阅读说明：本技术 用于开环控制和闭环控制具有发电机和异步机的内燃机的方法、开环控制和闭环控制机构以及内燃机 (Method for open-loop and closed-loop control of an internal combustion engine having a generator and an asynchronous machine, open-loop and closed-loop control device and internal combustion engine ) 是由 S.黑克尔 H.魏斯 于 2019-01-11 设计创作，主要内容包括：用于开环控制和闭环控制内燃机(BK)、尤其柴油马达或燃气马达的方法,所述内燃机具有发电机(G)和异步机(ASM),所述方法包括：探测所述发电机的至少一个电的特征参量,其中,所述电的特征参量从电流(I)、电压(U)或频率(f)中选出；确定所述发电机的电的特征参量在预先确定的时间间隔内的特征参量变化；将所述特征参量变化与第一边界值进行比较；并且对于所述特征参量变化大于所述第一边界值的情况,从所述内燃机的标准转速调节变换到前馈控制。(Method for open-loop and closed-loop control of an internal combustion engine (BK), in particular a diesel or gas motor, having a generator (G) and an asynchronous machine (ASM), comprising: detecting at least one electrical characteristic of the generator, wherein the electrical characteristic is selected from the group consisting of current (I), voltage (U) and frequency (f); determining a change in a characteristic variable of the electrical characteristic of the generator within a predetermined time interval; comparing the characteristic parameter change with a first boundary value; and for the case where the characteristic quantity change is larger than the first boundary value, a shift is made from a standard rotational speed adjustment of the internal combustion engine to a feed-forward control.)

1. Method for open-loop and closed-loop control of an internal combustion engine, in particular a diesel or gas engine, having a generator and an asynchronous machine, comprising

Detecting at least one electrical characteristic of the generator, wherein the electrical characteristic is selected from current, voltage or frequency,

determining a change in a characteristic variable of the electricity of the generator within a predetermined time interval,

-comparing the characteristic parameter change with a first boundary value,

-switching from a standard speed regulation of the internal combustion engine to a feed-forward control for a situation in which the characteristic variable change is greater than the first boundary value.

2. The method according to claim 1, in which method the feed-forward control comprises determining a matching theoretical injection quantity based on a measure of the characteristic variable change.

3. The method according to claim 2, wherein the larger the characteristic variable is, the larger the adapted theoretical injection quantity is.

4. Method according to one of claims 2 or 3, in which method the matched theoretical injection quantity is determined taking into account a measured maximum starting current of the asynchronous machine.

5. The method according to any of the preceding claims, further comprising

-a re-determination of the change of the characteristic quantity,

-comparing the characteristic variable change with a second boundary value, which is smaller than the first boundary value,

for the case where the characteristic variable change is smaller than the second limit value, a change is made from the feed-forward control back to the standard rotational speed regulation.

6. Method according to any one of the preceding claims, in which method the standard rotational speed adjustment comprises a continuous determination of a standard theoretical injection quantity based on a comparison between a theoretical rotational speed and an actual rotational speed of the internal combustion engine.

7. Open-loop control and closed-loop control mechanism for an internal combustion engine having a generator and an asynchronous machine, characterized in that the open-loop control and closed-loop control mechanism is configured to perform the method according to any one of claims 1 to 6.

8. An open-loop and closed-loop control mechanism according to claim 7, comprising a rotational speed regulator and a plant controller, wherein the rotational speed regulator is configured to perform the standard rotational speed regulation and the plant controller is configured to perform a feed-forward control, and the open-loop and closed-loop control mechanism is configured to cause a shift from dominance of the rotational speed regulator to dominance of the plant controller for a condition in which a characteristic parameter deviation or the characteristic parameter change is greater than the first boundary value.

9. Internal combustion engine, in particular diesel or gas motor, with a generator and an asynchronous machine, comprising an open-loop and closed-loop control mechanism according to any of claims 7 or 8.

Technical Field

The invention relates to a method for open-loop and closed-loop control of an internal combustion engine having a generator and an asynchronous machine, to an open-loop and closed-loop control mechanism for an internal combustion engine having a generator and an asynchronous machine, and to an internal combustion engine having a generator and an asynchronous machine.

Background

In projects and in the operation of internal combustion engines with generators, such as internal combustion motors, asynchronous machines are frequently used as load motors for different applications, for example as drive machines for fans, pumps and lifting devices. An asynchronous motor is one of the most widely produced electrical machines, since it can be produced simply and cost-effectively. Depending on the design, a high starting current of up to eight times the rated current occurs when the asynchronous machine is switched on. The high starting current causes a short-term power overshoot. In this case, for example, the rotational speed of an internal combustion motor with a synchronous generator is significantly disturbed (bricht … ein). The rotational speed regulation of the internal combustion motor must then react to the disturbance. There are already components on the market for drive technology which minimize this problem of high starting currents, as for example star delta start, soft start and frequency converters are to be mentioned. The most commonly used method is star-delta connection. In the case of a start with a star connection, the power and the torque are reduced to approximately one third. After the preparation time (Hochlaufzeit), the switching to delta operation is carried out by the commutation control (Umsteuerung) of the contactor. The frequency converter can be configured or programmed to operate the asynchronous motor (hochfahren) smoothly and load-matched at high speed. In safety-relevant applications, however, it is desirable, as before, to start the asynchronous motor directly in order to achieve a lower probability of failure by means of a smaller number of components and to save as far as possible expensive power-electronic components. At the same time, disturbances in the rotational speed of the combustion motor should be avoided.

Disclosure of Invention

According to a first aspect of the invention, the object is achieved by a method for open-loop and closed-loop control of an internal combustion engine, in particular a diesel or gas engine, having a generator and an asynchronous machine, comprising

Detecting at least one electrical characteristic of the generator, wherein the electrical characteristic is selected from current, voltage or frequency,

determining a change in a characteristic variable of the electricity of the generator within a predetermined time interval,

-comparing the characteristic parameter change with a first boundary value,

-switching from a standard speed regulation of the internal combustion engine to a feed-forward control for a change of the characteristic variable greater than a first boundary value.

The invention includes the recognition that by detecting the first current pulse in the case of an asynchronous machine start-up and by subsequently switching from a standardized (standard ä beta/igen) speed regulation to a feed-forward control, the start-up process of an asynchronous machine can be achieved by the internal combustion engine without first causing a disturbance in the speed of the internal combustion engine. By means of the feed-forward control, additional power-electronic components are not used and a direct start of the asynchronous machine is possible. That is to say, the load access (lastaufschaltsung) can be reacted predictively and it is not necessary to wait for a rotational speed disturbance before the countermeasures are introduced. In the case of a conventional load connection, a torque is applied (aufgepr ä gt) by the electrical load. By means of this torque, the combustion motor is braked and thus a disturbance of the combustion motor in its rotational speed occurs. Load access can now be reliably identified and countermeasures introduced. For this purpose, depending on the rotational speed disturbance, the fuel quantity is increased and an attempt is made to accelerate the motor again to the preset setpoint rotational speed.

Due to this state of the art of speed regulation, it is necessary in the prior art to wait for the overall system response of the internal combustion engine generator. The countermeasures can only be initiated after the rotational speed disturbance. By means of the method according to the invention, such waiting is not necessary, and by detecting the first current pulse via a change in the characteristic variable within a predetermined time interval, the load connection can be precisely identified and an immediate countermeasure can be initiated by the feed-forward control. Thereby, the load switching capability of the overall system (Lastschaltf ä highkey) can be improved. Furthermore, by means of the invention, sharp rotational speed fluctuations can be avoided. In addition, greater loads can be switched in while observing the limit values. Furthermore, by a fast prediction of the load, the assembly does not have to be so severely over-dimensioned. This results in cost savings and also in a smaller installation space. The assembly also operates in a better operating range due to the higher loading.

Advantageous refinements of the process are described below. Additional features of the embodiments can be combined with each other to form further refinements, unless the features are explicitly described in the description as alternatives with respect to each other.

Preferably, the feed forward control includes a determination of a matched theoretical injection amount. The matched theoretical injection quantity can be selected from the stored theoretical injection quantities. Preferably, the matched theoretical injection quantity is determined on the basis of the scale of the change of the characteristic variable (Ma β). The measurement of the characteristic variable enables, for example, a predictive algorithm to be used to estimate the rated power of the asynchronous machine, i.e., the load. With this information, the forthcoming load for the internal combustion engine can then be evaluated and a matching setpoint injection quantity can be determined. By means of the adapted setpoint injection quantity, the rotational speed control of the internal combustion engine can be optimized. The characteristic change can be determined as a gradient of the characteristic curve over time.

In this case, it is preferable for the matched theoretical injection quantity to be greater the change in the characteristic variable. Furthermore, the matched setpoint injection quantity is advantageously determined taking into account the measured maximum starting current of the asynchronous machine. The maximum starting current enables a further improved evaluation of the rated power of the asynchronous machine and thus an improved starting behavior of the overall system consisting of internal combustion engine, generator and asynchronous machine. Furthermore, the feed-forward control can provide additional measures for improving the load switching capability, such as for example a short-term voltage drop at the generator.

Advantageously, the method further comprises:

-a re-determination of the change of the characteristic quantity,

-comparing the characteristic variable variation with a second boundary value, which is smaller than the first boundary value,

for a change of the characteristic variable which is smaller than the second limit value, a change from the feed-forward control back to the standard rotational speed regulation is effected.

By means of these additional steps, it is determined, on the one hand, whether the start-up phase of the asynchronous machine has ended, by checking whether the characteristic variable has fallen to a correspondingly small level below the second limit value, and, on the other hand, if this is the case, the standard rotational speed control is activated again. If the characteristic value change continues to be greater than the second limit value, the feed-forward control remains active.

The standard rotational speed regulation comprises, in a further development, a continuous determination of a standard theoretical injection quantity based on a comparison between a theoretical rotational speed and an actual rotational speed of the internal combustion engine.

According to a second aspect, the invention relates to an open-loop control and closed-loop control mechanism for an internal combustion engine having a generator and an asynchronous machine, configured to perform the method according to the first aspect of the invention.

It is particularly preferred that the open-loop and closed-loop control means comprise a speed regulator and a machine controller, wherein the speed regulator is configured to carry out a standard speed regulation and the machine controller is configured to carry out a feed-forward control, and the open-loop and closed-loop control means are configured to cause a changeover from a dominance (sometimes called dominance) of the speed regulator to a dominance of the machine controller for the case in which the characteristic deviation or the characteristic change is greater than a first boundary value.

According to a third aspect, the invention relates to an internal combustion engine, in particular a diesel or gas motor, having a generator and an asynchronous machine, comprising an open-loop and a closed-loop control mechanism according to the second aspect of the invention.

The open-loop and closed-loop control mechanism according to the second aspect and the internal combustion engine with the generator and the asynchronous machine share the advantages of the method for open-loop and closed-loop control according to the first aspect of the invention.

Drawings

Embodiments of the invention are now described below with the aid of the figures. The figures should not necessarily present embodiments to scale, rather the figures in which the useful explanation is set forth in schematic and/or slightly distorted (verzerorrter) form. With regard to the supplements to the teachings that can be directly seen from the figures, reference is made to the relevant prior art. It is contemplated that various modifications and changes in form and detail could be made to the embodiments without departing from the general concept of the invention. The features of the invention disclosed in the description, in the drawing and in the claims can be essential for the development of the invention both individually and in any combination. Furthermore, all combinations of at least two of the features disclosed in the description, the drawings and/or the claims fall within the scope of the invention. The general idea of the invention is not limited to the precise forms or details of preferred embodiments shown and described below or to subject matter which is limited compared to subject matter claimed in the claims. In the measurement range specified, values within the mentioned limits should also be disclosed as limit values and can be used and requested as desired. For the sake of simplicity, the same reference numerals are used below for identical or similar components or components having identical or similar functions.

Further advantages, features and details of the invention emerge from the following description of preferred embodiments and with the aid of the drawings; the attached drawings are as follows:

fig. 1 shows a schematic representation of an exemplary course of the starting current of an asynchronous machine with respect to time;

an embodiment of an open-loop control and closed-loop control mechanism according to a second aspect of the invention is shown in a schematic diagram in fig. 2;

fig. 3 shows a schematic illustration of an exemplary embodiment of an internal combustion engine having a generator and an asynchronous machine according to a third aspect of the invention;

fig. 4 shows a schematic diagram of a method for open-loop and closed-loop control of an internal combustion engine having a generator and an asynchronous machine.

Detailed Description

Fig. 1 shows an exemplary course of the starting current of an asynchronous machine over time. In this case, the starting current I first rises sharply to a maximum starting current I_maxAnd then falls to operating level I_BThe asynchronous machine operates on the operating level after the start-up phase. The steep rise of the current profile at the beginning of the start phase is expressed as a gradient di/dt, i.e. a characteristic variable change over a certain time interval. According to the invention, the increase is detected as an electrical characteristic variable change, and a change from a standard rotational speed control of the internal combustion engine connected to the asynchronous machine to a feed-forward control is carried out as long as the characteristic variable change is above a first limit value. In this case, a setpoint injection quantity for the internal combustion engine is determined within the scope of the feed-forward control. This can be done from a predetermined value or on the basis of the scale of the change of the characteristic variable. In addition to the current, the voltage and the frequency are also considered as electrical characteristic variables.

Fig. 2 shows in a schematic representation an exemplary embodiment of an open-loop and closed-loop control mechanism SR for an internal combustion engine BK having a generator and an asynchronous machine, which includes a rotational speed regulator nR and a plant controller AS. The rotational speed regulator nR is designed to carry out a standard rotational speed regulation, which includes a continuous determination of a standard theoretical injection quantity Q1 based on a comparison between a theoretical rotational speed nSL and an actual rotational speed nfact of the internal combustion engine BK. In the exemplary embodiment shown, a filter F is additionally used for determining the actual rotational speed ncalcai from the detected rotational speed n. The open-loop and closed-loop control means SR are designed to detect at least one electrical characteristic of the generator, wherein the electrical characteristic is selected from the current I, the voltage U or the frequency f, and to determine a change dI/dt, dU/dt, df/dt of the electrical characteristic of the generator within a predetermined time interval. Furthermore, the open-loop and closed-loop control means are designed to compare the characteristic variable changes dI/dt, dU/dt, df/dt with a first limit value and to cause a changeover from the control of the rotational speed regulator nR to the control of the plant AS for the case of a deviation of the characteristic variable or a change of the characteristic variable greater than the first limit value. The equipment controller AS is configured to perform feed-forward control. The feed-forward control in the exemplary embodiment shown comprises determining a matched theoretical injection quantity Q2 on the basis of a measure of the characteristic change, wherein the larger the characteristic change, the larger the matched theoretical injection quantity. Furthermore, the open-loop control and closed-loop control means SR are configured to compare the characteristic variable change with a second limit value which is smaller than the first limit value after the characteristic variable change has been determined anew and to cause a change from the feed-forward control back to the standard rotational speed regulation for the case in which the characteristic variable change is smaller than the second limit value. The change from feed-forward control to standard speed regulation and vice versa is shown in the illustrated embodiment by a change in the switch position of the switch from 2 to 1 or from 1 to 2. The setpoint injection quantity Q output to the internal combustion engine BK therefore depends on the prevailing, i.e., either the matched setpoint injection quantity Q2 or the standard setpoint injection quantity Q1.

Fig. 3 shows a schematic illustration of an exemplary embodiment of an internal combustion engine BK having a generator G and an asynchronous machine ASM. Furthermore, the internal combustion engine BK includes an open-loop control and a closed-loop control mechanism including a rotational speed regulator and an equipment controller AS. The rotational speed controller is designed as a component of a motor control unit ECU. At least one electrical characteristic of the generator G, selected from the current I, the voltage U and the frequency f, is detected by the system controller AS and a dependent change in the characteristic is determined within a predetermined time interval. The characteristic variable change is compared with a first boundary value by the open-loop control and closed-loop control means, and for the case where the characteristic variable change is greater than the first boundary value, a change is made from a standard rotational speed regulation of the internal combustion engine by the rotational speed regulator to a feed-forward control by the plant controller by the open-loop control and closed-loop control means. Furthermore, the device controller AS is in the exemplary embodiment shown configured to switch on the asynchronous machine via the switch S.

Fig. 4 shows a method for open-loop and closed-loop control of an internal combustion engine with a generator and an asynchronous machine in a schematic representation. At least one electrical characteristic of the generator, selected from the group consisting of current, voltage and frequency, is detected in step S1 and a dependent characteristic change Δ is determined in step S2 within a predetermined time interval. The characteristic variable change Δ is compared with a first limit value in step S3, and for the case in which the characteristic variable change Δ is greater than the first limit value GW1, a change is made from a standard rotational speed control of the internal combustion engine to a feed-forward control in step S4. The feed-forward control in the exemplary embodiment shown comprises determining a matched setpoint injection quantity on the basis of a variable characteristic variable, wherein the larger the change in the characteristic variable, the larger the matched setpoint injection quantity.

List of reference numerals

I starting current

I_maxMaximum starting current

I_BOperation level

SR open-loop control and closed-loop control mechanism

BK internal combustion engine

G generator

ASM asynchronous machine

nR rotating speed regulator

AS equipment controller

Standard theoretical injection of Q1

nSL theoretical rotational speed

n actual speed of rotation

n detected rotational speed

Q2 matched theoretical injection

Theoretical amount of injected Q

F filter

S switcher

First boundary value of GW1

The Δ characteristic changes.