JPH0612311B2 - Electric inertial compensator for electric dynamometer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric inertia compensator for an electric dynamometer.

(Prior art and problems) Since the exhaust gas of automobiles was regulated for vehicle engines,
As is well known, a test equivalent to that of a human being actually driving is performed to measure transient characteristics during acceleration / deceleration, exhaust gas, and the like. At that time, an electric dynamometer is used as the load device, and so-called "running resistance control" is performed in which the load is applied according to the vehicle speed. The running resistance control is a control method for controlling the electric dynamometer torque as a function of running speed to give a load equivalent to that during running to the vehicle engine. For example, the running resistance torque T on the road of an automobile converted to the engine output shaft is generally lower. Given by the formula.

Inertial resistance torque in the above formula A device that gives a is called an inertia compensator, and a mechanical one using a flywheel has been used in the past, but recently, downsizing of the entire equipment, safety at high speed rotation, easy change of inertia amount, Electrical inertia compensation devices, which are advantageous in terms of price, have come to be adopted.

FIG. 1 is a block connection diagram of a running resistance control device equipped with this electric inertia compensating device. In FIG. 1, 1 is a test engine and 2 is an electric dynamometer, which is directly connected to the test engine 1 and is on the road of an automobile. Give a load equivalent to running. 3 is a pulse pick-up for detecting the rotation speed, 4 is an F / V conversion circuit for converting the rotation speed into a voltage signal, and 5, 6 and 7 are (1) respectively.
A + BN + CN ² + DWsinθ in formula, i.e. a flat road steady running resistance constant A, B, C and the resistance constant setting circuit for setting the uphill slope resistance D · W · sinθ, for detecting acceleration of dN / dt Differentiator circuit and inertia resistance constant Of the setting circuit, 8 is an adding circuit, and the output of the adding circuit is a torque command value. Reference numeral 9 is a load cell that detects the torque of the electric dynamometer 2, 10 is a voltage conversion circuit that converts a torque detection signal into a voltage signal, 11 is a comparison circuit, and 12
Is a thickener for torque control, 13 is a thickener for torque control 12
Of the output current of the variable power supply unit 16 and a load current detection value which is an output of the detector 17 for converting into a voltage signal proportional to the load current of the variable power source unit 16, a reference circuit 14 is a current control amplifier. Is a phase control circuit for shifting the phase of the gate signal, and the variable power supply unit 16 controls the exciting current in the main circuit current region of the electric dynamometer 2. The current control amplifier 14, the phase control circuit 15, the variable power supply unit 16 and the detector 17 form a minor loop circuit.

Now, when the engine 1 is started and the rotation speed is set to N1, the rotation speed N1 is detected by the pulse pick-up 3, the F / V converter 4 converts it into a voltage signal proportional to the rotation speed N1, and the resistance constant setting circuit 5 To the differentiating circuit 6. Since the output of the differentiating circuit 6 is zero when the rotation speed is constant at N1, the output of the resistance constant setting circuit 5 is a voltage signal proportional to the sum of the flat road steady running resistance torque and the uphill / downhill resistance torque. Is added to the comparison circuit 11. At that time, the electric dynamometer 2 has not yet absorbed the power, so that the output of the load cell 9, that is, the output of the voltage conversion circuit 10 is zero, and the output of the resistance constant setting circuit 5 is the travel resistance torque control amplification. Input to the container 12. The output of the amplifier 12 is given to the minor loop circuit as a current command value, and the comparison circuit 13
Then, the deviation value obtained by comparing the current command value with the detection value of the main circuit current detector 7 of the electric dynamometer 2 is used as the current control amplifier 1
4, the phase is increased appropriately, the phase control circuit 15 appropriately shifts the thyristor firing phase of the variable power supply unit 16, the main circuit current of the electric dynamometer 2 is controlled, and the engine rotation speed N1.
The running resistance torque of the car corresponding to is applied to the engine. When the electric dynamometer 2 generates torque, the output of the load cell 9 is applied to the comparison circuit 11 via the voltage conversion circuit 10, and automatic torque control is performed so that the deviation value from the output of the resistance constant setting circuit 5 becomes zero. It

When the rotation speed N1 of the engine 1 is changed to N2, a voltage proportional to the inertial resistance torque generated by the change of the rotation speed is applied to the addition circuit 8 through the differentiation circuit 6 and the inertia constant setting circuit 7 to set the resistance constant. The output of the circuit 5, that is, the sum of the flat road steady running resistance torque corresponding to the rotation speed at that time and the voltage proportional to the uphill / downhill resistance torque is the comparison circuit 1
Since it is added to 1 as a torque command value, electric dynamometer 2
Generates a torque corresponding to the torque command value and the engine 1
The load on the When the rotation speed of the engine 1 becomes N2, the output of the differentiating circuit 6 disappears, and only the rotation speed is different and the control is performed in the same manner as the case of the rotation speed N1.

In the above running resistance control device, the differentiating circuit 6 and the inertial resistance constant setting circuit 7 constitute an electric inertial compensating device, which has many advantages over the mechanical inertial compensating device as described above. Although it has, it has the following drawbacks.

When noise enters the circuit from the pulse pick-up 3 to the differentiating circuit 6, the signal output from the differentiating circuit 6 changes due to the mixed noise and enters the inertia constant setting circuit 7,
Due to the large equivalent inertial amount set by the setting circuit 7, a voltage proportional to a large inertial resistance torque is output. Therefore, the load torque of the engine 1 largely fluctuates irrespective of the rotation speed of the engine 1, and the function as the running resistance control device cannot be fulfilled.
A powerful wave device is built in for noise removal. Therefore, because the control delay due to the wave device is large,
The control loop gain is limited and cannot be too large. Therefore, the control loop gain is the equivalent inertial amount. To grow in proportion to Becomes larger, it becomes unstable. For example, during an equivalence test of a freight car engine, stable running resistance control was possible under empty conditions, but it became unstable under freight-loaded conditions, or the transmission was changed. The vehicle speed by K
When performing the equivalent test of doubling the speed, the equivalent inertial amount is K ²
The control system becomes unstable and the test cannot be continued.

The running resistance control device must follow the change in the rotation speed of the engine 1 without delay to generate a running resistance torque, which is a load of the engine 1, in the electric dynamometer 2. That is, the response characteristic of the control system must be improved, but for that purpose, the gain of the torque control amplifier 12 must be maximized. However, the torque detection circuit is restricted by many delay elements such as the oscillator of the electric dynamometer 2, the load cell 9 and the voltage conversion circuit 10, which are not shown in the figure, and is restricted.
The gain of 2 cannot be increased.

Also, the product of the gain of the torque command circuit, that is, the pulse pick-up 3, the F / V conversion circuit 4, the resistance constant setting circuit 5, the differentiation circuit 6, and the inertia resistance constant setting circuit 7 and the gain of the torque control amplifier 12 A certain control loop gain is large because the inertia compensating circuit gain consisting of the differentiating circuit 6 and the inertia resistance constant setting circuit 7 in the torque command circuit becomes large at the time of a transition in which the rotation speed changes, especially when the equivalent inertial amount is large. It becomes easy to become unstable as mentioned above.

In order to stabilize the unstable control system, it is necessary to reduce the gain of the torque control amplifier 12, but as the gain of the amplifier is reduced, the response characteristic of the entire control system is improved. As a result, the change of the running resistance with respect to the change of the engine speed, that is, the follow-up of the engine load is delayed, and accurate control cannot be performed. Finally, the running resistance control cannot be said.

(Object of the Invention) The present invention has been made in view of the above problems,
An object of the present invention is to provide an electric inertia compensator capable of performing stable running resistance control even if the equivalent inertia amount is large.

(Summary of the Invention) The present invention provides inertia compensation in the above-mentioned equation (1). Based on From rotation speed Then, inertia compensation is performed based on the equation (3) to achieve the above object by the speed control means.

In the above equation, τ is torque and H is a constant.

(Embodiment of the Invention) FIG. 2 is a block connection diagram showing an embodiment of the present invention. In FIG. 2, the same parts as those in FIG.

In the figure, reference numerals 18, 19 and 20 are comparison circuits, 21 is a rotary part inertia constant setting circuit of the electric dynamometer 2, 22 is an integrating circuit, 23 is an inertial resistance constant setting circuit of an automobile converted into an engine output shaft, and 24 is The amplifier for speed control is shown. Resistance constant setting circuit 5 outputs the conventional similar (1) of A + BN + CN ² + DWsinθ That signal proportional to the normal running resistance torque and the engine under test 1 by the differential circuit 6 and the inertia constant setting circuit 21 The torque generated by the rotating part of the electric dynamometer 2 when the rotational speed changes, that is, [However, Outputs a signal proportional to the inertial amount of the rotating portion of the electric dynamometer 2]. The rotating part of the electric dynamometer 2 constitutes a running resistance setting circuit 25 including torque compensation generated by a change in the rotation speed of the engine under test 1 by these 5, 6 and 21. The integrating circuit 22 and the inertial resistance constant setting circuit 23 of the automobile calculate the equation (3) and output a signal proportional to the rotation speed. The second
Reference numerals 2, 3, 4, 20, 24, 13, 14, 1 in the figure
5, 16 constitute a speed control circuit, and reference numerals 9, 10, 2
5, 18, 19, 22, and 23 form a speed command circuit.

When the engine under test 1 is started, the pulse pick-up 3, F
A voltage proportional to the rotation speed is applied to the comparison circuit 20 via the / V conversion circuit 4. Inertial resistance constant setting circuit for automobiles 2
If the output of 3, that is, the speed command value is still zero at the time of activation, the speed control circuit works to suppress the rotation speed to zero, so the electric dynamometer 2 sets the rotation speed of the engine 1 to zero. Generates torque. The torque passes through the load cell 9 and the voltage conversion circuit 10, is converted into a voltage signal proportional to the detected torque, and enters the proportional circuit 18. On the other hand, since the output of the F / V conversion circuit 4 is also supplied to the resistance constant setting circuit 5 and the differentiation circuit 6, a voltage signal proportional to the sum of the flat road steady running resistance torque and the uphill / downhill resistance torque is set as the resistance constant. The output of the circuit 5 is compared with the output of the voltage conversion circuit 10 in the comparison circuit 18, and the rotation speed change at the time of starting is output from the differentiating circuit 6 as a differential value, and the rotating portion of the electric dynamometer 2 The voltage passed through the inertia constant setting circuit 21 is compared with the comparison circuit 19. The voltage proportional to the torque deviation that has passed through the comparison circuit 1819 is integrated by the integration circuit 22, enters the comparison circuit 20 as the speed command value through the inertial resistance constant setting circuit 23 of the automobile, and is output to the output of the F / V conversion circuit 4. The deviation is set to zero. That is, the main circuit current or the exciting current of the electric dynamometer 2 is controlled so as to match the rotating speed of the electric dynamometer 2 with the speed command value. However, since the rotation speed is the rotation speed of the engine 1 which is separately controlled, the main circuit current of the electric dynamometer 2 or the main circuit current of the electric dynamometer 2 is set so that the deviation between the speed command value and the output of the F / V conversion circuit 4 becomes zero. Even if the exciting current is controlled, the rotation speed of the engine 1 does not change, and the load torque on the engine 1 changes. For example, when the rotation speed of the engine 1 is maintained at N1, the electric dynamometer 2 is controlled so that the deviation between the output of the speed command circuit and the output of the F / V conversion circuit 4 becomes zero, and the rotation speed of the engine 1 is increased. A traveling resistance torque equivalent to that when traveling at a vehicle speed corresponding to N1 is applied.

The above is described as the engine running resistance control device,
Of course, it can be applied to the case where the mechanical inertia compensator of the shear dynamometer is replaced with an electric inertia compensator.

(Effect of the invention) Since the circuit for detecting the speed is only the pulse pick-up 3 and the F / V conversion circuit 4 provided in the rotating part of the electric dynamometer 2, there are few delay elements, and the gain of the speed control amplifier 24 is small. Can be made sufficiently large. Although the speed command circuit includes the differentiating circuit 6 as in the conventional example, the inertia constant of the electric dynamometer 2 set by the inertia constant setting circuit 21 is the inertia of the automobile converted to the output shaft of the engine 1. It is much smaller than the resistance constant and does not have a large influence enough to make the control system unstable. As is clear from Eq. (3), the inertial resistance constant of the automobile set by 23 is equal to the gain Since it is inversely proportional to, if the speed control circuit is stable, it will not become unstable even if the signal of the speed command circuit is added.

According to the present invention, electric inertia compensation of an electric dynamometer is performed by integrating a deviation between a set running resistance torque and a generated torque of the electric dynamometer to obtain a speed command value, and running resistance control is performed by a speed control circuit. Since this is performed, it is possible to perform stable running resistance control with good response characteristics even when the equivalent inertial amount is large.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing a conventional running resistance control device equipped with an electric inertia compensator, and FIG. 2 is a block diagram of a running resistance control device equipped with an electric inertia compensator showing an embodiment of the present invention. It is a connection diagram. 1 is a test engine, 2 is an electric dynamometer, 3 is a pulse pick-up, 4 is an F / V conversion circuit, 5 is a resistance constant setting circuit, 9
Is a load cell, 10 is a voltage conversion circuit, 13,18,19,20 are comparison circuits, 14 is a current control amplifier, 15 is a phase control circuit, 16 is a variable power supply section, 22 is an integration circuit, and 23 is an inertial resistance. Constant setting circuit, 24 is speed control amplifier

Claims (1)

[Claims] 1. A speed control circuit of an electric dynamometer, a speed signal proportional to a rotation speed of the electric dynamometer is taken out and used as a feedback signal of the speed control circuit, and a resistance constant which receives the speed signal as an input. A setting circuit is provided, and a torque signal proportional to the torque generated by the electric dynamometer is taken out, the torque signal is compared with the output of the resistance constant setting circuit, the deviation is integrated, and the integrated output is calculated. An electric inertia compensator for an electric dynamometer, characterized in that the speed command signal of the speed control circuit is supplied via an inertia resistance constant setting circuit.