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公开(公告)号：US4126819A
公开(公告)日：1978-11-21
申请号：US812134
申请日：1977-07-01
摘要： Two transistors each have their emitter-collector circuits coupled in series between one end of a motor field winding and the opposite terminals of a D.C. voltage source to switch current flow in either direction through the winding. Two current sensors are provided, one coupled in series with each emitter-collector circuit. The voltage developed across each current sensor is applied through a driver circuit to the base of the other transistor so as to cut one transistor off when the other is conducting and vice versa, thereby eliminating the possibility of having both transistors conduct simultaneously which would short out the voltage source and burn out one or both transistors.
摘要翻译： 两个晶体管各自的发射极 - 集电极电路串联耦合在电动机励磁绕组的一端和直流电压源的相对端之间，以便通过绕组在任一方向上切换电流。 提供两个电流传感器，一个与每个发射极 - 集电极电路串联耦合。 在每个电流传感器上产生的电压通过驱动电路施加到另一个晶体管的基极，以便在另一个晶体管的基极处切断一个晶体管，反之亦然，从而消除了两个晶体管同时导通的可能性，这会导致短路 电压源并烧掉一个或两个晶体管。
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公开(公告)号：US4300086A
公开(公告)日：1981-11-10
申请号：US24561
申请日：1979-03-28
CPC分类号： H02P27/08
摘要： The voltage and frequency of an A.C. excitation signal applied to the stator windings of an A.C. induction motor are varied in proportion to the amplitude of current flowing in the stator windings. The stator current flow is sensed by a feedback resistor in series with the inverter which generates the A.C. excitation signal for the stator windings. The voltage drop aross the feedback resistor is summed with a VELOCITY COMMAND voltage which indicates the desired speed of the motor and the summed voltage controls the frequency and the amplitude of the A.C. excitation voltage in a constant volts per hertz manner. The stator current feedback holds the motor speed constant in spite of variations in the load on the motor.
摘要翻译： 施加到交流感应电动机的定子绕组的交流激励信号的电压和频率与在定子绕组中流动的电流的幅度成比例地变化。 定子电流由与产生定子绕组的交流励磁信号的逆变器串联的反馈电阻器感测。 跨越反馈电阻的电压降与VELOCITY COMMAND（VELOCITY COMMAND）电压相加，该VELOCITY COMMAND电压指示电机的所需速度，并且总和电压以恒定电压/赫兹方式控制交流励磁电压的频率和振幅。 定子电流反馈保持电机速度恒定，尽管电机负载有变化。
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公开(公告)号：US4292577A
公开(公告)日：1981-09-29
申请号：US19936
申请日：1979-03-12
CPC分类号： H02P27/045 , H02P27/10 , H02P2201/07 , H02P27/047
摘要： A tachometer is coupled to the rotor of an A.C. motor and generates an output voltage proportional to the rotor's speed. A VELOCITY COMMAND voltage is generated having an amplitude which specifies a desired rotor speed. The tachometer voltage is subtracted from the VELOCITY COMMAND voltage to produce a VELOCITY ERROR voltage. The output of a D.C. power source is chopped at a fixed frequency and variable pulse width, the pulse width being proportional at any time to the amplitude of the VELOCITY ERROR voltage. The chopped D.C. voltage is filtered to provide a variable D.C. voltage having an amplitude which is proportional to the amplitude of the VELOCITY ERROR voltage. The variable D.C. voltage is applied to an inverter which changes it into an A.C. voltage. The A.C. voltage is applied to the stator windings of the motor to drive the rotor thereof. The frequency of the A.C. voltage is variable and is proportional, at rotor speeds above 150 RPM, to the amplitude of the velocity command voltage. At rotor speeds below 150 RPM, the frequency of the A.C. voltage is held fixed at approximately 28 Hz. The amplitude of the A.C. voltage is proportional to the VELOCITY ERROR voltage at all speeds. The frequency of the A.C. voltage is determined by an oscillator which drives a ring counter whose counting direction is controlled by a direction flip-flop. The state of the direction flip-flop is changed whenever the polarity of the VELOCITY ERROR voltage changes so that deceleration of the motor always occurs in a plugging mode.
摘要翻译： 转速计耦合到交流电动机的转子，并产生与转子速度成比例的输出电压。 产生具有指定期望的转子速度的幅度的速度命令电压。 从VELOCITY COMMAND（VELOCITY COMMAND）电压中减去转速计电压，产生VELOCITY ERROR（VELOCITY ERROR）电压。 直流电源的输出以固定的频率和可变的脉冲宽度被切断，脉冲宽度随时间与VELOCITY ERROR电压的幅度成比例。 切断的直流电压被滤波以提供具有与VELOCITY ERROR电压的振幅成比例的振幅的可变直流电压。 可变直流电压被施加到将其变为交流电压的逆变器。 交流电压被施加到电动机的定子绕组以驱动其转子。 交流电压的频率是可变的，并且在高于150RPM的转子速度下与速度指令电压的幅度成比例。 转子速度低于150 RPM时，交流电压的频率固定在约28 Hz。 在所有速度下，交流电压的幅度均与VELOCITY ERROR电压成比例。 交流电压的频率由驱动其计数方向由方向触发器控制的环形计数器的振荡器确定。 每当VELOCITY ERROR电压的极性发生变化时，方向触发器的状态就会发生变化，从而电机的减速始终在插入模式下发生。
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