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There are many types of vehicle generators and their parameters are different. Therefore, the motor selected for the remanufacturing test bench should be suitable for most generators. Therefore, there is a certain requirement for the adjustment range of the motor speed. The AC-DC-AC frequency converter has a large frequency adjustment range, which can meet the motor speed control requirements. In this paper, the S imulink visual simulation tool Simulink modeling and simulation of AC-DC-AC inverter circuit, according to re-manufactured generator test to change the motor-related parameters, and the resulting waveform analysis.

As a raw material for remanufacturing production, the generator failure mode is different. To ensure the quality of the generator, we need to test the performance and quality of the remanufactured generator. Therefore, we need to develop a test stand with high precision, high efficiency, and general-purpose performance to test the generator. On the other hand, the parameters of the generator are different, so the motor of the test stand needs to meet the detection requirements of most generators. In the motor selection, the choice of speed control system is very important. Frequency conversion speed regulation is the main trend of current motor speed control, which is mainly divided into AC-AC frequency conversion and AC-DC-AC frequency conversion [

The schematic diagram of the AC-DC-AC variable frequency speed control system is shown in

We choose the frequency converter from the aspect of calculating power, and the following three formulas must be satisfied for continuously operating frequency converters.

① Meet the load output: P C N ≥ P N / η

② Meet the motor capacity: P C N ≥ 3 k U e I e × 10 − 3

③ Meet the motor current: I C N ≥ k I e

In the formula P C N ―Inverter capacity;

P N ―Load required motor shaft output power;

η ―Motor efficiency, usually 0.85;

k ―Current waveform compensation coefficient, usually about 1.05 ~ 1.1;

U e ―Motor rated voltage;

I e ―Motor rated current;

I C N ―Inverter rated current.

In the “untitled” model window, the corresponding components are found in the original Simulink library for connection according to the AC-DC-AC

Model | Power (Kw) | Rated current I e (A) | Rated speed n ( r p m ) | Efficiency η % | Power Factor ( cos ) |
---|---|---|---|---|---|

Y2-90L-2 | 2.2 | 4.9 | 2840 | 81 | 0.85 |

Standard applies to motor output power (Kw) | 2.2 | Output rated capacity KVA | 3.0 |
---|---|---|---|

Maximum applicable motor output power (Kw) | 3.8 | Output rated current A | 10 |

Output frequency range | 0.1 Hz - 400 Hz | ||

Overload capacity | 150 ED Output current operation 20 s | ||

Phase number voltage frequency | Single-phase/three-phase 200 - 240 V, 50/60 Hz | ||

Voltage, frequency allowable range of variation | Voltage: ±10%, frequency: ±5% |

inverter circuit. The AC-DC-AC frequency conversion circuit consists of three modules: rectifier, inverter and filter. Therefore, the three-phase bridge-type uncontrollable rectifier circuit, three-phase voltage-type inverter circuit and the filter circuit were first modeled separately.

The parameters of the asynchronous motor module in the inverter circuit are shown in

Finally, in the simulation/parameter window, select the ode23tb algorithm, the relative error is set to 1e−3, and the stop time is set to 0.1 s. The circuit simulation diagram obtained by the rectification, inversion, and filtering of the three modules is shown in

We set the power frequency to 60 Hz and 100 Hz, respectively.

When the output power frequency is 60 Hz, the resulting voltage simulation results are as follows

Through the analysis of the simulation results of the AC-DC-AC variable-frequency speed control system of

Power P n ( KW ) | Voltage V n ( V ) | Frequency f n ( HZ ) | Stator resistance R s ( ohm ) | Rotor resistance R ′ r ( ohm ) | Stator Inductance L 1 s ( H ) | Rotor inductance L ′ 1 r ( H ) | Moment of inertia J ( kg ⋅ m 2 ) | pole pairs P |
---|---|---|---|---|---|---|---|---|

2.2 | 380 | 50 | 0.435 | 0.816 | 2.0 × 10^{−3} | 2.0 × 10^{−3} | 69.3 × 10^{−3} | 2 |

current becomes a constant voltage DC voltage source after rectification, and the voltage waveform basically tends to a constant straight line. The wave after the inversion section is a square wave with adjustable pulse width. After feedback and LC filtering, it becomes a variable-frequency sine wave.

As we can see from

After filtering and frequency conversion of the three-phase voltage (

Through the comprehension and analysis of each part of the AC-DC-AC variable frequency speed control system, simulation experiments and research, based on the Matlab/Simulink simulation tool, the simulation model of the three-phase AC-DC frequency conversion speed control system was completed. Through the analysis of the operating results, we understand the basic working principle, characteristics and basic functions of the system, and basically realize the

purpose of frequency conversion speed regulation, which can meet the demand for re-manufactured generator test-bed motor speed control.

Lv, H.L. and Luo, Y.P. (2018) Simulation Design of Variable Frequency Speed Regulating System for Automobile Remanufactured Generator Test Bench Based on Matlab. Open Access Library Journal, 5: e4628. https://doi.org/10.4236/oalib.1104628