is arranged between the booster circuit and the power supply to be tested, the trap frequency of the band elimination filter circuit is the switching frequency of the electronic switch in the booster circuit, and the impedance of the filter capacitor and the second inductor in the band elimination filter circuit under the switching frequency is as small as possible, so that the alternating current component corresponding to the switching frequency in the output current of the booster circuit is filtered, and the alternating current components under other frequencies are allowed to be output. Because the high-frequency component contained in the output current of the power supply to be detected is not filtered by the band-elimination filter circuit, the output current of the booster circuit has high change speed, and the dynamic performance of the switch load is obviously improved. Meanwhile, the band elimination filter circuit filters alternating current components corresponding to the switching frequency in the output current of the booster circuit, so that the current ripple of the output current is small; under the condition of not increasing the current ripple value, the dynamic performance of the switch electronic load is improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the embodiments will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram of a composition structure of a switching electronic load provided in this embodiment;

fig. 2 is a schematic structural composition diagram of the boost circuit and the band-stop filter circuit provided in this embodiment;

fig. 3 is a schematic diagram of another structure of the band-stop filter circuit provided in this embodiment.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

The terms "first," "second," "third," and the like in the description and claims of this application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

In other instances, well-known or widely used techniques, elements, structures and processes may not have been described or shown in detail to avoid obscuring the understanding of the present invention by the skilled artisan. Although the drawings represent exemplary embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated or omitted in order to better illustrate and explain the present invention.

Fig. 1 is a schematic structural diagram of a switch electronic load provided in this embodiment, where the switch electronic load is connected to an output terminal of a power supply to be tested through a first branch and a second branch, and the first branch and the second branch form a complete power supply loop; referring to fig. 1, the switch electronic load includes a boost circuit, a control circuit and a band-stop filter circuit;

fig. 2 is a schematic structural diagram of the boost circuit and the band-stop filter circuit provided in this embodiment, please refer to fig. 2, in which the boost circuit includes a first inductor L1 and a freewheeling component arranged on the first branch, and a first electronic switch K1 and an energy-storage capacitor C2 connected in series between the first branch and the second branch; the first end of the first electronic switch K1 is connected to the output side of the first inductor L1 and the input side of the freewheeling component, the first end of the energy storage capacitor C2 is connected to the output side of the freewheeling component, and the second ends of the first electronic switch K1 and the energy storage capacitor C2 are grounded.

The output end of the control circuit is connected with the third end of the first electronic switch K1, and the output current of the first inductor L1 is controlled by controlling the on/off of the first electronic switch K1.

In this embodiment, the control circuit is mainly used for generating a square wave signal PWM with a certain duty ratio to control the first electronic switch K1 to be turned on or turned off. When the first electronic switch K1 is turned on, the tested power supply charges the first inductor L1; when the first electronic switch K1 is turned off, the output current of the first inductor L1 charges the energy storage capacitor C2. In this way, the capacitor voltage reaches a stable value. The frequency of the square wave signal PWM determines the switching frequency of the first electronic switch K1, and thus determines the frequency and magnitude of the output current of the first inductor L1. In one particular example, the first electronic switch K1 employs a transistor or other semiconductor device with a body diode.

The band-elimination filter circuit comprises a filter capacitor C1 and a second inductor L2 which are connected between the first branch and the second branch in series; the first end of the filter capacitor C1 is connected with the input side of the first inductor L1, and the second end is connected with the second inductor L2; the other end of the second inductor L2 is connected to ground.

Since the most dominant ac component of the current ripple in the output current of the first inductor L1 is the ac component corresponding to the switching frequency, the notch frequency of the band rejection filter circuit is the switching frequency of the first electronic switch K1 in the voltage boost circuit, and the impedance of the filter capacitor and the second inductor at the switching frequency is as small as possible, so as to filter the ac component corresponding to the switching frequency in the output current of the first inductor L1 and allow the ac components at other frequencies to be output.

In one specific example, the values of the filter capacitor C1 and the second inductor L2 in the band-stop filter circuit need to satisfy the following relationship:

wherein C1 represents the capacitance of the filter capacitor; l2 represents the inductance value of the second inductor; j represents a twiddle factor over the complex field; and w is the angular velocity corresponding to the switching frequency.

Under the condition that the values of the filter capacitor C1 and the second inductor L2 satisfy the above formula, the alternating current component corresponding to the switching frequency mainly passes through the band-elimination filter circuit consisting of the filter capacitor C1 and the second inductor L2, because the impedance of the band-elimination filter circuit at the switching frequency is 0, and the current preferentially passes through the branch circuit with low impedance. Therefore, the branch circuit formed by the filter capacitor C1 and the second inductor L2 has the effect of band-stop filtering. The band-elimination filter circuit has no obvious filter effect on high-frequency components at other frequencies, that is, the band-elimination filter circuit only filters the alternating current component corresponding to the switching frequency in the output current of the first inductor L1, but allows the alternating current component at other frequencies to be output. Therefore, the output current iLOAD of the power supply to be tested also contains high-frequency components, so the current iLOAD has a high change speed, and the dynamic performance of the switch load is obviously improved at the moment. Meanwhile, the alternating current component corresponding to the switching frequency in the output current of the first inductor L1 is filtered out by the band-elimination filter circuit, so that the current ripple in the output current is small; the embodiment improves the dynamic performance of the switch electronic load under the condition of not increasing the current ripple value.

In one specific example, the filter capacitor C1 is a thin film capacitor with low internal resistance and small parasitic parameters.

However, in practical circuit, the filter capacitor C1 and the second inductor L2 are deviated from the nominal value, so that the above equation (1) is difficult to satisfy,

in practice a very small impedance value will result. To address this problem, in a more preferred embodiment,referring to fig. 3, a third inductor Lin is introduced into the band-stop filter circuit, and is disposed on the first branch, a first end of the third inductor Lin is connected to an input side of the first inductor L1 and a first end of the filter capacitor C1, and a second end of the third inductor Lin is used as an input end of the switch electronic load and is connected to an anode of the power supply to be tested. The impedance value of the third inductor at the switching frequency is far greater than that of the band-elimination filter circuit at the switching frequency, and as the current preferentially passes through the branch circuit with low impedance, most of the current component of the switching frequency passes through the branch circuit formed by the filter capacitor C1 and the second inductor L2, so as to ensure the band-elimination filter effect of the branch circuit where the filter capacitor C1 and the second inductor L2 are located.

In a specific example, the impedance value of the third inductor Lin at the switching frequency is more than 800 times, and more preferably more than 1000 times, of the impedance value of the band-elimination filter circuit at the switching frequency, that is:

the inductance value of the third inductance Lin is typically 1 to 10 uH.

In this embodiment, the inductance value of the first branch where the first inductor L1 is located is a preset fixed value, and when the third inductor Lin is not provided, the inductance value of the first inductor L1 is the fixed value; after the third inductor Lin is set, the inductance value of the first inductor L1 is the difference between the fixed value and the inductance value of the third inductor, so as to ensure that the inductance value on the main circuit is unchanged.

Referring to fig. 2 and 3, in an alternative embodiment, the freewheeling module employs a second electronic switch K2; the first end of the second electronic switch K2 is connected to the first end of the energy storage capacitor C2, the second end is connected to the output side of the first inductor L1, and the third end is connected to the output end of the control circuit. The square wave signal PWM generated by the control circuit is also used to control the on or off of the second electronic switch K2.

After the second electronic switch K2 is provided, the boost circuit forms a synchronous boost circuit which is synchronously switched on and off, the second electronic switch K2 is switched off when the first electronic switch K1 is switched on, and the second electronic switch K2 is switched on when the first electronic switch K1 is switched off. Because first electronic switch K1, second electronic switch K2 all can let it be in saturation when switching on and switch on, the consumption on first branch way will greatly reduced like this, has improved the whole efficiency of equipment. In one specific example, the second electronic switch K2 employs a transistor with a body diode or other semiconductor device.

In the case of no consideration of power consumption, the second electronic switch K2 may also be replaced by a freewheeling diode, specifically, the diode is disposed between the energy storage capacitor and the first inductor, the anode of the diode is connected to the first end of the energy storage capacitor, and the cathode of the diode is connected to the output side of the first inductor.

With reference to fig. 1, in practical applications, the switching electronic load further includes a DC/AC inverter and an isolation circuit; the input end of the isolation circuit is connected with the booster circuit, and the direct-current voltage output by the booster circuit is obtained and transmitted to the DC/AC inverter; one end of the DC/AC inverter is connected with the isolation circuit, and the DC voltage output by the isolation circuit is obtained and inverted into AC; the other end of the switch is used as the output end of the switch electronic load, is in butt joint with an external power grid, and outputs the converted alternating current to the external power grid.

According to the switch electronic load provided by the utility model, the band elimination filter circuit is arranged between the booster circuit and the power supply to be tested, the trap frequency of the band elimination filter circuit is the switching frequency of the electronic switch in the booster circuit, and the impedance of the filter capacitor and the second inductor in the band elimination filter circuit under the switching frequency is as small as possible, so that the alternating current component corresponding to the switching frequency in the output current of the booster circuit is filtered, and the alternating current components under other frequencies are allowed to be output. Because the high-frequency component contained in the current of the power supply to be detected is not filtered by the band-elimination filter circuit, the current change speed is high, and the dynamic performance of the switch load is obviously improved. Meanwhile, the band elimination filter circuit filters an alternating current component corresponding to the switching frequency in the output current of the booster circuit, so that the current ripple of the output current is small; under the condition of not increasing the current ripple value, the dynamic performance of the switch electronic load is improved.

All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the utility model, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. A switch electronic load is connected with the output side of a power supply to be tested through a first branch circuit and a second branch circuit, and is characterized by comprising a booster circuit, a control circuit and a band elimination filter circuit;

the boosting circuit is provided with a first electronic switch connected between the first branch and the second branch in series;

the output end of the control circuit is connected with the first electronic switch to control the on or off of the first electronic switch;

the band-stop filter circuit comprises a filter capacitor and a second inductor which are connected in series between the first branch circuit and the second branch circuit; the first end of the filter capacitor is connected with the input side of the booster circuit, and the second end of the filter capacitor is connected with the second inductor; the other end of the second inductor is grounded; the notch frequency of the band elimination filter circuit is the switching frequency of a first electronic switch in the booster circuit.

2. The switched electronic load of claim 1, wherein the impedance of the band-stop filter circuit at the switching frequency of the first electronic switch is zero.

3. The switched electronic load of claim 1, further comprising a third inductor disposed in the band-reject filter circuit on the first leg;

and the first end of the third inductor is respectively connected with the input side of the booster circuit and the first end of the filter capacitor, and the second end of the third inductor is used as the input end of the switch electronic load and is used for connecting the anode of the power supply to be tested.

4. The switched electronic load of claim 3, wherein the impedance value of the third inductance at the switching frequency is greater than 800 times the impedance value of the band-stop filter circuit at the switching frequency.

5. The switched electronic load of claim 3, wherein said boost circuit further comprises a first inductor and freewheeling component disposed in said first branch, and an energy storage capacitor connected in series between said first branch and said second branch; the output side of the first inductor and the input side of the follow current assembly are respectively connected with the first end of the first electronic switch, and the first end of the energy storage capacitor is connected with the output side of the follow current assembly; the second ends of the first electronic switch and the energy storage capacitor are grounded.

6. The switched electronic load of claim 5, wherein said freewheeling component is a second electronic switch;

the first end of the second electronic switch is connected with the first end of the energy storage capacitor, the second end of the second electronic switch is connected with the output side of the first inductor, and the third end of the second electronic switch is connected with the output end of the control circuit.

7. The switched electronic load of claim 5, wherein the freewheeling component is a freewheeling diode;

and the anode of the freewheeling diode is connected with the first end of the energy storage capacitor, and the cathode of the freewheeling diode is connected with the output side of the first inductor.

8. The switched electronic load of claim 5, wherein the inductance value of said first branch is a predetermined fixed value; the sum of the inductances of the first and third inductors is the fixed value.

9. The switched electronic load of claim 8, wherein the inductance value of the third inductor is in the range of 1uH to 10 uH.

10. The switched electronic load of any of claims 1-9, further comprising a DC/AC inverter and an isolation circuit;

the isolation circuit acquires the direct-current voltage output by the booster circuit and transmits the direct-current voltage to the DC/AC inverter, and the DC/AC inverter converts the direct-current voltage into alternating current and outputs the alternating current.

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