JPH0196570A - Measuring instrument for characteristic constant of load - Google Patents

Abstract

PURPOSE:To measure various characteristic constants of a load circuit which is being operated, in a real time, and also, at a low cost by fetching a sum signal and a difference signal of a load current signal and a load voltage signal through a hybrid transformer, respectively. CONSTITUTION:Voltage signals vi, ve corresponding to a load current and a load voltage, respectively are fetched from a current transformer CT which has been connected in series to a load circuit L and a voltage transformer PT which has been connected in parallel to the load circuit L through a capacitor C. Subsequently, the voltage signals vi, ve are supplied to transformers Ti, Te and hybrid transformers Hs, Hd, their output voltages are rectified by rectifiers Ri, Re and Rs, Rd and a load current and a load voltage, and a DC voltage corresponding to the sum and a difference of them, respectively are fetched, and by performing an arithmetic operation to them, a characteristic impedance of the load circuit L is calculated. In the same way, characteristic constants of the load circuit L such as input power of the load circuit L, an input phase angle of the load circuit L, etc., can be calculated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a load for measuring characteristic constants such as impedance and transmission power of a load circuit such as a transmitting antenna for high-power medium-wave radio broadcasting or short-wave radio broadcasting. The present invention relates to a characteristic constant measuring device, and is particularly capable of measuring characteristic constants in real time while a load driving circuit is in an operating state such as a broadcasting machine is operating.

(Summary of the Invention) The present invention provides a method for measuring load current and load current from a load circuit or a transformer inserted in the load driving circuit in order to measure the characteristic constants of the load circuit while the load driving circuit is in its operating state. Each voltage signal proportional to the voltage is extracted, and these voltage signals are supplied to a hybrid transformer to form a sum signal and a difference signal between the two, and each rectified output DC that rectifies the voltage signal, sum signal, and difference signal, respectively. Based on the signal, load circuit impedance, input phase angle,
The present invention is designed to calculate characteristic constants such as input power, etc., and the present invention enables, for example,
By measuring the operating state of the antenna load during operation of a K-class high-power broadcaster, it can greatly contribute to stable operation, predictive maintenance, etc. of the broadcaster.

(Prior Art) Conventional measuring devices for measuring the characteristic constants, i.e., characteristic impedance, input power, etc. of this type of load circuit or load drive circuit include a CM type wattmeter, a CC type wattmeter, and a three-current needle method. , three-voltmeter method, etc.

A CC type wattmeter applies a current proportional to the load voltage and load current taken out through a capacitor (C) to a thermocouple, respectively, and multiplies the DC output current to determine the load power. In a power meter, a current proportional to the load current is measured by a mutual inductance (
M). In addition, the three current meter method is
3 including the current flowing through the resistor connected in parallel to the load circuit
The load power is calculated from the absolute value of the current vector as the scalar product of the load current vector and the current vector proportional to the load voltage. The load power is calculated from the absolute values of the three voltage vectors as the scalar product of the load voltage vector and the voltage vector proportional to the load current.

(Problems to be Solved by the Invention) However, all of the conventional load characteristic constant measuring devices described above have one of the following problems.

(1) The frequency range in which load characteristic constants can be measured using conventional equipment is narrow.

(2) The level of load power that can be measured using conventional equipment is too low.

(3) Conventional devices are complex, large-scale, and expensive.

(Means for Solving the Problems) An object of the present invention is to solve the above-mentioned conventional problems, and to achieve low It is an object of the present invention to provide a load characteristic constant measuring device capable of measuring load characteristic constants in a wide level range, such as a wide power level range from electric power to high power.

In order to achieve the above-mentioned object, the main point of the present invention is to measure a load characteristic constant using a hybrid transformer, and the use of the hybrid transformer provides the following advantages.

[1] The hybrid transformer is constructed using a ferrite core, and if the material, shape, etc. of the ferrite core are appropriately selected, it becomes possible to measure the load specific constant over a wide frequency range.

[2] In a hybrid transformer, since the isolation between input and output signals can be made sufficiently large, it is possible to measure characteristic constants with high precision without disturbing the operating state of the load circuit or load drive circuit.

[3] Since the hybrid transformer can be easily matched to a low-resistance thermocouple, the thermocouple can be effectively used for measuring load characteristic constants.

That is, the load characteristic constant measuring device of the present invention extracts the sum signal and the difference signal of the load current signal and the load voltage signal through the transformer inserted in the load circuit, respectively, and rectifies them through the hybrid transformer. A characteristic constant of the load circuit is calculated based on an output DC signal.

(Function) Therefore, according to the present invention, for example, even when a high-power broadcaster in the medium wave band or short wave band is operating, the impedance of the antenna load circuit driven by the broadcaster and the high frequency supplied to the antenna load can be adjusted. Power can be measured without disturbing the circuit state, and the frequency range in which load characteristic constants can be measured can be expanded from the number of power frequencies and audio frequency bands +llz to the VHF band, which extends to several hundred Mllz.
Furthermore, the measurable level range of load power can be expanded from IW to, for example, 500 kW.

(Example) The present invention will be described in detail below with reference to the drawings.

First, an example of the basic configuration of the measuring device of the present invention when measuring the impedance of a load circuit is shown in FIG. 1(a).
Shown in (b).

In this case, as shown in the same figure (a), a current transformer CT is connected in series to a load circuit such as an antenna driven by a drive circuit of a broadcaster, etc., and is connected in parallel to the load circuit via a capacitor C. Voltage signals Vi and V corresponding to the load current and load voltage, respectively, are taken out from the voltage transformer PT. Then, as shown in the same figure (b), those voltage signals V and V are connected to a transformer T
, and To and hybrid transformers H6 and H
d as shown in the figure, and the output voltages of these transformers are rectified by rectifiers R1 and Ro and R8 and R4 to obtain a DC voltage lVt In lv corresponding to the load current, load voltage, and their sum and difference, respectively.
e l, Ivt +v, 1.1vt-v, and I are respectively taken out, and the characteristic impedance of the load circuit is calculated by performing calculations as described below on these DC voltages.

Next, an example of the basic configuration of the measuring device of the present invention when measuring the directional coupling characteristics of a load circuit is shown in FIG. 2(a).
, shown in (b).

As shown in FIG. 5(a), voltage signals V and V corresponding to the load current and load voltage, respectively, were extracted in substantially the same manner as in the case of impedance measurement.

As shown in the same figure (b), the hybrid transformer H
, and H4, and the output voltages of these transformers are rectified by rectifiers R3 and R4 to extract DC voltages corresponding to the traveling wave toward the load circuit and the reflected wave from the load circuit, respectively.

Next, an example of the basic configuration of the measuring device of the present invention when measuring the input power of a load circuit is shown in FIG.
Shown in b).

As shown in the same figure (a), the voltage signals V and vo corresponding to the load current and load voltage respectively taken out in the same manner as in each case described above are transferred to the hybrid transformer H1 as shown in the same figure (b). and H4, the output voltages of these transformers are applied to thermocouples TH and THd, and the output DC currents corresponding to the load current and load voltage are connected in series and supplied to the DC ammeter P, and the input power is Give instructions.

Next, an example of the basic configuration of the measuring device of the present invention when measuring the input phase angle of a load circuit is shown in FIGS. 4(a) to 4(c).
).

As shown in the same figure (a), the voltage signals V and v8 corresponding to the load current and load voltage, respectively, taken out in the same manner as in the case of impedance measurement, are transferred to the hybrid transformer H3 as shown in the same figure (b). and H4, and the output voltages of those transformers are supplied to rectifiers R1 and R,
DC voltages lvi+Vsl and lVt corresponding to the sum and difference of the load current and load voltage, respectively, are rectified by
vol is taken out, and the input phase angle of the load circuit is calculated as described later based on the vector relationship shown in FIG.

Next, an example of the overall configuration of the measuring device of the present invention will be described with reference to FIG. 5 in the case of measuring each characteristic constant of the load circuit described above.

In the illustrated overall configuration, the sensor circuit 1 is shown in FIG.
As shown in a), the current transformer CT connected in series with the load circuit and the voltage transformer PT connected in parallel with the load circuit via the capacitor C are proportional to the load current and the load voltage shifted by 90°, respectively. voltage signal V
Take out i and V. Next, in the signal conversion circuit 2, a transformer Tt is installed in exactly the same manner as shown in FIG. 1(b).

T8 and hybrid transformer H,,H, and rectifier R
1. Direct current voltage 1v proportional to the load current and load voltage, and their sum and difference, respectively, is generated by gates R, ,R,,R, and 1. lve 1. lv.

+v01,1v! - Take out ■ and 1, respectively. Then,
The arithmetic circuit 3 performs arithmetic operations on these DC voltages according to the following equations (1) to (4).

, l vtl=a'l I l
(1) lv, 1=blEl (2)
l Vi+Va l =V1"+V@"+2Vi'
V@ ' sin θ (3)l Vi+V* l =
v+"+vaz-2vt 'V meeting' sin θ
(4) Here, ■ is the load current, E is the load terminal voltage,
a and b are current transformer CT and voltage transformer PT
θ is the phase difference between the load current ■ and the load terminal voltage E, and l V! +Val
"lv1-Vvl" = 4 Vi・Va
' sin θ (5).

In the arithmetic circuit 3, the following equations (6) to (13) are calculated from the load current and load voltage expressed by the above equations (1) to (4), and each direct current value proportional to their sum and difference, respectively. Various characteristic constants of the load circuit are calculated respectively.

cos θ=7−ri (8) Resistance: R=IZI cos θ (9
) Reactance: X= l Z 1sin θ
(10) where RO is the specified load impedance.

Next, in the display circuit 4, each characteristic constant of the load circuit calculated as described above is displayed numerically by the arithmetic circuit 3.

Therefore, with the measuring device of the present invention, it is possible to measure and display the characteristic constants of a load circuit such as an antenna without disturbing the operation of the load drive circuit such as a broadcaster while the load drive circuit is in operation. It becomes possible.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following remarkable effects can be achieved.

(1) By using a hybrid transformer, a voltage signal proportional to the load current and load voltage is taken out from the load circuit after a sufficient matching state with sufficient isolation, and based on these voltage signals, the voltage signal proportional to the load current and load voltage is extracted from the load circuit. Various characteristic constants of a circuit can be measured in real time.

(2) Load characteristic constants can be measured at low cost using a simple circuit device that combines a transformer using a ferrite core, a diode, and a thermocouple.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are block diagrams showing basic configuration examples of the measuring device of the present invention when measuring load characteristic impedance, and FIGS. FIGS. 3(a) and 3(b) are block diagrams showing basic configuration examples of the measuring device of the present invention when measuring load power, respectively. Block diagram, Figures 4(a), (b) and (C) are block diagrams and vector diagrams respectively showing basic configuration examples of the measuring device of the present invention when measuring load phase information, and Figure 5 is a vector diagram. FIG. 1 is a block diagram showing an example of the overall configuration of the load characteristic constant measuring device of the present invention. 1...Sensor circuit 2...Signal conversion circuit 3.
...Arithmetic circuit 4...Display circuit L...Load circuit D...Load drive circuit CT...Current transformer PT...Voltage transformer TiT,...Transformer Hs, Hd...Hybrid transformer R4+ Rta
+ L + Rd ”' Rectifier TH-, THd・
... Thermocouple P... DC wattmeter (a) 1, b (b) Fig. 3 (b) Fig. 4 Signal phase angle measurement supination fa) 1 ga Fe1l "Sear Met" Fig. 5

Claims (1)

[Claims] 1. A sum signal and a difference signal between a load current signal and a load voltage signal taken out through a transformer inserted in a load circuit are taken out through a hybrid transformer and rectified, and each rectified output DC signal is A load characteristic constant measuring device, characterized in that the characteristic constant of the load circuit is calculated based on. 2. The impedance of the load circuit is calculated based on each rectified output DC signal obtained by rectifying the load current signal, the load voltage signal, the sum signal, and the difference signal, respectively. A load characteristic constant measuring device according to claim 1. 3. The input phase angle of the load circuit is calculated based on each rectified output DC signal obtained by rectifying the sum signal and the difference signal, respectively. load characteristic constant measuring device. 4. The input power of the load circuit is calculated based on each output thermal current obtained by supplying the sum signal and the difference signal to thermocouples, respectively. The load characteristic constant measuring device described. 5. A patent characterized in that a traveling wave component to the load circuit and a reflected wave component from the load circuit are obtained from each rectified output DC signal obtained by rectifying the sum signal and the difference signal, respectively. A load characteristic constant measuring device according to claim 1.