The Clutch Control Strategy of EMCVT in AC Power Generation System Shenyang Institute of Technology, Shenyang, China Xiumin Yang, Yangyang Zhao, Song Zhang, Lei Zhang 20/05/2017

1. Introduction With the development of continuously variable transmission ( CVT ) technology and the increased strength research, the ability to transfer power of CVT is continuously improved and the application space also will be continuously expanded. This paper tries to apply new-pattern EMCVT to the frequency conversion control of the output micro power grid interconnection in the alternator and its corresponding clutch control strategies was studied.

2. The control requirements of EMCVT clutch in the alternator When the micro grid from the normal operation turning to the isolated island operation on account of some reason resulting in splitting of grid, or the inverse operation, this important point is how to control the micro grid switch smoothly and keep the system stable. So to make sure the control strategy of the CVT transmission of external clutch, by controlling the generator input shaft angle, the output voltage phase consistency with grid systems is guaranteed, avoiding the impact in interconnection.

3. The establishment of the clutch model 3.1 Dynamic model of the clutch By the above model, the dynamics equations of driving disc and driven disc of clutch are as shown in following formulas. the dynamics equation of the transmission system is as shown in following formula.

3.2 Control objectives and control parameters 3 The establishment of the clutch model 3.2 Control objectives and control parameters (1) Shock degree j. (2) Friction loss .

4. The fuzzy controller design of EMCVT 4.1 Control strategy of clutch engaging fuzzy 4.2 Selection of input and output variable in fuzzy control According to the control requirements, choose power grid load current i, source machine speed ne and EMCVT disc position variation as the inputs and clutch motor control signal as the output.

4. The fuzzy controller design of EMCVT 4.3 Fuzzification of the input variables In the research, the prime mover of alternator source of micro-grid uses a gasoline engine. The fuzzy language of input and output can be described as {very small, small, smaller, medium, bigger, big, very big}, expressed as {VS, S, LS, M, LB, B, VB}. The PWM control signal u of clutch motor can be described as {very low, low, lower, medium, higher, high, very high}, expressed as {VS, S, LS, M, LB, B,VB}. The set corresponds to the 13 quantitative levels[4]. The membership degree between fuzzy subset and quantitative level is determined by experience.

4. The fuzzy controller design of EMCVT 4.4 Establishment of the fuzzy control table The purpose of establishing the fuzzy control table is to find out a proper accurate value representing the fuzzy quantity. 4.5 Solve the fuzzy process The control voltage signal of clutch motor can be calculate by the following formula.

5. Experimental Research The CVT test table was built using the modified FC2000 dynamic test system. The control test of external clutch in EMCVT was finished. The motivation of EMCVT derived from the gasoline engine. The output shaft of EMCVT was connected with the dynamometer and throttle actuator achieved an automatic control by controlling a DC motor. In the experiments, a constant output shaft speed of EMCVT was regard as a control target. By adjusting the change rate of engine throttle and dynamometer load, conversion control effect between power system interconnection of micro grid and an island operation mode was simulated while control effect of both connection and disconnection of EMCVT was observed.

5. Experimental Research

5. Experimental Research The transient time of connection of clutch can be controlled within two seconds and the control accuracy of output speed of EMCVT can be controlled within four percent in the experiment. The theory was validated on the hardware platform. Because common dc motors were applied to clutch control and throttle control and mobility of mechanical transmission mechanism was not the most optimal, the process time of clutch engagement was longer in the experiment and the control precision and stability of output speed for EMCVT were lower. If servo motors and scroll-type mechanical transmission mechanisms were applied on the system, the control precision and stability would be improve dramatically.

6. Conclusion (1) When the EMCVT is applied into the alternating-current generator, electric power transmission, non-harmonic transformer and high efficiency, can have a function of constant frequency control. (2) Experimental Research can draw a conclusion that on the running processing of alternating-current generator system, the external clutch of EMCVT can ensure the output power in or out stablely. (3)The fussy control strategy of external clutch of EMCVT and the clutch model were present, which achieves the satisfied control for external clutch of EMCVT.

Thank you for your attention. This research was supported by the science and technology funds from Liaoning Education Department (serial number: L2015375)