34results about How to "Has the value of promotion and use" patented technology

The invention discloses a dual DC motor parallel system and a current hysteresis loop control method, which collects the rotational speed signal and the current signal of the dual DC motor; and obtains the speed error by passing the system set reference speed and the actual rotational speed signal of the DC motor through a speed adjustment module , the speed error is obtained through the PI controller to obtain the reference current; the current synthesis calculation is performed on the reference current to obtain three sets of combined current; the current reconstruction calculation is performed on the collected current signal to obtain three sets of reconstructed current signals; through the hysteresis comparator, The synthesized current signal is compared with the reconstructed current signal to generate a PWM pulse signal to control the working state of the switching device of the inverter circuit and realize the drive of the dual DC motors. The invention improves the current response speed, realizes the rapid supplement to the harmonic current, reduces the tracking error of the system, and has strong stability.

The invention discloses a vertical parting molding machine system. The vertical parting molding machine system comprises a PLC (Programmable Logic Controller) system, a floor type machine seat and a sandbox assembly, wherein a forward pressure plate, a backward pressure plate and a backward pressure plate framework are arranged at the front part of the floor type machine seat; a transverse slide way is formed on the backward pressure plate framework; the backward pressure plate slides on the transverse slide way; a main oil cylinder framework is arranged at the rear end of the floor type machine seat; a main oil cylinder is fixed on the main oil cylinder framework; the backward pressure plate framework is connected with the main oil cylinder framework through four guide rods; the sandbox assembly is guided by the guide rods to slide forwards and backwards; a piston rod extending end of the main oil cylinder is perpendicularly and fixedly connected with the forward pressure plate; a guide plate of the forward pressure plate is guided by the four guide rods to slide forwards and backwards; a sand jetting barrel and a pressure air pocket are arranged above the sandbox assembly; a clutch device is arranged at each of the left end and the right end of the guide plate of the forward pressure plate; a pair of slide plates are correspondingly arranged at the two ends of the sandbox assembly. The vertical parting molding machine system achieves mechanization and automation of sand molding, is low in construction cost and energy consumption and small in occupied area, causes little pollution and has extensive popularizing and using values.

The invention discloses a multi-DC motor forward series control system and method, wherein 2*(n+1) IGBT modules are connected in series in pairs to form n+1 bridge arms; the n+1 bridge arms are connected in parallel with positive and negative poles of a DC power supply, and n DC motors which are serially connected in a forward manner are respectively connected in series with the n+1 bridge arms; the n DC motors are connected to a reference voltage synthesizer through two-stage PI controllers via a speed sensor, a current sensor and a speed adjustment module in sequence, and the reference voltage synthesizer is connected to n+1 phase inverters by a PWM pulse generating unit; the n+1 phase inverters are connected to the reference voltage synthesizer via current regulating modules and one-stage PI controllers, and are connected to the PWM pulse generating unit through the reference voltage synthesizer; and pulse control signals generated by the PWM pulse generating unit control the on / offof the 2*(n+1) IGBT modules to drive the n DC motors. The number of circuit elements is small, the structure is simple, the performance stability is reliable, and the wide use value is achieved.