JPH0141945B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an equivalent load test method and apparatus for a non-commutator motor device (hereinafter referred to as a thyristor motor device) which is a combination of an electric motor and a thyristor power conversion device.

Conventionally, when shipping a thyristor motor device after manufacture, the electric motor and thyristor power conversion device (hereinafter simply referred to as the conversion device) are individually tested, and then the characteristics of the thyristor motor device are tested by combining them. It is common to do so. Recently, due to an increase in the production results of thyristor motor devices, advances in design and manufacturing technology, and advances in characteristic analysis calculations using large-scale electronic computers and simulation calculation technology for operating conditions, the results obtained from design calculation values and individual individual tests have increased. It is becoming possible to understand the main characteristics in a combination state using the characteristic values obtained. However, it is difficult to analyze the increase in stray load loss, increase in temperature rise, increase in mechanical vibration and electromagnetic noise due to the square wave current in the motor body, and it is difficult to analyze the increase in stray load loss, increase in temperature rise, increase in mechanical vibration and electromagnetic noise, etc. It is necessary to run a confirmation test. For this reason, conventionally, as shown in Figure 1, the electric motor THM is directly connected mechanically to a load generator G having a capacity commensurate with its output, and the output of the generator G is converted into a By consuming power with a load device such as a resistor LRH,
We are conducting a so-called combined actual load test, which places an actual load on the electric motor THM and converter THY, and examines the overall characteristics of the combination, temperature rise based on square wave current, vibration, and noise.

Therefore, when conducting the test, as mentioned above, a load generator, load device, and power supply device that match the output and rotational speed of the thyristor motor device are required. As the capacity increases, the cost required for such devices increases, and the power consumption for testing also becomes extremely large. Furthermore, with the diversification of thyristor motor devices, the number of vertical shaft electric motors is increasing, but it is difficult to actually connect a load generator directly to these, so it is not possible to conduct sufficient tests. Can not.

The present invention was made in view of the above-mentioned circumstances, and its purpose is basically to eliminate the need for a load generator and a load device, and to combine only a thyristor motor device or a simpler conversion device. An object of the present invention is to provide an equivalent load test method and device for a commutatorless motor device, which can realize a test equivalent to an actual load state by allowing an actual square wave current to flow through the motor in a combined state.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows an example of a schematic configuration of an equivalent load test of a thyristor motor device according to the present invention. 1 is a motor to be tested of a thyristor motor device, 1a is its armature winding, and 1b is a field winding. It is a line. 2 is an excitation DC power source equipped with voltage adjustment means for supplying power to the field winding; 3 is a thyristor inversion device for a thyristor motor device consisting of bridge-connected thyristors; the input side thereof is connected to a DC reactor 4; It is connected to the main circuit DC power supply 5 through the main circuit. Here, the main circuit DC power supply 5 is equipped with voltage adjustment means. Further, 3a is a phase control circuit that controls the firing phase of the thyristor motor of the inverse converter 3, which controls the reference voltage obtained from the speed control reference voltage setter (hereinafter referred to as speed reference device) SRH and the motor 1. Speed detector 6 directly connected to
The firing phase of the thyristor is determined based on the signal obtained by comparing the signal obtained by the output voltage with the output voltage converted by the circuit 3b which converts the signal into the speed feedback signal voltage, and the firing phase of the thyristor is determined according to the signal from the position detector 7 directly connected to the motor. The thyristors are configured to fire in sequence. In addition,
Although not shown in FIG. 2, various instruments necessary for measuring the amount of electricity, temperature, rotational speed, vibration noise, etc. of each part are appropriately arranged.

Next, an equivalent load test method for an apparatus having such a configuration will be described. Although circuit elements related to starting the thyristor motor are omitted in FIG. 2, for example, the DC power source can be turned on by a small starting motor or in accordance with the commutation timing of the thyristor of the inverter 3. By using conventional methods such as so-called intermittent starting to turn off the current, at least the current in the thyristor of the inverter 3 can be commutated using the back electromotive force induced in the armature winding 1a of the motor (usually at a speed that 5 of base velocity
~10% speed) or higher.

Generally, it is known that the characteristics of the electric motor of a thyristor motor device are expressed by the following approximate expression.

ω=V/Kφcosβ… VaV/cosβ… I=T/Kφcosβ… Here, ω…Rotational speed of the motor T…Rotational force K of the motor… 〃 constant φ… 〃 Air gap magnetic flux Va… 〃 terminal voltage (fundamental wave ) Line current of I... 〃 ( ) V... Equivalent sine wave voltage of power supply = V _dc ×π/3√6 V _dc ... DC power supply voltage β... Commutation lead angle From the above characteristic formula, commutation lead angle β If you increase , the motor speed ω increases even if the power supply voltage is kept constant, and from the equation, the motor terminal voltage increases.
The power supply voltage V (V _dc ) may be smaller than V _a ,
It can be seen from the formula that a large current I is required to obtain a small rotational force T.

As shown in Fig. 2, when the electric motor 1 is operated independently with no load, the rotational force generated by the electric motor is
It is sufficient to supply only a portion of the frictional windage loss and iron loss of the electric motor itself, which is approximately a few percent of the rated torque. Therefore, from the formula, in order to make the line current close to the rated current of the motor, the commutation lead angle β should be around 85° to 90°, and in this case, the terminal voltage of the motor
Even if V _a is set to the rated value, the power supply voltage V (V _dc ), including the resistance drop of the DC reactor 4 and the line, is the power supply required at a normal commutation advance angle (approximately 40° to 60°). It can be seen that a range of several percent to 10% of the voltage is sufficient.

The relationship between the voltage and current of the motor in the above state is as shown in Figure 3, and from the point where the two phase potentials of the motor e _{u e} are the same (30° to e _u ),
Commutation starts at the point where β (≒90°) has advanced.
An instantaneous trapezoidal waveform line current i _u flowing at 120° is flowing through the weight angle u, and the fundamental wave component of the current i _u is
As shown by the dotted line, I _u leads the phase voltage e _u by approximately 90°. In other words, this state corresponds to reactive power operation with a leading power factor of approximately zero (0) in a normal synchronous motor. However, since only active power can be supplied from a DC power source, it can be seen that the DC voltage may be low.

As is clear from the above explanation, armature winding 1a
When the output voltage of the DC power supply 5 is gradually decreased while adjusting the voltage of the excitation DC power supply 2 to keep the terminal voltage at a predetermined value, the phase control circuit 3a is used to keep the rotation speed constant at a predetermined rotation speed. Accordingly, the commutation advance angle β is automatically advanced, and the line current is increased accordingly. In this way, it is not only possible to flow the rated current at the rated voltage state of the motor, but also to freely realize any speed, voltage, and current state.

As mentioned earlier, the stray load loss, which is the first objective of testing a thyristor motor device as an electric motor, can be measured in advance by changing the line current at several points or more and measuring the input to the motor, and from the increase. It can be determined by subtracting the copper loss from the winding resistance and current. This stray load loss includes low resistance loss due to the current flowing through the damper due to commutation, and fluctuations in the air gap magnetic field due to the product of each harmonic current included in the square wave current flowing through the armature winding and the transient impedance. However, it is theoretically clear that the magnitude of these losses is almost determined by the magnitude of the armature current, and this test method and the current waveform during operation as a thyristor motor are almost equal, so it can be said that the degree of approximation of measurement by this test method is quite high.

In addition, since this test measures only the loss, the measurement accuracy is higher than that of a measurement method that separates small losses from measurements of large effective outputs (power), such as during actual load tests.

As for the second objective, temperature rise, it is generally accepted that the rated speed of the armature winding can be made almost equivalent to that during thyristor motor operation by conducting a temperature rise test with the rated current flowing. This is clear from the temperature rise test using the zero power factor method of a synchronous machine. Regarding the field winding, it was mentioned earlier that in this test method, the commutation lead angle β is approximately 90 degrees, but the demagnetizing force of the armature reaction due to this lead current is equal to that during normal thyristor motor operation. The commutation advance angle (β≒40°~60°) is sin90°: sin (60°~
40°)=1:(0.866 to 0.643), that is, about 15 to 35% larger, so the excitation current also becomes larger. Therefore, as with the zero power factor method for ordinary synchronous machines, the armature voltage V _a is lowered than the rated value and the armature current and field current are set to the rated values, but the difference in temperature rise of each winding at this time is Very little,
It is well known that the actual load condition can be sufficiently approximated.

The third purpose is to check the vibration and noise of the motor body due to torque pulsation based on square wave current.The magnitude of torque pulsation is calculated when the armature current, exciting current _F , and commutation advance angle β are , is known to be approximately proportional to × _F sinβ, but in this test method, β≒90, so sin90°/sinβ=
The value becomes larger by 1/sinβ. Therefore, either armature current or field current _F (or their product)
is reduced by sinβ to obtain torque pulsation equivalent to the actual load condition, and the vibration and noise of each part are measured. In reality, the current is corrected using an exact solution for torque pulsation.

Finally, for the commutation overlap angle u as a thyristor motor, the commutation margin angle (β-u) is an important amount for operational stability, and accurate estimation of the value is necessary. Using the measured value of u by this test _method and the commutation reactance
From the relationship cosβ=21 _DC・X _c /√6Va, the overlap angle u under actual load can be found, where I _DC
is the DC current flowing through the DC reactor 4.

Although it was not explained above, the direct current voltage V _DC
If is made sufficiently large, the commutation advance angle β can be made sufficiently small (β≒15 to 30), and the current will also be reduced accordingly, making it possible to achieve a state similar to that of a general synchronous machine, making it possible to measure iron loss and mechanical loss. It is. Needless to say, iron loss and mechanical loss may be measured by directly connecting other small capacity electric motors.

FIG. 4 shows the configuration of a second embodiment of an equivalent load test according to the present invention, in which a function for an equivalent load test device is added to a conventional thyristor motor device. In FIG. 4, parts that are the same as those in FIG. 2 are given the same reference numerals, and their explanation will be omitted, and only the different parts will be described here. In the figure, numeral 5 represents a thyristor conversion device for the DC power source, which is always provided in a normal thyristor motor system. 5a is a phase control circuit for the thyristor of the forward converter 5, and 5b is a speed control circuit. Further, 2 is a thyristor conversion device of the excitation power source, and 2a is a phase control circuit thereof. 3a is the inverse conversion device 3 as mentioned above.
This is a phase control circuit, and its configuration includes a circuit 3a _-1 that determines the device commutation advance angle β and generates an ignition pulse, and a circuit _3a that detects the overlap angle u and the actual voltage and current phase. _-2 , margin angle (β-u=)γ
It consists of circuit 3 _a-3 that sets Furthermore, in the part of circuit 3 _a-3 that sets the margin angle γ, the reference voltage e _i for the margin angle γ during normal thyristor motor operation and the reference voltage for the margin angle γ during the equivalent load test are used. A circuit is provided to generate e _p , respectively.
These can be selected and switched using a switch S.

In the device configured as described above, during normal thyristor motor operation, the switch S is switched to the reference voltage _{e i} side, a margin angle γ corresponding to the reference voltage e i is set in circuit 3 _a-3 , and circuit 3 _a-1 At circuit 3 _a-2
The commutation advance angle β is determined by adding the overlap angle u detected in the circuit 3 _a-1 , and the firing phase of the thyristor of the inverter 3 is controlled. In addition, when performing an equivalent load test device, the changeover switch S is switched to the voltage e _p side and the commutation advance angle β is determined in the same way, but in this case β should be close to 90° and fine adjustment should be made. The reference voltage e _p is made adjustable so that it is possible to do so.

In this way, in this configuration, since the commutation advance angle β is determined with priority, the rotational speed in each circuit 5a and 5b is determined by the speed standard according to the above-mentioned characteristic formula.
The firing phase of the thyristor of the forward converter 5 is changed to control the DC voltage V _dc so as to maintain the SRH at the set value, and as a result, the line current increases or decreases. On the other hand, in the circuit 2a, the speed signal obtained from the circuit 3b and the feedback signal of the armature voltage are used to control the excitation power supply thyristor converter 2 so as to maintain a predetermined relationship between the rotational speed and the armature voltage. Phase is controlled. Note that during the equivalent load test, a regulator VR may be provided so that the relationship between rotational speed and armature voltage can be adjusted.

As mentioned above, this configuration is equipped with a setting circuit for increasing the commutation margin angle γ in the conventional thyristor motor device, so that the commutation advance angle β can be adjusted to around 90°, and the motor can be used as a single motor. It is clear that it is possible to conduct an equivalent load test in the same way as the one described above by making it possible to flow a square wave current equivalent to that in the actual load state.

In this way, the electric motor 1 and the thyristor converter 3
When carrying out a load test on a non-commutated motor device consisting of a combination of The commutation advance angle β of the thyristor inverter 3 that supplies power to the line 1a is advanced to around 90° (electrical angle), which is much greater than that during normal thyristor motor operation, so that the motor power factor becomes approximately zero, and the electric motor The input/output characteristics of the motor 1 are determined by increasing the child current and using the field current and armature current of the motor 1 under test as the main parameters.
This is done by measuring temperature rise, vibration noise, etc., and estimating various characteristics of the commutatorless motor device under actual load conditions from the measured values.

Therefore, according to this equivalent load test method, the following effects can be obtained.

(1) Unlike conventional methods, a load generator and load device are not required. Therefore, any rating (rotation speed,
output voltage).

(2) During testing, it is only necessary to supply power for the amount of loss, so testing power can be significantly saved.

(3) Vertical shaft machines that cannot be connected to a load generator can also be tested.

(4) The inverter 3 needs to be compatible with the terminal voltage and line current of the motor 1 , but since the DC power supply voltage only needs to be a few percent to 10% of the rated voltage, conventional DC machine tests are not possible. DC power supply can be used for. In addition, even if new equipment is installed, a few percent of the rating of the thyristor motor device will be used.
~10%, which is good and extremely cheap.

(5) In the second embodiment, since a conversion device manufactured as a product is used, only a power source needs to be prepared. Furthermore, with such a configuration, it is not necessarily necessary to perform the combination at the manufacturing factory, and it is possible to carry out the adjustment operation after installing the motor at the final use site and before directly connecting it to the load machine. It becomes possible to significantly shorten the construction period.

Note that the present invention is not limited to the above embodiments.

In the above description, the speed detector 6 and the position detector 7 are separated, but it is also possible to obtain the speed signal from the signal of the position detector 7. In addition, in this test method, the commutation advance angle β
is very large, around 90°, and the voltage for commutation (reverse voltage applied to the thyristor immediately after commutation) is large.
The weight angle u is sufficiently small, and the margin angle γ is sufficiently large.
Therefore, the inverter 3 and the armature winding 1a of the motor
Even if a transformer is interposed between the transformer and the transformer, the leakage reactance of the transformer will only slightly increase the commutation margin angle. Nothing is different. On the other hand, by interposing this transformer, the voltage of the motor 1 and the voltage of the inverter 3 can be made different, and an inexpensive inverter can be used without preparing an expensive high voltage inverter. It becomes possible to test high voltage motors. Furthermore, by providing intermediate taps in the transformer windings and using several types of transformers with different transformation ratios,
It becomes possible to test motors with various voltages.

In addition, the present invention can be modified and implemented in various ways without changing the gist thereof.

As explained above, according to the present invention, there is basically no need for a load generator or a load device, and the electric motor can be actually operated by combining only the thyristor motor device or by combining it with a simpler converter. It is possible to provide a highly reliable equivalent load test method and apparatus for a commutatorless motor device, which allows a square wave current to flow and realizes a test equivalent to an actual load state.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an outline of an actual load test of a conventional thyristor motor device, Fig. 2 is a diagram showing an example of an equivalent load test according to the present invention, and Fig. 3 is a diagram showing the relationship between voltage and current of a thyristor motor. FIG. 4 is a diagram showing another embodiment of the equivalent load test according to the present invention. 1 ...Electric motor for thyristor motor device, 2...
Excitation power supply, 3... Reverse conversion device for thyristor motor device, 4... DC reactor for thyristor motor device, 5... Forward conversion device or DC power supply for thyristor motor device, 6... Rotation speed meter, 7
...Position detector. Subscripts a, b... indicate the parts of each of the above elements.

Claims (1)

[Scope of Claims] 1. When carrying out a load test on a non-commutated motor device comprising a combination of an electric motor and a thyristor power conversion device, the motor under test is operated in a state where the shaft output of the motor under test is zero or approximately zero. The commutation advance angle β of the thyristor inversion device that supplies power to the armature winding of the motor is advanced to around 90° (electrical angle), the motor power factor is brought to approximately zero, and the armature current is increased to perform operation, The input/output characteristics, temperature rise, vibration noise, etc. of the motor are measured using the field current and armature current of the motor under test as the main parameters, and the various characteristics of the non-commutated motor device under actual load are determined from the measured values. An equivalent load test method for commutatorless motor equipment that estimates . 2. In a non-commutator motor device consisting of a combination of a motor and forward and reverse thyristor power converters, a thyristor converter that supplies power to the motor under test, a speed feedback signal of the motor and its armature voltage a first phase control circuit that controls the phase of the thyristor converter based on a feedback signal; and a first phase control circuit that controls the phase of the thyristor forward power conversion device based on a speed control signal obtained from a speed reference signal and the speed feedback signal. The second phase control circuit generates a reference voltage for the margin angle during normal operation and a reference voltage for the margin angle at which the commutation advance angle during the equivalent load test is approximately 90° (electrical angle). A margin angle setting section which has a circuit to switch and set a margin angle commensurate with the reference voltage; an overlap angle detection section which detects an overlap angle from the phase of the armature voltage and current of the motor; and the margin angle setting section. The commutation lead angle setting part determines the commutation lead angle from the overlap angle which determines the commutation lead angle from the margin angle set by the overlap angle detected by the overlap angle detection part. An equivalent load test device for a non-commutator motor device, comprising: a third phase control circuit that controls the phase of the thyristor inverse power conversion device based on a lead angle. 3. The commutatorless motor device according to claim 2, wherein the thyristor reverse power conversion device side is made to match the rated voltage and current of the motor, and the voltage on the thyristor forward power conversion side is reduced. Equivalent load test equipment. 4. An equivalent load test device for a commutatorless motor device according to claim 2, wherein a transformer is interposed between the thyristor inversion device and the motor.