RESOLVER / DIGITAL CONVERTER CIRCUIT, RESOLVER SIGNAL PROCESSING DEVICE, RESOLVER SIGNAL PROCESSING METHOD AND PROGRAM

Abstract

Resolver / digital converter circuit, including: a control device (11G) of a resolver / digital converter circuit (11) which performs signal processing of a resolver sensor with a SIN excitation winding (12), a COS excitation winding (13) and a sensing winding (14), generates an excitation signal for the SIN excitation winding (12) and an excitation signal for the COS excitation winding (13), an excitation waveform generation unit (11D) which generates an excitation waveform for the SIN excitation winding (12) from the excitation signal generated by the control device (11G) for the SIN excitation winding (12) and generates an excitation waveform for the COS excitation winding (13) from the excitation signal generated by the control device (11G) for the COS excitation winding (13), and a wave detection unit (11C) which, based on a detection signal output by the detection winding (14), generates a signal that indicates a rotation angle of the resolver sensor, wherein the control device (11G) is a waveform generation unit (11G42) which generates a PDM (pulse density modulated) waveform corresponding to the excitation signal for the SIN excitation winding (12) and a PDM waveform corresponding to the excitation signal for the COS excitation winding (13) by means of ΔΣ modulation, a first waveform memory (11G451) in which information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) is stored, and a second waveform memory (11G452) in which information for generating the PDM waveform corresponding to the excitation signal for the COS excitation winding (13) is stored.

Description

Technical area

[0001] The present invention relates to a resolver / digital conversion circuit, a resolver signal processing apparatus, a resolver signal processing method, and a program. General state of the art

[0002] Patent Document 1 discloses a resolver signal processing device that performs signal processing of a resolver having an excitation winding with first and second windings whose phases are 90° different from each other and a detection winding with one phase. Paragraph 0023 states that a pulse generating circuit outputs a pulse-shaped excitation signal in which a sine wave signal is subjected to pulse width modulation (PWM) and applied to the excitation winding.

[0003] Patent Document 2 discloses, among other things, Fig. 1 and Fig. 28 to Fig. 35, an excitation circuit that outputs an excitation signal to an excitation winding of a resolver, and a resolver-to-digital converter to which a signal output from a SIN detection winding of the resolver and a signal output from a COS detection winding of the resolver are input, are specified. Paragraph 0055 states that a ΔΣ-type A / D converter is applied to a waveform generation circuit that generates an excitation waveform for the excitation winding. Paragraph 0086 of Patent Document 2 states that a ΔΣ-type waveform generation circuit is applied to the resolver-to-digital converter to which the signal output from the detection winding is input. Prior art documentsPatent documents Patent document 1: JP 4 344 991 B2 Patent document 2: JP 2007 - 52 001 A Brief description of the inventionTask of the invention

[0004] As described in detail below, the inventor of the present invention has discovered through intensive research that when an excitation signal generated by pulse width modulation (PWM) as in the technique of Patent Document 1 is used, distortion of the excitation waveform exciting the excitation coil occurs, which is difficult to eliminate using a filter circuit. It has been found that when an excitation signal generated by pulse density modulation (PDM) (more precisely, ΔΣ modulation) is used, the distortion of the excitation coil's excitation waveform can be reduced compared to pulse width modulation (PWM), thereby reducing an error in a rotation angle detected by a resolver sensor.

[0005] Through intensive research, the inventor also found that although applying ΔΣ modulation to a resolver as disclosed in Patent Document 2, for example, requires a higher sampling frequency compared to applying pulse width modulation (PWM), by means of a circuit configuration that stores a PWM (pulse density modulated) waveform generated by performing ΔΣ modulation in a memory, a high sampling frequency can be easily achieved even with a low-cost waveform generating circuit.

[0006] Therefore, an object of the present invention is to provide a resolver-to-digital converter circuit, a resolver signal processing apparatus, a resolver signal processing method, and a program capable of reducing the distortion of an excitation waveform exciting an excitation winding, reducing an error of a rotation angle detected by a resolver sensor, and achieving a cost reduction of the circuit configuration. Means of solving the task

[0007] One aspect of the present invention is a resolver-to-digital conversion circuit that performs signal processing of a resolver sensor having a SIN excitation winding, a COS excitation winding, and a detection winding, comprising a control device that generates an excitation signal for the SIN excitation winding and an excitation signal for the COS excitation winding, an excitation waveform generation unit that generates an excitation waveform for the SIN excitation winding from the excitation signal for the SIN excitation winding generated by the control device, and an excitation waveform for the COS excitation winding from the excitation signal for the COS excitation winding generated by the control device, and a wave detection unit that generates a signal indicative of a rotation angle of the resolver sensor based on a detection signal output from the detection winding, wherein the control device comprises a waveform generation unit,which generates a PDM (pulse density modulated) waveform corresponding to the excitation signal for the SIN excitation winding and a PDM waveform corresponding to the excitation signal for the COS excitation winding by means of ΔΣ modulation, a first waveform memory in which information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation winding is stored, and a second waveform memory in which information for generating the PDM waveform corresponding to the excitation signal for the COS excitation winding is stored.

[0008] In a resolver-to-digital converter circuit in one aspect of the present invention, the first waveform memory may store a modulation wave component and a carrier wave component as separate and independent information, and the second waveform memory may store a modulation wave component and a carrier wave component as separate and independent information.

[0009] In a resolver-to-digital converter circuit in one aspect of the present invention, the control device may include control logic that causes the waveform generation unit to perform processing for generating a PDM waveform, the control logic generating an excitation signal for the SIN excitation winding corresponding to the PDM waveform stored in the first waveform memory and an excitation signal for the COS excitation winding corresponding to the PDM waveform stored in the second waveform memory.

[0010] In a resolver-to-digital converter circuit in one aspect of the present invention, the waveform generation unit may include a storage unit in which an amplitude-modulated wave is stored, an amplifier that amplifies the amplitude-modulated wave stored in the storage unit, and a ΔΣ modulation unit that subjects the amplitude-modulated wave amplified by the amplifier to ΔΣ modulation, wherein the amplifier amplifies the amplitude-modulated wave according to a command from the control logic.

[0011] In a resolver-to-digital conversion circuit in one aspect of the present invention, the waveform generation unit may separately perform the generation of the PDM waveform corresponding to the excitation signal for the SIN excitation winding and the generation of the PDM waveform corresponding to the excitation signal for the COS excitation winding, and the control logic may generate the excitation signal for the SIN excitation winding and the excitation signal for the COS excitation winding at a timing different from the timing of the generation of the PDM waveform corresponding to the excitation signal for the SIN excitation winding or the PDM waveform corresponding to the excitation signal for the COS excitation winding by the waveform generation unit.

[0012] In a resolver-to-digital converter circuit in one aspect of the present invention, the control device may include a communication unit that receives a gain value command sent from the control logic to the amplifier from outside the control device.

[0013] In a resolver / digital converter circuit in one aspect of the present invention, the ΔΣ modulation unit may be formed by a ΔΣ modulator.

[0014] In a resolver / digital converter circuit in one aspect of the present invention, the resolver sensor may comprise a further SIN excitation winding, a further COS excitation winding, and a further detection winding, wherein the control device generates an excitation signal for the further SIN excitation winding and an excitation signal for the further COS excitation winding, wherein the resolver / digital converter circuit comprises an excitation waveform generation unit that generates an excitation waveform for the further SIN excitation winding from the excitation signal for the further SIN excitation winding generated by the control device, and an excitation waveform for the further COS excitation winding from the excitation signal for the further COS excitation winding generated by the control device, and a further wave detection unit that generates a signal based on a detection signal output from the further detection winding,which indicates a rotation angle of the resolver sensor, wherein the waveform generation unit generates a PDM waveform corresponding to the excitation signal for the further SIN excitation winding and a PDM waveform corresponding to the excitation signal for the further COS excitation winding by means of ΔΣ modulation, wherein the control device comprises a third waveform memory in which information for generating the PDM waveform corresponding to the excitation signal for the further SIN excitation winding is stored, and a fourth waveform memory in which information for generating the PDM waveform corresponding to the excitation signal for the further COS excitation winding is stored.

[0015] In a resolver-to-digital converter circuit in one aspect of the present invention, a control logic that causes the waveform generation unit to execute processing for generating a PDM waveform may generate an excitation signal for the further SIN excitation winding corresponding to the PDM waveform stored in the third waveform memory and an excitation signal for the further COS excitation winding corresponding to the PDM waveform stored in the fourth waveform memory.

[0016] In a resolver / digital converter circuit in one aspect of the present invention, the waveform generation unit may separately perform the generation of the PDM waveform corresponding to the excitation signal for the SIN excitation winding, the generation of the PDM waveform corresponding to the excitation signal for the COS excitation winding, the generation of the PDM waveform corresponding to the excitation signal for the further SIN excitation winding, and the generation of the PDM waveform corresponding to the excitation signal for the further COS excitation winding, and the control logic may generate the excitation signal for the SIN excitation winding, the excitation signal for the COS excitation winding, the excitation signal for the further SIN excitation winding, and the excitation signal for the further COS excitation winding at a time point different from the time point at which the waveform generation unit generates the PDM waveform corresponding to the excitation signal for the SIN excitation winding,generates the PDM waveform corresponding to the excitation signal for the COS excitation winding, the PDM waveform corresponding to the excitation signal for the further SIN excitation winding, or the PDM waveform corresponding to the excitation signal for the further COS excitation winding.

[0017] One aspect of the present invention is a resolver signal processing apparatus comprising a resolver-to-digital converter circuit and the resolver sensor comprising the SIN excitation winding, the COS excitation winding, and the detection winding.

[0018] One aspect of the present invention is a resolver signal processing device comprising a resolver-to-digital converter circuit and the resolver sensor comprising the SIN excitation winding, the COS excitation winding, the detection winding, the further SIN excitation winding, the further COS excitation winding and the further detection winding.

[0019] One aspect of the present invention is a resolver signal processing method comprising an excitation signal generation step, wherein a control device of a resolver-to-digital conversion circuit that performs signal processing of a resolver sensor having a SIN excitation winding, a COS excitation winding, and a detection winding generates an excitation signal for the SIN excitation winding and an excitation signal for the COS excitation winding, wherein the resolver-to-digital conversion circuit comprises an excitation waveform generation unit that generates an excitation waveform for the SIN excitation winding from the excitation signal for the SIN excitation winding generated by the control device and an excitation waveform for the COS excitation winding from the excitation signal for the COS excitation winding generated by the control device, and a wave detection unit,which generates a signal indicative of a rotation angle of the resolver sensor based on a detection signal output from the detection winding, comprising a waveform generation step in which the control device generates a PDM waveform corresponding to the excitation signal for the SIN excitation winding and a PDM waveform corresponding to the excitation signal for the COS excitation winding by means of ΔΣ modulation, a first waveform storage step in which the control device stores information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation winding generated in the waveform generation step, and a second waveform storage step in which the control device stores information for generating the PDM waveform corresponding to the excitation signal for the COS excitation winding generated in the waveform generation step.

[0020] One aspect of the present invention is a program for causing a computer that forms a control device of a resolver-to-digital conversion circuit for performing signal processing of a resolver sensor having a SIN excitation winding, a COS excitation winding, and a detection winding to execute an excitation signal generation step, wherein an excitation signal for the SIN excitation winding and an excitation signal for the COS excitation winding are generated, wherein the resolver-to-digital conversion circuit comprises an excitation waveform generation unit that generates an excitation waveform for the SIN excitation winding from the excitation signal for the SIN excitation winding generated by the control device and an excitation waveform for the COS excitation winding from the excitation signal for the COS excitation winding generated by the control device, and a wave detection unit,which generates a signal indicative of a rotation angle of the resolver sensor based on a detection signal output from the detection winding, and further performs a waveform generation step of generating a PDM waveform corresponding to the excitation signal for the SIN excitation winding and a PDM waveform corresponding to the excitation signal for the COS excitation winding by means of ΔΣ modulation, a first waveform storage step of storing information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation winding 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 winding generated in the waveform generation step. Effect of the invention

[0021] According to the present invention, a resolver-to-digital conversion circuit, a resolver signal processing apparatus, a resolver signal processing method, and a program can be provided, with which the distortion of an excitation waveform exciting an excitation winding can be reduced, an error of a rotation angle detected by a resolver sensor can be reduced, and a cost reduction of the circuit configuration can be achieved. Short description of the characters

[0022] They show: Fig. 1 is a view illustrating an example of a resolver signal processing device 1 of a first embodiment; Fig. 2 is a view illustrating an example of a control device 11G of the resolver signal processing device 1 of the first embodiment; Fig. 3 is a view illustrating an example of the relationship between control logic 11G41 of the control device 11G of the resolver signal processing device 1 of the first embodiment, a waveform generation unit 11G42, an SPI communication unit 11G44, and waveform memories 11G451, 11G452, 11G453, 11G454; Fig. 4 is a view illustrating a configuration of waveform generating units R42, R42-2, R42-3, R42-4 of the first modification example; Fig. 5 is a view illustrating an example of a configuration of a ΔΣ modulation unit 11G423 of the waveform generation unit 11G42 of the control device 11G of the resolver signal processing device 1 of the first embodiment; Fig. 6 is an explanatory view of a sin table for generating a PDM waveform according to the first embodiment; Fig. 7 is an explanatory view showing the details of the Sin table for generating a PDM waveform according to the first embodiment; Fig. 8 is an explanatory view of generating a PDM waveform according to the first embodiment; Fig. 9 is a view illustrating a concrete example of a band-pass filter 11A1 of an excitation waveform generating unit 11A of the resolver signal processing apparatus 1 of the first embodiment; Fig. 10 is a flowchart for explaining an example of processing executed by the control device 11G of the resolver signal processing device 1 of the first embodiment; Fig. 11 is a comparison view for frequency and signal strength (spectrum) between a resolver signal processing device of a first comparative example in which a PWM waveform is used and the resolver signal processing device 1 of the first embodiment in which a PWM waveform is used; Fig. 12 is a comparison view for the presence of occurrence of distortion in an envelope when digitally modulating a waveform of 250 kHz ± 16 kHz between 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 PWM waveform; Fig. 13 is an explanatory view showing the problem of the resolver signal processing device of the first comparative example in which a PWM waveform is used to generate the excitation waveform; Fig. 14 is an explanatory view of the action of the resolver signal processing apparatus 1 of the first embodiment in which a PWM waveform is used to generate the excitation waveform; Fig. 15 is a view illustrating an example of a resolver signal processing device 1 of a second embodiment; and Fig. 16 is a flowchart for explaining an example of processing executed by a control device 11G of the resolver signal processing device 1 of the second embodiment. Embodiments of the invention

[0023] Embodiments of a resolver-to-digital converter circuit, a resolver signal processing apparatus, a resolver signal processing method, and a program are described below with reference to the accompanying figures. First embodiment

[0024] Fig. 1 is a view illustrating an example of a resolver signal processing device 1 of a first embodiment. In the Fig. In the example shown in Figure 1, the resolver signal processing device 1 includes a resolver-to-digital converter (RDC) circuit 11, a resolver sensor 1A, and an external communication unit 1B. The resolver sensor 1A is, for example, a tape-winding resolver with a multiplier of nX, as described in WO 2022 / 124413 A1. The resolver sensor 1A includes a SIN excitation winding 12 for 1X, a COS excitation winding 13 for 1X, and a detection winding 14 for 1X. The resolver sensor 1A also includes a SIN excitation winding 15 for nX, a COS excitation winding 16 for nX, and a detection winding 17 for nX. The sensing windings 12-14 for 1X and the sensing windings 15-17 for nX sense rotational positions on the same axis and are arranged coaxially.

[0025] The resolver-to-digital conversion circuit 11 performs signal processing on signals input to and output from the resolver sensor 1A. The external communication unit 1B is a user interface or the like to another device connected to the resolver signal processing device 1 (for example, a motor control device or the like).

[0026] In the Fig. In the example shown in Figure 1, 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. That is, the function corresponding to the external communication unit 1B may also be provided separately from the resolver signal processing device 1.

[0027] In the Fig. 1, the resolver / digital converter circuit 11 includes an excitation waveform generation unit 11A, amplifiers 11B1, 11B2, a wave detection unit 11C, an excitation waveform generation unit 11D, amplifiers 11E1, 11E2, a wave detection unit 11F, and a controller 11G.

[0028] In the Fig. 1, the control device 11G may be formed by an FPGA (field programmable gate array), while in other examples, the control device 11G may be formed as a device other than an FPGA (for example, a DSP (digital signal processor), a PLD (programmable logic device), or an LSI (large scale integration) circuit such as an ASIC (application specific integrated circuit) or the like.

[0029] In the Fig. 1, the control device 11G generates an excitation signal Sin_1X for the SIN excitation winding 12 (see Fig. 3) and an excitation signal Cos_1X for the COS excitation winding 13 (see Fig. 3). The excitation signal Sin_1X and the excitation signal Cos_1X are digital signals for generating analog signals for output to the SIN excitation winding 12 and the COS excitation winding 13.

[0030] The excitation waveform generation unit 11A generates the analog signals by processing the digital signals output by the control device 11G. The excitation waveform generation unit 11A includes a bandpass filter 11A1 and a bandpass filter 11A2. The bandpass filter 11A1 generates an excitation waveform Sin for the SIN excitation winding 12 from the excitation signal Sin_1X for the SIN excitation winding 12 generated by the control device 11G. The bandpass filter 11A2 generates an excitation waveform Cos for the COS excitation winding 13 from the excitation signal Cos_1X for the COS excitation winding 13 generated by the control device 11G.

[0031] The amplifier 11B1 amplifies the excitation waveform Sin for the SIN excitation winding 12 generated by the bandpass filter 11A1 and supplies it to the SIN excitation winding 12. The amplifier 11B2 amplifies the excitation waveform Cos for the COS excitation winding 13 generated by the bandpass filter 11A2 and supplies it to the COS excitation winding 13.

[0032] The wave detection unit 11C includes a wave detection circuit 11C1 and a phase detection circuit 11C2. The wave detection circuit 11C1 performs demodulation on the detection signal (modulated waveform) output from the detection coil 14. Specifically, synchronous detection can be used as the demodulation method. The wave detection circuit 11C1 performs processing to extract a signal indicating the rotation angle of the resolver sensor 1A from the modulated wave output by the detection coil 14 by synchronous detection. The phase detection circuit 11C2 detects the rotation phase of the resolver sensor 1A from the signal extracted by the wave detection circuit 11C1. The shaft detection unit 11C thus generates a signal indicating the rotation angle of the resolver sensor 1A based on the detection signal output from the detection coil 14.

[0033] Since, in the illustrated example, the detection windings 12-14 are for 1X and the detection windings 15-17 are for nX, the resolver-to-digital conversion circuit 11 includes circuits for nX that are similar to the circuits for 1X described above. The figure shows the case where the circuits for nX are an excitation waveform generation unit 11D, the amplifier 11E1, the amplifier 11E2, and the wave detection unit 11F. The configuration of the excitation waveform generation unit 11D, the amplifier 11E1, the amplifier 11E2, and the wave detection unit 11F is the same as the configuration of the excitation waveform generation unit 11A, the amplifier 11B1, the amplifier 11B2, and the wave detection unit 11C, so their description is omitted.

[0034] Fig. 2 is a view illustrating an example of the control device 11G of the resolver signal processing device 1 of the first embodiment. In the Fig. In the example shown in Figure 2, the control device 11G includes phase calculation units 11G1, 11G2, a PLL (phase synchronization circuit) 11G3, a control unit 11G4, and waveform memories 11G451, 11G452, 11G453, 11G454. The phase calculation unit 11G1 calculates the rotation angle of the resolver sensor 1A based on the signal output from the phase detection circuit 11C2 of the wave detection unit 11C. The phase calculation unit 11G2 calculates the rotation angle of the resolver sensor 1A based on the signal output from the phase detection circuit 11F2 of the wave detection unit 11F. The PLL 11G3 outputs a clock to the phase calculation unit 11G1, the control unit 11G4 and the waveform memories 11G451, 11G452, 11G453, 11G454.

[0035] In the Fig. 2, the PLL 11G3 outputs a clock of 200 MHz to the phase calculation unit 11G1, a clock of 20 MHz to the control unit 11G4, and a clock of 100 MHz to the waveform memories 11G451, 11G452, 11G453, 11G454. In other examples, the frequency of the clocks output by the PLL 11G3 to the phase calculation unit 11G1, the control unit 11G4, and the waveform memories 11G451, 11G452, 11G453, 11G454 may be different from the example shown in Fig. 2 may differ.

[0036] In the Fig. In the example shown in Figure 2, 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 execute processing for generating a PDM waveform. The waveform generation unit 11G42 performs ΔΣ modulation and thus generates a waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12 (see Fig. 3) corresponding PDM waveform, one corresponding to the excitation signal Cos_1X for the COS excitation winding 13 (see Fig. 3) corresponding PDM waveform, one corresponding to the excitation signal Sin_nX for the SIN excitation winding 15 (see Fig. 3) corresponding PDM waveform and one corresponding to the excitation signal Cos_nX for the COS excitation winding 16 (see Fig. 3) corresponding PDM waveform.

[0037] The statistical processing unit 11G43 performs statistical processing on the rotation angle of the resolver sensor 1A calculated by the phase calculation unit 11G2 (for example, it performs processing for quantifying multiple values). The SPI communication unit 11G44, for example, is a communication port that performs communication with the external communication unit 1B. The communication method is not limited to SPI, and serial communication such as RS485, I2C, or the like, or other communication methods can also be used. The SPI communication unit is sometimes simply referred to as the communication unit.

[0038] The waveform memory 11G451 stores information for generating the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12. The waveform memory 11G451 can store a modulation wave component and a carrier wave component as separate and independent information. The waveform memory 11G452 stores information for generating the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13. The waveform memory 11G452 can store information including the modulation wave component and the carrier wave component as separate and independent information. The waveform memory 11G453 stores information for generating the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation winding 15. The waveform memory 11G453 can store information including the modulation wave component and the carrier wave component as separate and independent information.The waveform memory 11G454 stores information for generating the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation winding 16. The waveform memory 11G454 can store information including the modulation wave component and the carrier wave component as separate and independent information.

[0039] In the example from Fig. 2, the control logic 11G41 causes the waveform generation unit 11G42 to execute processing for generating the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12. The waveform memory 11G451 stores information for generating a PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12 generated by the waveform generation unit 11G42.

[0040] In addition, the control logic 11G41 generates an excitation signal Sin_1X for the SIN excitation winding 12, which corresponds to the information stored in the waveform memory 11G451 for generating the PDM waveform.

[0041] The control logic 11G41 causes the waveform generation unit 11G42 to execute processing for generating the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13. The waveform memory 11G452 stores information for generating a PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13 generated by the waveform generation unit 11G42.

[0042] In addition, the control logic 11G41 generates an excitation signal Cos_1X for the COS excitation winding 13, which corresponds to the information stored in the waveform memory 11G452 for generating the PDM waveform.

[0043] Since the excitation signal Sin_nX for the SIN excitation winding 15 is generated in the same way as the excitation signal Sin_1X for the SIN excitation winding 12 and the excitation signal Cos_nX for the COS excitation winding 16 is generated in the same way as the excitation signal Cos_1X for the COS excitation winding 13, the description for the excitation signal Sin_nX and the excitation signal Cos_nX is omitted.

[0044] Fig. 3 is a view illustrating an example of the relationship between the control logic 11G41 of the control device 11G of the resolver signal processing device 1 of the first, the waveform generation unit 11G42, the SPI communication unit 11G44, and the waveform memories 11G451, 11G452, 11G453, 11G454.

[0045] In the Fig. 3, the waveform generation unit 11G42 includes a storage unit 11G421, an amplifier 11G422, and a ΔΣ modulation unit 11G423.

[0046] The storage unit 11G421 stores an amplitude-modulated wave (see Fig. 3). The storage unit 11G421 may also store information including, as the information for generating the amplitude-modulated wave, the modulation wave component and the carrier wave component as separate and independent information. The storage unit 11G421 may be included in the waveform memory 11G451. The amplifier 11G422 amplifies the amplitude-modulated wave stored in the storage unit 11G421. That is, the amplifier 11G422 amplifies the Fig. 3 to the left of the amplifier 11G422 and generates a Fig. 3 shows the amplitude-modulated wave shown to the right of the amplifier 11G422. Specifically, the amplifier 11G422 amplifies the amplitude-modulated wave in response to a command from the control logic 11G41 specifying the amplitude value. Specifically, the control logic 11G41 causes the amplifier 11G422 to perform processing for amplifying the amplitude-modulated wave in response to a command from the SPI communication unit 11G44. The SPI communication unit 11G44 receives the amplitude value command from the external communication unit 1B outside the control device 11G.

[0047] The ΔΣ modulation unit 11G423 subjects the amplitude-modulated wave amplified by the amplifier 11G422 to ΔΣ modulation.

[0048] The information for generating the amplitude-modulated wave stored in the storage unit 11G421 may be, for example, a sine wave table. To reduce the amount of data used, the waveform generation unit 11G42 generates the modulated waveform by performing multiplication using a single table data entry. In the Fig. In the example shown in Figure 3, a modulated wave is generated from the sine wave table as the amplitude-modulated wave stored in the storage unit 11G421, thereby limiting the number of electronic components. The generation of the modulated wave is described in detail below. In the waveform generation unit 11G42, the analog waveform is used as the original waveform and amplitude adjustment is performed using the amplifier 11G422. A maximum value of an intermediate calculation value of the ΔΣ modulation is limited to 10 bits.

[0049] In the Fig. 3, the waveform generation unit 11G42 separately performs the generation of the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12, the generation of the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13, the generation of the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation winding 15, and the generation of the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation winding 16.

[0050] The control logic 11G41 generates the excitation signal Sin_1X for the SIN excitation winding 12, the excitation signal Cos_1X for the COS excitation winding 13, the excitation signal Sin_nX for the SIN excitation winding 15, and the excitation signal Cos_nX for the COS excitation winding 16 at a time different from the time at which the waveform generation unit 11G42 generates the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12, the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13, the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation winding 15, or the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation winding 16, and outputs it to the control device 11G.

[0051] In the Fig. 3 shown example, the need can be eliminated, as in a below described and in Fig. 4, a waveform generation unit R42 for generating the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12, a waveform generation unit R42-2 for generating the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13, a waveform generation unit R42-3 for generating the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation winding 15, and a waveform generation unit R42-4 for generating the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation winding 16 are provided separately (connected in parallel).

[0052] As discussed above, the Fig. 3, the waveform memory 11G451 stores the information for generating the PDM waveform corresponding to the excitation signal Sin_1X generated by the waveform generation unit 11G42 for the SIN excitation winding 12, the waveform memory 11G452 stores the information for generating the PDM waveform corresponding to the excitation signal Cos_1X generated by the waveform generation unit 11G42 for the COS excitation winding 13, the waveform memory 11G453 stores the information for generating the PDM waveform corresponding to the excitation signal Sin_nX generated by the waveform generation unit 11G42 for the SIN excitation winding 15, and the waveform memory 11G454 stores the information for generating the PDM waveform corresponding to the excitation signal Sin_nX generated by the waveform generation unit 11G42 Excitation signal Cos_nX for the COS excitation winding 16.

[0053] The control logic 11G41 can read the PDM waveform generation information stored in the waveform memory 11G451 to generate the excitation signal Sin_1X for the SIN excitation winding 12. The PDM waveform generation information is information including a modulation wave component and a carrier wave component. Therefore, according to the present embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component. The control logic 11G41 can read the PDM waveform generation information stored in the waveform memory 11G452 to generate the excitation signal Cos_1X for the COS excitation winding 13. The PDM waveform generation information is information including a modulation wave component and a carrier wave component.Therefore, according to the present embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component. The control logic 11G41 can also read out the PDM waveform generation information stored in the waveform memory 11G453 to generate the excitation signal Sin_nX for the SIN excitation winding 15. The PDM waveform generation information is information including a modulation wave component and a carrier wave component. Therefore, according to the present embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component. Also, the control logic 11G41 can read out the PDM waveform generation information stored in the waveform memory 11G454 to generate the excitation signal Cos_nX for the COS excitation winding 16.The information for generating the PDM waveform is information including a modulation wave component and a carrier wave component. Therefore, according to the present embodiment, the PDM waveform can be easily obtained based on the modulation wave component and the carrier wave component.

[0054] In the Fig. 3, the maximum operating frequency of the control device 11G does not determine the speed of signal processing for waveform generation, and instead, operation is possible up to the operating limit of the internal memory of the control device 11G.

[0055] In the Fig. 3, the waveform generating unit 11G42 can be operated even at low speed, and therefore, as described above, the amplitude value of the amplitude-modulated wave can be set to a variable and the amplitude value of the amplitude-modulated wave can be changed by communication from the outside.

[0056] Fig. 4 is a view illustrating a configuration of waveform generating units R42, R42-2, R42-3, R42-4 of the first modification example.

[0057] In the Fig. 4, a waveform generation unit R42 for generating the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12, a waveform generation unit R42-2 for generating the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13, a waveform generation unit R42-3 for generating the PDM waveform corresponding to the excitation signal Sin_nX for the SIN excitation winding 15, and a waveform generation unit R42-4 for generating the PDM waveform corresponding to the excitation signal Cos_nX for the COS excitation winding 16 are provided separately (connected in parallel).

[0058] The waveform generation units R42, R42-2, R42-3, and R42-4 each comprise 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 subjects the amplitude-modulated wave amplified by the amplifier R42C to ΔΣ modulation.

[0059] Considering that there is not enough memory space if the modulated waveform is kept unchanged in memory, the waveform is stored in the Fig. 4 shown first modification example is retained as PDM data (stored in the storage unit R42A), and the PDM data is temporarily converted back into an analog waveform by the digital filter R42B, after which the PDM waveform is generated again by the ΔΣ modulation unit R42D. The individual waveform generation units R42, R42-2, R42-3, R42-4 of Fig. 4 must therefore include the digital filter R42B, which is compared to the Fig. 3 leads to redundancy in the configuration.

[0060] In the Fig. 4, the waveform generating units R42, R42-2, R42-3, R42-4 must also be provided separately (in parallel), which is different from the example shown in Fig. 3, in which only one waveform generation unit 11G42 is present, also leads to redundancy in the configuration.

[0061] If the configuration of the Fig. Furthermore, when the first modification shown in Figure 4 is applied, the maximum value of the numerical values ​​of the ΔΣ modulation by the ΔΣ modulation unit R42D is large, requiring 17 bits (17 signals), which lowers the maximum operating frequency of the control device (FPGA). With this amplitude value, 66 MHz operation is not possible, and irregularities in the waveform occur.

[0062] In the Fig. In the first modification example shown in Figure 4, the amplitude value must therefore be specified fixedly due to the aforementioned problem of the maximum operating frequency, which is why, in the event that a change in the amplitude value is required, the software of the control device (FPGA) must be rewritten.

[0063] For example, in the resolver signal processing device 1 of the first embodiment, by Fig. 3 shown configuration is used, the problem of the Fig. 4 shown first modification example.

[0064] Fig. 5 is a view illustrating an example of a configuration of the ΔΣ modulation unit 11G423 of the waveform generation unit 11G42 of the control device 11G of the resolver signal processing device 1 of the first embodiment.

[0065] In the Fig. 5, the ΔΣ modulation unit 11G423 includes an addition unit 423A, an amplifier 423B, an addition unit 423C, a Z conversion unit 423D, a feedback unit 423E, an addition unit 423F, an amplifier 423G, an addition unit 423H, a Z conversion unit 423I, a feedback unit 423J, a comparator unit 423K, a feedback unit 423L, an amplifier 423M, and an amplifier 423N.

[0066] The addition unit 423A receives the signal generated by the amplifier 11G422 (see Fig. 3) Amplified amplitude-modulated wave (analog signal), etc. are input. The output signal of the addition unit 423A is input to the amplifier 423B. The amplifier 423B amplifies the signal input from the addition unit 423A.

[0067] The output signal of the amplifier 423B and the signal fed back by the feedback unit 423E are input to the addition unit 423C. The addition unit 423C adds the output signal of the amplifier 423B and the signal fed back by the feedback unit 423E and outputs them.

[0068] The output signal of the addition unit 423C is input to the Z conversion unit 423D. The Z conversion unit 423D performs a Z conversion on the signal input from the addition unit 423C. The output signal of the Z conversion unit 423D is input to the feedback unit 423E and the addition unit 423F.

[0069] The feedback unit 423E provides feedback of the output signal from the Z conversion unit 423D to the addition unit 423C.

[0070] The output signal of the Z conversion unit 423D, among other things, is input to the addition unit 423F. The output signal of the addition unit 423F is input to the amplifier 423G. The amplifier 423G amplifies the signal input from the addition unit 423F.

[0071] The output signal of amplifier 423G and the signal fed back by feedback unit 423J are input to the addition unit 423H. The addition unit 423H adds the output signal of amplifier 423G and the signal fed back by feedback unit 423J and outputs them.

[0072] The output signal of the addition unit 423H is input to the Z conversion unit 423I. The Z conversion unit 423I performs a Z conversion on the signal input from the addition unit 423H. The output signal of the Z conversion unit 423I is input to the feedback unit 423J and the comparator unit 423K.

[0073] The feedback unit 423J provides feedback of the output signal from the Z conversion unit 423I to the addition unit 423H.

[0074] The output signal of the Z conversion unit 423I is input to the comparator unit 423K. The comparator unit 423K outputs the excitation signal Sin_1X for the SIN excitation winding 12 (see Fig. 3) corresponding PDM waveform to the waveform memory 11G451. The comparator unit 423K outputs the excitation signal Cos_1X for the COS excitation winding 13 (see Fig. 3) outputs the PDM waveform to the waveform memory 11G452. The waveform corresponding to the excitation signal Sin_nX for the SIN excitation winding 15 (see Fig. 3) corresponding PDM waveform is output to the waveform memory 11G453 and the excitation signal Cos_nX for the COS excitation winding 16 (see Fig. 3) corresponding PDM waveform is output to the waveform memory 11G454.

[0075] The feedback unit 423L feeds back the output signal from the comparator unit 423K to the amplifier 423M and the amplifier 423N. The output signal of the comparator unit 423K, fed back by the feedback unit 423L, is thus input to the amplifier 423M. Likewise, the output signal of the comparator unit 423K, fed back by the feedback unit 423L, is input to the amplifier 423N.

[0076] The amplifier 423M amplifies the output signal of the comparator unit 423K fed back by the feedback unit 423L. The output signal of the amplifier 423M is input to the addition unit 423A. The addition unit 423A adds the output signal of the amplifier 11G422 (see Fig. 3) (amplitude modulated wave) and the output signal of the amplifier 423M.

[0077] Amplifier 423N amplifies the output signal of comparator unit 423K fed back through feedback unit 423L. The output signal of amplifier 423N is input to addition unit 423F. Addition unit 423F adds the output signal of Z conversion unit 423D and the output signal of amplifier 423N.

[0078] In the Fig. In the example shown in Figure 5, the ΔΣ modulation unit 11G423 is thus a second-order ΔΣ modulator formed by a feedback-type ΔΣ modulator.

[0079] For digital operation, the sampling frequency must be in a sufficiently high frequency band compared to the analog signal band. For example, it must be 100 times higher. If 250 kHz is used as the carrier wave frequency, signal processing at 25 MHz or higher is required.

[0080] In the Fig. 2 and in Fig. In the example shown in Figure 5, the clock of 100 MHz output by the PLL11G3 is used.

[0081] Next, with reference to Fig. 6 to 8, an example of PDM waveform generation is described. In the present embodiment, when generating the modulated waveform underlying the PDM signal, sine wave data may be retained as a table. To reduce the amount of data used, the sine wave data retained as a table may be a table data entry, and the modulated waveform may be generated by performing multiplication on the sine wave data.

[0082] Fig. 6 is an explanatory view of a sin table for generating the PDM waveform according to the first embodiment. Referring to this figure, a sin table (a single table data item) for generating the modulated waveform underlying the PDM signal will be described. The left side of the figure shows a fundamental wave (Sin(θ)) and a waveform whose oscillation frequency is 32 times the fundamental wave (Sin(32θ)) (in other words, the wavelength is 1 / 32). According to the present embodiment, by multiplying these waveforms, the waveform shown on the right (Sin(θ)×Sin(32θ)=Sin(32θ+θ)+Sin(32θ-θ)) can be obtained.

[0083] The example curve shown is to be understood as a pictorial representation, and the amplitude, frequency, and the like may differ from those of a real-life waveform.

[0084] Fig. Figure 7 is an explanatory view of the details of the sin table for generating a PDM waveform according to the first embodiment. Referring to this figure, details of the sin table (a single table data entry) for generating the modulated waveform underlying the PD M signal will be described. Since the sin function is symmetrical, separate processing is performed depending on the value of the input θ, thereby reducing the amount of stored data to 1 / 4. Fig. Figure 7(A) shows an example of the sin table for the fundamental wave. Fig. Figure 7(B) shows an example of the stored data. In the view from Fig. 7(A) and Fig. 7(B), the horizontal axis shows the angle and the vertical axis the amplitude. As in Fig. As shown in Figure 7(B), the data actually stored is a portion of the fundamental wave (specifically, the range from 0 degrees to 90 degrees). For 8-bit data, the data volume is Fig. The waveform shown in Figure 7(B) is 8 [bit]×2^(12-2)=8192 [bit], which is data that fits into a block memory (Block RAM) with a single block.

[0085] When the modulation wave is directly tabulated, the modulation wave lacks symmetry, making it difficult to reduce the data volume. The data volume when the modulation wave is directly tabulated is 8 [bit] × 2^12 = 32 [kbit], which requires four EBR blocks. By storing a portion of the fundamental wave (specifically, the range from 0 degrees to 90 degrees), the data volume can be reduced to a quarter.

[0086] PDM waveform generation processing can be performed at low speed, so the modulation wave can be generated using a single sin function table and multiplying after reading the input θ and then 32θ. In this case, one EBR block is sufficient for processing. Using two blocks allows for expanded memory space and increased resolution to 2^13, allowing for the generation of a more accurate modulation wave.

[0087] Fig. Figure 8 is an explanatory view of the generation of the PDM waveform according to the first embodiment. The generation of the PDM waveform will be described with reference to this figure. Configuration R8 is described with reference to Fig. 6 shows an example of a concrete configuration for performing the processing for generating the PDM waveform. Configuration R8 is configured with configuration elements R81 to R89. Configuration element R81 is an amplifier. Configuration element R81 amplifies θ by 32 times and outputs the amplification result. Configuration element R82 is a selector. θ and 32θ are input to configuration element R82, and configuration element R82, which is a selector, outputs one of θ and 32θ. The output result of configuration element R82 is input to configuration element R83. Configuration element R83 performs an output according to the angle of the input of θ or 32θ. Configuration element R84 is a storage unit (for example, a block memory). A part of a sin table for the fundamental wave (for example, a quarter of a wavelength) is stored in configuration element R84.Configuration element R84 outputs the stored data to configuration element R85 or configuration element R86. Configuration element R85 is an amplifier. Configuration element R85, which is an amplifier, multiplies the output of configuration element R84 by -1 and outputs this to configuration element R86. Configuration element R86 is a selector. Configuration element R86 stores a portion of a sin table for the fundamental wave (for example, a quarter of a wavelength) or data corresponding to -1 times this portion. The output of configuration element R86, which is a selector, is controlled by configuration element R83. The output of configuration element R86 is stored in configuration element R87 or configuration element R88.Configuration element R87 and configuration element R88 are registers for storing values. Configuration element R87 stores the waveform of Sin(θ), and configuration element R88 stores the waveform of Sin(32θ). The Sin(θ) stored in configuration element R87 and the Sin(32θ) stored in configuration element R88 are input to configuration element R89. Configuration element R89 outputs Sin(θ)×Sin(32θ), the result of multiplying the inputs Sin(θ) and Sin(32θ).

[0088] Fig. 9 is a view illustrating a concrete example of the bandpass filter 11A1 of the excitation waveform generating unit 11A of the resolver signal processing device 1 of the first embodiment. In particular, Fig. 9(A) is a view illustrating a concrete example of the band-pass filter 11A1 of the excitation waveform generating unit 11A of the resolver signal processing apparatus 1 of the first embodiment, while Fig. 9(B) is a view illustrating a modification example of the excitation waveform generating unit 11A and the amplifier 11B1 of the resolver signal processing apparatus 1 of the first embodiment.

[0089] In the Fig. In the example shown in Fig. 9(A), the bandpass filter 11A1 of the excitation waveform generating unit 11A of the resolver signal processing apparatus 1 of the first embodiment is formed by an LC-π filter.

[0090] In the modification example from Fig. 9(B) (Example of a direct switching method) is used instead of the excitation waveform generating unit 11A and the amplifier 11B1 of Fig. 1 a FET (field effect transistor) is used.

[0091] Fig. 10 is a flowchart for explaining an example of processing executed by the control device 11G of the resolver signal processing device 1 of the first embodiment.

[0092] In the Fig. In the example shown in Fig. 10, 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 winding 12 by means of ΔΣ modulation.

[0093] 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 winding 12 generated in step S1A.

[0094] 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 winding 13 by means of ΔΣ modulation.

[0095] 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 winding 13 generated in step S2A.

[0096] 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 winding 15 by means of ΔΣ modulation.

[0097] 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 winding 15 generated in step S3A.

[0098] 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 winding 16 by means of ΔΣ modulation.

[0099] 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 winding 16 generated in step S4A.

[0100] In step S5, the control logic 11G41 of the control device 11G generates the excitation signal Sin_1X for the SIN excitation winding 12, the excitation signal Cos_1X for the COS excitation winding 13, the excitation signal Sin_nX for the SIN excitation winding 15, and the excitation signal Cos_nX for the COS excitation winding 16 and outputs them from the control device 11G. Example

[0101] The inventor conducted an analysis to compare the distortion of the excitation waveform and the associated angle error of the resolver sensor 1A in the resolver signal processing device 1 of the first embodiment, which uses the PWM waveform to generate the excitation waveform for the SIN excitation winding 12, the COS excitation winding 13, the SIN excitation winding 15, and the COS excitation winding 16, and the distortion of the excitation waveform and the associated angle error of the resolver sensor in the resolver signal processing device of the first comparative example, in which a PWM (Pulse Width Modulation) waveform is used to generate the excitation waveform.

[0102] In the resolver signal processing device of the first comparative example using the PWM waveform, the angle error of the resolver sensor was ±2.34°, while the angle error of the resolver sensor 1A of the resolver signal processing device 1 of the first embodiment using the PWM waveform was ±0.12° and could thus be reduced to 1 / 20.

[0103] Fig. 11 is a comparison view for frequency and signal strength (spectrum) between the resolver signal processing device of the first comparative example, which uses a PWM waveform, and the resolver signal processing device 1 of the first embodiment, which uses a PWM waveform. More specifically, Fig. 11(B) is an enlarged view of the area at the frequency of 1000 (kHz) of the horizontal axis Fig. 11(A).

[0104] As the two arrows in Fig. 11(B), in the resolver signal processing device of the first comparative example using a PWM waveform, there are places where the signal strength increases further than in the resolver signal processing device 1 of the first embodiment using a PWM waveform.

[0105] Fig. 12 is a comparison view for the occurrence of distortion in an envelope when digitally modulating a waveform of 250 kHz ± 16 kHz between 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 PWM waveform. In particular, Fig. 12(A) is a comparison regarding the occurrence of distortion in an envelope upon digital modulation of a waveform of 250 kHz ± 16 kHz between 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 PWM waveform, while Fig. 12(B) shows a comparison between a zero-crossing time point for the case where distortion occurs in the envelope and a zero-crossing time point for the case where no distortion occurs in the envelope.

[0106] If, as in Fig. 12(A), in the resolver signal processing device 1 of the first comparative example using a PWM waveform and the resolver signal processing device 1 of the first embodiment using a PWM waveform, a waveform of 250 kHz ± 16 kHz is digitally modulated, respectively, in the resolver signal processing device 1 of the first comparative example using a PWM waveform, a harmonic of 250 kHz ± 32 kHz and ± 16 kHz × 2 is generated, and envelope distortion occurs, while in the resolver signal processing device 1 of the first embodiment using a PWM waveform, no envelope distortion occurs.

[0107] In a modulation wave type resolver such as the resolver sensor 1A of the resolver signal processing device 1 of the first, a synthesized sin / cos signal is detected, and the rotation angle of the resolver is calculated from the zero-crossing time point of the synthesized signal.

[0108] As in Fig. As shown in Figure 12(B), in the case of envelope distortion, the zero-crossing time of the synthesized signal changes, causing an error in the detection angle of the resolver. Since envelope distortion does not occur in the resolver signal processing device 1 of the first embodiment using a PWM waveform, the angle error of the resolver sensor 1A can be reduced.

[0109] Fig. Figure 13 is an explanatory view of the problem of the resolver signal processing device of the first comparative example, in which a PWM waveform is used to generate the excitation waveform. In particular, Fig. 13 is a spectrum of the resolver signal processing device of the first comparative example in which a PWM waveform is used to generate the excitation waveform.

[0110] As in Fig. 13 under “Waveform Distortion”, in the resolver signal processing device of the first comparative example in which a PWM waveform is used to generate the excitation waveform, the harmonic of the modulation wave component ±16 kHz×n (±16 kHz, ±48 kHz, ±80 kHz, ...) when demodulated results in a distortion of 16 kHz (the distortion shown in Fig. 12(A)), resulting in an absolute angle error of the resolver sensor.

[0111] As in Fig. 13 under "Transition Region", in the resolver signal processing device of the first comparative example in which a PWM waveform is used to generate the excitation waveform, a cutoff frequency Fc of a filter for attenuating discretization noise is extremely close to the carrier frequency, although there is a transition region, but since a filter constant L also fluctuates (that is, the cutoff frequency Fc of the filter fluctuates), if it is too close, there will be a problem that even the main signal is attenuated.

[0112] Fig. Fig. 14 is an explanatory view of the action of the resolver signal processing device 1 of the first embodiment, in which a PWM waveform is used to generate the excitation waveform. In particular, Fig. 11 is a spectrum of the resolver signal processing apparatus 1 of the first embodiment in which a PDM waveform is used to generate the excitation waveform.

[0113] As in Fig. 14 under “Waveform distortion” and “Spectrum characteristics”, there exists in the resolver signal processing device of the first comparative example, in which a Fig. 10 is used, the harmonics of the modulation wave component observed in the spectrum characteristic are ±16 kHz×n (±16 kHz, ±48 kHz, ±80 kHz, ...) in the spectrum characteristic of the resolver signal processing device 1 of the first embodiment in which a Fig. 14 is used.

[0114] As in Fig. 14 under "Transition Region", in the resolver signal processing apparatus 1 of the first embodiment using a PDM waveform, the main component and the discretization noise spectrum are separated from each other, and therefore the cutoff frequency Fc of the filter can be kept away from the main component, so that it is not easily affected by fluctuations in the filter constant.

[0115] In addition, the harmonic component 500 kHz, 750 kHz, 1000 kHz, ... of the carrier wave component 250 kHz±16 kHz, which is included in the Fig. 13 of the resolver signal processing device 1 of the first comparative example using a PWM waveform is observed in the spectrum characteristic of the resolver signal processing device 1 of the first embodiment using a PWM waveform. In the spectrum characteristic of the resolver signal processing device 1 of the first embodiment using a PWM waveform, discretization noise tends to be on the high frequency side. Therefore, in the resolver signal processing device 1 of the first embodiment using a PWM waveform, attenuation by the filter is more effective, and the number of filter stages can be reduced.

[0116] As described above, in the resolver signal processing apparatus 1 of the first embodiment, as compared with the case where an excitation signal generated by pulse width modulation is used, distortion of the excitation waveform that excites the excitation windings (SIN excitation winding 12 for 1X, COS excitation winding 13 for 1X, SIN excitation winding 15 for nX, COS excitation winding 16 for nX) can be reduced, and therefore errors of the rotation angle detected by the resolver sensor 1A can be reduced.

[0117] In addition, since the resolver signal processing apparatus 1 of the first embodiment adopts the circuit construction method in which the PDM waveform generated by ΔΣ modulation is stored in the waveform memories 11G451, 11G452, 11G453, 11G454, the cost of the circuit configuration can be reduced compared to the case where ΔΣ modulation is applied to a resolver with single-phase excitation and two-phase output. Second embodiment

[0118] A second embodiment of the resolver-to-digital converter circuit, the resolver signal processing apparatus, the resolver signal processing method, and the program will be described below.

[0119] Except for the point discussed below, the resolver signal processing device 1 of the second embodiment is configured in the same way as the resolver signal processing device 1 of the first embodiment. Therefore, the resolver signal processing device 1 of the second embodiment can achieve the same effects as the resolver signal processing device 1 of the first embodiment, except for the point discussed below.

[0120] Fig. 15 is a view illustrating an example of the resolver signal processing device 1 of the second embodiment. In the Fig. 15, the resolver signal processing device 1 comprises a resolver / digital converter circuit 11, a resolver sensor 1A and an external communication unit 1B. In the example shown in Fig. 1, the resolver sensor 1A comprises the SIN excitation winding 12 for 1X, the COS excitation winding 13 for 1X, the detection winding 14 for 1X, the SIN excitation winding 15 for nX, the COS excitation winding 16 for nX and the detection winding 17 for nX, while the resolver sensor 1A in the example shown in Fig. 15, the SIN excitation winding 12 for 1X, the COS excitation winding 13 for 1X and the detection winding 14 for 1X, but the SIN excitation winding 15 for nX (see Fig. 1), the COS excitation winding 16 for nX (see Fig. 1) and the detection winding 17 for nX (see Fig. 1) is not included.

[0121] In the Fig. 1, the resolver / digital converter circuit 11 comprises the excitation waveform generation unit 11A, amplifiers 11B1, 11B2, the wave detection unit 11C, the excitation waveform generation unit 11D, the amplifiers 11E1, 11E2, the wave detection unit 11F and the control device 11G, while the resolver / digital converter circuit 11 in the example shown in Fig. 12 includes the excitation waveform generating unit 11A, the amplifiers 11B1, 11B2, the wave detection unit 11C and the control device 11G, but the excitation waveform generating unit 11D (see Fig. 1), the amplifiers 11E1, 11E2 (see Fig. 1) and the wave detection unit 11F (see Fig. 1) is not included.

[0122] In the resolver signal processing device 1 of the first embodiment, the control device 11G includes the waveform memories 11G451, 11G452, 11G453, 11G454, while in the resolver signal processing device 1 of the second embodiment, the control device 11G includes the waveform memories 11G451, 11G452, but the waveform memories 11G453, 11G454 (see Fig. 2 and Fig. 3) is not included.

[0123] In the resolver signal processing device 1 of the first embodiment, the control device 11G includes the phase calculation units 11G1, 11G2 and the statistical processing unit 11G43, while in the resolver signal processing device 1 of the second embodiment, the control device 11G includes the phase calculation unit 11G1, but the phase calculation unit 11G2 (see Fig. 2) and the statistical processing unit 11G43 (see Fig. 2) is not included.

[0124] In the resolver signal processing device 1 of the second embodiment, the waveform generation unit 11G42 generates the waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12 (see Fig. 3) corresponding PDM waveform and the excitation signal Cos_1X for the COS excitation winding 13 (see Fig. 3) Corresponding PDM waveform. Specifically, the waveform generation unit 11G42 separately generates the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12 and the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13.

[0125] The control logic 11G41 generates the excitation signal Sin_1X for the SIN excitation winding 12 and the excitation signal Cos_1X for the COS excitation winding 13 at a timing different from the timing at which the waveform generation unit 11G42 generates the PDM waveform corresponding to the excitation signal Sin_1X for the SIN excitation winding 12 or the PDM waveform corresponding to the excitation signal Cos_1X for the COS excitation winding 13, and outputs them from the control device 11G.

[0126] Fig. 16 is a flowchart for explaining an example of processing executed by the control device 11G of the resolver signal processing device 1 of the second embodiment.

[0127] In the Fig. In the example shown in Fig. 16, 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 winding 12 by means of ΔΣ modulation.

[0128] 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 winding 12 generated in step S6A.

[0129] 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 winding 13 by means of ΔΣ modulation.

[0130] 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 winding 13 generated in step S7A.

[0131] In step S8, the control logic 11G41 of the control device 11G generates the excitation signal Sin_1X for the SIN excitation winding 12 and the excitation signal Cos_1X for the COS excitation winding 13 and outputs them from the control device 11G.

[0132] While the present invention has been described above with reference to embodiments, the present invention is not limited to these embodiments, and various modifications and substitutions may be made without departing from the spirit of the present invention. The configurations shown in the above-described embodiments and examples may be combined as appropriate.

[0133] All or some of the functions of the resolver signal processing device 1 of the above-described embodiments can be implemented by recording a program for implementing these functions on a computer-readable storage medium, and reading the program recorded on this storage medium into and executing it in a computer system. A computer system as used herein includes an operating system and hardware such as peripheral devices and the like.

[0134] A computer-readable storage medium refers to a portable data carrier such as a floppy disk, an optical disk, ROM, a CD-ROM, and the like, or a storage device such as a hard disk built into a computer system, and the like. A computer-readable storage medium may also include a device that dynamically retains the program for a short time, such as a data transmission line when a program is sent over a network such as the Internet or the like, or a communication line such as a telephone line or the like, or a device that retains the program for a specific time, such as a volatile memory inside a computer serving as a server or client.The program may be designed to implement part of the above functions or may be implemented in combination with a program in which the above functions have already been recorded in a computer system. Explanation of reference symbols 1 resolver signal processing device 11 Resolver / digital converter circuit 11A Excitation waveform generation unit 11A1 bandpass filter 11A2 bandpass filter 11B1 amplifier 11B2 amplifier 11C Wave detection unit 11C1 Wave detection circuit 11C2 Phase detection unit 11D Excitation waveform generation unit 11D1 bandpass filter 11D2 bandpass filter 11E1 amplifier, 11E2 amplifier 11F Wave detection unit 11F1 wave detection circuit 11F2 Phase detection unit 11G control device 11G1 Phase measuring unit 11G2 phase measurement unit 11G3 PLL 11G4 control unit 11G41 Control logic 11G42 Waveform generation unit 11G421 memory 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 winding 13 COS excitation winding 14 Detection winding 15 SIN excitation winding 16 COS excitation winding 17 Detection winding 1A resolver sensor 1B external communication unit

Claims

[1] Resolver / digital converter circuit comprising: a control device (11G) of a resolver / digital converter circuit (11) which performs signal processing of a resolver sensor having a SIN excitation winding (12), a COS excitation winding (13) and a detection winding (14), generates an excitation signal for the SIN excitation winding (12) and an excitation signal for the COS excitation winding (13), an excitation waveform generation unit (11D) that generates an excitation waveform for the SIN excitation winding (12) from the excitation signal for the SIN excitation winding (12) generated by the control device (11G) and generates an excitation waveform for the COS excitation winding (13) from the excitation signal for the COS excitation winding (13) generated by the control device (11G), and a shaft detection unit (11C) which generates a signal indicating a rotation angle of the resolver sensor based on a detection signal output from the detection winding (14), wherein the control device (11G) comprises a waveform generating unit (11G42) which generates a PDM (pulse density modulated) waveform corresponding to the excitation signal for the SIN excitation winding (12) and a PDM waveform corresponding to the excitation signal for the COS excitation winding (13) by means of ΔΣ modulation, a first waveform memory (11G451) in which information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) is stored, and a second waveform memory (11G452) in which information for generating the PDM waveform corresponding to the excitation signal for the COS excitation winding (13) is stored. [2] A resolver / digital converter circuit according to claim 1, wherein said first waveform memory (11G451) stores a modulation wave component and a carrier wave component as separate and independent information, and said second waveform memory (11G452) stores a modulation wave component and a carrier wave component as separate and independent information. [3] The resolver / digital converter circuit according to claim 1, wherein the control device (11G) comprises control logic (11G41) that causes the waveform generation unit (11G42) to execute processing for generating a PDM waveform, the control logic (11G41) generating an excitation signal for the SIN excitation winding (12) corresponding to the PDM waveform stored in the first waveform memory (11G451) and an excitation signal for the COS excitation winding corresponding to the PDM waveform stored in the second waveform memory (11G452). [4] The resolver / digital converter circuit according to claim 3, wherein the waveform generation unit (1142G) comprises a storage unit (11G421) that stores an amplitude-modulated wave, an amplifier (11G422) that amplifies the amplitude-modulated wave stored in the storage unit (11G421), and a ΔΣ modulation unit (11G423) that subjects the amplitude-modulated wave amplified by the amplifier (11G422) to ΔΣ modulation, the amplifier (11G422) amplifying the amplitude-modulated wave in response to a command from the control logic (11G41) that specifies an amplitude value. [5] The resolver-to-digital converter circuit according to claim 3, wherein the waveform generation unit (11G42) separately performs the generation of the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) and the generation of the PDM waveform corresponding to the excitation signal for the COS excitation winding (13), and the control logic (11G41) generates the excitation signal for the SIN excitation winding (12) and the excitation signal for the COS excitation winding (13) at a timing different from the timing at which the waveform generation unit (11G42) generates the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) or the PDM waveform corresponding to the excitation signal for the COS excitation winding (13), and outputs them from the control device (11G). [6] The resolver / digital converter circuit of claim 4, wherein the control device comprises a communication unit that receives a gain value command sent from the control logic (11G41) to the amplifier (11G422) from outside the control device (11G). [7] Resolver / digital converter circuit according to claim 4, wherein the ΔΣ modulation unit (11G423) is formed by a ΔΣ modulator. [8] Resolver / digital converter circuit according to claim 1, wherein the resolver sensor comprises a further SIN excitation winding (15), a further COS excitation winding (16) and a further detection winding (17), wherein the control device (11G) generates an excitation signal for the further SIN excitation winding (15) and an excitation signal for the further COS excitation winding (16), wherein the resolver / digital converter circuit comprises an excitation waveform generation unit (11A) which generates an excitation waveform for the further SIN excitation winding (15) from the excitation signal for the further SIN excitation winding (15) generated by the control device (11G) and generates an excitation waveform for the further COS excitation winding (16) from the excitation signal for the further COS excitation winding (16) generated by the control device, and a further wave detection unit (11F) which generates a signal indicating a rotation angle of the resolver sensor based on a detection signal output from the further detection winding (17), wherein the waveform generating unit (11G42) generates a PDM waveform corresponding to the excitation signal for the further SIN excitation winding (15) and a PDM waveform corresponding to the excitation signal for the further COS excitation winding (16) by means of ΔΣ modulation, wherein the control device (11G) comprises a third waveform memory (11G453) in which information for generating the PDM waveform corresponding to the excitation signal for the further SIN excitation winding (15) is stored, and a fourth waveform memory (11G454) in which information for generating the PDM waveform corresponding to the excitation signal for the further COS excitation winding (16) is stored. [9] The resolver / digital converter circuit according to claim 8, wherein the control logic that causes the waveform generating unit (11G42) to execute processing for generating a PDM waveform generates an excitation signal for the further SIN excitation winding (15) corresponding to the PDM waveform stored in the third waveform memory (11G453) and an excitation signal for the further COS excitation winding (16) corresponding to the PDM waveform stored in the fourth waveform memory (11G454). [10] Resolver / digital converter circuit according to claim 9, wherein the waveform generation unit (11G42) separately performs the generation of the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12), the generation of the PDM waveform corresponding to the excitation signal for the COS excitation winding (13), the generation of the PDM waveform corresponding to the excitation signal for the further SIN excitation winding (15), and the generation of the PDM waveform corresponding to the excitation signal for the further COS excitation winding (16), wherein the control logic (11G41) separately generates the excitation signal for the SIN excitation winding (12), the excitation signal for the COS excitation winding (13), the excitation signal for the further SIN excitation winding (15), and the excitation signal for the further COS excitation winding (16). generated at a time different from the timeat which the waveform generation unit (11G42) generates the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12), the PDM waveform corresponding to the excitation signal for the COS excitation winding (13), the PDM waveform corresponding to the excitation signal for the further SIN excitation winding (15), or the PDM waveform corresponding to the excitation signal for the further COS excitation winding (16). [11] A resolver signal processing device comprising the resolver / digital converter circuit (11) according to claim 1 and the resolver sensor comprising the SIN excitation winding (12), the COS excitation winding (13) and the detection winding (14). [12] Resolver signal processing device comprising the resolver / digital converter circuit (11) according to claim 8 and the resolver sensor comprising the SIN excitation winding (12), the COS excitation winding (13), the detection winding (14), the further SIN excitation winding (15), the further COS excitation winding (16) and the further detection winding (17). [13] A resolver signal processing method comprising an excitation signal generation step, wherein a control device (11G) of a resolver / digital converter circuit (11) performing signal processing of a resolver sensor having a SIN excitation winding (12), a COS excitation winding (13) and a detection winding (14) generates an excitation signal for the SIN excitation winding (12) and an excitation signal for the COS excitation winding (13), wherein the resolver / digital conversion circuit (11) comprises an excitation waveform generation unit (11A) for generating an excitation waveform for the SIN excitation winding (12) from the excitation signal for the SIN excitation winding (12) generated by the control device and for generating an excitation waveform for the COS excitation winding (13) from the excitation signal for the COS excitation winding (13) generated by the control device (11G), and a wave detection unit (11C) for generating a signal indicative of a rotation angle of the resolver sensor based on a detection signal output from the detection winding (14), comprising a waveform generation step for generating a PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) and a PDM waveform corresponding to the excitation signal for the COS excitation winding (13) by the control device (11G) by means of ΔΣ modulation,a first waveform storage step for storing information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) generated in the waveform generation step by the control device (11G), and, a second waveform storing step of storing information for generating, by the control device, the PDM waveform corresponding to the excitation signal for the COS excitation winding (13) generated in the waveform generating step. [14] A program for causing a computer forming a control device of a resolver / digital converter circuit (11) that performs signal processing of a resolver sensor having a SIN excitation winding (12), a COS excitation winding (13) and a detection winding (14) to perform an excitation signal generation step, wherein an excitation signal for the SIN excitation winding (12) and an excitation signal for the COS excitation winding (13) are generated, wherein the resolver / digital conversion circuit (11) comprises an excitation waveform generation unit (11A) that generates an excitation waveform for the SIN excitation winding (12) from the excitation signal for the SIN excitation winding (12) generated by the control device (11G) and generates an excitation waveform for the COS excitation winding from the excitation signal for the COS excitation winding (13) generated by the control device (11G), and a wave detection unit that generates a signal indicating a rotation angle of the resolver sensor based on a detection signal output from the detection winding (14), and which further causes a waveform generation step in which a PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) and a PDM waveform corresponding to the excitation signal for the COS excitation winding (13) are generated by means of ΔΣ modulation, a first waveform storage step in which information for generating the PDM waveform corresponding to the excitation signal for the SIN excitation winding (12) generated in the waveform generation step is stored, and a second waveform storing step in which information for generating the PDM waveform corresponding to the excitation signal for the COS excitation winding (13) generated in the waveform generating step is stored.

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