CN112688510A

CN112688510A - Method of heating a coil component, system for heating a coil component and method of manufacturing an electric machine

Info

Publication number: CN112688510A
Application number: CN201910992422.4A
Authority: CN
Inventors: 吴朋; 张帆; 薛廷民; 彭践
Original assignee: Bosch Automotive Products Changsha Co Ltd
Current assignee: Bosch Automotive Products Changsha Co Ltd
Priority date: 2019-10-18
Filing date: 2019-10-18
Publication date: 2021-04-20

Abstract

A method of heating a coil component, a system for heating a coil component and a method of manufacturing an electric machine are disclosed. The method of heating a coil component includes connecting a coil winding of the coil component with a constant power direct current power supply to provide direct current to the coil winding, wherein an output power of the constant power direct current power supply is controlled to heat the coil component during a power supply process. The heating device has the effects of high efficiency, short heating time and stable temperature.

Description

Method of heating a coil component, system for heating a coil component and method of manufacturing an electric machine

Technical Field

This application belongs to the motor manufacturing field. In particular, the present application relates to a method of heating a coil component, a system for heating a coil component and a method of manufacturing an electrical machine.

Background

The process for carrying out insulation treatment on the coil winding comprises the processes of dropping paint, dipping paint and the like. For example, in a motor manufacturing process, a coil winding of a rotor or a stator of the motor is preheated, then an insulation process, i.e., a resin is introduced to cover the surface of the coil to form a paint layer, and finally cured. Wherein the preheating step is to drive off moisture from the coil and to subject the coil to an elevated temperature for subsequent resin impregnation. When the temperature rises to a certain extent and the resistance of the coil is kept constant, the preheating step is completed.

The preheating step may employ various heating methods. It is common to use conductive heating, using air or other medium, or induction heating. In the first heating mode, a medium (e.g., air) is used as the transfer energy. Typically, the rotor or stator of the motor is placed in a warm chamber or furnace and reaches a set temperature after a period of heating. In another heating mode, a set of electromagnetic induction devices is used to generate electric current to the object to be heated, thereby generating heat energy. The apparatus includes at least an induction coil, an alternating current power source, and a cooling element.

For conduction heating, longer heating times and associated equipment are required due to the use of a medium to transfer thermal energy. The warm chamber or furnace is bulky, which results in a partial heat loss and thus requires more energy consumption. Another problem with the larger volume is the non-uniformity of the flow of the medium and thus the non-uniform temperature distribution. In addition, the internal temperature of the heated object is difficult to obtain. The energy transfer is hysteresis-loaded, so this approach is generally less efficient.

The problem of induction heating is that, in the first place, the electromagnetic induction apparatus is complicated. Second, the coil temperature is difficult to determine by physical methods, and there is also unevenness in temperature. This non-uniformity can interfere with the subsequent resin introduction step, which can make it difficult to form a uniform layer of paint on the coil.

Disclosure of Invention

An aspect of the technical problem to be solved by the present application is to provide a method of heating a coil component of an electric machine during a manufacturing process of the electric machine.

The method includes connecting a coil winding of the coil assembly to a constant power dc power supply to provide dc current to the coil winding, wherein an output power of the constant power dc power supply is controlled to heat the coil assembly during a power supply process.

In an embodiment of the heating method, the instruction is transmitted to the constant-power dc power supply through a control interface disposed on the constant-power dc power supply to control the output power of the constant-power dc power supply.

In one embodiment of the heating method, a power output terminal and a detection terminal provided on the constant-power dc power supply are respectively brought into contact with the component, and a current and a voltage are obtained through the detection terminal.

In an embodiment of the heating method, the output power of the constant-power direct-current power supply is modified based on the current and the voltage.

In one embodiment of the heating method, the output power of the constant-power dc power supply is controlled such that the power value of the output power is gradually decreased until the heating is finished.

In one embodiment of the heating method, wherein the maximum current supplied by the constant-power dc power supply to the coil winding is not less than 120A, the inductance generated by the coil winding is not more than 6.25mH, and the time period during which the output power is gradually decreased is not less than 1.5 s.

In one embodiment of the heating method, when the coil member is a rotor, the constant-power direct-current power supply is connected to the coil winding in a diagonal manner via a commutator of the rotor; when the coil component is a stator, the constant-power direct-current power supply is directly connected with a coil winding of the stator.

Another aspect of the present application is directed to a system for heating a coil component, comprising:

a constant power DC power supply configured to be connected to a coil winding of the coil component to be heated to provide DC current to the coil winding; and

a controller configured to be connected to the constant power DC power supply to control an output power of the constant power DC power supply to heat the coil member.

In one embodiment of the above system, the constant-power dc power supply has a control interface, and the controller is connected to the constant-power dc power supply via the control interface to transmit instructions to the constant-power dc power supply to control the output power of the constant-power dc power supply.

Yet another aspect of the present application is to provide a method of manufacturing an electric machine. The method comprises the following steps:

providing a component wound with a coil;

heating said part by the method described above; and

and carrying out insulation treatment on the coil of the component.

Compared with the existing heating technology, the method can directly heat the coil on the component of the motor, and the temperature is controlled by a proper measuring system. Therefore, the heating temperature required for the subsequent insulation treatment can be accurately obtained, and the error range of the heating temperature is very small. Thereby, a high quality paint layer in terms of thickness and uniformity can be obtained.

Energy is supplied directly to the components by the power supply, so there is no energy loss, which reduces waste. Also by such a heating method of the present application, heating to a set temperature can be performed in a short time (in contrast, for example, conduction heating takes several tens of minutes).

The entire heating system is stable and accuracy is improved. The temperature can be quickly obtained through the current resistance value and the target resistance value, and the resistance value can be obtained through the calculation of collected data. This facilitates closed loop control.

The entire heating system requires only a power supply and associated electronics, utilizes coil energization for self-heating of the components of the motor, does not require bulky thermometers, temperature gauges, heating actuators and cooling equipment, and is therefore also cost effective.

Other aspects and features of the present application will become apparent from the following detailed description, which proceeds with reference to the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the application, for which reference should be made to the appended claims. It should be further understood that the drawings are merely intended to conceptually illustrate the structures and procedures described herein, and that, unless otherwise indicated, the drawings are not necessarily drawn to scale.

Drawings

The present application will be more fully understood from the detailed description given below with reference to the accompanying drawings, in which like reference numerals refer to like elements throughout the views. Wherein:

FIG. 1 is a schematic view of a system for heating an electric motor to which the present application relates;

FIG. 2 is a flow chart of a method of heating a component of an electric machine to which the present application relates;

FIG. 3 is a flow chart of a method of manufacturing an electric machine to which the present application relates;

FIG. 4 is a schematic view of a rotor of the motor in the field;

FIG. 5 is a flow chart of heating a rotor of an electric machine according to a method of the present application;

FIG. 6 is a schematic representation of a temperature versus heating time curve established in accordance with the method of FIG. 5;

FIG. 7 is a graphical representation of output power versus heating time established in accordance with the method of FIG. 5.

Detailed Description

To assist those skilled in the art in understanding the subject matter claimed herein, specific embodiments thereof are described below in detail with reference to the accompanying drawings.

The present application relates to a method for use in a process for insulating a coil winding during the manufacturing process of an electrical machine. The method of the present application is a pre-treatment step of the process that can be used for stators and rotors of electric machines wound with coils. Here, the process of insulating the coil winding includes a known paint dropping process or a paint dipping process, for example, but not limited to, a rotor is placed in a paint dropping apparatus to rotate at a high speed, the paint dropping apparatus pours paint (e.g., resin) on the coil winding of the rotor, and the paint is infiltrated into the coil winding by its own weight, thereby forming a paint layer on the coil winding. The process can improve the electrical strength, mechanical strength, moisture resistance, chemical stability and the like of the coil winding.

In the existing insulation process, taking a rotor as an example, the rotor wound with a coil is first placed in a warm chamber, then is heated by conduction with air, then is subjected to a paint dropping process, and finally is dried and cooled to solidify the paint.

Fig. 1 shows a schematic view of a system for heating a coil component of an electric machine according to the present application. The system comprises a constant power direct current power supply and a controller. A constant power dc power supply is connected to the coil windings of the coil components of the motor to be heated, not shown, to power the coil windings and thereby heat the components of the motor. The controller is connected to the constant power DC power supply to control the output power of the constant power DC power supply such that the components of the motor are heated at a target temperature.

Here, the constant power dc power supply is a power controlled power supply that outputs dc power. In contrast to other types of power supplies that output a steady voltage or current, constant power dc power supplies are capable of controlling the power output during the power supply process, rather than controlling the voltage or current. As shown in fig. 1, it has a control interface via which a controller is connected to a constant power dc power supply, e.g. a control unit in the power supply. Through the control interface, the peripheral controller transmits instructions to the internal control unit, so as to control the output power of the power supply. The constant-power direct-current power supply is provided with a power output end and a detection end, wherein the power output end is connected with a coil component of a motor to be heated, and parameters reflecting the heating state of the coil component of the motor can be obtained through the detection end.

Fig. 2 shows a heating process to which the present application relates. The rotor is used as a heating object. At block 101, the rotor is connected to a power output of a constant power dc power supply so that the power supply can supply power to the rotor. When the power supply is energized, current flows through the rotor to form a power supply loop. The coil windings can be considered as resistances through which the current generates a heating effect, thereby heating the rotor.

At block 102, parametric data of the rotor in the energized state is collected. The data may be data in a detection circuit for the rotor or data in a circuit in which the rotor is located. The data may be obtained by a monitoring unit carried by the power supply itself, or by one or more detection instruments. The data to be collected may be one or more, for example, but not limited to, current, voltage, etc. From these acquired data, the resistance values of the coil windings of the rotor can be derived.

Based on the current, voltage values, the actual temperature of the rotor can be known. The actual temperature of the rotor can be obtained and recorded in real time. In the rotor heating process, it is not said that the higher the heating temperature is, the better the temperature rise speed is. The ideal heating state is to heat to a certain temperature, and the heating state is stable, including what the rotor temperature is when stable, how long the stabilization time is, not too fast the heating, etc. These heating requirements for the rotor may come from customer requirements or standard specifications within the industry, or may be established based on physical attributes of the rotor. Based on these heating requirements, a target heating profile, such as a time-temperature profile, for the rotor may be developed that may reflect a target heating time for the rotor, a target temperature at which heating is complete, how much time the target temperature is reached, etc. Accordingly, a curve of the output power of the constant power dc power supply over time can also be formulated. The output power curve may reflect an output of the output power that remains constant as the temperature rises and a change in the output power during the temperature maintenance. Due to the dc heating, if the temperature of the rotor exceeds a certain value, a relatively large induced current is generated in the coil winding of the rotor, which may result in an undesirably long heating time, damage to the winding material, and the like. Therefore, the rotor can be heated stably under ideal conditions by controlling the output power through the constant power supply.

At block 103, an error between the actual temperature and the target temperature is calculated to correct the output power of the constant power dc power supply. After the heating is started, errors between the actual situation and the heating requirement may occur, so a correction method may be set in this step to make the actual heating process more accurately meet the heating requirement by correcting the output power of the constant-power dc power supply.

Different from the mode of regulating current or voltage, the mode of controlling the output power of the power supply is a direct control means, changes the field heating state of the rotor, does not need to consider the initial parameters, the environmental conditions and the like of the rotor, saves conversion and redundant control steps, feeds back in time and can improve the production efficiency.

When the output power of the constant-power direct-current power supply is adjusted, the data can be collected again and calculated again. That is, blocks 102 through 103 may be repeated to determine whether to again modify the output power of the power supply. Thereby, a closed loop optimization procedure is formed, so that the actual rotor heating situation approaches the ideal situation.

It should be appreciated that in the embodiment illustrated in FIG. 2, the order of the steps may be altered unless otherwise indicated or otherwise logically inferred. For example, but not by way of limitation, the data acquisition may be performed while power is being supplied.

Fig. 3 illustrates a method of manufacturing an electric machine to which the present application relates. Still taking the rotor as an example, at block 201, a rotor wound with coils is provided.

At block 202, the rotor core is heated. Pre-heated by induction heating for a short period of time, such as 20 seconds.

At block 203, the coil windings of the rotor are heated. Heating is carried out in the above-mentioned heating step, and the coil winding is connected to a constant-power dc power supply and energized for a short period of time, such as 30 seconds.

At block 204, the coil windings of the rotor are insulated. This step can be carried out in a known manner, such as by placing the rotor in a paint-dropping machine and impregnating it with resin.

At block 205, the paint layer is cured. And (3) putting the rotor into a warm cavity for drying and cooling, so that a paint layer is formed on the surface of the coil winding of the rotor. This step can be carried out in a known manner.

It should be appreciated that in the embodiment illustrated in FIG. 3, the order of the steps may be altered unless otherwise indicated or otherwise logically inferred. For example, but not by way of limitation, the core may be heated by other heating means, or the core and coil windings may be heated simultaneously, or a target heating profile may be set prior to core and coil winding heating.

The embodiments of fig. 1-3 are also applicable to the process parts of heating and manufacturing the stator of an electric machine.

Fig. 4 shows a schematic representation of the heating method according to the present application in use in the field. The rotor is still taken as an example. Only a portion of the constant power dc power supply 300 is shown in the figure, and includes a first terminal 301 and a second terminal 302, where the first terminal 301 and the second terminal 302 may be a positive terminal and a negative terminal, respectively. The rotor 400 stands upright and is located intermediate the first end 301 and the second end 302. The rotor 400 may be positioned on the base 500 or otherwise secured. When connected, the first and second ends 301 and 302 are drawn toward the rotor 400 and contact the rotor 400, thereby forming a power circuit between the rotor 400 and the constant-power dc power supply 300.

The first terminal 301 and the second terminal 302 each have a

power output terminal

311, 321 and a

detection terminal

313, 323, as shown in the figure, a power output terminal having a large contact area and a detection terminal having a relatively small contact area. These ports maintain contact with the rotor 400 during power supply, thereby enabling power supply and detection. The

detection terminals

313, 323 are retractable terminals, and in the illustrated embodiment, have a length greater than the

power output terminals

311, 321. When the

power output terminals

311, 321 are in contact with the member to be heated, a power supply loop is formed. When the detection ends 313, 323 are in contact with the member to be heated, a detection loop is formed. The

sensing terminals

313, 323 are provided long, and the

sensing terminals

313, 323 can be contracted and kept in contact with the member to be heated while the

power output terminals

311, 321 are in contact with the member to be heated. A direct current passes through the rotor 400 between the two

power outputs

311, 321. The

detection terminals

313, 323 monitor the circuit data of the rotor, and the circuit data value can be obtained through the

detection terminals

313, 323. The constant-power direct-current power supply can also be provided with only a power output end, and circuit data can be obtained through a detection circuit which is additionally arranged, for example, a detection instrument is connected with the rotor in series to form a detection circuit.

In the illustrated embodiment, the constant-power dc power supply 300 is connected to the rotor commutator 404. The commutator 404 is connected to the coil windings 408, and thus the power outputs 311, 321 may be connected to the commutator 404 in a diagonal manner (also spaced 180 apart or referred to as in the diametrical direction), which facilitates the electrical connection of the rotor 400. Of course, the power output terminal may be connected to the coil winding wound on the rotor body or connected to the coil winding on another portion of the rotor. In the case of a stator, the power output is connected directly to the coil winding.

Only one pair of first and second ends 301, 302 contacting the rotor is shown, and there may be multiple pairs of first and second ends for a greater number of rotors to heat in batches for efficiency.

Fig. 5 shows a flow chart through the components of the heating motor to which the present application relates. Taking the rotor as an example, at block 601, the initial resistance and temperature of the rotor are recorded.

At block 602, a constant power dc power source is connected. In the manner shown in fig. 4, the rotor 400 is clamped between the first end 301 and the second end 302 of the constant power dc power supply 300. The

power output terminals

311, 321 of the first 301 and second 302 terminals are in diagonal contact with the commutator 404 of the rotor. The

sensing terminals

313, 323 are simultaneously in contact with the commutator 404.

At block 603, the current and voltage are collected by the

sensing terminals

313, 323, resulting in a resistance value of the coil windings of the rotor, e.g. calculated by the formula resistance = voltage/current.

At block 604, the actual temperature of the rotor is calculated from the initial resistance and temperature, and the resistance value. The actual temperature is linearly related to the resistance value of the rotor without material changes. For example, but not by way of limitation, the initial resistance R is known₀Initial temperature T₀If the resistance value at a given point in time is Rt, then the formula Rt = R₀(1+α(Tt-T₀) The actual temperature Tt at that point in time can be obtained. Where α is the temperature coefficient of resistance. The actual temperature is obtained through calculation, and the data accuracy is improved. Of course, the actual temperature may also be detected by the instrument.

At block 605, a heating curve reflecting the target temperature and the heating time of the rotor is established based on the defined target temperature and the heating time of the rotor, and the actual temperature of the rotor, see fig. 6, where the curve in fig. 6 reveals the relationship between the target temperature and the heating time, with the abscissa being the heating time and the ordinate being the temperature value corresponding to the heating time. As can be seen from fig. 6, the target temperature gradually increases with the heating time.

At block 606, a plot of output power and heating time of the constant power dc power supply is derived from the plot of target temperature and heating time. Referring to fig. 7, the graph in fig. 7 shows the relationship between the output power of the power supply and the heating time, where the abscissa is the heating time and the ordinate is the output power value of the power supply corresponding to the heating time. It can be seen from fig. 7 that the output power of the constant power dc power supply is kept constant at a certain output power value at the beginning, and after heating for a certain period of time, the temperature of the rotor reaches the required temperature, from which point on the rotor needs to be kept at that temperature to avoid generating excessive induced currents in the coil windings, so accordingly, the output power starts to gradually decrease until the end of the required 3s heating time, the output power gradually decreases to a zero value. The reduction time of the output power is related to the maximum current provided by the constant power dc power supply and the maximum inductance generated by the coil winding during heating. For example, and without limitation, in the illustrated embodiment, the constant power DC power source may provide a maximum supply current of 120A to the rotor. The constant-power direct-current power supply can provide the maximum power supply current for the rotor to be not less than 120A, the inductance of the coil winding is not more than 6.25mH, and the reduction time of the control output power value can be not less than 1.5 s. For example, the maximum supply current is 120A, 130A, 150A, 180A, 200A or 250A, the inductance of the coil winding is 6.25mH, 6.75mH, 7.25mH, 7.75mH, 8.25mH, 8.75mH, 9.25mH or 10.25mH, and the reduction time of the output power value is controlled to be 1.5s, 2.0s, 2.5s, 3.5s, 4.5s, 6.5s, 7.5s, 8.5s or 10.5 s. According to the inductance formula U = L di/dt, when the maximum supply current is 120A, the inductance of the coil winding is 6.25mH, and the reduction time of the output power value is controlled to be 1.5s, an accurate detection result can be obtained in real time, for example, the accuracy of the detection result of the real-time voltage is maintained within 0.5V in the heating stage and within 0.1V in the stabilization stage, in this case, t = L i/U = (6.25/1000) = 120/0.5=1.5s is calculated according to the above formula, that is, the reduction time of the output power value is 1.5 s.

It should be appreciated that the target curves shown in fig. 6 and 7 are merely examples, and that other target mathematical models may also exist.

In the actual heating process, it may occur that the actual heating situation does not completely conform to the target heating curve.

At block 607, the output power of the actual power source is compared to the output power of the target power source. The actual power supply output power may be calculated based on the collected current and voltage data, and the actual temperature may be calculated from the collected current and voltage data as described above.

And adjusting the power output of the constant-power direct-current power supply according to the comparison result. If the actual output power is large, then at block 608, the power output of the power supply is reduced; if the actual output power is small, then at block 609, the power output of the power supply is increased. Additionally, one may return to block 604 and again collect current and voltage data and again calculate the actual temperature of the rotor. The comparison of the actual output power and the target output power is again performed until they are equal, ending at block 610.

While specific embodiments of the present application have been shown and described in detail to illustrate the principles of the application, it will be understood that the application may be embodied otherwise without departing from such principles.

Claims

1. A method of heating a coil component, comprising:

connecting a coil winding of the coil component with a constant-power direct-current power supply to provide direct current for the coil winding, wherein the output power of the constant-power direct-current power supply is controlled to heat the coil component in the power supply process.

2. The method of claim 1, further comprising: and transmitting an instruction to the constant-power direct-current power supply through a control interface arranged on the constant-power direct-current power supply so as to control the output power of the constant-power direct-current power supply.

3. The method of claim 1, further comprising: and respectively contacting a power output end and a detection end arranged on the constant-power direct-current power supply with the coil component, and acquiring current and voltage through the detection end.

4. The method of claim 3, wherein: and correcting the output power of the constant-power direct-current power supply based on the acquired current and the acquired voltage.

5. The method of claim 1, further comprising: and controlling the output power of the constant-power direct-current power supply to gradually reduce the power value of the output power until the heating is finished.

6. The method of claim 5, wherein: the maximum current provided by the constant-power direct-current power supply for the coil winding is not less than 120A, the inductance generated by the coil winding is not more than 6.25mH, and the time period of gradual reduction of the output power is not less than 1.5 s.

7. The method according to any of claims 1-6, characterized by: when the coil component is a rotor, the constant-power direct-current power supply is connected with the coil winding in a diagonal manner through a commutator of the rotor; when the coil component is a stator, the constant-power direct-current power supply is directly connected with a coil winding of the stator.

8. A system for heating a coil component, comprising:

9. The system of claim 8, wherein: the controller is connected to the constant-power direct-current power supply through the control interface so as to transmit instructions to the constant-power direct-current power supply to control the output power of the constant-power direct-current power supply.

10. A method of manufacturing an electrical machine comprising the steps of:

providing a component wound with a coil;

heating the component by the method of any of claims 1-6; and

and carrying out insulation treatment on the coil of the component.