Miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier
By combining isolation transformers and isolation operational amplifiers and employing high-frequency modulation technology, the size and accuracy problems of traditional resolver analog circuits have been solved, realizing miniaturized, highly integrated, and high-bandwidth resolver analog circuits suitable for high-precision motor control systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-08
- Publication Date
- 2026-04-14
AI Technical Summary
Traditional resolver simulation circuits are large in size, difficult to integrate, have poor dynamic response, and are difficult to guarantee parameter consistency, which limits the accuracy and bandwidth of resolver simulation.
By employing a combination of isolation transformers and isolation operational amplifiers, signal isolation is achieved through high-frequency modulation. High-frequency isolated power supplies and isolation operational amplifier chips are used to achieve miniaturization, integration, and high bandwidth of the signal, thereby improving signal accuracy.
It achieves miniaturization and integration of resolver analog circuits, improves signal bandwidth and accuracy, and is suitable for high-precision motor control systems with limited space.
Smart Images
Figure CN224124052U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of hardware-in-the-loop simulation technology for motor control, and in particular to a miniaturized rotary transformer simulation circuit based on isolated power supply and isolated operational amplifier. Background Technology
[0002] Motor control systems are widely used in high-tech industries such as new energy vehicles, electrified transportation, industrial automation, and intelligent robots. Hardware-in-the-loop (HIL) simulation technology is a crucial means to accelerate the research and development and testing of motor control systems. The resolver, as a key sensor component in motor control systems, is a vital link in the HIL simulation system. The resolver simulation circuit takes a sinusoidal excitation signal as input, converts it via an ADC, processes it through the resolver simulation calculation circuit, and outputs two sets of sine and cosine signals carrying the motor rotor position information via a DAC. These signals are then processed by signal conditioning and amplification circuits. To ensure consistency with a real resolver device, the sine and cosine position signals output by the resolver simulation circuit typically require electrical isolation. Traditional resolver simulation circuits use isolation transformers for electrical isolation; however, isolation transformers are large and difficult to integrate with PCB designs, usually requiring external connections, which is inconvenient. More importantly, isolation transformers have poor dynamic response and difficulty in ensuring parameter consistency, limiting the accuracy and bandwidth of resolver simulation. Utility Model Content
[0003] The purpose of this invention is to provide a miniaturized resolver simulation circuit based on isolated power supply and isolated operational amplifier, which breaks through the size and accuracy bottlenecks of traditional isolation transformer solutions, and achieves miniaturized, highly integrated, high-precision and high-bandwidth simulation, providing an effective technical solution for the next generation of hardware-in-the-loop simulation for high-precision motor control.
[0004] The resolver analog circuit provided in this solution uses a combination of isolation transformers and isolation operational amplifiers to achieve signal isolation, including:
[0005] The circuit includes a resolver analog computing circuit, two isolated operational amplifiers, and a power amplifier circuit connected to the isolated operational amplifiers. Each isolated operational amplifier is powered by an independent isolated power supply to achieve electrical isolation.
[0006] The sinusoidal excitation signal EXC+ / EXC- is input to the resolver analog calculation circuit, which generates two signals DAC1 and DAC2 containing the motor rotor position information. DAC1 and DAC2 are output as isolated signals after passing through their respective isolation operational amplifiers. The isolated signals are then output as sine and cosine signals SIN+ / SIN- and COS+ / COS-, respectively, containing the motor rotor position information, after passing through their respective power amplifier circuits.
[0007] Compared with existing technologies, this technical solution has the following characteristics and beneficial effects:
[0008] 1. Miniaturization: Traditional solutions use isolation transformers, which are large in size because they need to isolate signals at lower frequencies (10kHz and below). In contrast, the isolation operational amplifiers and isolation power supplies used in this solution are electrically isolated by high-frequency modulation, and their size is much smaller than that of the isolation transformers in traditional solutions. This makes the size of the entire resolver analog circuit ≤10×10×3mm, which is suitable for space-constrained scenarios.
[0009] 2. Integration: The isolation transformers in traditional solutions are large and irregularly shaped, making them difficult to integrate into the PCB. In contrast, the components used in this solution are smaller and have regular packaging, allowing them to be directly integrated into the PCB and automatically soldered. The manufacturing process and wiring methods are also simpler.
[0010] 3. High bandwidth: Traditional circuits are limited by the bandwidth of isolation transformers, making it difficult to process wideband signals and prone to high-frequency distortion. The isolation operational amplifier chip in this solution covers the 0-250kHz frequency band, accurately isolating and amplifying signals of different frequencies to meet the high-frequency response requirements of motor control systems.
[0011] 4. High precision: In traditional solutions, the consistency of the isolation transformer is difficult to guarantee, and the parameter error is large. However, the isolation operational amplifier used in this solution has good consistency and higher signal precision. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of a conventional rotary transformer analog circuit.
[0013] Figure 2 This is a schematic diagram of the miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier provided in this solution.
[0014] Figure 3 This is a schematic diagram of a push-pull isolation circuit used to implement an isolated power supply.
[0015] Figure 4 This is the isolation principle diagram of the isolation operational amplifier. Detailed Implementation
[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model are within the protection scope of the present utility model.
[0017] Those skilled in the art should understand that, in the disclosure of this utility model, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limitations on this utility model.
[0018] This solution provides a novel approach to isolating resolver analog signals based on a combination of isolation transformers and isolation operational amplifiers.
[0019] Figure 1 It is a circuit diagram of a traditional resolver analog circuit, by Figure 1 As can be seen, traditional resolver analog circuits achieve resolver signal isolation through isolation transformers. However, the frequency of the resolver output signal may be as low as 1kHz, and the output voltage amplitude may be as high as ±20V. The size of the transformer is determined by the voltage and frequency, resulting in a large isolation transformer in traditional resolver analog circuits. In addition, the poor consistency and poor isolation dynamic response of the isolation transformer limit the signal accuracy and bandwidth of the resolver analog.
[0020] like Figure 2 As shown, the resolver simulation circuit provided in this solution includes: a resolver simulation calculation circuit, two isolated operational amplifiers, and a power amplifier circuit connected to the isolated operational amplifiers. Each isolated operational amplifier uses an independent isolated power supply chip to achieve isolated power supply. The sinusoidal excitation signals EXC+ and EXC- are input into the resolver simulation calculation circuit to generate two DAC1 and DAC2 containing motor rotor position information. DAC1 and DAC2 are output as isolated signals after passing through their respective isolated operational amplifiers. The isolated signals are then output as SIN+ / SIN- and COS+ / COS- signals after passing through their respective power amplifier circuits.
[0021] In some embodiments, the isolation power supply is selected from any one of a forward converter circuit, a flyback circuit, an isolated full-bridge circuit, an isolated half-bridge circuit, and an isolated push-pull circuit.
[0022] Furthermore, the isolated power supply chip is selected from ADP1074, LT8302, MAX13256, ADUM4221, SN6507 and other power driver chips with isolation functions.
[0023] To further reduce the overall size of the isolated power supply, this solution uses an isolated power supply chip with a switching frequency greater than 1MHz. At high frequencies, the transformer size can be as small as 4*5*3mm.
[0024] The following uses the first isolated operational amplifier as an example to illustrate its circuit connection with the corresponding isolated power supply and resolver analog signal. The non-isolated side positive and negative power supply pins (VDD1 and GND1) of the isolated operational amplifier are connected to the positive and negative terminals (VDD and GND) of the non-isolated power supply, respectively. The input positive and negative terminals of the isolated power supply are connected to the positive and negative terminals (VDD and GND) of the non-isolated power supply, respectively. The output positive and negative terminals (VDD_ISO1 and GND_ISO1) of the isolated power supply are connected to the isolated side positive and negative power supply pins (VDD2 and GND2) of the isolated operational amplifier, respectively. The signal input pin (IN) of the isolated operational amplifier is connected to the signal output (DAC1) of the resolver analog calculation circuit, and the signal output pin (OUT) of the isolated operational amplifier is connected to the power amplifier circuit to finally output the isolated resolver analog signal (SIN+ / SIN-).
[0025] like Figure 3 The diagram shows a push-pull isolation circuit for implementing an isolated power supply. The isolated power supply includes an isolation power supply driver chip (U1, model SN6507), a transformer (T1), two Schottky diodes (D1 and D2) with identical parameters, an inductor (L1), and a capacitor (C1). The VCC pin of the isolation power supply chip is connected to the positive terminal (VDD) of the non-isolated power supply and to the center tap of the primary side of the transformer. The GND pin of the isolation power supply chip is connected to the negative terminal (GND) of the non-isolated power supply. The SW1 and SW2 pins of the isolation power supply chip are connected to the positive and negative terminals of the primary side of the transformer (T1), respectively. The positive and negative terminals of the secondary side of the transformer (T1) are connected to the anodes of Schottky diodes D1 and D2, respectively. The cathodes of D1 and D2 are connected to the positive output terminal (VDD_ISO) of the isolated power supply through inductor L1. The center tap of the secondary side of the transformer is connected to the negative output terminal (GND_ISO) of the isolated power supply. The filter capacitor C1 is connected between the positive and negative output terminals (VDD_ISO and GND_ISO) of the isolated power supply.
[0026] like Figure 4 The diagram illustrates the isolation principle of an isolated operational amplifier. An "internal clock" generates a series of high-frequency pulse signals, serving as the time reference and modulation signal source for the entire isolated transmission process. In the "input signal superimposed with high-frequency modulation signal passing through the isolation barrier" stage, the original "high-side input signal" to be transmitted is superimposed and modulated with the high-frequency signal generated by the "internal clock." The superimposed and modulated signal can cross the isolation barrier of the operational amplifier. The isolation barrier blocks the direct electrical connection between the input and output, preventing electrical interference and ground loops, but allows the modulated signal to be transmitted via non-electrical connections such as magnetic fields or light. The signal transmitted to the low side after passing through the isolation barrier is "restored to the original signal and output to the low side," thus obtaining a signal at the output that is consistent with the original signal at the input, except that electrical isolation is achieved between the input and output, effectively preventing signal interference and noise propagation, and ensuring system stability and reliability.
[0027] Since isolation operational amplifiers achieve signal isolation and amplification through modulation and demodulation circuits of high-frequency carriers, they can be compatible with bandwidths in the range of 0-250kHz and have a very small size and very high integration.
[0028] In some embodiments, the isolation operational amplifier is selected from ISO224, ADUM4195, AMC1350 and other operational amplifiers with isolation capabilities.
[0029] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been 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.
[0030] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier, characterized in that, include: The circuit consists of a resolver analog computing circuit, two isolated operational amplifiers, and a power amplifier circuit connected to the isolated operational amplifiers. Each isolated operational amplifier is powered by an independent isolated power supply to achieve electrical isolation. The sinusoidal excitation signal EXC+ / EXC- is input to the resolver analog calculation circuit, which generates two signals DAC1 and DAC2 containing the motor rotor position information. DAC1 and DAC2 are output as isolated signals after passing through their respective isolation operational amplifiers. The isolated signals are then output as sine and cosine signals SIN+ / SIN- and COS+ / COS-, respectively, containing the motor rotor position information, after passing through their respective power amplifier circuits.
2. The miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier according to claim 1, characterized in that, The isolation power supply can be any of the following: forward converter, flyback converter, isolated full-bridge converter, isolated half-bridge converter, isolated push-pull converter, or other solutions that can be used as isolation power supplies.
3. The miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier according to claim 2, characterized in that, The isolated power driver chip is selected from ADP1074, LT8302, MAX13256, ADUM4221, SN6507 and other power driver chips with isolation function.
4. The miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier according to claim 3, characterized in that, The switching frequency of the isolated power supply driver chip is not less than 100kHz.
5. The miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier according to claim 1, characterized in that, The positive and negative power supply pins on the isolation side of the isolated operational amplifier are connected to the positive and negative output terminals on the isolation side of the isolated power supply, respectively.
6. The miniaturized rotary transformer analog circuit based on isolated power supply and isolated operational amplifier according to claim 1, characterized in that, The isolation operational amplifiers are selected from ISO224, ADUM4195, AMC1350 and other operational amplifiers with isolation functions.