Current-free synthesis of improved parameter-free zero-impedance converter

• US 5,034,872 A
• Filed: 08/09/1990
• Issued: 07/23/1991
• Est. Priority Date: 08/09/1990
• Status: Expired due to Fees

• Current Assignee: Ljubomir D. Varga, Losic, Novica A.
• Original Assignee: Ljubomir D. Varga, Losic, Novica A.
• Inventors: Losic, Novica A., Varga, Ljubomir D.
• Primary Examiner(s): Beha, Jr., William H.
• Assistant Examiner(s): VOELTZ, EMANUEL T
• Application Number:
  US07/564,573
• Time in Patent Office: 348 Days
• Field of Search: 363/21, 363/97, 323/285, 323/286, 323/287, 323/282, 323/351, 318/811, 388/811
• US Class Current: 363/21.01
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02P 27/08 with pulse width modulation

Abstract

A method of synchesizing a system which effectively forces finite value of an impedance to zero comprising a most inner positive voltage feedback loop and an inner negative voltage feedback loop and an outer negative voltage feedback loop, whereby a voltage difference between the most inner positive feedback loop and the inner negative feedback loop is fed back to compensate for the voltage drop across the impedance of interest in both steady state and transient and whereby no current through the impedance is sensed and no parameters of the impedance including parameters of the plant under the control are required to be known implying minimization of measurement noise and adaptive/self-tuning operation, respectively, in applications in which the method is used to synthesize load independent switch mode power converters and electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero order dynamics.

Claims

1. A method for current-free synthesizing improved parameter-free zero-impedance converter comprising:

accepting a source of electrical energy of a constant voltage at an input,

coupling through an output filter to a load to be energized at an output,

controlling a power flow from said input to said output,

modulating a power converter for the control of said power flow in a pulse width modulation manner,

supplying a resulting total control signal for modulating said power converter,

supplying a reference voltage,

passing said reference voltage through a direct path circuit;

thereby producing a direct path signal,

passing said reference voltage through a feedforward circuit;

thereby producing a feedforward signal,

sampling a voltage across said load,

feeding back a sampled voltage signal in a negative feedback loop with respect to said direct path signal and summing said sampled voltage signal and said direct path signal,

passing a signal obtained as an algebraic sum of said sampled voltage signal and said direct path signal through a stabilizing network;

thereby producing a processed error signal proportional to a difference between said direct path signal and said sampled voltage signal,

passing the sampled voltage across said load through a voltage gain circuit;

thereby producing a processed output voltage signal,

sampling said resulting total control signal,

subtracting said processed output voltage signal from the sampled resulting total control signal in a voltage algebraic summer;

thereby producing a resulting total voltage,

feeding back said resulting total voltage in a positive feedback loop with respect to said processed error signal and said feedforward signal and summing said processed error signal and said resulting total voltage and said feedforward signal,

supplying said resulting total control signal, obtained as the sum of said processed error signal and said resulting total voltage and said feedforward signal, for modulating said power converter for the control of the flow of power from the input electrical source to the output load, whereby impedance of an inductor of said output filter is being forced to zero making said voltage across said load independent of said load in a current free manner with respect to a current through said inductor of said output filter and a parameter free manner with respect to parameters of said output filter and a gain of said power converter and making a transfer function from said reference voltage to said voltage across said load a constant in said current free manner and said parameter free manner.

2. The method of claim 1 wherein said voltage gain circuit is physically implemented as a constant gain circuit.

3. The method of claim 1 wherein said direct path circuit is physically implemented as a circuit of constant gain

4. The method of claim 1 wherein said feedforward circuit is physically implemented as a circuit of constant gain

5. A method for current-free synthesizing improved parameter-free zero-impedance converter comprising:

accepting a source of electrical energy of a constant voltage at an input,

coupling mechanically a shaft of an electric motor to a load to be driven at an output,

controlling a power flow from said input to said output,

modulating a power converter for the control of said power flow in a pulse width modulation manner,

supplying a resulting total control signal for modulating said power converter,

supplying a velocity signal voltage obtained as a differentiated position command,

passing said velocity signal voltage through a velocity direct path circuit;

thereby producing a velocity command voltage,

passing said velocity signal voltage through a feedforward circuit;

thereby producing a feedforward signal,

supplying a velocity feedback signal,

feeding back said velocity feedback signal in a negative feedback loop with respect to said velocity command voltage and summing said velocity feedback signal and said velocity command voltage;

thereby producing a resulting error voltage,

passing said resulting error voltage through a stabilizing and control circuit;

thereby producing a control signal proportional to the algebraic sum of said velocity command voltage and said velocity feedback signal, sampling said resulting total control signal,

sensing an angular shaft speed of said electric motor by a tach;

thereby producing said velocity feedback signal,

subtracting said velocity feedback signal from the sampled resulting total control signal in a voltage algebraic summer;

thereby producing a resulting total voltage,

feeding back said resulting total voltage in a positive feedback loop with respect to said control signal and said feedforward signal and summing said resulting total voltage and said control signal and said feedforward signal, supplying said resulting total control signal, obtained as the sum of said control signal and said feedforward signal and said resulting total voltage, for modulating said power converter for the control of the flow of power from the input electrical source to the output mechanical load, whereby impedance of said electric motor is being forced to zero making an angular shaft position and speed independent of said load in a current free manner with respect to a current through said electric motor and a parameter free manner with respect to electrical and mechanical parameters of said electric motor and a gain of said power converter and making a transfer function from said position command to said angular shaft position a constant and therefore of zero order in said current free manner and said parameter free manner.

6. The method of claim 5 wherein said velocity direct path circuit is physically implemented as a circuit of constant gain

7. The method of claim 5 wherein said feedforward circuit is physically implemented as a circuit of constant gain