JP3183559B2 - AC electronic load device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC electronic load device, and more particularly to an AC electronic load device capable of arbitrarily adjusting load characteristics.

[0002]

2. Description of the Related Art With the development of a wide range of devices from large power devices such as broadcasting equipment to low power devices such as LSIs, optimal power supplies are required for each device, and various DC and AC developed for that purpose are required. Power supply devices are widely used.
In order to test and evaluate the performance of the power supply device itself, a load device that simulates the actual operation state of the device is used. This type of load device is provided with characteristic functions such as current, impedance and power factor with respect to power supplied from a power supply. As a conventional AC load device of this type, a load device including a passive element in which a single-turn sliding transformer is combined with a resistor, a coil, and a capacitor element whose values are fixed in advance corresponding to the power supply, or a transistor. Electronic load devices using semiconductor elements such as FETs have been used.

[0003]

As described above, an AC load device comprising a conventional passive element is provided with a single-turn sliding transformer having a resistance, a coil and a capacitor whose values are fixed and set in advance according to the power supply. It is configured by combining containers. Therefore, the AC load device configured as described above can be used only for the one power supply, and different load characteristics for the one power supply, for example, load impedance and power factor cannot be independently changed, There is a problem with versatility. Further, in the AC load device having the above configuration, there is a problem that the load characteristic changes when the power supply frequency changes, and there is also a problem that operation as a non-linear load is impossible. On the other hand, an AC electronic load device using a semiconductor such as a transistor or an FET has a problem that any load characteristics cannot be obtained when used as an AC load.

An object of the present invention is to provide an AC electronic load device that can change the load characteristics arbitrarily and does not change in the load characteristics with a change in the power supply frequency.

[0005]

In order to solve the above-mentioned problems, an AC electronic load device according to one aspect of the present invention includes a power receiving circuit for receiving an AC power signal from an external power supply, and a terminal voltage of the power receiving circuit. A level detection circuit for generating a DC voltage proportional to the input voltage, a load mode switching circuit for receiving an output of the level detection circuit or a DC voltage as an input signal, and a terminal voltage of the power receiving circuit and an output of the load mode switching circuit. A dividing circuit, a current detecting circuit having means for detecting a current flowing through the power receiving circuit, and changing the detection result by an external signal, a phase shift circuit connected to an output of the current detecting circuit, An error amplifier circuit that compares the output of the divider and the output of the phase shift circuit, and a drive circuit that drives and controls the power receiving circuit according to the output of the error amplifier circuit. Wherein the amplitude of the AC power signal received by the power receiving circuit, and controls the phase, the parameters of the waveform or the like, and the load characteristics with respect to the external power source is configured to be variable. An AC electronic load device according to another aspect of the present invention includes a power receiving circuit that receives an AC power signal from an external power supply, a voltage detecting circuit that detects a terminal voltage of the power receiving circuit, and an output of the voltage detecting circuit. Is connected to a non-linear circuit capable of changing its parameters, a first current detection circuit for detecting a current flowing in the non-linear circuit, and detecting a current flowing in the power receiving circuit,
A second current detection circuit having means for changing the detection result by an external signal; an error amplifier circuit for comparing an output of the first current detection circuit with an output of the second current detection circuit; A driving circuit for driving and controlling the power receiving circuit according to the output of the amplifier circuit, and controlling parameters such as amplitude, phase, and waveform of the AC power signal received by the power receiving circuit, and Is configured to be variable.

[0006]

According to the present invention, versatility is achieved by receiving power supplied from a power supply and arbitrarily adjusting load characteristics relating to the power supply, such as amplitude, phase, waveform, power factor, and linearity. Is expanding.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing one embodiment of an AC electronic load device according to the present invention. The AC electronic load device according to the present embodiment functions as a constant current or constant impedance load for the power supply connected to the terminals 1A and 1B. A power signal received from a power source via terminals 1A and 1B is supplied to a power circuit 2 through a low-pass filter 1 including a coil L and a capacitor C. The power circuit 2
The DC or AC power received via the terminals 1A and 1B is converted into DC power with high efficiency and supplied to the DC power supply 12 to perform a charging operation.

The voltage detection amplifier 4 has input terminals 1A and 1B
Between the input signal voltages. The current flowing into the terminal 1B is supplied to the power circuit 2 via the shunt resistor RS and the low-pass filter 1. The current detection amplifier 8 detects the voltage across the shunt resistor RS and outputs a voltage proportional to the inflow current.

The level detector 5 supplies a DC voltage proportional to the output voltage from the voltage detection amplifier 4 (the voltage between the terminals 1A and 1B) to the input terminal 6A of the selector 6. A fixed value "1" is supplied to the other input terminal 6B of the selector 6, and its output is supplied to one terminal of the divider 7 as a B signal. The output voltage of the voltage detection amplifier 4 is supplied to the other input terminal of the divider 7 as an A signal.
The divider 7 supplies a Y signal obtained by performing an operation of Y = A / B to the input signals A and B to the + input terminal of the adder 10. Further, the output from the current detection amplifier 8 is phase-shifted by θ by a phase shifter 9 that can adjust the phase shift amount θ from the outside, and is supplied to the − input terminal of the adder 10.

[0010] The adder 10 subtracts the output of the phase shifter 9 from the output of the divider 7. The output of the adder 10 is amplified by the error amplifier 11 and supplied to the drive circuit 3. Drive circuit 3
Supplies a predetermined time width pulse signal to the switching elements (transistors) Q1 to Q4 constituting the power circuit 2 so as to be appropriately turned on to output a predetermined voltage between the collector of the transistor Q1 and the emitter of the transistor Q4. ing.

The power circuit 2 includes the four transistors Q
1 to Q4, diodes D1 to D4 connected in parallel between the emitter and the collector of each transistor, and a smoothing capacitor C1 connected between the collector of the transistor Q1 and the emitter of the transistor Q4 to remove ripples and switching components. In the example, it operates to convert AC into DC with high efficiency. A pulse whose duty ratio is determined based on the output of the error amplifier 11 is supplied from the drive circuit 3 to the base of each transistor to control the ON / OFF operation, thereby performing so-called PWM (pulse width modulation) control.

FIG. 2 shows the operation of the power circuit 2 in this embodiment.
This will be described with reference to the waveform timing chart of FIG. Power circuit 2
Operate equivalently as a full-wave rectifier circuit and have resistive input characteristics. Therefore, the output of the voltage detection amplifier 4 and the output of the current detection amplifier 8 have the same phase, and the output signal Δe of the error amplifier 11 has the same voltage waveform as the input signal e1 supplied between the terminals 1A and 1B. Transistor Q
1, Q4, Q2, and Q3 are driven in opposite phases, and are driven by pulse signals eb1, eb4 and eb2, eb3 supplied from the drive circuit 3. When the polarity of the input signal e1 and the polarity of the input current signal to the terminal 1A are both positive, the energy of the power supplied during the period when the transistors Q2 and Q3 are ON is accumulated in the coil L of the low-pass filter 1. You. as a result,
When the transistors Q2 and Q3 are turned off, back electromotive force is generated in the coil L, and the diodes D1 and D4 connected in parallel with the transistors Q1 and Q4 are turned on. The voltage e2 between the emitter of the transistor Q1 and the emitter of the transistor Q3 is
The transistors Q1 to Q4 provide a PWM whose average value matches the average value of the full-wave rectified waveform of the input AC voltage e1.
Obtained as waves.

As described above, the output DC voltage in which the ripple and the pulse component of the PWM wave are smoothed by the capacitor C1 is obtained between the collector of the transistor Q1 and the emitter of the transistor Q4. As a result, if the phase polarities of the voltage signal and the current signal input to the adder 10 are appropriately selected, the following load characteristics can be obtained. FIG.
In, the DC power supply 12 can be arbitrarily installed with a chargeable power supply.

In FIG. 1, when the input terminal 6A of the selector 6 is selected, the output Y of the divider 7 becomes A / B
Therefore, the amplitude reference value is normalized, and a constant Y signal is supplied to the adder 10 irrespective of the output voltage of the voltage detection amplifier 4, resulting in a constant current load characteristic. At this time,
If the amount of phase shift by the phase shifter 9 is changed, the phase between voltage and current can be arbitrarily changed. If the gain of the current detection amplifier 8 is changed by the Z input, the current value as a constant current load can be changed. When the input terminal 6B of the selector 6 is selected, the B signal becomes “1”.
Then, since Y = A, it functions as a constant impedance load for the power supply. Further, by changing the phase shift amount (phase shift change amount) by the phase shifter 9, the load power factor can be arbitrarily changed. At this time, even if the power supply frequency changes, the power factor is kept constant unless the phase shift change amount of the phase shifter 9 changes. Also, the gain of the current detection amplifier 8 is Z
If it is changed by an input, the impedance value as a constant impedance load can be changed.

FIG. 3 is a circuit diagram showing another embodiment of the AC electronic load device according to the present invention, and shows an example of the device operating as a non-linear load. In FIG. 3, components denoted by the same reference numerals as those in FIG. 1 indicate circuit components having the same functions.
In the present embodiment, the output side of the voltage detection amplifier 4 is connected to the current detection amplifier 14 via the full-wave capacitor input type rectifying / smoothing circuit 13. The full-wave capacitor input type rectifier / smoothing circuit 13 includes a rectifier circuit DD composed of a bridge-connected diode, a resistor R2 and a capacitor C connected in parallel to two opposite terminals of the rectifier circuit DD, and a resistor R1.
Functions as a full-wave capacitor input type rectifying smoothing load. The two output terminals of the voltage detection type amplifier 4 have one output terminal connected to another two opposite terminals different from the two opposite terminals of the rectifying / smoothing circuit 13 via a resistor R1. The voltage generated by the inflow current flowing through the resistor R1 is detected by the current detection amplifier 14 and supplied to the + input terminal of the adder 10 as a reference signal. In the configuration of FIG. 3, by changing the values of the capacitor C and the resistor R2 connected to the rectifier circuit DD, distortion such as the crest factor of the current waveform flowing into the terminals 1A and 1B can be adjusted.

In the embodiment shown in FIG. 3, a capacitor-input type full-wave rectifier circuit is used.
Of course, it operates as a non-linear load having a waveform. Although the power circuit 2 in FIGS. 2 and 3 shows a switching operation, the operation may be a linear operation. In this case, the power received from the external power supply is consumed inside the power element. When the power circuit 2 operates linearly, a low-pass filter is not required.

[0017]

As described above, the AC electronic load device according to the present invention receives electric power supplied from a power supply and arbitrarily sets a load characteristic for the power supply with respect to amplitude, phase, waveform, power factor, linearity, and the like. Therefore, the versatility as an electronic load for alternating current is greatly expanded.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of an AC electronic load device according to the present invention.

FIG. 2 is a waveform timing chart for explaining the operation of the embodiment apparatus of FIG. 1;

FIG. 3 is a circuit diagram showing another embodiment of the AC electronic load device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Low-pass filter 2 Power circuit 3 Drive circuit 4 Voltage detection amplifier 5 Level detector 6 Selector 7 Divider 8,14
Current detection amplifier 9 Phase shifter 10 Adder 11 Error amplifier 12 DC power supply 13 Full-wave capacitor input type rectifying and smoothing circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-86073 (JP, A) JP-A-1-100468 (JP, A) JP-A-3-124217 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) H02M ^7/ 00-7/40 G01R 31/00

Claims (2)

(57) [Claims] A power receiving an AC power signal from an external power supply
A receiving circuit for generating a DC voltage proportional to a terminal voltage of the power receiving circuit;
A level detection circuit, and an output or a DC voltage of the level detection circuit as an input signal.
A load mode switching circuit for receiving, a terminal voltage of the power receiving circuit, and a load mode switching circuit.
A dividing circuit having an output of a path as an input , and detecting a current flowing through the power receiving circuit, and detecting the current.
Current detection with means for changing the result by an external signal
Circuit, a phase shift circuit connected to an output of the current detection circuit, and an output of the divider and an output of the phase shift circuit.
An error amplifier circuit, and driving the power receiving circuit in accordance with an output of the error amplifier circuit
A driving circuit for controlling, and a vibration of the AC power signal received by the power receiving circuit.
By controlling parameters such as width, phase, and waveform,
Characterized by variable load characteristics to the source
Electronic load device . 2. An electric power receiving an AC power signal from an external power supply.
A receiving circuit, a voltage detecting circuit for detecting a terminal voltage of the power receiving circuit, and an output of the voltage detecting circuit.
And a first current detecting circuit for detecting a current flowing through the non-linear circuit.
And a current flowing through the power receiving circuit, and detecting the current.
A second power supply having means for changing the result by an external signal;
Current detection circuit, an output of the first current detection circuit, and a second current detection
An error amplifier circuit for comparing the output of the circuit, and driving the power receiving circuit according to the output of the error amplifier circuit
A driving circuit for controlling, and a vibration of the AC power signal received by the power receiving circuit.
By controlling parameters such as width, phase, and waveform,
Characterized by variable load characteristics to the source
Electronic load device.