Rotary transformer driving circuit and device and vehicle

Abstract

The invention relates to a rotary transformer driving circuit and device and a vehicle, and the rotary transformer driving circuit comprises a signal recognition circuit which is connected with the output end of a rotary transformer and is used for receiving a response signal of the rotary transformer; the switching circuit is connected with the signal identification circuit and is used for outputting an opening signal when the signal identification circuit receives the response signal, and otherwise, outputting a closing signal; the power factor compensation circuit is connected with the signal identification circuit and the excitation power supply and is used for working in response to a starting signal, performing power factor compensation on an excitation signal provided by the excitation power supply and stopping compensation in response to a closing signal; by adopting the rotary transformer, the problem of low operation efficiency of the rotary transformer in the prior art can be improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a rotary transformer drive circuit, device and vehicle. Background Art

[0002] A resolver is also called a synchronous resolver. It is a small AC motor used to measure angles and is used to measure the angular displacement and angular velocity of a rotating object. When the excitation winding of the resolver is excited by an AC current of a certain frequency, the voltage of the output winding can be in a functional relationship with the sine and cosine of the rotation angle, or in a linear relationship within a certain range.

[0003] At present, most rotary transformer drive circuits generally use power drive circuits to directly drive the rotary transformer. Since the rotary transformer has an inductor coil inside, the equivalent model of the rotary transformer in the circuit is a series connection of R+L, where R is generally a few Ω to several hundred Ω, and L is generally a few hundred uH to several thousand uH. Due to the characteristic that the current in the inductor lags behind the voltage by 90 degrees, there is a large amount of reactive power in the circuit during actual operation, which reduces the efficiency of the power supply. Summary of the invention

[0004] Based on this, a rotary transformer driving circuit, a device and a vehicle are provided to improve the problem of low efficiency of the rotary transformer during operation in the prior art.

[0005] On the one hand, a rotary transformer driving circuit is provided, comprising:

[0006] A signal recognition circuit, connected to the output end of the rotary transformer, for receiving a response signal of the rotary transformer;

[0007] A switch circuit, connected to the signal recognition circuit, configured to output an on signal when the signal recognition circuit receives the response signal, and output an off signal otherwise;

[0008] The power factor compensation circuit is connected to the signal identification circuit and the excitation power supply, and is used to work in response to the start signal to perform power factor compensation on the excitation signal provided by the excitation power supply, and to stop compensation in response to the shutdown signal.

[0009] In one embodiment, the signal recognition circuit is connected to a sine output terminal or a cosine output terminal of the rotary transformer.

[0010] In one embodiment, the signal recognition circuit includes an operational amplifier, the positive response end and the negative response end of the output end of the rotary transformer are respectively connected to two input ends of the operational amplifier, and the output end of the operational amplifier is connected to the input end of the switch circuit.

[0011] In one embodiment, the signal identification circuit further includes two first capacitors, the two first capacitors are respectively connected to the in-phase input terminal and the inverting input terminal of the operational amplifier, and the positive response terminal and the negative response terminal of the rotary transformer are respectively connected to the two first capacitors.

[0012] In one embodiment, the signal identification circuit also includes a first resistor, a second resistor and a third resistor, the non-inverting input terminal of the operational amplifier is connected to one end of the first resistor, the other end of the first resistor is connected to a power supply, the inverting input terminal of the operational amplifier is connected to one end of the second resistor, the other end of the second resistor is connected to the power supply, the non-inverting input terminal of the operational amplifier is also connected to one end of the third resistor, the other end of the third resistor is grounded, and a feedback resistor is connected between the inverting input terminal and the output terminal of the operational amplifier.

[0013] In one embodiment, the switching circuit includes a first switching element, a second switching element, a diode, a second capacitor and a fourth resistor. The first switching element and the second switching element each include a control end, a first controlled end and a second controlled end. The control ends of the first switching element and the second switching element are both connected to the cathode of the diode, the anode of the diode is connected to the signal identification circuit, the cathode of the diode is also connected to one end of the second capacitor and one end of the fourth resistor, the other end of the second capacitor, the other end of the fourth resistor, the second controlled end of the first switching element and the first controlled end of the second switching element are all grounded, and the first controlled end of the first switching element and the second controlled end of the second switching element are connected to the power factor compensation circuit.

[0014] In one embodiment, the first switch element and the second switch element are both N-type metal oxide semiconductors.

[0015] In one embodiment, the excitation power supply includes an excitation first input terminal and an excitation second input terminal, the power factor compensation circuit includes a first compensation circuit and a second compensation circuit, the first compensation circuit and the second compensation circuit both include a third capacitor and a fifth resistor in parallel, one end of the third capacitor of the first compensation circuit is connected to the excitation first input terminal, and the other end is connected to the switching circuit; one end of the third capacitor of the second compensation circuit is connected to the excitation second input terminal, and the other end is connected to the switching circuit; the excitation first input terminal is connected to the excitation first output terminal, and the excitation second input terminal is connected to the excitation second output terminal.

[0016] On the other hand, a rotary transformer driving device is provided, comprising an excitation power supply and the rotary transformer driving circuit, wherein the excitation power supply is connected to the rotary transformer driving circuit.

[0017] Also provided is an electric vehicle, comprising the rotary transformer drive circuit, or comprising the rotary transformer drive device.

[0018] The above-mentioned rotary transformer driving circuit receives the response signal of the rotary transformer through the signal recognition circuit. When the response signal exists, the switch circuit outputs an on signal, so that the power factor compensation circuit starts to work, performs power factor compensation on the excitation signal provided by the excitation power supply, improves the power factor, and improves the power utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the drive connection of a rotary transformer in the prior art;

[0020] Figure 2 This is a schematic diagram of the connection between the rotary transformer drive circuit, the rotary transformer, and the excitation power supply in one embodiment of the present application;

[0021] Figure 3 is a structural block diagram of a rotary transformer driving circuit in one embodiment;

[0022] Figure 4 FIG. 4 is a schematic diagram of a circuit structure of a rotary transformer driving circuit in an embodiment.

[0023] Figure numerals: signal recognition circuit 100, operational amplifier Amp, first capacitor C1, first resistor R1, second resistor R2, third resistor R3, feedback resistor Rf, switching circuit 200, first switching element M1, second switching element M2, diode D1, second capacitor C2, fourth resistor R4, power factor compensation circuit 300, first compensation circuit 310, second compensation circuit 320, third capacitor C3, fifth resistor R5. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] A resolver, or resolver for short, is a special signal element that works based on the principle of electromagnetic induction. Its characteristic is that the output voltage changes with the change of the rotor angle, which makes the angle of rotation a key factor in determining the voltage output waveform.

[0026] In new energy vehicles, resolvers are widely used in electric drive systems as position sensors to monitor the position and speed of the motor rotor in real time and convert this information into signals to feed back to the motor control system, which is crucial for achieving precise control of the motor.

[0027] The rotary transformer has a structure such as Figure 1 As shown, it is divided into 1 stator and 1 rotor. In terms of electrical signals, the rotary transformer has an excitation coil connected to 2 signal excitation terminals (excitation +, excitation -), a sine response coil and a cosine response coil connected to 4 signal response terminals (sin+, sin-, cos+, cos-), respectively; the excitation signal is usually a sinusoidal signal of a specific frequency. When the rotary transformer is in different positions, the response signal appears as a sinusoidal signal with sine and cosine envelopes. The position of the rotor relative to the stator can be calculated by mathematically analyzing the envelope of the corresponding signal.

[0028] However, the rotary transformer drive circuit generally uses a power drive circuit to directly drive the rotary transformer. Since the rotary transformer has an inductor coil inside, the equivalent model of the rotary transformer in the circuit is a series connection of resistance R + inductance L. R is generally a few Ω to several hundred Ω, and L is generally a few hundred uH to several thousand uH. Due to the characteristic that the current in the inductor lags behind the voltage by 90 degrees, there is a large amount of reactive power in the circuit during actual operation, which reduces the efficiency of the power supply.

[0029] The present application provides a rotary transformer driving circuit, and the connection method between the rotary transformer and the excitation power supply is as follows Figure 2 As shown, in the rotary transformer of the above structure, the efficiency of the power supply is improved by power factor compensation.

[0030] In one embodiment, if Figure 3 As shown, the invention comprises a signal recognition circuit 100 , a switch circuit 200 and a power factor compensation circuit 300 .

[0031] The signal recognition circuit 100 is connected to the output end of the rotary transformer and is used to receive the response signal of the rotary transformer. The rotary transformer is connected to the circuit as a load of the excitation power supply. At this time, the rotary transformer works normally and the output end of the rotary transformer has normal cos and sin response signals. The signal recognition circuit 100 can issue an indication instruction when the cos or sin response signal is recognized.

[0032] The switch circuit 200 is used to instruct the power factor compensation circuit 300 to switch on and off, and is connected to the signal recognition circuit 100. When the signal recognition circuit 100 receives the response signal, it outputs an on signal, otherwise it outputs a off signal.

[0033] The power factor compensation circuit 300 is connected to the signal recognition circuit 100 and the excitation power supply. When receiving the start signal of the switch circuit 200, the power factor compensation circuit 300 starts to work, otherwise it remains closed. When the power factor compensation circuit 300 works, the excitation signal provided by the excitation power supply is adjusted to improve the power factor. The power factor compensation is described below:

[0034] Power Factor Compensation (PFC) is mainly used to reduce power loss and improve power efficiency. In the power system, power factor refers to the ratio of active power to apparent power in the AC circuit, which reflects the degree to which the power output of the power supply is effectively used by the actual load.

[0035] Active power P: In an AC circuit, the part of power consumed in the resistance element and irreversibly converted, reflects the ability of the AC power supply to do work on the resistance element. In fact, it is the average value of the instantaneous power of the AC power in one cycle, which is equal to the product of the effective value of the voltage across the resistance element and the effective value of the current passing through the resistance element.

[0036] Reactive power Q: The power exchanged between the inductor or capacitor element and the AC power supply is called reactive power, that is, the part of the electrical power that can be reversibly converted.

[0037] Apparent power S: The total power that an AC power source can provide. The numerical value is the product of the voltage and current in the AC circuit. It is usually used to indicate the capacity of an AC power source device (such as a transformer).

[0038] The power factor cosθ=P / S, where θ is the power factor angle, that is, the impedance angle of the load. In the resolver, the equivalent model of the resolver is a series connection of R+L, the current lags the voltage by 90 degrees, and the power factor is small.

[0039] PFC is divided into active PFC and passive PFC. Passive PFC improves the power factor by compensating for reactive power. Capacitive loads connected in series with inductors and inductive loads connected in parallel with capacitors can both compensate for reactive power.

[0040] Active PFC, also known as active PFC, is generally controlled by a dedicated IC. It samples the input voltage and current, controls the on and off of the switch, compensates for the phase difference between current and voltage, allows the input current to follow the input voltage changes, and realizes power factor correction.

[0041] In one embodiment of the present application, the PFC compensation circuit includes at least one compensation capacitor, which is connected in parallel to the two input ends of the excitation power supply. The switching circuit 200 controls the connection or disconnection of the compensation capacitor, thereby realizing phase difference compensation for the input current and input voltage, thereby improving the power factor.

[0042] The rotary transformer driving circuit provided in the present application connects the rotary transformer into the circuit as the load of the excitation power supply. The rotary transformer works normally and has normal cos and sin response signals. When the signal recognition circuit 100 works normally and detects a corresponding signal, the switch circuit 200 is turned on. At this time, the PFC compensation circuit is connected to the excitation power supply and starts working.

[0043] When the rotary transformer is disconnected, the signal recognition circuit 100 cannot detect the response signal. At this time, the switch circuit 200 is closed, the PFC compensation circuit does not work, and the circuit can enter a lower energy consumption working state; if the PFC compensation circuit cannot be disconnected normally, the PFC compensation circuit will cause a large power consumption loss as a capacitive load, so the signal recognition circuit 100 and the switch circuit 200 are necessary.

[0044] It can be understood that when the rotary transformer is working, both cos and sin response signals will be generated, so the signal recognition circuit 100 can be connected to one of the sine output terminal or the cosine output terminal of the rotary transformer. In this embodiment, the signal recognition circuit 100 is connected to the cosine output terminal of the rotary transformer.

[0045] The rotary transformer drive circuit can be used as an execution carrier of the circuit structure, for example, each circuit module is configured as a component of the product, and the connection between each circuit module is configured as a determined connection relationship between the components of the product. The signal can be collected, processed and output through the components of the product to realize the recognition of the signal, the on and off of the switch circuit 200 and the power factor compensation function. Exemplarily, the signal recognition circuit 100 can use a voltage sensor to convert the output signal of the rotary transformer into an electrical signal; the switch circuit 200 and the power factor compensation circuit 300 can use various units that can realize adjustable signals, such as various single-chip microcomputers, microcontrollers, DSPs (digital signal processors), FPGAs (Field-Programmable Gate Arrays, i.e., field programmable gate arrays), host computers or central processing units (CPUs). In some embodiments, the power factor compensation circuit 300 may include a single-chip microcomputer, and various control functions can be realized by programming the single-chip microcomputer. For example, in this embodiment, the phase difference compensation of the excitation signal current and voltage is realized, and the switch circuit 200 starts or closes the power factor compensation circuit 300 by responding to the output signal of the signal recognition circuit 100.

[0046] In one embodiment, if Figure 4As shown, the signal recognition circuit 100 includes an operational amplifier Amp, the positive response end and the negative response end of the output end of the rotary transformer are respectively connected to the two input ends of the operational amplifier Amp, and the output end of the operational amplifier circuit is connected to the input end of the switch circuit 200.

[0047] The cos+ response end and the cos- response end of the rotary transformer are respectively connected to the two input ends of the operational amplifier Amp. When there is a pressure difference between the cos+ response end and the cos- response end, the operational amplifier Amp can amplify the weak input signal to a level suitable for subsequent processing, thereby driving the switch circuit 200 to function, turning on the switch circuit 200, and connecting the PFC compensation circuit to the two ends of the excitation power supply.

[0048] The signal recognition circuit 100 includes an operational amplifier Amp, a first resistor R1, a second resistor R2 and a third resistor R3. A feedback resistor Rf is connected between the inverting input and the output of the operational amplifier Amp. The non-inverting input of the operational amplifier Amp is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to a power supply. The inverting input of the operational amplifier Amp is connected to one end of the second resistor R2, and the other end of the second resistor R2 is connected to the power supply. The non-inverting input of the operational amplifier Amp is also connected to one end of the third resistor R3, and the other end of the third resistor R3 is grounded. By setting the first resistor R1 and the second resistor R2, and connecting the first resistor R1 and the second resistor R2 to the power supply, the operational amplifier Amp can maintain an initial default state when there is no response signal feedback.

[0049] In particular, the signal recognition circuit 100 also includes two first capacitors C1, the two first capacitors C1 are respectively connected to the non-inverting input terminal and the inverting input terminal of the operational amplifier Amp, the positive response terminal and the negative response terminal of the rotary transformer are respectively connected to the two first capacitors C1, and the first capacitors C1 provide a filtering function for the response signal.

[0050] In one embodiment, the switch circuit 200 is implemented based on a switch element, and is turned on in response to a signal from the signal recognition circuit 100 . After the switch element is turned on, the PFC compensation circuit starts to work.

[0051] Exemplarily, the switch circuit 200 is as follows Figure 4As shown, it includes a first switch element M1, a second switch element M2, a diode D1, a second capacitor C2 and a fourth resistor R4. The first switch element M1 and the second switch element M2 both include a control end, a first controlled end and a second controlled end. When the control end receives a start signal, the first controlled end and the second controlled end are turned on, otherwise they are turned off. The control ends of the first switch element M1 and the second switch element M2 are both connected to the cathode of the diode D1, the anode of the diode D1 is connected to the signal recognition circuit 100, the cathode of the diode D1 is also connected to one end of the second capacitor C2 and one end of the fourth resistor R4, the other end of the second capacitor C2, the other end of the fourth resistor R4, the second controlled end of the first switch element M1, and the first controlled end of the second switch element M2 are all grounded, and the first controlled end of the first switch element M1 and the second controlled end of the second switch element M2 are connected to the power factor compensation circuit 300.

[0052] In this embodiment, the first switch element M1 and the second switch element M2 are both N-type metal oxide semiconductors (NMOS). The cathode of the diode D1 is connected to the gates of the two NMOS, the source of one NMOS is connected to the drain of the other NMOS, and the connection point is grounded, and the remaining source and drain are used as output terminals and connected to the power factor compensation circuit 300.

[0053] When there is a pressure difference between the cos+ response end and the cos- response end, the output end of the operational amplifier Amp is at a high level, so that the gates of the two NMOS are at a high level and are in an open state, connecting the PFC compensation circuit to the excitation power supply. Otherwise, the two NMOS are in a closed state, disconnecting the PFC compensation circuit.

[0054] Exemplarily, the power factor compensation circuit 300 includes a first compensation circuit 310 and a second compensation circuit 320, the first compensation circuit 310 and the second compensation circuit 320 are respectively connected to the first controlled end of the first switching element M1 and the second controlled end of the second switching element M2, the first compensation circuit 310 and the second compensation circuit 320 both include a third capacitor C3 and a fifth resistor R5 connected in parallel, one end of the third capacitor C3 of the first compensation circuit 310 is connected to the first input end of excitation (excitation+input), and the other end is connected to the switching circuit 200; one end of the third capacitor C3 of the second compensation circuit 320 is connected to the second input end of excitation (excitation-input), and the other end is connected to the switching circuit 200; the first input end of excitation is connected to the first output end of excitation (excitation+output), and the second input end of excitation is connected to the second output end of excitation (excitation-output).

[0055] It can be understood that when the gates of the two NMOS are at a high level, the two NMOS are turned on at the same time. Whether they are turned on depends on the characteristics of the excitation signal. If the excitation + and excitation - are orthogonal signals, the two NMOS are turned on alternately, and the third capacitor C3 performs phase compensation on the excitation current and excitation voltage of the excitation power supply.

[0056] The rotary transformer driving circuit provided in the present application can automatically improve the working efficiency of the excitation power supply of the rotary transformer, reduce the heat generation of the excitation power supply, and improve the reliability of the power supply. It can also miniaturize the power supply and reduce the cost. In the case of abnormal load, the PFC compensation circuit can be effectively turned off to avoid power supply damage.

[0057] The following example illustrates the change in power factor before and after resolver compensation.

[0058] Assume that the resolver has the following parameters: DC resistance R = 15Ω, inductance 1500nH.

[0059] Assume that the excitation power supply has the following parameters: the power supply is a 10KHz AC sinusoidal voltage with a peak-to-peak value of 14V.

[0060] Calculate the active power P, reactive power Q, apparent load power S, and power factor cosθ of the circuit respectively.

[0061] When there is no PFC compensation, it is as follows:

[0062] Total impedance of RL series connection: Z = 15 + i·2·π·1500·10 -6 10000 = 15 + 94.2478i;

[0063] Active power:

[0064] Reactive power:

[0065] Apparent power:

[0066] Power Factor:

[0067] The power factor is only 0.15718 at this time. The power factor reflects the efficiency of the power supply. It can be seen that the circuit efficiency is low when there is no PFC compensation. At this time, the apparent power of the excitation power supply reaches 0.25672W.

[0068] When there is PFC compensation, the circuit parameters are consistent with the above. Assuming that the PFC compensation circuit in the circuit works normally, the PFC capacitor (the equivalent capacitance of the two third capacitors C3 connected in series) is 160nF:

[0069] Power peak value: U pp=14;

[0070] Voltage RMS:

[0071] Load resistance: R=15;

[0072] Load inductance: L = 1500 10 -6 =0.0015;

[0073] PFC capacitor: C = 160 10 -9 =1.6×10 -7 ;

[0074] Working frequency: freq=10000;

[0075] Inductive reactance: X L =2·π·freq·L=2·3.1416·10000·0.0015=94.2478;

[0076] Capacitive reactance:

[0077] RL series impedance:

[0078] RL series current:

[0079] RL series impedance complex form: Z RL_i =R+i·X L =15+94.2478i;

[0080] Capacitive reactance plural form: X Ci =0-i·X C = -99.4718i;

[0081] The total impedance complex form of RL in series and C in parallel is:

[0082]

[0083] Total impedance modulus:

[0084] Active power: P = I RL 2 R = 0.040351;

[0085] Apparent power:

[0086] Power Factor:

[0087] The power factor is 0.98432, the power supply output efficiency is greatly improved, and the apparent power of the excitation power supply is only 0.040993W at this time, and the effective power output of the power supply is almost all absorbed by the rotary transformer.

[0088] In one embodiment, a rotary transformer driving device is provided, comprising an excitation power supply and a rotary transformer driving circuit as described above, wherein the excitation power supply is connected to the rotary transformer driving circuit. The rotary transformer driving circuit comprises a signal recognition circuit 100 connected to the output end of the rotary transformer and used to receive a response signal of the rotary transformer; a switch circuit 200 connected to the signal recognition circuit 100 and used to output an on signal when the signal recognition circuit 100 receives the response signal, otherwise output a off signal; and a power factor compensation circuit 300 connected to the signal recognition circuit 100 and the excitation power supply, used to work in response to the on signal, perform power factor compensation on the excitation signal provided by the excitation power supply, and stop compensation in response to the off signal.

[0089] Exemplarily, the signal recognition circuit 100 includes an operational amplifier Amp, and a positive response end (eg, cos+) and a negative response end (eg, cos-) of the output end of the rotary transformer are respectively connected to two input ends of the operational amplifier Amp.

[0090] The switch circuit 200 includes a first switch element M1, a second switch element M2, a diode D1, a second capacitor C2 and a fourth resistor R4, wherein the first switch element M1 and the second switch element M2 each include a control end, a first controlled end and a second controlled end. The control ends of the first switch element M1 and the second switch element M2 are both connected to the cathode of the diode D1, the anode of the diode D1 is connected to the output end of the operational amplifier Amp, the cathode of the diode D1 is also connected to one end of the second capacitor C2 and one end of the fourth resistor R4, and the other end of the second capacitor C2, the other end of the fourth resistor R4, the second controlled end of the first switch element M1 and the first controlled end of the second switch element M2 are all grounded.

[0091] The power factor compensation circuit 300 includes a first compensation circuit 310 and a second compensation circuit 320, which are respectively connected to the first controlled end of the first switch element M1 and the second controlled end of the second switch element M2. The first compensation circuit 310 and the second compensation circuit 320 both include a third capacitor C3 and a fifth resistor R5 connected in parallel. One end of the third capacitor C3 of the first compensation circuit 310 is connected to the first input end of excitation (excitation+input), and the other end is connected to the switch circuit 200; one end of the third capacitor C3 of the second compensation circuit 320 is connected to the second input end of excitation (excitation-input), and the other end is connected to the switch circuit 200; the first input end of excitation is connected to the first output end of excitation (excitation+output), and the second input end of excitation is connected to the second output end of excitation (excitation-output).

[0092] For the specific definition of the rotary transformer drive device, please refer to the definition of the rotary transformer drive circuit above, which will not be repeated here. Each module in the above rotary transformer drive device can be implemented in whole or in part by software, hardware and a combination thereof. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0093] In one embodiment, an electric vehicle is provided, and the electric vehicle includes the aforementioned rotary transformer drive circuit, or includes the aforementioned rotary transformer drive device.

[0094] The resolver used in the resolver drive circuit is fixed on the electric vehicle motor stator. It is installed coaxially with the motor rotor. The motor controller (MCU) is responsible for monitoring the resolver signal. Based on the output sine and cosine signals, the current rotor position of the drive motor can be obtained after analysis by the internal resolver encoder.

[0095] It should be understood that the terms used in the implementation methods of the embodiments of the present application are only used to explain the embodiments of the present application, and are not intended to limit the present application. Unless otherwise defined, the technical terms or scientific terms used in the implementation methods of the present application should be the common meanings understood by people with ordinary skills in the field to which the present application belongs.

[0096] The illustrations provided in this application are only used to illustrate the basic concept of this application in a schematic manner. Therefore, the drawings only show components related to this application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0097] The structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0098] For example, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0099] Likewise, "at least one" means one or more than one, and "plurality" means two or more than two.

[0100] Words such as “include” or “comprising” and the like mean that the elements or objects preceding “include” or “comprising” include the elements or objects listed after “include” or “comprising” and their equivalents, and do not exclude other elements or objects.

[0101] “Up”, “down”, “left” or “right” etc. are only used to indicate relative position relationship. When the absolute position of the described object changes, the relative position relationship may also change accordingly.

[0102] "And / or" indicates that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship.

[0103] In this specification, "connection" includes the case where components are connected together through an element having some electrical function. There is no particular limitation on the "element having some electrical function" as long as it can transmit and receive electrical signals between the connected components. Examples of "element having some electrical function" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other elements having various functions.

[0104] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A rotary transformer driving circuit, characterized in that: include: A signal recognition circuit (100), connected to the output end of the rotary transformer, and used for receiving a response signal of the rotary transformer; A switch circuit (200), connected to the signal recognition circuit (100), configured to output an on signal when the signal recognition circuit (100) receives the response signal, and output an off signal otherwise; The power factor compensation circuit (300) is connected to the signal recognition circuit (100) and the excitation power supply, and is used to operate in response to an on signal to perform power factor compensation on the excitation signal provided by the excitation power supply, and to stop compensation in response to a off signal.

2. The rotary transformer driving circuit according to claim 1, characterized in that: The signal recognition circuit (100) is connected to the sine output terminal or the cosine output terminal of the rotary transformer.

3. The rotary transformer driving circuit according to claim 1, characterized in that: The signal recognition circuit (100) comprises an operational amplifier (Amp), a positive response end and a negative response end of the output end of the rotary transformer are respectively connected to two input ends of the operational amplifier (Amp), and the output end of the operational amplifier (Amp) is connected to the input end of the switch circuit (200).

4. The rotary transformer driving circuit according to claim 3, characterized in that: The signal recognition circuit (100) further comprises two first capacitors (C1), the two first capacitors (C1) being respectively connected to the in-phase input terminal and the inverting input terminal of the operational amplifier (Amp), and the positive response terminal and the negative response terminal of the rotary transformer being respectively connected to the two first capacitors (C1).

5. The rotary transformer driving circuit according to claim 3, characterized in that: The signal recognition circuit (100) further comprises a first resistor (R1), a second resistor (R2) and a third resistor (R3); the in-phase input terminal of the operational amplifier (Amp) is connected to one end of the first resistor (R1), the other end of the first resistor (R1) is connected to a power supply, the inverting input terminal of the operational amplifier (Amp) is connected to one end of the second resistor (R2), the other end of the second resistor (R2) is connected to the power supply, the in-phase input terminal of the operational amplifier (Amp) is also connected to one end of the third resistor (R3), the other end of the third resistor (R3) is grounded, and a feedback resistor (Rf) is connected between the inverting input terminal and the output terminal of the operational amplifier (Amp).

6. The rotary transformer driving circuit according to claim 1, characterized in that: The switch circuit (200) comprises a first switch element (M1), a second switch element (M2), a diode (D1), a second capacitor (C2) and a fourth resistor (R4); the first switch element (M1) and the second switch element (M2) each comprise a control end, a first controlled end and a second controlled end; the control ends of the first switch element (M1) and the second switch element (M2) are both connected to the cathode of the diode (D1); the anode of the diode (D1) is connected to the signal recognition circuit (100); the cathode of the diode (D1) is also connected to one end of the second capacitor (C2) and one end of the fourth resistor (R4); the other end of the second capacitor (C2), the other end of the fourth resistor (R4), the second controlled end of the first switch element (M1) and the first controlled end of the second switch element (M2) are all grounded; the first controlled end of the first switch element (M1) and the second controlled end of the second switch element (M2) are connected to the power factor compensation circuit (300).

7. The rotary transformer driving circuit according to claim 6, characterized in that: The first switch element (M1) and the second switch element (M2) are both N-type metal oxide semiconductors.

8. The rotary transformer driving circuit according to claim 1, characterized in that: The excitation power supply comprises an excitation first input terminal and an excitation second input terminal, the power factor compensation circuit (300) comprises a first compensation circuit (310) and a second compensation circuit (320), the first compensation circuit (310) and the second compensation circuit (320) both comprising a third capacitor (C3) and a fifth resistor (R5) connected in parallel, one end of the third capacitor (C3) of the first compensation circuit (310) being connected to the excitation first input terminal, and the other end being connected to the switch circuit (200); one end of the third capacitor (C3) of the second compensation circuit (320) being connected to the excitation second input terminal, and the other end being connected to the switch circuit (200); the first excitation input terminal being connected to the first excitation output terminal, and the second excitation input terminal being connected to the second excitation output terminal.

9. A rotary transformer driving device, characterized in that: It comprises an excitation power supply and a rotary transformer driving circuit as claimed in any one of claims 1 to 8, wherein the excitation power supply is connected to the rotary transformer driving circuit.

10. An electric vehicle, characterized in that: The rotary transformer driving circuit comprises any one of claims 1 to 8, or the rotary transformer driving device comprises the rotary transformer driving device according to claim 9.

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