Resolver / digital conversion circuit, resolver signal processing device, resolver signal processing method, and computer program product

Abstract

A resolver / digital conversion circuit performs signal processing of a resolver sensor having a SIN excitation coil, a COS excitation coil, and a detection coil. The resolver / digital conversion circuit includes: a control device that generates an excitation signal for the SIN excitation coil and an excitation signal for the COS excitation coil; an excitation waveform generation unit that generates an excitation waveform for the SIN excitation coil based on the excitation signal for the SIN excitation coil and generates an excitation waveform for the COS excitation coil based on the excitation signal for the COS excitation coil; and a detection unit that generates a signal representing the rotation angle of the resolver sensor based on the detection signal output from the detection coil. The control device includes: a waveform generation unit that generates a PDM waveform by performing ΔΣ modulation; a first waveform memory that stores the PDM waveform corresponding to the excitation signal for the SIN excitation coil; and a second waveform memory that stores the PDM waveform corresponding to the excitation signal for the COS excitation coil.

Description

Technical Field

[0001] The present invention relates to a resolver / digital conversion circuit, a resolver signal processing device, a resolver signal processing method, and a program. Background Art

[0002] In Patent Document 1, a resolver signal processing device for performing signal processing of a resolver is described. The resolver has an exciting coil and a one-phase detection coil. The exciting coil has a first coil and a second coil with a 90° phase difference. In paragraph 0023, it is described that a pulse generating circuit outputs a pulsed exciting signal obtained by pulse-width modulating (PWM) a sine wave signal and applies it to the exciting coil.

[0003] In Patent Document 2 Figure 1 such as FIGS. 28 to 35, etc., an exciting circuit that outputs an exciting signal to the exciting coil of the resolver and a resolver / digital converter that inputs a signal output from the SIN detection coil of the resolver and a signal output from the COS detection coil of the resolver are described. In paragraph 0055, it is described that a ΔΣ type A / D converter is applied to a waveform generating circuit that generates an exciting waveform for the exciting coil. Further, in paragraph 0086 of Patent Document 2, it is described that a ΔΣ type waveform generating circuit is applied to the resolver / digital converter that inputs the signal output from the detection coil.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent No. 4344991 Gazette

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2007-52001 Summary of the Invention

[0008] -Problems to be Solved by the Invention-

[0009] As will be described in detail later, the present inventors have confirmed in a careful study that when an exciting signal generated by pulse-width modulation (PWM) is applied as in the technology described in Patent Document 1, deformation of the exciting waveform for exciting the exciting coil occurs and it is difficult to eliminate it by a filter circuit. It has been found that deformation of the exciting waveform for exciting the exciting coil can be reduced more in the case of applying an exciting signal generated by pulse density modulation (PDM) (specifically, ΔΣ modulation) than in the case of pulse-width modulation (PWM), and the error of the rotation angle detected by the resolver sensor can be reduced.

[0010] In addition, the present inventors have found in their careful research that, for example, in the case of applying ΔΣ modulation to the resolver described in Patent Document 2, a higher sampling frequency is required compared to the case of applying pulse width modulation (PWM). By providing a circuit structure that stores in a memory the PDM (pulse density modulation) waveform generated by performing ΔΣ modulation, even a low-cost waveform generation circuit can easily achieve a high sampling frequency.

[0011] In other words, an object of the present invention is to provide a resolver / digital conversion circuit, a resolver signal processing device, a resolver signal processing method, and a program that can reduce distortion of an excitation waveform for exciting an excitation coil, can reduce an error in a rotation angle detected by a resolver sensor, and can reduce the cost of a circuit structure.

[0012] -Means for Solving the Problem-

[0013] One aspect of the present invention is a resolver / digital conversion circuit that performs signal processing of a resolver sensor including a SIN excitation coil, a COS excitation coil, and a detection coil. The resolver / digital conversion circuit includes: a control device that generates an excitation signal for the SIN excitation coil and an excitation signal for the COS excitation coil; an excitation waveform generation unit that generates an excitation waveform for the SIN excitation coil based on the excitation signal for the SIN excitation coil generated by the control device, and generates an excitation waveform for the COS excitation coil based on the excitation signal for the COS excitation coil generated by the control device; and a detection unit that generates a signal representing the rotation angle of the resolver sensor based on a detection signal output from the detection coil. The control device includes: a waveform generation unit that generates a PDM (pulse density modulation) waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil by performing ΔΣ modulation; a first waveform memory that stores information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation coil; and a second waveform memory that stores information for generating the PDM waveform corresponding to the excitation signal for the COS excitation coil.

[0014] In the resolver / digital conversion circuit according to one aspect of the present invention, the first waveform memory may store the modulation wave component and the carrier wave component as separate and independent information, and the second waveform memory may store the modulation wave component and the carrier wave component as separate and independent information.

[0015] In a resolver / digital conversion circuit according to an aspect of the present invention, the control device may also include: a control logic that causes the waveform generation unit to perform a process of generating a PDM waveform, the control logic generating an excitation signal for the SIN excitation coil corresponding to the PDM waveform stored in the first waveform memory, and generating an excitation signal for the COS excitation coil corresponding to the PDM waveform stored in the second waveform memory.

[0016] In a resolver / digital conversion circuit according to an aspect of the present invention, the waveform generation unit may also include: a storage unit that stores an amplitude-modulated wave; an amplifier that amplifies the amplitude-modulated wave stored in the storage unit; and a ΔΣ modulation unit that performs ΔΣ modulation on the amplitude-modulated wave amplified by the amplifier, the amplifier amplifying the amplitude-modulated wave according to an instruction of an amplitude value from the control logic.

[0017] In a resolver / digital conversion circuit according to an aspect of the present invention, the waveform generation unit may separately generate a PDM waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil, and the control logic generates the excitation signal for the SIN excitation coil and the excitation signal for the COS excitation coil at a timing different from the timing when the waveform generation unit generates the PDM waveform corresponding to the excitation signal for the SIN excitation coil or the PDM waveform corresponding to the excitation signal for the COS excitation coil.

[0018] In a resolver / digital conversion circuit according to an aspect of the present invention, the control device may also include: a communication unit that receives, from outside the control device, an instruction of an amplitude value sent from the control logic to the amplifier.

[0019] In a resolver / digital conversion circuit according to an aspect of the present invention, the ΔΣ modulation unit may be constituted by a ΔΣ modulator.

[0020] In a resolver / digital conversion circuit according to an aspect of the present invention, the resolver sensor may further include: another SIN excitation coil, another COS excitation coil, and another detection coil. The control device generates an excitation signal for the another SIN excitation coil and an excitation signal for the another COS excitation coil. The resolver / digital conversion circuit includes: another excitation waveform generation unit that generates an excitation waveform for the another SIN excitation coil based on the excitation signal for the another SIN excitation coil generated by the control device, and generates an excitation waveform for the another COS excitation coil based on the excitation signal for the another COS excitation coil generated by the control device; and another detection unit that generates a signal representing the rotation angle of the resolver sensor based on a detection signal output from the another detection coil. The waveform generation unit generates a PDM waveform corresponding to the excitation signal for the another SIN excitation coil and a PDM waveform corresponding to the excitation signal for the another COS excitation coil by performing ΔΣ modulation. The control device includes: a third waveform memory that stores information for generating the PDM waveform corresponding to the excitation signal for the another SIN excitation coil; and a fourth waveform memory that stores information for generating the PDM waveform corresponding to the excitation signal for the another COS excitation coil.

[0021] In a resolver / digital conversion circuit according to an aspect of the present invention, the waveform generation unit may execute control logic for generating a PDM waveform to generate the excitation signal for the another SIN excitation coil corresponding to the PDM waveform stored in the third waveform memory, and generate the excitation signal for the another COS excitation coil corresponding to the PDM waveform stored in the fourth waveform memory.

[0022] In a resolver / digital conversion circuit according to an aspect of the present invention, the waveform generation unit may respectively generate: a PDM waveform corresponding to the excitation signal for the SIN excitation coil, a PDM waveform corresponding to the excitation signal for the COS excitation coil, a PDM waveform corresponding to the excitation signal for the other SIN excitation coil, and a PDM waveform corresponding to the excitation signal for the other COS excitation coil. The control logic generates the excitation signal for the SIN excitation coil, the excitation signal for the COS excitation coil, the excitation signal for the other SIN excitation coil, and the excitation signal for the other COS excitation coil at a timing different from the timing at which the waveform generation unit generates the PDM waveform corresponding to the excitation signal for the SIN excitation coil, the PDM waveform corresponding to the excitation signal for the COS excitation coil, the PDM waveform corresponding to the excitation signal for the other SIN excitation coil, or the PDM waveform corresponding to the excitation signal for the other COS excitation coil.

[0023] One aspect of the present invention is a resolver signal processing device including: a resolver / digital conversion circuit; and the resolver sensor including the SIN excitation coil, the COS excitation coil, and the detection coil.

[0024] One aspect of the present invention is a resolver signal processing device including: a resolver / digital conversion circuit; and the resolver sensor including the SIN excitation coil, the COS excitation coil, the detection coil, the other SIN excitation coil, the other COS excitation coil, and the other detection coil.

[0025] One aspect of the present invention is a resolver signal processing method, which includes an exciting signal generation step. In the exciting signal generation step, a control device generates an exciting signal for the SIN exciting coil and the exciting signal for the COS exciting coil. The control device is provided in a resolver / digital conversion circuit that processes signals of a resolver sensor including a SIN exciting coil, a COS exciting coil, and a detection coil. The resolver / digital conversion circuit includes: an exciting waveform generation unit that generates an exciting waveform for the SIN exciting coil according to the exciting signal for the SIN exciting coil generated by the control device, and generates an exciting waveform for the COS exciting coil according to the exciting signal for the COS exciting coil generated by the control device; and a detection unit that generates a signal representing the rotation angle of the resolver sensor based on the detection signal output from the detection coil. The resolver signal processing method further includes: a waveform generation step in which the control device generates a PDM waveform corresponding to the exciting signal for the SIN exciting coil and a PDM waveform corresponding to the exciting signal for the COS exciting coil by performing ΔΣ modulation; a first waveform storage step of storing information for generating the PDM waveform corresponding to the exciting signal for the SIN exciting coil generated by the control device in the waveform generation step; and a second waveform storage step of storing information for generating the PDM waveform corresponding to the exciting signal for the COS exciting coil generated by the control device in the waveform generation step.

[0026] One aspect of the present invention is a program that causes a computer constituting a control device included in a resolver / digital conversion circuit to execute an excitation signal generation step of generating an excitation signal for a SIN excitation coil and an excitation signal for a COS excitation coil. The resolver / digital conversion circuit performs signal processing of a resolver sensor including a SIN excitation coil, a COS excitation coil, and a detection coil. The resolver / digital conversion circuit includes: an excitation waveform generation unit that generates an excitation waveform for the SIN excitation coil based on the excitation signal for the SIN excitation coil generated by the control device, and generates an excitation waveform for the COS excitation coil based on the excitation signal for the COS excitation coil generated by the control device; and a detection unit that generates a signal representing the rotation angle of the resolver sensor based on a detection signal output from the detection coil. The computer further executes the following steps: a waveform generation step of generating a PDM waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil by performing ΔΣ modulation; a first waveform storage step of storing information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation coil generated in the waveform generation step; and a second waveform storage step of storing information for generating the PDM waveform corresponding to the excitation signal for the COS excitation coil generated in the waveform generation step.

[0027] -Advantages of the Invention-

[0028] According to the present invention, it is possible to provide a resolver / digital conversion circuit, a resolver signal processing device, a resolver signal processing method, and a program that can reduce distortion of an excitation waveform for exciting an excitation coil, can reduce an error in a rotation angle detected by a resolver sensor, and can reduce the cost of a circuit structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 FIG. is an example showing a resolver signal processing device 1 according to the first embodiment.

[0030] Figure 2 FIG. is an example showing the structure of a control device 11G of the resolver signal processing device 1 according to the first embodiment.

[0031] Figure 3 FIG. is an example showing the relationship between a control logic 11G41, an excitation waveform generation unit 11G42, an SPI communication unit 11G44, and waveform memories 11G451, 11G452, 11G453, 11G454 of the control device 11G of the resolver signal processing device 1 according to the first embodiment.

[0032] Figure 4 This is a diagram showing the structures of the waveform generation units R42, R42-2, R42-3, and R42-4 of the first modification example.

[0033] Figure 5 This is a diagram showing an example of the structure of the ΔΣ modulation unit 11G423 of the waveform generation unit 11G42 of the control unit 11G of the resolver signal processing device 1 of the first embodiment.

[0034] Figure 6 This is a diagram for explaining the Sin table used to generate the PDM waveform according to the first embodiment.

[0035] Figure 7 This is a diagram for explaining in detail the Sin table used to generate the PDM waveform according to the first embodiment.

[0036] Figure 8 This is a diagram for explaining the generation of the PDM waveform according to the first embodiment.

[0037] Figure 9 This is a diagram showing a specific example of the band-pass filter 11A1 of the excitation waveform generation unit 11A of the resolver signal processing device 1 of the first embodiment, etc.

[0038] Figure 10 This is a flowchart for explaining an example of the processing executed by the control unit 11G of the resolver signal processing device 1 of the first embodiment.

[0039] Figure 11 This is a diagram comparing the relationship between frequency and signal strength (spectrum) of the resolver signal processing device of the first comparative example using the PWM waveform and the resolver signal processing device 1 of the first embodiment using the PDM waveform.

[0040] Figure 12 This is a diagram comparing, for example, the presence or absence of distortion in the envelope when digitally modulating a waveform of 250 kHz ± 16 kHz between the resolver signal processing device of the first comparative example using the PWM waveform and the resolver signal processing device 1 of the first embodiment using the PDM waveform.

[0041] Figure 13 This is a diagram for explaining the problems of the resolver signal processing device of the first comparative example using the PWM waveform to generate the excitation waveform.

[0042] Figure 14 This is a diagram for explaining the effects of the resolver signal processing device 1 of the first embodiment using the PDM waveform to generate the excitation waveform.

[0043] Figure 15 This is a diagram showing an example of the resolver signal processing device 1 according to the second embodiment.

[0044] Figure 16 This is a flowchart for explaining an example of the processing executed by the control device 11G of the resolver signal processing device 1 according to the second embodiment. Detailed Embodiment

[0045] Hereinafter, embodiments of the resolver / digital conversion circuit, resolver signal processing device, resolver signal processing method, and program of the present invention will be described with reference to the accompanying drawings.

[0046] <First Embodiment>

[0047] Figure 1 This is a diagram showing an example of the resolver signal processing device 1 according to the first embodiment.

[0048] In Figure 1 In the example shown, the resolver signal processing device 1 includes: a resolver / digital conversion circuit (RDC circuit) 11, a resolver sensor 1A, and an external communication unit 1B.

[0049] The resolver sensor 1A is, for example, a sheet coil type resolver with an axis multiple angle of nX described in International Publication WO2022 / 124413. The resolver sensor 1A includes: a SIN excitation coil 12 for 1X, a COS excitation coil 13 for 1X, and a detection coil 14 for 1X. In addition, the resolver sensor 1A includes: a SIN excitation coil 15 for nX, a COS excitation coil 16 for nX, and a detection coil 17 for nX. The detection coils 12 to 14 for 1X and the detection coils 15 to 17 for nX detect the rotational position of the same axis and are arranged coaxially.

[0050] The resolver / digital conversion circuit 11 performs signal processing on the signals input to the resolver sensor 1A and the signals output from the resolver sensor 1A. The external communication unit 1B is a user interface or the like with other devices (such as a motor control device, etc.) connected to the resolver signal processing device 1.

[0051] In Figure 1 In the example shown, the resolver signal processing device 1 includes the external communication unit 1B, but in other examples, the resolver signal processing device 1 may not include the external communication unit 1B. In other words, the function equivalent to the external communication unit 1B may also be provided independently of the resolver signal processing device 1.

[0052] In Figure 1In the example shown, the resolver / digital conversion circuit 11 includes: an excitation waveform generation unit 11A, amplifiers 11B1 and 11B2, a detection unit 11C, an excitation waveform generation unit 11D, amplifiers 11E1 and 11E2, a detection unit 11F, and a control device 11G.

[0053] In Figure 1 the example shown, the control device 11G is constituted by an FPGA (Field Programmable Gate Array), but in other examples, the control device 11G may also be constituted by components other than the FPGA (for example, an LSI (Large Scale Integration) such as a DSP (Digital Signal Processor), a PLD (Programmable Logic Device), or an ASIC (Application Specific Integrated Circuit)).

[0054] In Figure 1 the example shown, the control device 11G generates an excitation signal Sin_1X for the SIN excitation coil 12 (see Figure 3 ) and an excitation signal Cos_1X for the COS excitation coil 13 (see Figure 3 ). The excitation signal Sin_1X and the excitation signal Cos_1X are digital signals for generating analog signals to be output to the SIN excitation coil 12 and the COS excitation coil 13, respectively.

[0055] The excitation waveform generation unit 11A generates an analog signal by smoothing the digital signal output from the control device 11G. The excitation waveform generation unit 11A includes a band-pass filter 11A1 and a band-pass filter 11A2. The band-pass filter 11A1 generates an excitation waveform Sin for the SIN excitation coil 12 based on the excitation signal Sin_1X for the SIN excitation coil 12 generated by the control device 11G. The band-pass filter 11A2 generates an excitation waveform Cos for the COS excitation coil 13 based on the excitation signal Cos_1X for the COS excitation coil 13 generated by the control device 11G.

[0056] The amplifier 11B1 amplifies the excitation waveform Sin for the SIN excitation coil 12 generated by the band-pass filter 11A1 and supplies it to the SIN excitation coil 12. The amplifier 11B2 amplifies the excitation waveform Cos for the COS excitation coil 13 generated by the band-pass filter 11A2 and supplies it to the COS excitation coil 13.

[0057] The detection unit 11C includes a detection circuit 11C1 and a phase detection unit 11C2. The detection circuit 11C1 demodulates the detection signal (modulated wave) output from the detection coil 14. Additionally, as a specific demodulation method, a synchronous detection method can also be used. The detection circuit 11C1 performs processing to extract a signal representing the rotation angle of the resolver sensor 1A from the modulated wave output from the detection coil 14 through synchronous detection. The phase detection unit 11C2 detects the rotation phase representing the rotation angle of the resolver sensor 1A based on the signal extracted by the detection circuit 11C1. That is, the detection unit 11C generates a signal representing the rotation angle of the resolver sensor 1A based on the detection signal output from the detection coil 14.

[0058] In addition, in one example shown in the figure, since there are detection coils 12 to 14 for 1X and detection coils 15 to 17 for nX, the resolver / digital conversion circuit 11 includes the same circuit as the above-mentioned 1X circuit as the nX circuit. In this figure, it shows the case where an excitation waveform generation unit 11D, an amplifier 11E1, an amplifier 11E2, and a detection unit 11F are included as the nX circuit. Additionally, regarding the structures of the excitation waveform generation unit 11D, the amplifier 11E1, the amplifier 11E2, and the detection unit 11F, they are the same as those of the excitation waveform generation unit 11A, the amplifier 11B1, the amplifier 11B2, and the detection unit 11C, so the description is omitted.

[0059] Figure 2 It is a diagram showing an example of the structure of the control device 11G of the resolver signal processing device 1 according to the first embodiment.

[0060] In Figure 2 the example shown, the control device 11G includes phase measurement units 11G1, 11G2, a PLL (phase synchronization circuit) 11G3, a control unit 11G4, and waveform memories 11G451, 11G452, 11G453, 11G454.

[0061] The phase measurement unit 11G1 measures the rotation angle of the resolver sensor 1A based on the signal output from the phase detection unit 11C2 of the detection unit 11C. The phase measurement unit 11G2 measures the rotation angle of the resolver sensor 1A based on the signal output from the phase detection unit 11F2 of the detection unit 11F. The PLL 11G3 outputs a clock to the phase measurement unit 11G1, the control unit 11G4, and the waveform memories 11G451, 11G452, 11G453, 11G454.

[0062] In Figure 2In the example shown, PLL11G3 outputs a 200 MHz clock to the phase measurement unit 11G1, a 20 MHz clock to the control unit 11G4, and a 100 MHz clock to the waveform memories 11G451, 11G452, 11G453, and 11G454. In other examples, the frequencies of the clocks output from PLL11G3 to the phase measurement unit 11G1, the control unit 11G4, and the waveform memories 11G451, 11G452, 11G453, and 11G454 can also be different from Figure 2 the example shown.

[0063] In Figure 2 the example shown, the control unit 11G4 includes: a control logic 11G41, a waveform generation unit 11G42, a statistical processing unit 11G43, and an SPI (Serial Peripheral Interface) communication unit 11G44. The control logic 11G41 causes the waveform generation unit 11G42 to perform a process of generating a PDM waveform. The waveform generation unit 11G42 generates a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 (refer to Figure 3 ) by performing ΔΣ modulation, a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 (refer to Figure 3 ), a PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15 (refer to Figure 3 ), and a PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16 (refer to Figure 3 ).

[0064] The statistical processing unit 11G43 performs statistical processing of the rotation angle of the resolver sensor 1A measured by the phase measurement unit 11G2 (for example, a process of quantifying multiple values, etc.). The SPI communication unit 11G44 is, for example, a communication port or the like and performs communication with the external communication unit 1B. The communication method is not limited to SPI communication, and serial communication such as RS485 and I2C or other communication methods can also be used. The SPI communication unit may be abbreviated as the communication unit.

[0065] The waveform memory 11G451 stores information for generating a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12. The waveform memory 11G451 may also store the modulation wave component and the carrier wave component as separate and independent information. The waveform memory 11G452 stores information for generating a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13. The waveform memory 11G452 may also store information that includes the modulation wave component and the carrier wave component as separate and independent information. The waveform memory 11G453 stores information for generating a PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15. The waveform memory 11G453 may also store information that includes the modulation wave component and the carrier wave component as separate and independent information. The waveform memory 11G454 stores information for generating a PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16. The waveform memory 11G454 may also store information that includes the modulation wave component and the carrier wave component as separate and independent information.

[0066] In Figure 2 In the example shown, the control logic 11G41 causes the waveform generation unit 11G42 to perform a process of generating a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12. The waveform memory 11G451 stores information for generating the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 generated by the waveform generation unit 11G42.

[0067] Furthermore, the control logic 11G41 generates the excitation signal Sin_1X for the SIN excitation coil 12 corresponding to the information for generating the PDM waveform stored in the waveform memory 11G451.

[0068] The control logic 11G41 causes the waveform generation unit 11G42 to perform a process of generating a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13. The waveform memory 11G452 stores information for generating the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 generated by the waveform generation unit 11G42.

[0069] Furthermore, the control logic 11G41 generates the excitation signal Cos_1X for the COS excitation coil 13 corresponding to the information for generating the PDM waveform stored in the waveform memory 11G452.

[0070] In addition, the excitation signal Sin_nX for the SIN excitation coil 15 is generated in the same manner as the excitation signal Sin_1X for the SIN excitation coil 12, and the excitation signal Cos_nX for the COS excitation coil 16 is generated in the same manner as the excitation signal Cos_1X for the COS excitation coil 13. Therefore, the descriptions of the excitation signal Sin_nX and the excitation signal Cos_nX are omitted.

[0071] Figure 3 FIG. is an example showing the relationship among the control logic 11G41, the waveform generation unit 11G42, the SPI communication unit 11G44, and the waveform memories 11G451, 11G452, 11G453, and 11G454 of the control device 11G of the resolver signal processing device 1 according to the first embodiment.

[0072] In Figure 3 In the example shown, the waveform generation unit 11G42 includes a storage unit 11G421, an amplifier 11G422, and a ΔΣ modulation unit 11G423.

[0073] The storage unit 11G421 stores an amplitude-modulated wave (refer to Figure 3 ). As information for generating the amplitude-modulated wave, the storage unit 11G421 may also store information including a modulation wave component and a carrier component as separate and independent information. The storage unit 11G421 may be included in the waveform memory 11G451.

[0074] The amplifier 11G422 amplifies the amplitude-modulated wave stored in the storage unit 11G421. In other words, the amplifier 11G422 amplifies the amplitude-modulated wave shown on the left side of the amplifier 11G422 in Figure 3 to generate the amplitude-modulated wave shown on the right side of the amplifier 11G422 in Figure 3 . Specifically, the amplifier 11G422 amplifies the amplitude-modulated wave according to an indication of an amplitude value from the control logic 11G41. More specifically, the control logic 11G41 causes the amplifier 11G422 to perform a process of amplifying the amplitude-modulated wave according to an indication from the SPI communication unit 11G44. The SPI communication unit 11G44 receives an indication of an amplitude value from an external communication unit 1B outside the control device 11G.

[0075] The ΔΣ modulation unit 11G423 performs ΔΣ modulation on the amplitude-modulated wave amplified by the amplifier 11G422.

[0076] As information for generating the amplitude-modulated wave stored in the storage unit 11G421, for example, it may also be a sine wave table. In order to save data volume, the waveform generation unit 11G42 generates a modulation waveform by performing multiplication using one table data. That is, in Figure 3In the example shown, the modulation wave is generated from a sine wave table as the amplitude modulation wave stored in the storage unit 11G421, thereby reducing the number of electronic components. Details of the modulation wave generation will be described later. Furthermore, the waveform generation unit 11G42 uses the analog waveform as the source waveform and performs amplitude adjustment via the amplifier 11G422. Furthermore, the maximum value of the intermediate calculation value of the ΔΣ modulation is limited to 10 bits.

[0077] In addition, Figure 3 In the example shown, the waveform generating unit 11G42 independently generates a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12, generates a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13, generates a PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15, and generates a PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16.

[0078] The control logic 11G41 generates the excitation signal Sin_1X for the SIN excitation coil 12, the excitation signal Cos_1X for the COS excitation coil 13, the excitation signal Sin_nX for the SIN excitation coil 15, and the excitation signal Cos_nX for the COS excitation coil 16 at a timing different from the timing at which the waveform generating unit 11G42 generates the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12, the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13, the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15, or the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16, and outputs them from the control device 11G.

[0079] Therefore, in Figure 3 In the example shown, it is possible to exclude the following Figure 4 There is a necessity to separately (in parallel) provide a waveform generating unit R42 for generating a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12, a waveform generating unit R42-2 for generating a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13, a waveform generating unit R42-3 for generating a PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15, and a waveform generating unit R42-4 for generating a PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16 as in the first variant shown.

[0080] exist Figure 3In the example shown above, as described above, the waveform memory 11G451 stores information for generating a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 generated by the waveform generation unit 11G42, the waveform memory 11G452 stores information for generating a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 generated by the waveform generation unit 11G42, the waveform memory 11G453 stores information for generating a PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15 generated by the waveform generation unit 11G42, and the waveform memory 11G454 stores information for generating a PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16 generated by the waveform generation unit 11G42.

[0081] To generate the excitation signal Sin_1X for the SIN excitation coil 12, the control logic 11G41 only needs to read the information for generating the PDM waveform stored in the waveform memory 11G451. The information for generating the PDM waveform specifically refers to the information including the modulation wave component and the carrier wave component. Therefore, according to this embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component. In addition, to generate the excitation signal Cos_1X for the COS excitation coil 13, the control logic 11G41 only needs to read the information for generating the PDM waveform stored in the waveform memory 11G452. The information for generating the PDM waveform specifically refers to the information including the modulation wave component and the carrier wave component. Therefore, according to this embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component. Further, to generate the excitation signal Sin_nX for the SIN excitation coil 15, the control logic 11G41 only needs to read the information for generating the PDM waveform stored in the waveform memory 11G453. The information for generating the PDM waveform specifically refers to the information including the modulation wave component and the carrier wave component. Therefore, according to this embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component. In addition, to generate the excitation signal Cos_nX for the COS excitation coil 16, the control logic 11G41 only needs to read the information for generating the PDM waveform stored in the waveform memory 11G454. The information for generating the PDM waveform specifically refers to the information including the modulation wave component and the carrier wave component. Therefore, according to this embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component.

[0082] Therefore, in Figure 3 the example shown, there is no speed limit in the signal processing for waveform generation for the control device 11G, and it can operate until the operation limit of the built-in memory unit of the control device 11G.

[0083] In Figure 3 the example shown, the waveform generation unit 11G42 can also operate at a low speed. Therefore, as described above, the amplitude value of the amplitude-modulated wave can be set as a variable, and the amplitude value of the amplitude-modulated wave can be changed according to external communication.

[0084] Figure 4 FIG. is a diagram showing the structure of the waveform generation units R42, R42-2, R42-3, and R42-4 of the first modified example.

[0085] In Figure 4 the first modified example shown, the waveform generation unit R42 that generates a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12, the waveform generation unit R42-2 that generates a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13, the waveform generation unit R42-3 that generates a PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15, and the waveform generation unit R42-4 that generates a PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16 are separately (in parallel) provided.

[0086] The waveform generation units R42, R42-2, R42-3, and R42-4 each include: a storage unit R42A, a digital filter R42B, an amplifier R42C, and a ΔΣ modulation unit R42D. The storage unit R42A stores the PDM waveform (PDM data). The digital filter R42B converts the PDM waveform (PDM data) output from the storage unit R42A into an amplitude-modulated wave (analog waveform). The amplifier R42C amplifies the amplitude-modulated wave (analog waveform) generated by the digital filter R42B. The ΔΣ modulation unit R42D performs ΔΣ modulation of the amplitude-modulated wave amplified by the amplifier R42C.

[0087] In other words, in Figure 4 the first modified example shown, in view of the shortage of memory if the modulation wave waveform is directly held, the waveform is held (stored in the storage unit R42A) as PDM data, and the PDM data is temporarily returned to an analog waveform by the digital filter R42B, and a PDM waveform is regenerated by the ΔΣ modulation unit R42D. As a result, Figure 4 the waveform generation units R42, R42-2, R42-3, and R42-4 shown need to each include a digital filter R42B, and the structure becomes more redundant than that of Figure 3 the waveform generation unit 11G42 shown.

[0088] In addition, in Figure 4In the first modified example shown, it is necessary to independently (in parallel) provide the waveform generation units R42, R42-2, R42-3, and R42-4. Therefore, the structure becomes more redundant than the example shown in Figure 3 which only has one waveform generation unit 11G42.

[0089] Furthermore, when adopting the structure of the first modified example shown in Figure 4 , the maximum value of the numerical value of the ΔΣ modulation process based on the ΔΣ modulation unit R42D is large, and 17 bits (17 signal lines) are required. Therefore, the maximum operating frequency of the control device (FPGA) becomes low. Depending on the amplitude value, the operation at 66 MHz cannot be satisfied, resulting in waveform chaos.

[0090] Therefore, in the first modified example shown in Figure 4 , when it is necessary to fixedly describe the amplitude value due to the above-mentioned maximum operating frequency problem and the amplitude value needs to be changed, rewriting of the software of the control device (FPGA) is required.

[0091] In the resolver signal processing device 1 of the first embodiment, for example, by adopting the structure shown in Figure 3 , the problems of the first modified example shown in Figure 4 can be eliminated.

[0092] Figure 5 FIG. is an example diagram showing the structure of the ΔΣ modulation unit 11G423 of the waveform generation unit 11G of the control device 11G of the resolver signal processing device 1 of the first embodiment.

[0093] In the example shown in Figure 5 , the ΔΣ modulation unit 11G423 includes: an adder 423A, an amplifier 423B, an adder 423C, a Z conversion unit 423D, a feedback unit 423E, an adder 423F, an amplifier 423G, an adder 423H, a Z conversion unit 423I, a feedback unit 423J, a comparator 423K, a feedback unit 423L, an amplifier 423M, and an amplifier 423N.

[0094] An amplitude-modulated wave (analog signal) amplified by the amplifier 11G422 (refer to Figure 3 ) is input to the adder 423A. The output signal from the adder 423A is input to the amplifier 423B. The amplifier 423B amplifies the signal input from the adder 423A.

[0095] The output signal from the amplifier 423B and the signal fed back by the feedback unit 423E are input to the adder 423C. The adder 423C adds the output signal from the amplifier 423B and the signal fed back by the feedback unit 423E and outputs the result.

[0096] The Z-transform unit 423D receives the output signal from the adder unit 423C. The Z-transform unit 423D performs the Z-transform of the signal input from the adder unit 423C. The output signal from the Z-transform unit 423D is input to the feedback unit 423E and the adder unit 423F.

[0097] The feedback unit 423E feeds back the output signal from the Z-transform unit 423D to the adder unit 423C.

[0098] The output signal from the Z-transform unit 423D and the like are input to the adder unit 423F. The output signal from the adder unit 423F is input to the amplifier 423G. The amplifier 423G amplifies the signal input from the adder unit 423F.

[0099] The output signal from the amplifier 423G and the signal fed back by the feedback unit 423J are input to the adder unit 423H. The adder unit 423H adds the output signal from the amplifier 423G and the signal fed back by the feedback unit 423J and outputs the result.

[0100] The output signal from the adder unit 423H is input to the Z-transform unit 423I. The Z-transform unit 423I performs the Z-transform of the signal input from the adder unit 423H. The output signal from the Z-transform unit 423I is input to the feedback unit 423J and the comparator 423K.

[0101] The feedback unit 423J feeds back the output signal from the Z-transform unit 423I to the adder unit 423H.

[0102] The output signal from the Z-transform unit 423I is input to the comparator 423K. The comparator 423K outputs the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 (refer to Figure 3 ). In addition, the comparator 423K outputs the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 (refer to Figure 3 ). Further, the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15 (refer to Figure 3 is output to the waveform memory 11G453, and the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16 (refer to Figure 3 ) is output to the waveform memory 11G454.

[0103] The feedback unit 423L feeds back the output signal from the comparator 423K to the amplifiers 423M and 423N. In other words, the output signal from the comparator 423K fed back by the feedback unit 423L is input to the amplifier 423M. In addition, the output signal from the comparator 423K fed back by the feedback unit 423L is also input to the amplifier 423N.

[0104] The amplifier 423M amplifies the output signal from the comparator 423K fed back by the feedback unit 423L. The output signal from the amplifier 423M is input to the adder 423A. The adder 423A adds the output signal (amplitude-modulated wave) from the amplifier 11G422 (see Figure 3 ) to the output signal from the amplifier 423M.

[0105] The amplifier 423N amplifies the output signal from the comparator 423K fed back by the feedback unit 423L. The output signal from the amplifier 423N is input to the adder 423F. The adder 423F adds the output signal from the Z-transform unit 423D to the output signal from the amplifier 423N.

[0106] In other words, in the example shown in Figure 5 , the ΔΣ modulation unit 11G423 is a second-order ΔΣ modulator and is composed of a feedback-type ΔΣ modulator.

[0107] For digital operation, the sampling frequency needs to be a frequency band that is sufficiently high compared to the analog signal band. For example, about 100 times is required. When using 250 kHz as the frequency of the carrier, signal processing above 25 MHz is required.

[0108] In Figure 2 and Figure 5 , the 100 MHz clock output by the PLL11G3 is used in the example shown.

[0109] Next, referring to Figures 6 to 8 , an example of PDM waveform generation will be described. In the present embodiment, when generating the original modulation wave waveform as a PDM signal, sine wave data can also be held in a table. In order to save the amount of data used, the sine wave data held in the table can be a single table data, or the modulation waveform can be generated by performing multiplication based on the sine wave data.

[0110] Figure 6This is a diagram for explaining the Sin table used to generate the PDM waveform according to the first embodiment. Referring to this diagram, the Sin table (a table data) for generating the original modulated wave waveform as a PDM signal will be explained. On the left side of this diagram, the fundamental wave (Sin(θ)) and the waveform with the frequency of the fundamental wave multiplied by 32 (Sin(32θ)) are shown (the wavelength can also be one thirty-second). According to this embodiment, by multiplying these waveforms, the waveform shown on the right can be obtained (Sin(θ)×Sin(32θ)=Sin(32θ + θ)+Sin(32θ - θ)).

[0111] In addition, an example of the illustrated chart is a picture, and the amplitude, frequency, etc. may be different from the actual waveform.

[0112] Figure 7 This is a diagram for explaining the details of the Sin table used to generate the PDM waveform according to the first embodiment. Referring to this diagram, the details of the Sin table (a table data) for generating the original modulated wave waveform as a PDM signal will be explained. Here, since the Sin function has symmetry, by considering different cases according to the value of the input θ, the amount of data to be stored can be set to 1 / 4. Figure 7 An example of the Sin table as the fundamental wave is shown in (A) of. Figure 7 An example of the stored data is shown in (B) of. Figure 7 In (A) of and Figure 7 The horizontal axis of the diagram shown in (B) of is the angle, and the vertical axis is the amplitude. As shown in Figure 7 In (B) of, the actually stored data is a part of the fundamental wave (specifically, the interval from 0 degrees to 90 degrees). In the case of 8-bit data, Figure 7 the amount of data of the waveform shown in (B) of is 8 [bit]×2^(12 - 2)=8192 [bit], which is the amount of data for a block memory (block RAM) converging to one block.

[0113] In addition, when directly tabulating the modulated wave, since the modulated wave has no symmetry, it is difficult to reduce the amount of data. The amount of data when directly tabulating the modulated wave is 8 [bit]×2^12 = 32 [Kbit], which is the amount of data for 4 EBRs. That is, by storing a part of the fundamental wave (specifically, the interval from 0 degrees to 90 degrees), the amount of data can be set to 1 / 4.

[0114] Since the generation process of the PDM waveform can be processed at a low speed, a Sin function table can also be used. After sequentially reading the input θ and 32θ and then performing multiplication, a modulated wave can be generated. In this case, one EBR for processing is sufficient. Additionally, when using two pieces, the storage area can be expanded. Therefore, by setting the resolution to 2^13, a modulated wave with higher precision can be generated.

[0115] Figure 8 FIG. is for explaining the generation of the PDM waveform according to the first embodiment. Referring to this figure, the generation of the PDM waveform will be explained. Structure R8 is an example of a specific method for performing the PDM waveform generation process described with reference to Figure 6 and is an example of a specific method for performing the PDM waveform generation process. Structure R8 is configured to include structural elements R81 to R89. Structural element R81 is an amplifier. Structural element R81 amplifies θ by 32 times and outputs the amplified result. Structural element R82 is a selector. θ and 32θ are input to structural element R82, and as a selector, structural element R82 outputs either θ or 32θ. The output result of structural element R82 is input to structural element R83. Structural element R83 performs an output corresponding to the angle of the input θ or 32θ. Structural element R84 is a storage unit (e.g., a block memory). A part of the Sin table as the fundamental wave (e.g., one-fourth of one wavelength) is stored in structural element R84. Structural element R84 outputs the stored data to structural element R85 or structural element R86. Structural element R85 is an amplifier. As an amplifier, structural element R85 sets the output value of structural element R84 to -1 times and outputs it to structural element R86. Structural element R86 is a selector. Input to structural element R86 is a part of the Sin table as the fundamental wave (e.g., one-fourth of one wavelength) or the data with this part set to -1 times. The output of structural element R86 as a selector is controlled by structural element R83. The output of structural element R86 is stored in structural element R87 or structural element R88. Structural elements R87 and R88 are registers for storing values. The waveform of Sin(θ) is stored in structural element R87, and the waveform of Sin(32θ) is stored in structural element R88. Sin(θ) stored in structural element R87 and Sin(32θ) stored in structural element R88 are input to structural element R89. Structural element R89 outputs the result of multiplying the input Sin(θ) and Sin(32θ), i.e., Sin(θ)×Sin(32θ).

[0116] Figure 9 FIG. shows a specific example of the band-pass filter 11A1 of the excitation waveform generation unit 11A of the resolver signal processing device 1 according to the first embodiment, etc. Specifically, Figure 9The (A) shows a specific example of the band-pass filter 11A1 of the excitation waveform generation unit 11A of the resolver signal processing device 1 according to the first embodiment. Figure 9 The (B) shows a modified example of the excitation waveform generation unit 11A and the amplifier 11B1 of the resolver signal processing device 1 according to the first embodiment.

[0117] In Figure 9 In the example shown in the (A), the band-pass filter 11A1 of the excitation waveform generation unit 11A of the resolver signal processing device 1 according to the first embodiment is constituted by a π-shaped LC filter.

[0118] In Figure 9 In the modified example (example of the direct switching method) shown in the (B), an FET (field effect transistor) is used in place of Figure 1 the excitation waveform generation unit 11A and the amplifier 11B1 shown.

[0119] Figure 10 It is a flowchart for explaining an example of the processing executed by the control device 11G of the resolver signal processing device 1 according to the first embodiment.

[0120] In Figure 10 In the example shown, in step S1A, the waveform generation unit 11G42 of the control device 11G generates a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 by performing ΔΣ modulation.

[0121] Next, in step S1B, the waveform memory 11G451 of the control device 11G stores the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 generated in step S1A.

[0122] In addition, in step S2A, the waveform generation unit 11G42 of the control device 11G generates a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 by performing ΔΣ modulation.

[0123] Next, in step S2B, the waveform memory 11G452 of the control device 11G stores the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 generated in step S2A.

[0124] In addition, in step S3A, the waveform generation unit 11G42 of the control device 11G generates a PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15 by performing ΔΣ modulation.

[0125] Next, in step S3B, the waveform memory 11G453 of the control device 11G stores the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation coil 15 generated in step S3A.

[0126] In addition, in step S4A, the waveform generation unit 11G42 of the control device 11G generates a PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16 by performing ΔΣ modulation.

[0127] Next, in step S4B, the waveform memory 11G454 of the control device 11G stores the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation coil 16 generated in step S4A.

[0128] Next, in step S5, the control logic 11G41 of the control device 11G generates the excitation signal Sin_1X for the SIN excitation coil 12, the excitation signal Cos_1X for the COS excitation coil 13, the excitation signal Sin_nX for the SIN excitation coil 15, and the excitation signal Cos_nX for the COS excitation coil 16 and outputs them from the control device 11G.

[0129] [Embodiment]

[0130] The present inventor has performed an analysis comparing the deformation of the excitation waveforms in the first embodiment resolver signal processing device 1 that uses PDM waveforms to generate the excitation waveforms for the SIN excitation coil 12, the COS excitation coil 13, the SIN excitation coil 15, and the COS excitation coil 16, and the accompanying angular error of the resolver sensor 1A, with the deformation of the excitation waveforms in the resolver signal processing device of the first comparative example that uses PWM (pulse width modulation) waveforms to generate the excitation waveforms and the accompanying angular error of the resolver sensor.

[0131] In the resolver signal processing device of the first comparative example that uses PWM waveforms, the angular error of the resolver sensor is ±2.34°. In contrast, in the resolver signal processing device 1 of the first embodiment that uses PDM waveforms, the angular error of the resolver sensor 1A is ±0.12°, which can be reduced by 1 / 20.

[0132] Figure 11 It is a graph comparing the relationship between frequency and signal intensity (spectrum) between the resolver signal processing device of the first comparative example using PWM waveforms and the resolver signal processing device 1 of the first embodiment using PDM waveforms. Specifically, Figure 11 of (B) is Figure 11A graph showing an expansion near a frequency of 1000 (kHz) on the horizontal axis of (A).

[0133] As Figure 11 As shown by the two arrows in (B) below, in the resolver signal processing device of the first comparative example using a PWM waveform, a position where the signal intensity is higher than that of the resolver signal processing device 1 of the first embodiment using a PDM waveform is generated.

[0134] Figure 12 It is a graph or the like for comparing whether there is distortion in the envelope when digitally modulating a waveform of 250 kHz ± 16 kHz by using the resolver signal processing device of the first comparative example using a PWM waveform and the resolver signal processing device 1 of the first embodiment using a PDM waveform. Specifically, Figure 12 In (A) below, it is compared whether there is distortion in the envelope when digitally modulating a waveform of 250 kHz ± 16 kHz by using the resolver signal processing device of the first comparative example using a PWM waveform and the resolver signal processing device 1 of the first embodiment using a PDM waveform. Figure 12 In (B) below, the zero-crossing times when there is distortion in the envelope and the zero-crossing times when there is no distortion in the envelope are compared.

[0135] As Figure 12 As shown in (A) below, when digitally modulating a waveform of 250 kHz ± 16 kHz in the resolver signal processing device of the first comparative example using a PWM waveform and the resolver signal processing device 1 of the first embodiment using a PDM waveform respectively, in the resolver signal processing device of the first comparative example using a PWM waveform, high harmonics of 250 kHz ± 32 kHz and ±16 kHz × 2 times are generated, and the envelope is distorted. In contrast, in the resolver signal processing device 1 of the first embodiment using a PDM waveform, the envelope is not distorted.

[0136] In a modulation-wave resolver such as the resolver sensor 1A of the resolver signal processing device 1 according to the first embodiment, a composite signal of Sin / Cos signals is detected, and the rotation angle of the resolver is calculated based on the zero-crossing time of the composite signal.

[0137] As Figure 12 As shown in (B) below, when there is distortion in the envelope, the zero-crossing time of the composite signal changes, resulting in an error in the detected angle of the resolver. In the resolver signal processing device 1 of the first embodiment using a PDM waveform, the envelope is not distorted, so the angle error of the resolver sensor 1A can be reduced.

[0138] Figure 13 This is a diagram for explaining the problem of the resolver signal processing device of the first comparative example that uses a PWM waveform to generate an excitation waveform. Specifically, Figure 13 It shows the spectrum of the resolver signal processing device of the first comparative example that uses a PWM waveform to generate an excitation waveform.

[0139] As Figure 13 shown in "Waveform distortion" in, in the resolver signal processing device of the first comparative example that uses a PWM waveform to generate an excitation waveform, the high harmonics ±16 kHz × n (±16 kHz, ±48 kHz, ±80 kHz,...) of the modulation wave component become the distortion of 16 kHz during demodulation ( Figure 12 the distortion of the envelope shown in (A) of), and become the absolute angle error of the resolver sensor.

[0140] As Figure 13 shown in "Migration region" in, in the resolver signal processing device of the first comparative example that uses a PWM waveform to generate an excitation waveform, in order to attenuate the quantization noise, it is desired to make the cut-off frequency Fc of the filter as close as possible to the carrier frequency. However, due to the existence of the migration region and further the deviation of the filter constant L (= the deviation of the cut-off frequency Fc of the filter), there is a problem of attenuation to the main signal if it is too close.

[0141] Figure 14 This is a diagram for explaining the effect of the resolver signal processing device 1 of the first embodiment that uses a PDM waveform to generate an excitation waveform. Specifically, Figure 11 It shows the spectrum of the resolver signal processing device 1 of the first embodiment that uses a PDM waveform to generate an excitation waveform.

[0142] As Figure 14 shown in "Waveform distortion" and "Spectrum characteristics" in, Figure 10 the high harmonics ±16 kHz × n (±16 kHz, ±48 kHz, ±80 kHz,...) of the modulation wave component seen in the spectrum characteristics of the resolver signal processing device of the first comparative example using a PWM waveform shown in Figure 14 become non-existent in the spectrum characteristics of the resolver signal processing device 1 of the first embodiment using a PDM waveform shown in.

[0143] As Figure 14 shown in "Migration region" in, in the resolver signal processing device 1 of the first embodiment using a PDM waveform, the main component is separated from the quantization noise spectrum. Therefore, the cut-off frequency Fc of the filter can be separated from the main component, and it is difficult to be affected by the filter constant deviation.

[0144] Furthermore, in the frequency spectrum characteristics of the resolver signal processing device 1 according to the first embodiment using the PDM waveform, there is no Figure 13 high harmonic components of 500 kHz, 750 kHz, 1000 kHz, etc. of the carrier component 250 kHz ± 16 kHz as seen in the frequency spectrum characteristics of the resolver signal processing device according to the first comparative example using the PWM waveform. In the frequency spectrum characteristics of the resolver signal processing device 1 according to the first embodiment using the PDM waveform, since the quantization noise is close to the high-frequency side, in the resolver signal processing device 1 according to the first embodiment using the PDM waveform, the attenuation based on the filter is likely to be effective, and the number of filter stages can be reduced.

[0145] As described above, in the resolver signal processing device 1 according to the first embodiment, compared with the case of applying the excitation signal generated by pulse width modulation, the distortion of the excitation waveform for exciting the excitation coils (the SIN excitation coil 12 for 1X, the COS excitation coil 13 for 1X, the SIN excitation coil 15 for nX, and the COS excitation coil 16 for nX) can be reduced, and the error of the rotation angle detected by the resolver sensor 1A can be reduced.

[0146] Furthermore, in the resolver signal processing device 1 according to the first embodiment, by adopting the circuit manufacturing method in which the waveform memories 11G451, 11G452, 11G453, and 11G454 store the PDM waveform generated by performing ΔΣ modulation, compared with the case of applying ΔΣ modulation to the "one-phase excitation two-phase output resolver", the circuit structure can be cost-reduced.

[0147] <Second Embodiment>

[0148] Hereinafter, a second embodiment of the resolver / digital conversion circuit, the resolver signal processing device, the resolver signal processing method, and the program of the present invention will be described.

[0149] The resolver signal processing device 1 according to the second embodiment is configured in the same manner as the resolver signal processing device 1 according to the first embodiment described above, except for the aspects described later. Therefore, the resolver signal processing device 1 according to the second embodiment can achieve the same effects as the resolver signal processing device 1 according to the first embodiment described above, except for the aspects described later.

[0150] Figure 15 is a diagram showing an example of the resolver signal processing device 1 according to the second embodiment.

[0151] In Figure 15In the example shown, the resolver signal processing device 1 includes a resolver / digital conversion circuit 11, a resolver sensor 1A, and an external communication unit 1B.

[0152] In Figure 1 the example shown, the resolver sensor 1A includes a SIN excitation coil 12 for 1X, a COS excitation coil 13 for 1X, a detection coil 14 for 1X, a SIN excitation coil 15 for nX, a COS excitation coil 16 for nX, and a detection coil 17 for nX. However, in Figure 15 the example shown, the resolver sensor 1A includes a SIN excitation coil 12 for 1X, a COS excitation coil 13 for 1X, and a detection coil 14 for 1X, and does not include a SIN excitation coil 15 for nX (see Figure 1 ), a COS excitation coil 16 for nX (see Figure 1 ), or a detection coil 17 for nX (see Figure 1 ).

[0153] In Figure 1 the example shown, the resolver / digital conversion circuit 11 includes an excitation waveform generation unit 11A, amplifiers 11B1, 11B2, a detection unit 11C, an excitation waveform generation unit 11D, amplifiers 11E1, 11E2, a detection unit 11F, and a control device 11G. However, in Figure 12 the example shown, the resolver / digital conversion circuit 11 includes an excitation waveform generation unit 11A, amplifiers 11B1, 11B2, a detection unit 11C, and a control device 11G, and does not include an excitation waveform generation unit 11D (see Figure 1 ), amplifiers 11E1, 11E2 (see Figure 1 ), or a detection unit 11F (see Figure 1 ).

[0154] In the resolver signal processing device 1 of the first embodiment, the control device 11G includes waveform memories 11G451, 11G452, 11G453, 11G454. However, in the resolver signal processing device 1 of the second embodiment, the control device 11G includes waveform memories 11G451, 11G452, and does not include waveform memories 11G453, 11G454 (see Figure 2 and Figure 3 ).

[0155] In addition, in the resolver signal processing device 1 of the first embodiment, the control device 11G includes phase measurement units 11G1, 11G2, and a statistical processing unit 11G43. However, in the resolver signal processing device 1 of the second embodiment, the control device 11G includes a phase measurement unit 11G1 and does not include a phase measurement unit 11G2 (seeFigure 2 ), statistical processing unit 11G43 (see Figure 2 ).

[0156] In the resolver signal processing device 1 of the second embodiment, the waveform generation unit 11G42 generates a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 (see Figure 3 ) and a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 (see Figure 3 ) by performing ΔΣ modulation. Specifically, the waveform generation unit 11G42 generates a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 and a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13, respectively.

[0157] The control logic 11G41 generates the excitation signal Sin_1X for the SIN excitation coil 12 and the excitation signal Cos_1X for the COS excitation coil 13 at a timing different from the timing when the waveform generation unit 11G42 generates the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 or the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13, and outputs them from the control device 11G.

[0158] Figure 13 is a flowchart for explaining an example of the processing executed by the control device 11G of the resolver signal processing device 1 according to the second embodiment.

[0159] In Figure 13 the example shown, in step S6A, the waveform generation unit 11G42 of the control device 11G generates a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 by performing ΔΣ modulation.

[0160] Next, in step S6B, the waveform memory 11G451 of the control device 11G stores the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation coil 12 generated in step S6A.

[0161] In addition, in step S7A, the waveform generation unit 11G42 of the control device 11G generates a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 by performing ΔΣ modulation.

[0162] Next, in step S7B, the waveform memory 11G452 of the control device 11G stores the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation coil 13 generated in step S7A.

[0163] Next, in step S8, the control logic 11G41 of the control device 11G generates an excitation signal Sin_1X for the SIN excitation coil 12 and an excitation signal Cos_1X for the COS excitation coil 13 and outputs them from the control device 11G.

[0164] The above has described the present specific embodiment using the embodiments, but the present invention is not limited to such embodiments, and various modifications and substitutions can be added without departing from the gist of the present invention. The structures described in the above embodiments and examples can also be appropriately combined.

[0165] In addition, the functions of all or part of the components included in the resolver signal processing device 1 in the above embodiment can also be realized by recording a program for realizing these functions on a computer-readable recording medium and causing a computer system to read and execute the program recorded in the recording medium. Here, the so-called "computer system" refers to hardware including an OS, peripheral devices, and the like.

[0166] Furthermore, the so-called "computer-readable recording medium" refers to a storage unit such as a floppy disk, an optical disk, a ROM, a CD-ROM, and other removable media, and a hard disk built in a computer system. Further, the so-called "computer-readable recording medium" may also include a medium that dynamically holds a program for a short time, such as a communication line when sending a program via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain time, such as a volatile memory inside a computer system of a server or a client in this case. In addition, the above program can be used to realize a part of the above functions, or can be further realized by combining the above functions with a program already recorded in the computer system.

[0167] -Symbol Explanation-

[0168] 1…Resolver signal processing device, 11…Resolver / digital conversion circuit, 11A…Excitation waveform generation unit, 11A1…Band-pass filter, 11A2…Band-pass filter, 11B1…Amplifier, 11B2…Amplifier, 11C…Detection unit, 11C1…Detection circuit, 11C2…Phase detection unit, 11D…Excitation waveform generation unit, 11D1…Band-pass filter, 11D2…Band-pass filter, 11E1…Amplifier, 11E2…Amplifier, 11F…Detection unit, 11F1…Detection circuit, 11F2…Phase detection unit, 11G…Control device, 11G1…Phase measurement unit, 11G2…Phase measurement unit, 11G3…PLL, 11G4…Control unit, 11G41…Control logic, 11G42…Waveform generation unit, 11G421…Storage unit, 11G422…Amplifier, 11G423…ΔΣ modulation unit, 423A…Addition unit, 423B…Amplifier, 423C…Addition unit, 423D…Z conversion unit, 423E…Feedback unit, 423F…Addition unit, 423G…Amplifier, 423H…Addition unit, 423I…Z conversion unit, 423J…Feedback unit, 423K…Comparator, 423L…Feedback unit, 423M…Amplifier, 423N…Amplifier, 11G43…Statistical processing unit, 11G44…SPI communication unit, 11G451…Waveform memory, 11G452…Waveform memory, 11G453…Waveform memory, 11G454…Waveform memory, 12…SIN excitation coil, 13…COS excitation coil, 14…Detection coil, 15…SIN excitation coil, 16…COS excitation coil, 17…Detection coil, 1A…Resolver sensor, 1B…External communication unit.

Claims

1. A resolver / digital conversion circuit that processes signals of a resolver sensor having a SIN excitation coil, a COS excitation coil, and a detection coil, the resolver / digital conversion circuit comprising: A control device that generates an excitation signal as an amplitude modulation wave for the SIN excitation coil and an excitation signal as an amplitude modulation wave for the COS excitation coil; An excitation waveform generation unit that generates an excitation waveform for the SIN excitation coil based on the excitation signal for the SIN excitation coil generated by the control device, and generates an excitation waveform for the COS excitation coil based on the excitation signal for the COS excitation coil generated by the control device; And A detection unit that generates a signal representing the rotation angle of the resolver sensor based on a detection signal output from the detection coil, The detection unit detects a rotation phase based on the detection signal and generates a signal representing the rotation angle, The control device includes: A waveform generation unit that generates a PDM waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil by performing ΔΣ modulation, where the PDM waveform is a pulse density modulation waveform; A first waveform memory that stores information for generating a PDM waveform corresponding to the excitation signal for the SIN excitation coil; A second waveform memory that stores information for generating a PDM waveform corresponding to the excitation signal for the COS excitation coil; and Control logic that causes the waveform generation unit to execute a process of generating a PDM waveform, The waveform generation unit generates a PDM waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil respectively, The control logic generates the excitation signal for the SIN excitation coil corresponding to the PDM waveform stored in the first waveform memory, And generates the excitation signal for the COS excitation coil corresponding to the PDM waveform stored in the second waveform memory, The control logic generates the excitation signal for the SIN excitation coil and the excitation signal for the COS excitation coil at a timing different from the timing when the waveform generation unit generates a PDM waveform corresponding to the excitation signal for the SIN excitation coil or a PDM waveform corresponding to the excitation signal for the COS excitation coil.

2. The resolver / digital conversion circuit according to claim 1, wherein The first waveform memory stores the modulation wave component and the carrier wave component as separate and independent information, The second waveform memory stores the modulation wave component and the carrier wave component as separate and independent information.

3. The resolver / digital conversion circuit according to claim 1, wherein The waveform generation unit includes: A storage unit that stores an amplitude modulation wave; An amplifier that amplifies the amplitude modulation wave stored in the storage unit; and A ΔΣ modulation unit that performs ΔΣ modulation on the amplitude modulation wave amplified by the amplifier, The amplifier amplifies the amplitude-modulated wave according to an indication of the amplitude value from the control logic.

4. The resolver / digital conversion circuit according to claim 3, wherein the control device includes a communication unit that receives, from outside the control device, an indication of the amplitude value sent from the control logic to the amplifier.

5. The resolver / digital conversion circuit according to claim 3, wherein the ΔΣ modulation unit is constituted by a ΔΣ modulator.

6. A resolver signal processing device, comprising: the resolver / digital conversion circuit according to claim 1; and the resolver sensor including the SIN excitation coil, the COS excitation coil, and the detection coil.

7. A resolver / digital conversion circuit that processes signals of a resolver sensor including a SIN excitation coil, a COS excitation coil, and a detection coil, the resolver / digital conversion circuit comprising: a control device that generates an excitation signal as an amplitude-modulated wave for the SIN excitation coil and an excitation signal as an amplitude-modulated wave for the COS excitation coil; an excitation waveform generation unit that generates an excitation waveform for the SIN excitation coil to be supplied to the SIN excitation coil according to the excitation signal for the SIN excitation coil generated by the control device, and generates an excitation waveform for the COS excitation coil to be supplied to the SIN excitation coil according to the excitation signal for the COS excitation coil generated by the control device; and a detection unit that generates a signal indicating the rotation angle of the resolver sensor based on the detection signal output from the detection coil, the control device includes: a waveform generation unit that generates a PDM waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil by performing ΔΣ modulation, where the PDM waveform is a pulse density modulation waveform; a first waveform memory that stores information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation coil; and a second waveform memory that stores information for generating the PDM waveform corresponding to the excitation signal for the COS excitation coil, the resolver sensor includes an additional SIN excitation coil, an additional COS excitation coil, and an additional detection coil, the control device generates an excitation signal for the additional SIN excitation coil and an excitation signal for the additional COS excitation coil, the resolver / digital conversion circuit includes: an additional excitation waveform generation unit that generates an excitation waveform for the additional SIN excitation coil according to the excitation signal for the additional SIN excitation coil generated by the control device, and generates an excitation waveform for the additional COS excitation coil according to the excitation signal for the additional COS excitation coil generated by the control device; and an additional detection unit that generates a signal indicating the rotation angle of the resolver sensor based on the detection signal output from the additional detection coil, The waveform generation unit generates a PDM waveform corresponding to the excitation signal for the other SIN excitation coils and a PDM waveform corresponding to the excitation signal for the other COS excitation coils by performing ΔΣ modulation. The control device includes: a third waveform memory that stores information for generating a PDM waveform corresponding to the excitation signal for the other SIN excitation coils; and a fourth waveform memory that stores information for generating a PDM waveform corresponding to the excitation signal for the other COS excitation coils.

8. The resolver / digital conversion circuit according to claim 7, wherein the control logic that causes the waveform generation unit to perform the process of generating the PDM waveform generates the excitation signal for the other SIN excitation coils corresponding to the PDM waveform stored in the third waveform memory, and generates the excitation signal for the other COS excitation coils corresponding to the PDM waveform stored in the fourth waveform memory.

9. The resolver / digital conversion circuit according to claim 8, wherein the waveform generation unit separately performs: generation of a PDM waveform corresponding to the excitation signal for the SIN excitation coils, generation of a PDM waveform corresponding to the excitation signal for the COS excitation coils, generation of a PDM waveform corresponding to the excitation signal for the other SIN excitation coils, and generation of a PDM waveform corresponding to the excitation signal for the other COS excitation coils, and the control logic generates the excitation signal for the SIN excitation coils, the excitation signal for the COS excitation coils, the excitation signal for the other SIN excitation coils, and the excitation signal for the other COS excitation coils at a timing different from the timing when the waveform generation unit generates the PDM waveform corresponding to the excitation signal for the SIN excitation coils, the PDM waveform corresponding to the excitation signal for the COS excitation coils, the PDM waveform corresponding to the excitation signal for the other SIN excitation coils, or the PDM waveform corresponding to the excitation signal for the other COS excitation coils.

10. A resolver signal processing device includes: the resolver / digital conversion circuit according to claim 7; and the resolver sensor including: the SIN excitation coil, the COS excitation coil, the detection coil, the other SIN excitation coils, the other COS excitation coils, and the other detection coils.

11. A resolver signal processing method includes an excitation signal generation step in which a control device generates an excitation signal as an amplitude modulation wave for a SIN excitation coil and an excitation signal as an amplitude modulation wave for a COS excitation coil, and the control device is included in a resolver / digital conversion circuit that processes signals of a resolver sensor including the SIN excitation coil, the COS excitation coil, and a detection coil. The resolver / digital conversion circuit includes: An exciting waveform generation unit generates an exciting waveform for the SIN exciting coil based on the exciting signal for the SIN exciting coil generated by the control device, and generates an exciting waveform for the COS exciting coil based on the exciting signal for the COS exciting coil generated by the control device; A detection unit generates a signal representing the rotation angle of the resolver sensor based on the detection signal output from the detection coil; and Control logic causes the waveform generation unit to perform a process of generating a PDM waveform, The detection unit detects a rotation phase based on the detection signal and generates a signal representing the rotation angle, The resolver signal processing method includes: A waveform generation step, in which the control device generates a PDM waveform corresponding to the exciting signal for the SIN exciting coil and a PDM waveform corresponding to the exciting signal for the COS exciting coil by performing ΔΣ modulation; A first waveform storage step of storing information for generating a PDM waveform corresponding to the exciting signal for the SIN exciting coil generated by the control device in the waveform generation step; and A second waveform storage step of storing information for generating a PDM waveform corresponding to the exciting signal for the COS exciting coil generated by the control device in the waveform generation step, In the waveform generation step, a PDM waveform corresponding to the exciting signal for the SIN exciting coil and a PDM waveform corresponding to the exciting signal for the COS exciting coil are generated respectively, The resolver signal processing method further includes: A step in which the control logic generates an exciting signal for the SIN exciting coil corresponding to the PDM waveform stored in the first waveform memory; and A step in which the control logic generates an exciting signal for the COS exciting coil corresponding to the PDM waveform stored in the second waveform memory, The exciting signal for the SIN exciting coil and the exciting signal for the COS exciting coil are generated at a timing different from the timing when the waveform generation step generates a PDM waveform corresponding to the exciting signal for the SIN exciting coil or a PDM waveform corresponding to the exciting signal for the COS exciting coil.

12. A computer program product causes a computer constituting a control device included in a resolver / digital conversion circuit to execute an exciting signal generation step of generating an exciting signal for the SIN exciting coil as an amplitude modulation wave and an exciting signal for the COS exciting coil as an amplitude modulation wave, and the resolver / digital conversion circuit performs signal processing of a resolver sensor including the SIN exciting coil, the COS exciting coil, and a detection coil, The resolver / digital conversion circuit includes: An exciting waveform generation unit generates an exciting waveform for the SIN exciting coil based on the exciting signal for the SIN exciting coil generated by the control device, and generates an exciting waveform for the COS exciting coil based on the exciting signal for the COS exciting coil generated by the control device; A detection unit that generates a signal representing the rotation angle of the resolver sensor based on a detection signal output from the detection coil; and A control logic that causes the waveform generation unit to perform a process of generating a PDM waveform, The detection unit detects a rotation phase based on the detection signal and generates a signal representing the rotation angle, Causing a computer to execute the following steps: A waveform generation step of generating a PDM waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil by performing ΔΣ modulation; A first waveform storage step of storing information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation coil generated in the waveform generation step; and A second waveform storage step of storing information for generating the PDM waveform corresponding to the excitation signal for the COS excitation coil generated in the waveform generation step, The waveform generation step generates a PDM waveform corresponding to the excitation signal for the SIN excitation coil and a PDM waveform corresponding to the excitation signal for the COS excitation coil respectively, Causing the computer to further execute the following steps: A step in which the control logic generates the excitation signal for the SIN excitation coil corresponding to the PDM waveform stored in the first waveform memory; and A step in which the control logic generates the excitation signal for the COS excitation coil corresponding to the PDM waveform stored in the second waveform memory, The excitation signal for the SIN excitation coil and the excitation signal for the COS excitation coil are generated at a timing different from the timing when the waveform generation step generates the PDM waveform corresponding to the excitation signal for the SIN excitation coil or the PDM waveform corresponding to the excitation signal for the COS excitation coil.

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