Step-by-steps the electrical machinery is one kind transforms the electricity signal impulse the corresponding angular displacement’s special electrical machinery, changes a circular telegram condition every time, step-by-steps electrical machinery’s rotor to rotate one step. At present majority step-by-steps the electrical machinery controller to need the master-control unit transmission clock signal, and must a I/O mouth come the secondary control and the monitoring at least step-by-steps electrical machinery’s operational aspect. In the monolithic integrated circuit or in the DSP application system, coordinates CPLD or FPGA frequently realizes the specific function. This article introduced that realizes through FPGA step-by-steps the electrical machinery controller. This controller may take the monolithic integrated circuit or a DSP direct digital control peripheral device, only need to controller’s control register and the frequency division register write data, namely the Yamagimachi realizes to step-by-steps electrical machinery’s control.
1 step-by-steps electrical machinery’s control principle
Step-by-steps the electrical machinery is the numerical control electrical machinery, it transforms the signal impulse the angular displacement, namely for a signal impulse, step-by-steps the electrical machinery to rotate an angle, therefore very suitably to number system’s control. Step-by-steps the electrical machinery to be possible to divide into the equation to step-by-step the electrical machinery (i.e. “VR”), the static type to step-by-step the electrical machinery (i.e. “PM”) and the mixed style step-by-steps the electrical machinery (i.e. “HB”).
Step-by-steps the electrical machinery to distinguish in other controls electrical machinery’s most major characteristic is, carries on the control through the input pulse signal, namely the electrical machinery always rotates the angle to decide by the input pulse number, but electrical machinery’s rotational speed decided by the signal impulse frequency.
Step-by-steps electrical machinery’s driving circuit basis control signal work, the control signal produces by each kind of controller. Its basic principle function is as follows:
①The control phase change order, electrifies the phase change. This process is called “the pulse assignment”. For example: The four-phase step-by-steps electrical machinery’s list four racket working, its each electrifies the order is A-B-C-D. The circular telegram steering impulse must control A, B, C, the D make-and-break separately strictly according to this order, the control step-by-steps electrical machinery’s change. If assigns the working positive sequence phase change circular telegram, then step-by-steps the electrical machinery clockwise; If according to inverted sequence phase change circular telegram, then the electrical machinery reverses.
②The control step-by-steps electrical machinery’s speed. If for step-by-steps the electrical machinery to send a steering impulse, it transfers one step, sends a pulse again, it will transfer one step again. Two pulse’s gaps are shorter, step-by-step the electrical machinery to transfer quickly. Adjusts pulse frequency which the controller sends out, may to step-by-step the electrical machinery to carry on the velocity modulation.
2 controller’s system designs
Controller’s exterior interface circuit as shown in Figure 1. Various pins’ function is as follows:
Controller’s internal functional block diagram as shown in Figure 2, by order character register (Cmd_reg), frequency division coefficient backup register (fdiv_back), the frequency divider, the phase output state machine is composed.
And order character register Cmd_reg composes (corresponding address as follows is “00″):
X has not used the position.
Ini to the controller initialization is when 1 effective. When this is 1, backup register’s data direct loading frequency divider’s register reg_data[15~0], after loading, sets at O automatically by the hardware.
When Newr to is moving when the controller reads in the new frequency division coefficient, to this position 1; A frequency divider outputs immediately when the clkout clock arrives, reads in reg_data[15~0] fdiv_back, the frequency divider then presses the new frequency division coefficient to carry on the frequency division.
The Manner[1~0] electric motor’s drive type, uses for the control phase to output state machine’s output, “00″ the expression list four racket ways, four phase outputs are (A-B-C-D); “Ol” an expression pair of four racket, four phase outputs are (ABBC-CD-DA), eight pat (A-AB-B-BC-C-CD-DDA).
The frequency division coefficient backup register (fdiv_back) two bytes registers, reg_data[15~0] is frequency divider’s 16 registers, receives fdiv_back the value, to system’s frequency division is 2~65536. Regarding 12MHz input frequency, after the frequency division, the frequency is 6MHz~183Hz, (in this design, step-by-steps electrical machinery’s start rotational speed, extension distance, acceleration acts according to the actual situation computation after user) the frequency division each clkout to walk a step pitch angle. Regarding step pitch angle for 1.8° the electrical machinery, may satisfy each kind of speed the request.
3 frequency divider’s designs
The frequency divider is the key which this controller realizes, in a here achievement independent module, data[15~0] is the frequency division coefficient. After system clock Clk by frequency division coefficient register in value frequency division, outputs Clkout to output state machine’s clock as the phase, when each Clkout arrival, produces a phase to transform, step-by-steps the electrical machinery to move a step pitch angle. Frequency divider’s procedure is as follows:
Shown in Figure 3 is when 3 frequency divisions list four racket output simulation charts.
Conclusion
This article innovation for will step-by-step the electrical machinery controller’s control word and the frequency division coefficient mapping in the master-control unit (DSP or monolithic integrated circuit and so on) the memory space, when the control only need carry on to it writes the operation, causes to step-by-step electrical machinery’s control becomes simple convenient; Moreover, may save the master-control unit (DSP or monolithic integrated circuit and so on) the peripheral resource, reduces on the board the load. In the system may join the electrical machinery to move the total step control register and the electric circuit, the acceleration register and the control circuit and so on, makes an intelligence to step-by-step the electrical machinery controller.
