CN105469966A - Rotary transformer - Google Patents

Abstract

The invention discloses a rotary transformer, which relates to the technical field of motor control and detection. It at least includes two parts, a stator and a rotor. The stator and the rotor respectively contain at least a winding and a ferromagnetic material, wherein the rotor excitation winding is opened in the rotary transformer. The rotary transformer of the present invention can be used to sense the rotor position of a coaxially installed motor, and at the same time, the excitation receiving winding on the rotor side is opened, and an impedance-sensitive temperature sensing element arranged on the coaxial rotor side can be additionally connected to monitor the stator excitation input The voltage and current of the winding identify the impedance of the temperature sensing element, and then obtain the rotor temperature, so as to realize the integrated detection of the motor rotor position and rotor temperature.

Description

a rotary transformer

technical field

The invention relates to the technical field of motor control and detection, in particular to a rotary transformer.

Background technique

In many cases, the motor control system needs to use the rotor position sensor to know the rotor position of the motor in order to achieve precise control of the motor. The sine-cosine resolver is one of the widely used rotor position sensors. Its working method is: the stator and the rotor side are respectively arranged with an excitation input winding and an excitation receiving winding. The two form a toroidal transformer, and the excitation input winding is connected to The AC excitation voltage of a certain frequency and amplitude will induce a certain AC voltage in the excitation receiving winding, which supplies power to the rotor excitation winding connected in parallel with it, and performs rotor excitation. The winding senses the position of the rotor magnetic field.

At the same time, in many cases, the motor control system also needs to detect the temperature information of the motor rotor, and perform necessary derating or protection treatment to prevent the rotor temperature from being too high to damage the insulation or cause the permanent magnet to demagnetize. Most of the commonly used rotor temperature detection methods are Additional temperature detection equipment is required, which will increase the complexity of the system and greatly increase the cost.

Therefore, how to develop an integrated rotor position and rotor temperature detection device with simple structure, low cost and high reliability has become an urgent problem to be solved.

Contents of the invention

In view of the problems existing in the existing motor control system in detecting the position and temperature information of the motor rotor, the object of the present invention is to provide a rotary transformer that can be used for detecting the position and temperature information of the motor rotor.

In order to achieve the above object, the present invention adopts following technical scheme:

A rotary transformer includes at least two parts, a stator and a rotor. The stator and the rotor respectively contain at least windings and ferromagnetic materials, and the rotor excitation winding is opened in the rotary transformer.

Preferably, the winding contains at least:

A pair of excitation input windings arranged on the stator and excitation receiving windings on the rotor, both of which form a toroidal transformer;

A rotor excitation winding arranged on the rotor, connected to and powered by the excitation receiving winding;

A pair of mutually orthogonal sine output windings and cosine output windings arranged on the stator for sensing the rotor magnetic field;

Wherein, the winding on the stator side is provided with a lead-out terminal on the stator, and the excitation receiving winding on the rotor side is provided with a lead-out terminal on the rotor.

Preferably, the rotor excitation winding is connected in parallel with the excitation receiving winding.

Preferably, the rotor side of the resolver further includes a self-short-circuit compensation winding orthogonal to the rotor excitation winding.

Preferably, the lead-out wire of the excitation receiving winding on the rotor side in the resolver is connected to the temperature sensing element and supplies power to it, so as to detect the temperature of the rotor in a non-contact manner.

The solution provided by the present invention is based on the structure of the sine-cosine resolver for position sensing, the rotor excitation winding is opened, and the integrated detection of the rotor position and rotor temperature can be realized by connecting the impedance-sensitive temperature-sensing element arranged on the rotor. Equipped with additional temperature detection equipment, the whole system has the advantages of simple structure, low cost and high reliability.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

FIG. 1 is a schematic diagram of the electrical structure of a resolver provided in an embodiment of the present invention;

Fig. 2 is a schematic diagram of the wiring of the resolver to realize the rotor temperature measurement function in the embodiment of the present invention.

detailed description

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific illustrations.

In this example, on the basis of the structure of the sine-cosine resolver, the rotor excitation winding is opened to access the impedance-sensitive temperature-sensing element arranged on the rotor, so as to realize the integrated detection of the rotor position and rotor temperature, and has a simple structure, Advantages of low cost and high reliability.

Referring to FIG. 1 , it is a schematic diagram of the electrical structure of the resolver in this embodiment. It can be seen from the figure that the resolver mainly includes the following parts:

Contains two parts, the stator and the rotor, while the stator and the rotor contain windings and ferromagnetic materials, respectively.

The windings in it contain:

A pair of excitation input windings S1-S2 arranged on the stator and excitation receiving windings R1-R2 on the rotor respectively, which form a toroidal transformer;

A rotor excitation winding R3-R4 arranged on the rotor, connected in parallel with the winding R1-R2, and powered by it;

A pair of mutually orthogonal sine output windings S3-S4 and cosine output windings S5-S6 arranged on the stator for sensing the rotor magnetic field;

Among them, the stator side winding has lead-out terminals on the stator, which are used to connect external circuits to realize power supply from the external circuits; the rotor-side windings R1-R2 are provided with lead-out terminals on the rotor, which are used to realize non-contact rotor temperature detection .

On this basis, the rotary transformer can also include a self-short-circuit compensation winding orthogonal to the rotor excitation winding on the rotor side, thereby further improving the reliability and stability of the rotary transformer.

This constitutes a resolver that will have a rotor position detection function and can be used to sense the rotor position of a coaxially mounted motor.

When detecting the position of the rotor of the motor, an AC excitation voltage of a certain frequency and amplitude is first passed through the excitation input winding S1-S2 in the resolver;

As a result, a certain AC voltage will be induced in the excitation receiving winding R1-R2 to supply power for the rotor excitation winding connected in parallel with it;

Next, the rotor is excited, and the position information of the rotor is obtained by demodulating the output voltage signals of the mutually orthogonal sinusoidal and cosine output windings S3-S4, S5-S6 arranged on the stator side.

Furthermore, since the resolver also opens the rotor side excitation receiving winding, it also has a rotor temperature detection function, and it is a non-contact detection method.

For this reason, this resolver utilizes the open rotor side excitation receiving winding (the lead-out terminal on the rotor), and additionally connects the temperature sensing element arranged on the coaxial rotor side, and monitors the voltage and current of the stator excitation input winding. , identify the resistance of the temperature sensing element, and then obtain the rotor temperature, so as to realize the integrated detection of the motor rotor position and rotor temperature.

Referring to FIG. 2 , it is a schematic diagram of wiring for realizing the rotor temperature measurement function by using the resolver based on the above principles.

It can be seen from the figure that the lead-out wires of the rotor excitation receiving windings R1-R2 of the resolver are connected to the impedance-sensitive temperature sensing element 200 fixed on the rotor 100 of the coaxial motor, and supply power to it.

Wherein, in this embodiment, the temperature sensing element 200 is a negative temperature coefficient thermistor (NTC).

Therefore, the impedance of the temperature sensing element connected to the rotor excitation receiving winding can be identified by detecting the voltage and current of the excitation input winding S1-S2 in the resolver, and the rotor temperature can be obtained according to its temperature impedance characteristics.

The resolver formed based on the above scheme will integrate rotor position and rotor temperature detection functions. When it uses the function of position detection and rotor temperature at the same time, its stator excitation input winding current will contain two components, one of which is the rotor excitation current, which remains basically unchanged during the working process; the other component is the rotor temperature The element load current is the actual current flowing through the temperature sensing element converted to the power supply current of the excitation winding according to the transformer principle.

Therefore, by monitoring the load current of the rotor temperature sensing element and the input voltage of the excitation winding, according to the transformation relationship of the transformer impedance, the impedance of the rotor temperature sensing element can be obtained, and then the rotor temperature can be obtained according to its temperature impedance characteristics.

Specifically, the AC voltage of the excitation input winding is marked as Vs, the load current component of the rotor temperature sensing element in the excitation input winding is Is_ntc, the resistance of NTC is a function of temperature t, denoted as R _ntc (t), the rotor excitation receiving winding and the stator The voltage transformation ratio of the excitation input winding is Nr/Ns, which can be obtained according to the principle of transformer impedance transformation:

R _ntc (t)＝(Nr/Ns)^2×(Vs/Is_ntc)

Therefore, by observing the voltage and current of the excitation input winding, the value of R _ntc (t) can be calculated through the above formula, and the rotor temperature t near the NTC can be obtained by looking up the table or calculating through the temperature characteristic curve of the NTC.

It can be seen from the above that the resolver realizes integrated detection of rotor position and rotor temperature, and has the advantages of simple structure, low cost and high reliability.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. A rotary transformer, the rotary transformer at least comprises two parts, a stator and a rotor, the stator and the rotor contain at least a winding and a ferromagnetic material respectively, it is characterized in that the rotor excitation winding is opened in the rotary transformer. 2. A rotary transformer according to claim 1, wherein the winding at least contains: A pair of excitation input windings arranged on the stator and excitation receiving windings on the rotor, both of which form a toroidal transformer; A rotor excitation winding arranged on the rotor, connected to and powered by the excitation receiving winding; A pair of mutually orthogonal sine output windings and cosine output windings arranged on the stator for sensing the rotor magnetic field; Wherein, the winding on the stator side is provided with a lead-out terminal on the stator, and the excitation receiving winding on the rotor side is provided with a lead-out terminal on the rotor. 3 . The rotary transformer according to claim 2 , wherein the rotor excitation winding is connected in parallel with the excitation receiving winding. 4 . 4. A rotary transformer according to claim 2, characterized in that, the rotor side of the rotary transformer further includes a self-short-circuit compensation winding orthogonal to the rotor excitation winding. 5. A rotary transformer according to claim 1 or 2, characterized in that, in the rotary transformer, the lead-out wire of the excitation receiving winding on the rotor side is connected to the temperature sensing element and supplies power to it, and the temperature of the rotor is non-contacted. type detection.